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Demonstration of accessory mental foramen using rotational panoramic radiography compared with cone-beam computed tomography
Abstract
Rotational panoramic radiography is routinely used in dental practice. It has not been clarified, however, whether an accessory mental foramen can be demonstrated using this technique. The visibility of accessory mental foramina on rotational panoramic radiographs was compared with those on para-panoramic images reconstructed from cone-beam computed tomographic (CBCT) images.
A total of 365 patients (130 males and 235 females) were retrospectively analyzed. Para-panoramic images were reconstructed from CBCT images with the accessory mental foramen/foramina using three-dimensional visualization and measurement software, and then the accessory mental foramen on rotational panoramic images was compared with that on para-panoramic images.
A total of 37 accessory mental foramina were observed in 28 patients on CBCT images. The rate of being able to visualize the accessory mental foramen or bony canal between the point of bifurcation from the mandibular canal and the accessory mental foramen on rotational panoramic radiographs was 48.6% (18 of 37 accessory mental foramina).
Approximately half of the accessory mental foramina-positive CBCT images demonstrated the accessory mental foramen, or bony canal between the point of bifurcation from the mandibular canal and accessory mental foramen on rotational panoramic radiographs.
... In addition, we have added to each photograph an image that represents where the neurovascular bundle should go based on imaging studies that have reported this, which is between 0.74 mm and 0.89 mm, with which a total of 8 (3.07%) jaws were found that presented with an AMF, of which 5 were unilateral, 3 right (Figure 1), and 2 left (Figure 2), while 3 mandibles presented with an AMF bilaterally ( Figure 3). This information was compared with 19 similar studies using the same exclusion criteria presented in Table 1 [2,3,7,9,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] in order to compare the results and determine whether there was similarity with the data presented in Table 1, Chilean sample. Regarding the prevalence of AMFs, the studies were compared with the current study. ...
... On the other hand, previous studies that did report the sex of the sample showed that this particular variant occurred in 127 women, which is equivalent to 21.27% of the samples with the AMF variant, while 125 men presented the AMF variant, which is equivalent to 20.93% (Table 2). This information was compared with 19 similar studies using the same exclusion criteria presented in Table 1 [2,3,7,9,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] in order to compare the results and determine whether there was similarity with the data presented in Table 1, Chilean sample. Regarding the prevalence of AMFs, the studies were compared with the current study. ...
... Regarding the prevalence of AMFs, the studies were compared with the current study. First, the This information was compared with 19 similar studies using the same exclusion criteria presented in Table 1 [2,3,7,9,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] in order to compare the results and determine whether there was similarity with the data presented in Table 1, Chilean sample. Regarding the prevalence of AMFs, the studies were compared with the current study. ...
Citation: Bruna-Mejias, A.; Nova-Baeza, P.; Torres-Riquelme, F.; Delgado-Retamal, M.F.; Orellana-Donoso, M.; Suazo-Santibañez, A.; Sepulveda-Loyola, W.; Valdés-Orrego, I.; Sanchis-Gimeno, J.; Valenzuela-Fuenzalida, J.J.
... In other cases, it can be called an "accessory branch to the mental artery," as it is an additional branch arising from the main IAA or branch in the course of the mental artery. [6,8,9] The aberrant branch of the IAA supplying the premolar region may pass through an accessory foramen or canal. It is important to note that the exact origin and location of the accessory foramen or canal through which the aberrant branch of the IAA passes can vary and can be affected by many factors, such as (i) variations in the development of the blood vessels during embryonic development; (ii) trauma to the mandibular canal (can cause an aberrant branch to form following neo-angiogenesis); (iii) certain genetic conditions (may predispose the formation of an aberrant branch); (iv) variations in the anatomy of the mandible and surrounding structures (can affect the path of the IAA and lead to the formation of an aberrant branch); and (v) as a person ages, the vessels may become more tortuous, and sometimes the aberrant branching may appear for collateral circulation. ...
... It is important to note that the exact causes and mechanisms behind the formation of an aberrant branch of the IAA are not fully understood, and more research is needed in this area. [6][7][8] In the present case, the aberrant branch of IAA exited a foramen present 15 mm superior to the mental foramen and had no communication with the latter, as confirmed by CBCT and MRI imaging. Hence, as per the definition of accessory mental foramina by Naitoh et al., it cannot be ascribed to as an accessory mental foramen rather, can be classified as one of the unnamed accessory buccal foramen of the mandible. ...
... Hence, as per the definition of accessory mental foramina by Naitoh et al., it cannot be ascribed to as an accessory mental foramen rather, can be classified as one of the unnamed accessory buccal foramen of the mandible. [8][9][10] As per the best of our knowledge, this is the first reported case of an aberrant branch of the IAA in the premolar region, arising from an accessory buccal foramen and serving as an intraosseous feeder vessel to the lobular capillary hemangioma lesion identified using advanced radio-diagnostic measures such as CBCT, CT angiography, and contrast-enhanced MRI. ...
The aim of this case report is to present a unique and rare finding in a 29-year-old male with the chief complaint of swelling in the gums related to the back teeth of the lower left jaw, since 20 days. In the absence of any alarming findings on the intraoral periapical radiograph and blood profile, an excisional biopsy of the provisionally diagnosed pyogenic granuloma was planned with a high-power diode LASER (Light Amplification by Stimulated Emission of Radiation). Following the excision, an unusual amount of bleeding was encountered from a single point on the buccal cortical plate between the teeth #35 and #36. On reevaluating the left face with advanced radiodiagnostic methods, an accessory buccal foramen was reported distal to #35 which housed a thin, tortuous, and aberrant branch of the inferior alveolar artery. The swelling was histopathologically diagnosed as lobular capillary hemangioma, and the aberrant artery was labeled as its feeder vessel. The patient had no episode of recurrence until 2 years of follow-up.
... In other cases, it can be called an "accessory branch to the mental artery," as it is an additional branch arising from the main IAA or branch in the course of the mental artery. [6,8,9] The aberrant branch of the IAA supplying the premolar region may pass through an accessory foramen or canal. It is important to note that the exact origin and location of the accessory foramen or canal through which the aberrant branch of the IAA passes can vary and can be affected by many factors, such as (i) variations in the development of the blood vessels during embryonic development; (ii) trauma to the mandibular canal (can cause an aberrant branch to form following neo-angiogenesis); (iii) certain genetic conditions (may predispose the formation of an aberrant branch); (iv) variations in the anatomy of the mandible and surrounding structures (can affect the path of the IAA and lead to the formation of an aberrant branch); and (v) as a person ages, the vessels may become more tortuous, and sometimes the aberrant branching may appear for collateral circulation. ...
... It is important to note that the exact causes and mechanisms behind the formation of an aberrant branch of the IAA are not fully understood, and more research is needed in this area. [6][7][8] In the present case, the aberrant branch of IAA exited a foramen present 15 mm superior to the mental foramen and had no communication with the latter, as confirmed by CBCT and MRI imaging. Hence, as per the definition of accessory mental foramina by Naitoh et al., it cannot be ascribed to as an accessory mental foramen rather, can be classified as one of the unnamed accessory buccal foramen of the mandible. ...
... Hence, as per the definition of accessory mental foramina by Naitoh et al., it cannot be ascribed to as an accessory mental foramen rather, can be classified as one of the unnamed accessory buccal foramen of the mandible. [8][9][10] As per the best of our knowledge, this is the first reported case of an aberrant branch of the IAA in the premolar region, arising from an accessory buccal foramen and serving as an intraosseous feeder vessel to the lobular capillary hemangioma lesion identified using advanced radio-diagnostic measures such as CBCT, CT angiography, and contrast-enhanced MRI. ...
The aim of this case report is to present a unique and rare finding in a 29-year-old male with the chief complaint of swelling in the gums related to the back teeth of the lower left jaw, since 20 days. In the absence of any alarming findings on the intraoral periapical radiograph and blood profile, an excisional biopsy of the provisionally diagnosed pyogenic granuloma was planned with a high-power diode LASER (Light Amplification by Stimulated Emission of Radiation). Following the excision, an unusual amount of bleeding was encountered from a single point on the buccal cortical plate between the teeth #35 and #36. On reevaluating the left face with advanced radiodiagnostic methods, an accessory buccal foramen was reported distal to #35 which housed a thin, tortuous, and aberrant branch of the inferior alveolar artery. The swelling was histopathologically diagnosed as lobular capillary hemangioma, and the aberrant artery was labeled as its feeder vessel. The patient had no episode of recurrence until 2 years of follow-up.
... The pathway of the IAN and the MF abandoning the mandible has always been a particularly important factor in surgical procedures planned for the mandible. In recent years, with advancements in CBCT, the anatomical structure of this nerve has become clearer and the rate of identification of extra outputs in the AMF has increased considerably [4,7]. It is difficult to distinguish AMFs on panoramic radiographs [8]. ...
... Muinelo-Lorenzo et al. [10] found a prevalence of 13% in Spain; Krishnan et al. [20] noted a frequency of 12.8% in Australia; Iwanaga et al. [1] reported a prevalence of 14.8% in Japan; Kalender et al. [6] noted a frequency of 11.9% in Turkey; whereas frequencies as low as 2% were also reported from Turkey [5]. The frequencies reported in most reports range between 6% and 8% [7,15,16,21,22]. We found that the frequency of AMF in our study was 11.97%. ...
... Our results are consistent with the previous findings. AMFs and unilateral AMF formation were more frequent on the mandible's right side, as declared in some previous studies [16,23], although conflicting results were also evident [5][6][7]. The frequency of double AMFs has been reported to range between 0.6-1.1% [24,25], although we found a slightly lower incidence of 0.5%. ...
Background:
The mental foramen (MF) is an important anatomical landmark on the mandible. MFs may occur singly or with extra foramina (accessory mental foramen (AMF)).
Objective:
The aim of the present study was to discuss the importance of recognition and classification of AMFs.
Methods:
This study assessed CBCT images of 593 patients (208 male, 385 female) and proposed an AMF classification scheme based on three different characteristics: (1) location of the AMF with respect to the MF; (2) relationship of AMFs with tooth apices; and (3) origin of the AMF. The chi-squared test was used to compare the qualitative data as well as descriptive statistical methods when the study data were evaluated. Significance was assessed at the p < 0.05 level.
Results:
A total of 80 AMFs were found in 71 patients. Six cases involved bilateral AMFs, whereas three cases showed double AMFs. The most common AMF location was the region posterior of the MF. Notably, all the AMFs detected in line with the mesial half of the first molar were present in female patients. Based on AMF origins, 44.5%, 48.6%, and 6.7% of the AMFs were categorized as type I, type II, and a new category identified in this study, type III.
Conclusion:
This study revealed some foramina locations were not considered in the previous classification. Recognition and identification of these foramina might be critical to prevent possible complications. The proposed classification scheme may facilitate this objective and can be a new focus for future studies.
... For the purpose of the study, it was assumed that the age of the animal had no significant effect on the number of mental foramina (Oliveira- Santos et al. 2011;Sisman et al. 2012). In this study, the authors decided to define the accessory mental foramina according to Naitoh et al. (2009aNaitoh et al. ( , 2011 and Sisman et al. (2012) who described AMFs in cone-beam computed tomographic (CBCT) images as foramina continuous with the mandibular canal, appearing smaller than the MF. Whereas, MF from AMFs was differentiated on the basis of the foramina surface measurements made using NRECON SkyScan software (version 1.6.5) ...
... The mental foramen (MF) and accessory mental foramina (AMF 1-3) observed on the surface of the mandible constitute the exterior end of the mandibular canal (MC). Identification of each foramen was based on the assumption by Naitoh et al. (2009aNaitoh et al. ( , 2011 and Sisman et al. (2012) that whenever accessory mental foramina (AMF) appear, they are smaller than the main MF. It can clearly be seen that larger foramina (MF, AMF1 and AMF2) are located in close distance to each other and the smaller single foramen (AMF3) is located slightly above the "cluster". ...
... According to Naitoh et al. (2009aNaitoh et al. ( , 2011 and Sisman et al. (2012), if accessory foramina appear, they are smaller than the MF. The average MF area in the analyzed material corresponds to the average AMF area in the human mandible (Naitoh et al. 2009a). ...
This study aimed to determine the number of mental foramina (MFs) in vervet monkeys of the Cercopithecini tribe and perform a µCT analysis of mental foramina and mandibular canal morphology. A total of 19 simian skulls belonging to Chlorocebus aethiops species were used in the analyses. An average of three mental foramina was present in most individuals from the analyzed group. The Mann–Whitney test revealed no statistically significant difference between the number of foramina on the right- and left-hand side. Likewise, no statistically significant differences between the number of MFs across sexes were observed. Correlation coefficient values between mandibular length and the ipsilateral number of MF indicate a weak and statistically non-significant (p > 0.05) linear relationship. Volumetric reconstructions revealed the presence of a single periosteal sheathed mandibular canal terminated with four small mental foramina.
... In some humans and many non-human hominoids, there are one or more additional, smaller foramina in the vicinity of the mental foramen that are typically referred to as accessory mental foramina (AMFs) (Figure 1). Some researchers, particularly in the dental literature, restrict this term to foramina that are connected by an accessory canal to the mandibular canal and refer to other foramina that are entry sites for arteries supplying the cancellous bone as nutrient, or buccal, foramina (Katakami et al., 2008;Naitoh et al., 2009a;Naitoh et al., 2009b;Naitoh et al., 2010;Naitoh et al., 2011;Kalender et al., 2012;Garay and Cantín, 2013;Göregen et al., 2013;Jaju et al., 2013;Von Arx et al., 2014;Iwanaga et al., 2015Iwanaga et al., , 2016Paraskevas et al., 2015;Torres et al., 2015). Others have used size as a criterion, identifying any foramen more than half the size of the mental foramen as a double foramen, and smaller foramina of a certain size (e.g., over 1 mm) as AMFs (Jaffar et al., 2002;Oliveira-Santos et al., 2011). ...
... Partly due to the importance of identifying variation in nervous and vasculature positions during surgical procedures to avoid tissue damage and to properly anesthetize nerves, the frequency of the presence of AMFs has been well documented in human populations (Simonton, 1923;Montagu, 1954;Riesenfeld, 1956;DeVilliers, 1968;Mwaniki and Hassanali, 1992;Sawyer et al., 1998;Hanihara and Ishida, 2001;Kieser et al., 2002;Agthong et al., 2005;Apinhasmit et al., 2006;Prabodha and Nanayakkara, 2006;Katakami et al., 2008;Liang et al., 2009;Naitoh et al., 2009a;Naitoh et al., 2009b;Naitoh et al., 2010;Naitoh et al., 2011;Oliveira-Santos et al., 2011;Gupta and Soni, 2012;Imada et al., 2012;Kalender et al., 2012;Budhiraja et al., 2013;Göregen et al., 2013;Orhan et al., 2013;Udhaya et al., 2013;Paraskevas et al., 2015;Lam et al., 2019) (Table 1). However, few studies have examined diversity among non-human hominoids, the closest living relatives of humans, in the frequency and number of accessory foramina and, to our knowledge, there are no published data on this character for Pan paniscus or hylobatids. ...
... This could be due to a number of variables including, but not limited to: techniques used in scanning (e.g., CT scans of different resolution, radiograph scans, etc.), the use of cadaveric vs. dry skulls, the inclusion (or not) of older individuals exhibiting bone resorption due to tooth loss, certain authors choosing arbitrary cutoffs for what qualifies as a foramen (e.g., AMF's below 1 mm in size are often not reported), differences in sample size and make up (i.e., which populations in each region are sampled), some studies restricting the term accessory mental foramen to those that connect by an accessory canal with the mandibular canal or to those that are not re-entry points for branches of an artery, and how many individuals are placed in the correct population when they self-report their genetic background (e.g., are individuals from admixed backgrounds included in the sample for each population?). For example, Naitoh et al. (2011) found that rotational panoramic radiographs detected fewer than 50% of AMFs and were more likely to only report larger ones. Similarly, Naitoh et al. (2009b) suggest that studying dry bone vs. mandibles with intact tissues affects the accuracy of identifying the number of foramina present. ...
Nerves providing sensation to the lower face and jaw exit the mandibular canal via the mental foramen. In humans, there are many documented occurrences of additional foramina (accessory mental foramina, AMFs) on the lateral mandibular surface that may also contain nervous structures. There are large discrepancies in the literature regarding how often AMFs occur in humans, and investigations of non‐human hominoid AMFs are rare. Consequently, the causes of interspecific diversity in this variable have not been explored. This project seeks to compare the frequency and number of AMFs between males and females, and among human regional groups and hominoid subspecies and species, and to investigate possible causal factors for any differences identified. No significant differences were found between males and females in any group. Gorillas and orangutans had the highest percentages of individuals with AMFs and the highest mean number of foramina, while modern humans and siamangs had the lowest figures for these variables. Significant differences (p < .05) were found for the mean number of foramina between most pairs of species. The results also showed that species with mandibles that are larger overall, have a larger area anterior to mental foramen, and a longer mandibular canal typically present more AMFs. The strongest correlation was found between the mean number of mental foramina and mandibular canal length. We suggest that these results provide preliminary support for the hypothesis that increasing mandibular canal length increases the likelihood that that nerves will ramify, leading to greater frequencies of accessory mental foramina.
... Previous studies have reported on the incidence of AMF which ranged widely from 1.4-14.3% (Sawyer et al., 1998;Katakami et al., 2008;Naitoh et al., 2009;Haktanır et al., 2010;Naitoh et al., 2011;Oliveira-Santos et al., 2011;Kalender et al., 2012;Udhaya et al., 2013;Cantekin and Şekerci, 2014;Imada et al., 2014;Khojastepour et al., 2015;Muinelo-Lorenzo et al., 2015;Paraskevas et al., 2015;Iwanaga et al., 2016). However, all of these studies (except one) had sample sizes of less than 400, and the sample populations were restricted to a limited number of ethnic groups. ...
... Additionally, an AMF can present as a periapical radiolucency on conventional plain film radiology, leading to misdiagnosis, hence it is important to be aware of the possibility of multiple mental foramina (Iwanaga et al., 2016;Borghesi et al., 2018). Although a number of studies have previously assessed the AMF prevalence, all exhibited similar weaknesses of small sample sizes (63-386) and relatively homogenous populations (Sawyer et al., 1998;Katakami et al., 2008;Naitoh et al., 2009;Haktanır et al., 2010;Naitoh et al., 2011;Oliveira-Santos et al., 2011;Kalender et al., 2012;Udhaya et al., 2013;Cantekin and Şekerci, 2014;Imada et al., 2014;Khojastepour et al., 2015;Muinelo-Lorenzo et al., 2015;Paraskevas et al., 2015;Iwanaga et al., 2016). This subset is not large enough to accurately evaluate prevalence. ...
... Previous studies reported a range from 2.2-12.2% (Katakami et al., 2008;Naitoh et al., 2009;Naitoh et al., 2011;Oliveira-Santos et al., 2011;Udhaya et al., 2013;Muinelo-Lorenzo et al., 2015). No significant difference was discovered on the frequency of occurrence of AMF between sides, as was reported in previous studies (Sawyer et al., 1998;Muinelo-Lorenzo et al., 2015). ...
The presence of accessory mental foramina (AMF) is an important consideration prior to any dental implant and surgical treatment to avoid injury to the neurovascular bundle and subsequent postoperative complications. The aim of this retrospective study was to determine the prevalence of AMF from a substantially large sample of the Australian population. The cone beam computed tomography (CBCT) scans of 4,000 patients showing the mandible were examined. All mental foramen (MF) were visualized and no cases were excluded. The number of MF/AMF, sex, and age were recorded. The prevalence of AMF was found to be 6.4% (254 patients) in this study. Twelve patients exhibited bilateral AMF, and 11 had three mental foramina on one side. One case had a total of five mental foramina with three on the right and two on the left side. No significant sex preference was discovered. This is the largest study ever to be conducted to evaluate the prevalence of AMF. With nearly one in 15 individuals found to have AMF, clinicians must be acutely aware of this anatomical variation and treatment plan for each case accordingly. Clin. Anat. 32:1048–1052, 2019. © 2019 Wiley Periodicals, Inc.
... The prevalence of AMF in panoramic radiograph was low because AMF may not appear on conventional radiographs [7,14]. Moreover, AMF was studied regardless of association with neurovasuclar bundle. ...
... However, CBCT can provide various reformatted images with software. Therefore, it enables to evaluate the presence and configurations of AMF more accurately than panoramic radiography [7,14]. ...
... In the studies of the similar definitions of AMF, the incidence rate were reported to be 7.0-14.3 % [8,10,11,14]. ...
Purpose
To determine the prevalence and anatomical features of accessory mental foramina (AMFs) associated with neurovascular bundle using reformatted CBCT images in Korean population.
Materials and methods
Three-dimensional, cross-sectional, and axial images of CBCT from total 446 patients were evaluated. To include only AMF associated with neurovascular bundle, the course of accessory nerve through AMF was evaluated on three-dimensional images. The prevalence, locations to mental foramen (MF), and distribution to the adjacent tooth of AMF were analyzed. Additionally, the distance from MF and dimension of AMF were measured.
Results
AMFs were found in 36 (8.1 %) patients in the 446 Koreans. The prevalence rate of AMFs in male was significant higher than that in female (p < 0.05). Most AMFs were located anterior–superior to MF. The shortest distance between the center of AMF and that of MF was 5.80 mm (SD ± 2.90, 1.40–13.0). Variance of location of AMF in relation to MF was greater in the horizontal direction than in the vertical direction. In related to adjacent tooth, AMF was mainly distributed between the first and second premolars. The horizontal dimension and vertical dimension of AMF were 1.54 mm (SD ± 1.41, 0.70–9.80) and 1.44 mm (SD ± 0.41, 0.70–2.30), respectively.
Conclusions
Knowledge of AMF is important for performing effective nerve block and avoiding injuries to neurovascular bundles passing through AMF. Evaluation of the course of AMF in three-dimensional image of CBCT is effective for confirming AMF associated with inferior alveolar nerve.
... In the study of Naitoh et al., AMF is most often positioned posteroinferior. [32] A study of Kumari et al. showed that in all cases when AMF was on the right side of the mandible, it was positioned anterior to MF. [29] In cases where AMF was on the left side, there was an equal frequency in inferior, superior, posterior, and posteroinferior localization, 25% each localization. [29] Katakami et al. [24] showed posteriorly positioned AMF to MF as the most common in 41% of cases, and inferior position in 29% as the second according to the frequency. ...
... [21] was 1.5 mm 2 , which is similar to other studies. [32,33] The distance of AMF from the inferior border of the mandible was also analyzed. The mean distance from the inferior border of the mandible in our study was 14.44 ± 1.14 mm. ...
Introduction: Accessory mental foramen (AMF) is defined as any additional opening on the anterior surface of the mandible body that is connected to the mandibular canal. The presence of AMF is an important anatomical parameter when planning the therapy to avoid neurovascular bundle injury and other complications. Cone-beam computed tomography (CBCT) provides an accurate, three-dimensional determining of the position, its dimensions and the relation of AMF to the mental foramen (MF), as well as the distinction from nutritive openings. Material and Methods: The research was carried out at the Department of Dentistry, Faculty of Medical Sciences, University of Kragujevac, as a retrospective study where 148 CBCT images were analyzed. The analysis of the position of AMF, the relation to and the distance from the MF were made on cross-sectional and axial images. Only those openings that have had a clear connection with the mandibular canal were counted as AMF. Results: AMF was present in 12 (8.11%) patients. In most cases, AMF was positioned superior to MF, in 27% of patients. There was no significant statistical difference between sex and the jaw side. The average distance of AMF from MF was 4.52 ± 2.21 mm. In most cases, AMF is round shaped (60%). The average value of the surface area is 1.62 ± 1.14 mm². Discussion and Conclusion: Timely detection of AMF using CBCT contributes to the diagnosis and planning of appropriate dentures, surgical technique, preventing possible damage to adjacent anatomical structures, or some other therapy. © 2020 Journal of the Anatomical Society of India. All rights reserved.
... Mandible canal is generally unique, but there is a series of reports 2,3,9 in the literature demonstrating by means of different types of examination the presence of bifurcations which may be bifid or even trifid. 10 6 Fukami et al. and Kuribayashi et al. emphasise that anatomical variations of mandibular canals can be identified on panoramic radiographs, but the overlapping of structures and distortion of radiographic images may lead to misinterpretations. ...
... With regard to the affected side, we have found that 32% of the cases of BMC were on the right side, whereas the left side had 9 24.5%. These data are in accordance with studies by Ohran et al. 13 12 Correr et al. and Freitas et al. who also found a higher prevalence of BMC on the right side, ranging from 32.2% to 62.5% of the cases. ...
The sample consisted of 300 CBCT examinations obtained with Classic I-Cat scanner operating at voxel of 0.25 mm and FOV of 13 x 17 cm. Of the 300 patients, 188 (62.7%) were female and 112 (37.3%) male, with age ranging from 13 to 87 years old. Of the 300 examinations assessed, bifurcations were found in 90 cases (30%), with 51 (56.7%) belonging to females and 39 (43.3%) to males. With regard to affected sides, 32.2% of the cases (n = 29) were on the right side and 24.5% (n = 22) on the left side, with 43.3% (n = 39) on both. According to the results of the present study, it was possible to conclude that the localisation of BMC was at the centre of the mandibular body, presenting a relatively short distance between CM1 and CM2.
... 56 Naitoh et al found 28 of 356 patients (7.70%) displaying AMFs. 57 Orhan et al observed AMFs in 6.34% of children aged 7-16 years using 63 CBCT images. 58 The results of the present study are consistent with the incidence of AMFs reported in the literature. ...
... Naitoh et al found that approximately half (48.6%) of AMFs detected using CBCT were also demonstrated on panoramic radiographs. 57 The present study indicated no statistically significant association between the presence of an AMF and the sex of the patient, race/ethnicity of the patient, or side of the mandible. This indication that the manifestation of an AMF is unpredictable within the general population supports the necessity of performing volumetric imaging within the proximity of the MF before surgical procedures. ...
The purpose of this study was to evaluate the prevalence of accessory mental foramina (AMFs) through the use of cone beam computed tomography (CBCT). The secondary purpose was to analyze the location of AMFs, mean distance from the nearest tooth, mean distance from the alveolar bone crest, exit angle dimensions, and whether sex, side of the mandible, or racial disparities exist. Two hundred CBCT scans were analyzed for the presence and characteristics of bifurcations of the inferior alveolar nerve. AMFs were observed in 11.5% of patients and 6.5% of all hemimandibles examined. The majority of patients with 1 or more AMFs were female (60.9%). Bilateral AMFs were found in 1.52% of patients. The location of the AMF relative to the mental foramen (MF) was evaluated, and 30.0% of AMFs were located anterosuperiorly and 23.3% posterosuperiorly to the MF. Associations between patient sex and the greatest and smallest diameters of AMFs, circumference and area of AMFs, and ratio of AMF-MF area were evaluated via statistical analysis. Additional analyses evaluated the prevalence on each side of the mandible as well as the association between race/ethnicity and occurrence of AMFs. Statistical analyses showed no association between the occurrence of AMFs and sex, side of the mandible, or race/ethnicity of the study population. This demonstrates the importance of preoperative CBCT prior to all mandibular surgery to reduce the risk of injury to the neurovascular bundles that pass through AMFs.
... The AMF is defined as a buccal foramen continuing with the mandibular canal. If the buccal foramen shows no continuity with the mandibular canal, it is defined as a nutrient foramen (Naitoh et al. 2009(Naitoh et al. , 2011Sisman et al. 2012). The AMF contains mostly blood vessels and/or branches of the inferior alveolar nerve (Kabak et al. 2017). ...
... The widespread use of CBCT has resulted in an increase in the number of studies focusing on AMF and its variations. Naitoh et al. (2011) reported that panoramic AMF examination yields a lower detection rate than does CBCT. Iwanaga et al. (2015) suggested CBCT scans for preoperative diagnosis during implant, periodontal, and periapical surgery with periosteal detachment. ...
Purpose
The aim of this study was to evaluate the frequency and location of accessory mental foramen (AMF) in a Turkish population using cone beam computerized tomography (CBCT).
Method
CBCT images of 1005 patients were retrospectively reviewed from the archive of the Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Izmir Katip Celebi University. The prevalence, size, and localization of AMFs were assessed according to gender and age. In addition, the vertical and horizontal dimension of the mental foramen (MF) with and without AMF was measured to investigate the relationship between MF dimensions and the presence and absence of AMF. The average distance between the MF and AMF was also calculated. All measurements were then analyzed statistically.
Results
A total of 149 AMFs in 123 (12.23%) patients were identified on the CBCT images of the 1005 patients reviewed. There was no significant correlation between presence of AMF and gender (p = 0.152). The most common localization of an AMF with respect to the MF was posterio-inferior (n = 52; 34.89%). A statistically significant difference was also found between the vertical and horizontal dimensions of the MF with and without AMF (p < 0.05).
Conclusion
The results of this study demonstrate the high prevalence of AMF in the studied Turkish population. Considering the high prevalence and the structures passing through it, recognition of AMF and its detection using CBCT is important to prevent complications that may occur during and after surgical procedures.
... In the sample studied, there was a prevalence of 7.9%, a percentage similar to that found in previous studies, which averaged 7.0% [15,21]. Likewise, neither the literature nor the present study found a statistically significant difference between the presence of accessory mental foramen and the anatomical side, gender and age range [21,22]. ...
... It is important to emphasize that the accessory mental foramen is characterized as a vestibular foramen with continuity and communication with the mandibular canal, located near the mental foramen. Other foramina may present the same location, but of smaller diameter, with continuity in the mandibular body, but without presenting communication with the mandibular canal; in this case, these foramina are called nutrient, nutritional or nutritive channels [22]. The knowledge of this differentiation guarantees a correct diagnosis of the presence of these anatomical variations. ...
Purpose
This study aimed at identifying the course of the mandibular canal, the presence of anterior loop and accessory mental foramen, as well as verifying the association between these variables through the analysis of cone beam computed tomography (CBCT) exams.
Methods
CBCT images were analyzed to identify the type of mandibular canal path, classified into three types: (I) catenary; (II) progressive descending; and (III) straight. In addition, the presence of anterior loop and accessory mental foramen was analyzed. The variables were summarized by measures of absolute frequency, relative, mean and standard deviation. The Chi square and Fisher’s exact tests were used in the comparative analysis of the frequency distribution. The level of significance was 5%.
Results
The most frequent mandibular canal course was straight type (74.4%), followed by catenary (19.4%) and finally the progressive descending (6.2%). It was observed a prevalence of 10.2% for anterior loop and 7.9% for accessory mental foramen. There was no association between the presence of anterior loop (P = 0.798) and accessory mental foramen (P 0.480) with the mandibular canal course pattern, as well as no association between the anterior loop and the presence of the accessory mental foramen (P = 0.407).
Conclusions
The CBCT analysis is the best methodology for the investigation and localization of mandibular anatomical variations, which provides a good image quality of the bone tissue and details of the anatomical structures, reducing the risk of injury to the lower alveolar vascular-nervous bundle and, consequently, cause paralysis and hemorrhage in the anterior region of the mandible and adjacent structures.
... An AMF is defined as a smaller buccal foramen present in the region of the MF that has a demonstrable communication with the mandibular canal (MC) (9,10). It has been variously reported to occur in 1.4%-14% of patients (9,11) depending to some extent on the method of investigation, with panoramic radiography detecting only half of these compared with CBCT-based evaluations (12). The ability of CBCT imaging to identify AMFs has been positively correlated by surgical dissections in cadaver specimens (9). ...
... In this study, the prevalence of an AMF was at the higher end of the reported range of 1.4%-14%, which is also known to vary with ethnicity (11). The ethnicity of the subjects examined in this study was not known, but the figure of 12.8% is similar to the previous studies on Japanese subjects (9,12). With respect to location, the frequent superior-medial and inferior-medial locations were in contradiction to that reported by Katakami et al (28), who found accessory canals to be in a more posterior or inferior relation to the MF. ...
Introduction:
The aim of this retrospective observational study was to evaluate the cone-beam computed tomographic (CBCT)-based characteristics of the mental foramen (MF), accessory mental foramen (AMF), anterior loop (AL), lateral lingual foramen (LLF), lateral lingual canal (LLC) and to explore any relationships between their characteristics.
Methods:
The location and dimension of the MF; the incidence, location, and dimension of the AMF along with its distance to the MF; the presence and dimension of the AL; and the presence, location, angle of entry of the LLF and LLC, and its relation with the mandibular canal (MC) were evaluated in 109 CBCT scans. The data were analyzed descriptively, and associations were tested using the chi-square and analysis of variance tests.
Results:
The MF was most frequently located between the first and second mandibular premolar teeth (43.5%) or below the second premolar (34.3%). The mean horizontal dimension of the MF was 3.1 mm, the vertical dimension was 2.8 mm, and the mean vertical distance from the alveolar crest was 14.2 mm. An AMF was observed in 12.8% of cases with a mean distance of 4.1 mm from the MF. An AL was present in 47.2% of cases with a mean loop length of 3.38 mm. An LLF was present in 20.4% of cases, predominantly below the first premolar (27.3%) with a mean angle of entry of 148°. The LLC always communicated with the MC and generally not with the tooth apex. A statistically significant association existed between the presence of the LLF and AMF.
Conclusions:
The anatomic complexity of the MF region was confirmed; hence, CBCT-based evaluation is essential before surgical exploration of this region.
... Conventional radiographs could not precisely identify the presence and the course of the mandibular canal, the mental foramen and the accessory mental foramina due to the distortion of the image or the low contrast between the foramen and the mandibular trabecular bone [5]. Naitoh et al. detected only 18 accessory mental foramina using panoramic radiographs in contrast with CBCT which reveal 37 accessory mental foramina [6]. ...
... Cases with AMF located above the level of MF are supposed to be more clinically significant because of higher risk for surgical injury during implantation or endodontic surgery [6,11]. ...
The purpose of this study was to assess the incidence, location, and sizes of the accessory mental
foramina in Bulgarian population using Cone-Beam Computed Tomography (CBCT). The CBCT
records of 1400 Bulgarian patients were evaluated for Accessory Mental Foramina (AMF) by two expert
radiologists familiar with CBCT interpretation. Their presence and location in relation to the Mental
Foramen (MF) were assessed using axial, panoramic and cross-sectional 2-dimensional CBCT images.
The long and short axes diameters of the AMF were also measured. Accessory mental foramina were
observed in 3.86% of the patients: up to two foramina on one side, unilaterally presented in 94.4% of
cases with AMF. Their location regarding MF was distally and inferiorly in 62.9%. In 35.5 % of cases
with AMF the foramen was situated above the level of MF and therefore needs special attention before
surgery. The mean inner long and short axis diameters were 1.5 mm (SD: 0.4 mm) and 1.2 mm (SD: 0.3
mm) respectively. The measurements ranged from 0.7-2.5 mm for the long axis and 0.7-2 mm for the
short axis. Demonstration of AMF using CBCT can improve the surgery treatment planning in anterior
part of the mandible and thus helps to avoid unwanted neurovascular damage and possible malpractice
litigations. This is the first study about the incidence, location, and sizes of the accessory mental
foramina in Bulgarian population and adds additional information regarding the Caucasian race.
... The differences between the groups were evaluated using a paired t-test with a p-value < 0.05 considered as significant. In this study, the AMF were defined as a smaller foramen compared with the mental foramen (MF), which had continuity with the mandibular canal [13]. As a cadaveric examination, the present study did not require approval by an ethics committee at our institutions and the work was performed in accordance with the requirements of the Declaration of Helsinki (64th WMA General Assembly, Fortaleza, Brazil, October 2013). ...
... In addition, oral surgeons and oral radiologists are familiar with interpreting CT images of the mandible, while many general dentists are not. Most previous reports regarding AMF have been authored by oral surgeons, radiologists, or anatomists [2,13,18]. These studies have analyzed AMFs in both cross-sectional and 3D reconstructed images, but not in surface rendered images, which many general dentists use for developing treatment plans. ...
Introduction
The accessory foramina could not be identified on some imaging modalities such as surface-rendered images. The purpose of this study was to investigate the ability of surface-rendered images in detecting these foramina.
Materials and methods
We analyzed 20 accessory mental foramina (AMF) in nine mandibles removed from cadavers with cone-beam computed tomography (CBCT) and assessed in surface-rendered images. All AMF were divided into three groups depending on their visibility.
Results
Group 1 included AMF that were clearly visible as foramina, Group 2 were not clearly visible but could be recognized with concave parts, and Group 3 were not visible and the smooth surface of the bone was observed. Group 1 ranged from 1.3 to 5.1 mm², Group 2 from 0.3 to 3.8 mm², and Group 3 from 0.2 to 1.1 mm². A statistically significant difference in the mean size between Groups 1 and 3 was observed. Even if the AMF are smaller (e.g., 1 mm in diameter), they should still be avoided to prevent injury.
Conclusions
The clinician should be aware that smaller foramina might not be detected on these images.
... In their study, the evaluation of AMF was performed using CBCT and digital panoramic radiography, with results showing no cases of AMF observed in panoramic images, while 4 cases of AMF were detected with CBCT. Additionally, Naitoh et al. [30] compared the diagnostic capability of AMF between panoramic radiography and CBCT, revealing that panoramic radiography could detect AMF in only 48.6% of cases. This study used CBCT imaging to detect AMF, evaluate its size, and determine its position in the study population. ...
Purpose
This study aimed to assess the prevalence, dimensions, and positions of AMF and LLF in an Iranian population using CBCT imaging.
Methods and materials
In this cross-sectional study, CBCT images of 2082 patients were retrospectively reviewed based on inclusion criteria, including images from the mandibular region taken in the past five years with accurate demographic data. Exclusion criteria included images with significant pathologies, fractures, or poor quality. CBCT images were captured, and AMF and LLF presence, dimensions, and positions were recorded relative to the mental foramen and adjacent teeth. Data analysis was performed using the Chi-square test with a 5% significance level.
Results
A total of 2082 CBCT samples (46.54% females and 53.46% males) with a mean age of 48.30 ± 12.7 years were examined. Among these, 246 AMFs were observed in 222 individuals, with 24 having two AMFs. AMF was mostly observed unilaterally, with bilateral occurrence noted in 10.81% of patients with AMF. There were no significant differences between genders in AMF and LLF prevalence. Additionally, 68 patients were found to have lateral lingual foramina (LLFs).
Conclusion
AMF and LLF were detectable using CBCT, with a prevalence of 11.81% for AMF and 5.91% for LLF in the selected Iranian population. AMF was commonly situated posterior and superior to the mental foramen, while LLF was often found near the first premolar. This knowledge is crucial for preventing nerve injury during surgery and ensuring effective nerve block procedures.
... A neurovascular lesion in the mental bundle can lead to complications such as hemorrhage and paresthesia in the region, which can produce sensations such as heat, tingling and pressure in the area of innervation of the mental nerve. 1,4,5 For Sankar et al., 6 this makes the anatomical knowledge of the region essential for the performance of more efficient and safe anesthetic blocks. ...
Introduction: The mental foramen (MF) is located in the anterolateral region of the mandible body and through it passes the mental nerve and vessels. Its precise location is important in dental and anesthetic surgical procedures to avoid damage to the neurovascular structures that pass through it. However, due to the presence of variations in the incidence, shape, position and multiplicity of this foramen, controversies arise among authors regarding its exact location. Our study aimed to study the morphometric variations of the mental foramen correlating with sex. Materials and methods: A total of 252 human dry mandibles present in the Laboratory of Anatomy of the Department of Morphology of the Federal University of Sergipe were analyzed. The distance from the MF to the mental protuberance (MF-MP), the vertical distance from the MF to the inferior margin of the mandible (MF-IMM), the distance from the MF to the margin of the inferior alveolar process (MF-IAP), the width and the height of the MF and the multiplicity of the MF, as well as its position in relation to the lower molars and premolars. Results: The height of the MF showed no significant difference between genders on the right side (p=0.137), the same occurring on the left side (p=0.030). The width was similar in males and females on the right (p=0.241) and left (p=0.269). The most common position found for MF was in line with the second premolar, with no significant difference being found on the right (p=0.265) and left (p=0.435) sides. Sixty (11.9%) accessory mental foramens (AMF) were verified and there was no association between the occurrence of AMF and gender on the right (p=0.786) and left (p=0.748) sides. Male mandibles showed higher values of MF-IMM and MF-IAP than females on both sides. The MF-MP values were similar between the two sexes on the right and left sides. Conclusion: It is concluded that there was no correlation between the morphometric variables of MF and gender. RESUMO Introdução: O forame mental (MF) está localizado na região anterolateral do corpo mandibular e através dele passa o nervo e vasos mentais. A sua localização precisa é importante nos procedimentos cirúrgicos dentários e anestésicos para evitar danos nas estruturas Brazilian Journal of Health Review neurovasculares que passam através dele. No entanto, devido à presença de variações na incidência, forma, posição e multiplicidade deste forame, surgem controvérsias entre os autores quanto à sua localização exacta. O nosso estudo visava estudar as variações morfométricas do forame mental que se correlacionam com o sexo. Materiais e métodos: Foram analisados 252 mandíbulas secas humanas presentes no Laboratório de Anatomia do Departamento de Morfologia da Universidade Federal de Sergipe. A distância do MF à protuberância mental (MF-MP), a distância vertical do MF à margem inferior da mandíbula (MF-IMM), a distância do MF à margem do processo alveolar inferior (MF-IAP), a largura e a altura do MF e a multiplicidade do MF, bem como a sua posição em relação aos molares inferiores e pré-molares.Resultados: A altura do MF não mostrou diferença significativa entre os géneros no lado direito (p=0,137), o mesmo acontecendo no lado esquerdo (p=0,030). A largura foi semelhante nos machos e fêmeas do lado direito (p=0,241) e esquerdo (p=0,269). A posição mais comum encontrada para MF estava de acordo com o segundo pré-molar, não se encontrando nenhuma diferença significativa nos lados direito (p=0,265) e esquerdo (p=0,435). Sessenta (11,9%) foram verificados foramens mentais acessórios (FMA) e não houve associação entre a ocorrência de FMA e o sexo do lado direito (p=0,786) e do lado esquerdo (p=0,748). As mandíbulas masculinas mostraram valores mais elevados de MF-IMM e MF-IAP do que as femininas de ambos os lados. Os valores de MF-MP eram semelhantes entre os dois sexos, do lado direito e esquerdo. Conclusão: Conclui-se que não houve correlação entre as variáveis morfométricas de MF e género. Palavras-chave: foramen mental, morfometria, anatomia, sexo.
... A neurovascular lesion in the mental bundle can lead to complications such as hemorrhage and paresthesia in the region, which can produce sensations such as heat, tingling and pressure in the area of innervation of the mental nerve. 1,4,5 For Sankar et al., 6 this makes the anatomical knowledge of the region essential for the performance of more efficient and safe anesthetic blocks. ...
Introduction: The mental foramen (MF) is located in the anterolateral region of the mandible body and through it passes the mental nerve and vessels. Its precise location is important in dental and anesthetic surgical procedures to avoid damage to the neurovascular structures that pass through it. However, due to the presence of variations in the incidence, shape, position and multiplicity of this foramen, controversies arise among authors regarding its exact location. Our study aimed to study the morphometric variations of the mental foramen correlating with sex. Materials and methods: A total of 252 human dry mandibles present in the Laboratory of Anatomy of the Department of Morphology of the Federal University of Sergipe were analyzed. The distance from the MF to the mental protuberance (MF-MP), the vertical distance from the MF to the inferior margin of the mandible (MF-IMM), the distance from the MF to the margin of the inferior alveolar process (MF-IAP), the width and the height of the MF and the multiplicity of the MF, as well as its position in relation to the lower molars and premolars. Results: The height of the MF showed no significant difference between genders on the right side (p=0.137), the same occurring on the left side (p=0.030). The width was similar in males and females on the right (p=0.241) and left (p=0.269). The most common position found for MF was in line with the second premolar, with no significant difference being found on the right (p=0.265) and left (p=0.435) sides. Sixty (11.9%) accessory mental foramens (AMF) were verified and there was no association between the occurrence of AMF and gender on the right (p=0.786) and left (p=0.748) sides. Male mandibles showed higher values of MF-IMM and MF-IAP than females on both sides. The MF-MP values were similar between the two sexes on the right and left sides. Conclusion: It is concluded that there was no correlation between the morphometric variables of MF and gender.
... Es por esto, que se recomienda el uso de CBCT para estudios prequirúrgicos en la zona (Muinelo-Lorenzo et al., 2015). Se comparó la detección de FMA mediante radiografía panorámica y CBCT, concluyendo que la radiografía panorámica detectó solo 48,6 % de FMA de todos los detectados por el CBCT (Naitoh et al., 2011). Conocer la existencia de esta estructura anatómica es fundamental, ya que su detección previa puede reducir el riesgo de complicaciones, como hemorragia, dolor postoperatorio y parálisis (Goyushov et al., 2017). ...
The recognition of key anatomical structures is decisive to avoid complications in the dental clinical practice. Cone Beam Computed Tomography (CBCT) is a complementary exam recommended for the planning of different procedures in dentistry. With this exam, anatomical variants can be identified, such as the Accessory Mental Foramen (AMF). The objective of this work was to determine the frequency and characteristics of AMF in an adult Chilean population from the city of Valdivia, Chile. This is an observational study that included 247 CBCT exams from different radiological centers in Valdivia. According to the selection criteria, 143 CBCT exams were included. This study was approved by the Scientific Ethics Committee of the Valdivia Health Services. AMF was identified in 25 patients representing 17.48 %. From this result, 80 % were found in females. AMF was most frequently identified in patients from 18 to 39 years old. The average distance between AMF and Mental Foramen (MF) was 5.76 mm, which corresponds to 2 mm the minimum distance and 11.5 mm the maximum distance. The average distance between AMF and the nearest dental apex was 5.36 mm, and the minimum and maximum distance were 0.8 mm and 10.2 mm, respectively. The root apex of the second premolar was most frequently associated with the AMF, representing 60 % (n=15). This study confirms the importance of the correct evaluation of the mental region before initiating procedures in the area, which is vital to prevent injuries associated with this anatomical variant.
... The path and shape of the mandibular canal and mental foramen are significant milestones in surgical operations performed on the mandible such as implant placement, periapical surgeries, enucleations of pathologies, surgical correction of jaw deformities, and extraction of impacted teeth [1]. The mental foramen (MF) is placed on the anterolateral side of the mandible [2,3]. ...
Aim:
Accessory mental foramen (AMF) is a not common anatomical variation. During the surgical procedures involving the mandible such as implant surgery, periapical surgery, jaw surgeries, and periapical surgery and enucleation of pathologies at the mental region, obvious attention should be given to prevent postoperative sequelae. Case Report. Orthopantomograph (OPG) is routinely taken to visualize the maxillofacial region at a dental clinic. OPG shows exactly upper and lower jaw and teeth but superficially reveals some pathology or anatomic variation. It misses sometimes an anatomic landmark such as AMF. As the surgery is planned to a maxillofacial region, a detailed knowledge should be known before going into surgery to not interfere with anatomic landmarks. A 52-year-old male patient was referred to Kütahya Health Science University Dental Hospital, Turkey, to rehabilitate his bilateral partial edentulous lower jaw region. Implant surgery was planned in our patient. OPG was taken to evaluate the maxillofacial region but was unremarkable. Before the implant surgery, CBCT was obtained from our patient. CBCT and a three-dimensional reconstructed model of the male patient showed bilateral accessory mental foramen (AMF).
Conclusion:
Accessory mental foramen (AMF) carries additional innervation to the chin, mandibular anterior gingiva, and mental region. Reflection and protection of the AMF during the surgery can prevent hemorrhage and neurosensory disturbance at the mental region and can improve quality of life for the patient. CBCT has higher precision but also a higher price and radiation dose. Although anatomical variations are uncommon, they can be found on digital panoramic radiographs but in limited percentage.
... The CBCT were divided into three groups according to the TF: 30 brachyfacial, 30 mesofacial and 30 dolichofacial patients. The BMC were classified according to Naitoh et al. (2011). The images were classified and evaluated by a trained radiologist, using the Dolphin Imaging ® 11.0 and XoranCat ® software. ...
Objetivo: Avaliar a prevalência dos canais mandibulares bífidos (CMB) e correlacioná-los com os tipos faciais (TF) por meio de tomografia computadorizada de feixe cônico (TCFC). Material e método: A amostra, composta por 180 hemimandíbulas (90 pacientes), foi determinada por: TF, sexo, idade e lado da face. O TF foi determinado utilizando o índice VERT de Ricketts. As TCFC foram dispostas em três grupos de acordo com os TF: 30 pacientes braquifaciais, 30 mesofaciais e 30 dolicofaciais. Os CMB foram classificados de acordo com Naitoh et al. (2011). As imagens foram classificadas e avaliadas por um radiologista treinado, utilizando os softwares Dolphin Imaging® 11.0 e XoranCat®. A comparação entre os grupos em relação ao sexo, lado acometido e classe do CMB foi feita pelo teste Qui-quadrado ou Exato de Fisher; a influência da idade em relação ao sexo e presença de CMB, pelo teste de Mann-Whitney e, em relação ao TF, pelo teste de Kruskal-Wallis. A relação entre o sexo dos pacientes e presença do CMB, pelo teste Exato de Fisher. O nível de significância considerado foi de 5% para todos os testes. Resultados: A proporção de pacientes com CMB na amostra foi de 14.4%, sendo o mais frequente o tipo C sentido alveolar (53.8%), seguidos dos tipos D sentido retromolar (15.4%), tipo E sentido lingual (15.4%) e tipo F sentido base da mandíbula (7.7%). Quando o CMB estava presente, não houve predominância de lado nem influência pelo sexo. Conclusão: O TF não afeta a presença ou o tipo de CMB. Objetivo: Avaliar a prevalência dos canais mandibulares bífidos (CMB) e correlacioná-los com os tipos faciais (TF) por meio de tomografia computadorizada de feixe cônico (TCFC). Material e método: A amostra, composta por 180 hemimandíbulas (90 pacientes), foi determinada por: TF, sexo, idade e lado da face. O TF foi determinado utilizando o índice VERT de Ricketts. As TCFC foram dispostas em três grupos de acordo com os TF: 30 pacientes braquifaciais, 30 mesofaciais e 30 dolicofaciais. Os CMB foram classificados de acordo com Naitoh et al. (2011). As imagens foram classificadas e avaliadas por um radiologista treinado, utilizando os softwares Dolphin Imaging® 11.0 e XoranCat®. A comparação entre os grupos em relação ao sexo, lado acometido e classe do CMB foi feita pelo teste Qui-quadrado ou Exato de Fisher; a influência da idade em relação ao sexo e presença de CMB, pelo teste de Mann-Whitney e, em relação ao TF, pelo teste de Kruskal-Wallis. A relação entre o sexo dos pacientes e presença do CMB, pelo teste Exato de Fisher. O nível de significância considerado foi de 5% para todos os testes. Resultados: A proporção de pacientes com CMB na amostra foi de 14.4%, sendo o mais frequente o tipo C sentido alveolar (53.8%), seguidos dos tipos D sentido retromolar (15.4%), tipo E sentido lingual (15.4%) e tipo F sentido base da mandíbula (7.7%). Quando o CMB estava presente, não houve predominância de lado nem influência pelo sexo. Conclusão: O TF não afeta a presença ou o tipo de CMB.
... In several studies, AMF has been found to be commonly located in the posterioinferior position [1,5,[10][11][12][13]28,34,35]. However, in the present study, most of the AMFs were located in the anterioinferior position and this is in accordance with a Turkish study in which most of the AMF were present in the anterioinferior position [36]. ...
... O tipo de variação mais frequente é a presença de forame mentual duplo, que tem uma incidência relatada variando de 1,4 a 12,5%, por sua vez, a incidência de forame mentual triplo é mais rara, variando Research, Society andDevelopment, v. 10, n. 4, e35510414294, 2021 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v10i4.14294 6 de 0,7 a 1,2% (Naitoh et al., 2011;Sawyer et al., 1998). Com relação ao sexo, a literatura tem reportado maior prevalência de FMA em homens do que em mulheres (Han et al., 2016). ...
O forame mentual é uma importante estrutura anatômica que se apresenta geralmente por uma abertura única, bilateralmente na região vestibular do corpo da mandíbula, situado adjacente ao ápice dos pre-molares inferiores. Variações anatômicas podem ocorrer, como a presença de forames mentuais acessórios, que devem ser cuidadosamente avaliados no planejamento pré-operatório na região, afim de evitar danos aos feixes neurovasculares que emergem dos forames. O presente relato descreve a presença de forames mentuais acessórios bilateralmente na mandíbula, detectados através de tomografia computadorizada de feixe cônico prévio a cirurgia de colocação de implantes dentários. Dentro desse contexto, a avaliação tomográfica se faz mandatória, no intuito de ausência de danos ao feixe vásculo-nervoso e ocorrência de parestesias pós-operatórias.
... Katakami et al reported that the diameter of the mandibular AMFs was 1.2 mm (3). Naitoh et al reported an average size of 1.5 mm for AMFs and suggested that the frequency of AMFs was unrelated to the diameter of the MFs after comparing the sizes of the ipsilateral and contralateral MFs (24). The average diameter of the AMFs measured in this study was 1.32 mm, with 33 (68.75%) larger than 1 mm. ...
Anatomical data of accessory mental foramina (AMFs) were investigated in a Chinese Han population using cone beam CT (CBCT). A retrospective analysis was performed on 527 selected sets of CBCT images. The average frequency and diameter of AMFs, the diameter of the ipsilateral mental foramen (MF), and the center distance and relative position between the AMFs and MF were measured and calculated by three professional dentists. Among the 527 patients, AMFs were identified in 36 cases (frequency 6.83%), of which 68.75% of AMFs were larger than 1 mm. The mean diameters of the AMFs and the ipsilateral MF were 1.32±0.61 mm and 3.26±0.90 mm, respectively. The average distance from the AMFs to the alveolar ridge crest (ARC) was 15.05±3.50 mm, and the average distance to the mandibular plane was 15.87±3.64 mm. The positions of the AMFs relative to the MF varied widely. The AMFs were mostly positioned distal-inferior to the ipsilateral MF and under the mandibular second premolars. Nutrient foramina around the MFs were distinguished from AMFs. The reference plane for measuring AMFs was suggested to be the mandibular plane to increase the repeatability and accuracy of the experiment. Standard planes were proposed to determine the relative position between AMFs and the MFs. Based on our results, we propose that for implant surgeries, the safety region of 2 mm above the MFs should be reevaluated. CBCT examination is recommended before the operation to identify important anatomical structures around the MF region and their variations and set the safety distance on an individual basis.
... According to Orhan et al. 2 there are several classifications of the anatomical variations of the mandibular canal that consider width, extension, direction and presence of additional foramens. Naitoh et al. 23 suggested a classification of bifid mandibular canals into four types based on trajectory: buccal-lingual (type I), mesial direction (type II), alveolar ridge direction (type III) and retromolar direction (type IV). Freitas et al. 9 suggested a more elaborate classification that took into account directions of the bifid mandibular canal that were not contemplated in previous classifications, Class A (buccal direction), Class B (mesial direction), Class C (alveolar direction), Class D retromolar direction), Class E (lingual direction) and Class F (body of the mandible direction). ...
Resumo Objetivo: O presente trabalho objetiva verificar a prevalência e classificação das alterações do canal da mandíbula por meio de exames de tomografia computadorizada de feixe cônico nos diferentes tipos faciais. O trabalho foi submetido e aprovado ao comitê de ética e pesquisa através do parecer n˚ 2.065.839. Material e método: A amostra foi composta por 90 tomografias, divididas em três grupos de acordo com os tipos faciais, braquicefálico, dólicocefálico e mesocefálico. Todas as imagens foram obtidas no banco de dados da Faculdade São Leopoldo Mandic, Campinas-SP. Resultado: Dos 90 pacientes pesquisados, 23 apresentaram os canais da mandíbula bífidos, ou seja, 25,6% da amostra total. Desses, 60,9% pertenciam ao sexo masculino e 39,1% ao sexo feminino. Em 39,1% o direcionamento era para região retromolar (classe D), enquanto em 21,7%, a trajetória era no sentido alveolar ou superior (classe C). Com menor proporção, 13,1% foi constatada a classificação C-E. Para as demais classificações encontradas (A, E, F e A-E), as frequências foram na faixa de 8,7% a 4,3%. Em nenhum dos 23 casos de bifurcação do canal da mandíbula foi encontrada classificação (B), ou seja, em direção mesial. Conclusão: De acordo com os resultados obtidos nesse estudo, encontrou-se uma prevalência de 25,6% de canais da mandíbula bífidos, o tipo de canal bífido mais prevalente foi classe D para região retromolar e a maior ocorrência dos canais mandibulares bífidos foi unilateral esquerda. Quando avaliada a ocorrência dos canais da mandíbula bífidos em relação aos tipos faciais, os pacientes braquifaciais foram os mais acometidos. Descritores: Cirurgia; anatomia; mandíbula. Abstract Objetive: The aim of this study is to establish the prevalence and classification of mandibular canal alterations using cone beam computed tomography (CBCT) in different facial types. This research was submitted and approved by the research ethics committee, registration number 2.065.839. Material and method: The sample consisted of 90 CBCTs from the São Leopoldo Mandic Dental School database (Campinas-SP), divided into three groups according to brachycephalic, dolichocephalic and mesocephalic facial types. Result: Of the 90 patients, 23 presented bifid mandible canals (25.6%), of which 60.9% were in males and 39.1% in females. In 39.1%, the canal bifurcation occurred towards the retromolar region (class D), 21.7% had a trajectory to an alveolar or upper direction (class C) and 13.1% were classified as C-E. For the remaining classifications (A, E, F and A-E), the frequencies were in the range of 8.7% to 4.3%. None of the 23 cases of mandibular canal bifurcation was classified as B (mesial direction). Conclusion: According to the results obtained from this study, the prevalence of bifid mandibular canals was found to be 25.6%, with class D being the most prevalent for the retromolar region and the highest occurrence was unilaterally on the left side. When evaluating the occurrence of bifid mandibular canals in relation to facial types, brachycephalic patients were the most affected.
... The AMF's incidence ranges from 2.0% to 14.3% (Iwanaga et al. 2015;Iwanaga et al. 2016), and this variant's injury may lead to irreversible paresthesia of the chin. Several studies of the AMF that used cone beam computed tomography (CBCT) have been reported (Katakami et al. 2008;Naitoh et al. 2011;Kalender et al. 2012;Muinelo-Lorenzo et al. 2015) and showed that it can appear either as a single foramen or multiple foramina, unilateral or bilateral. Only two articles have investigated the AMF's relation to innervation of the accessory mental nerve (Toh et al. 1992;Iwanaga et al. 2016). ...
Most of the studies of the mandible's anatomical variations have presented the authors' speculations, and only a limited number has provided evidence that demonstrated the actual complications injury to the variant structures caused. To our knowledge, no study has evaluated the risks associated with these variant anatomical structures' injury. We reviewed articles that described clinical cases of the injury to, and anatomical studies of, three anatomical variants of the mandible—the accessory mental, lingual, and retromolar foramina—with which dentists are relatively familiar and that are mentioned often in the context of implant and third molar surgeries, to describe risk assessment methods with which to evaluate potential complications preoperatively. Only a limited number of the clinical reports of injury to the mandible's accessory foramina were available. The potential severe complication of injury of the accessory mental foramen (AMF) is sensory disturbance of the lower lip. Risk of neurosensory disturbance of lower lip can be assessed by AMF/MF ratio and positional relations to the MF. Potential severe complication of injury of the lingual foramen is bleeding and hemorrhage in the oral cavity's floor. Risk of bleeding can be assessed by diameter and positional relation between the mental spine/mylohyoid line. A risk assessment of the retromolar foramen could not be made because of inadequate data. We hope the risk assessments suggested will encourage dentists to predict intraoperative/postoperative complications caused by damaging the mandible's accessory foramina. Clin. Anat. 32:672–677, 2019. © 2019 Wiley Periodicals, Inc.
... According to Orhan et al. 2 there are several classifications of the anatomical variations of the mandibular canal that consider width, extension, direction and presence of additional foramens. Naitoh et al. 23 suggested a classification of bifid mandibular canals into four types based on trajectory: buccal-lingual (type I), mesial direction (type II), alveolar ridge direction (type III) and retromolar direction (type IV). Freitas et al. 9 suggested a more elaborate classification that took into account directions of the bifid mandibular canal that were not contemplated in previous classifications, Class A (buccal direction), Class B (mesial direction), Class C (alveolar direction), Class D retromolar direction), Class E (lingual direction) and Class F (body of the mandible direction). ...
Objetive
The aim of this study is to establish the prevalence and classification of mandibular canal alterations using cone beam computed tomography (CBCT) in different facial types. This research was submitted and approved by the research ethics committee, registration number 2.065.839.
Material and method
The sample consisted of 90 CBCTs from the São Leopoldo Mandic Dental School database (Campinas-SP), divided into three groups according to brachycephalic, dolichocephalic and mesocephalic facial types.
Result
Of the 90 patients, 23 presented bifid mandible canals (25.6%), of which 60.9% were in males and 39.1% in females. In 39.1%, the canal bifurcation occurred towards the retromolar region (class D), 21.7% had a trajectory to an alveolar or upper direction (class C) and 13.1% were classified as C-E. For the remaining classifications (A, E, F and A-E), the frequencies were in the range of 8.7% to 4.3%. None of the 23 cases of mandibular canal bifurcation was classified as B (mesial direction).
Conclusion
According to the results obtained from this study, the prevalence of bifid mandibular canals was found to be 25.6%, with class D being the most prevalent for the retromolar region and the highest occurrence was unilaterally on the left side. When evaluating the occurrence of bifid mandibular canals in relation to facial types, brachycephalic patients were the most affected.
... 20,23,25,30 However, some authors used digital panoramic images in their studies. 48,28,31,32 Based on previously published evidence, we can conclude that 2D radiograph assessment methods are limited, they can underestimate this variation, and they are not trustable for presurgical planning evaluations. 17,[33][34][35] In this review article, we found a difference about the prevalence of the AMF, ranging between 0.564% and 55% in radiologic studies. ...
The presence of the additional mental foramen of the mandible is considered to be a rare anatomical occurrence. Only a few cases have been reported. In these cases, only 1 foramen is called the mental foramen and the others are termed either accessory mental foramen or accessory buccal foramen. The purpose of this article was to present a case with computed tomography images and suggest that preoperative cone beam computed tomography should be performed to detect any anatomical variation. In addition, we present all reasonable terminology to ease the communication through unique terminology among surgeons.
... It has been suggested that separation of the mental nerve into several fasciculi earlier than the formation of the mental foramen up to the 12th gestational week could explain why accessory mental foramina are formed (Hasan et al. 2010). Naitoh et al. (2011) analyzed 365 patients (130 males and 235 females). Para-panoramic images were reconstructed from cone-beam computed tomography (CBCT) images of the accessory mental foramen/foramina using 3D visualization and measurement so ware. ...
This chapter discusses the bones in the human skull, including frontal bone, occipital bone, parietal bone, temporal bone, and ethmoid bone. Bony bridges may exist between the inferior and middle nasal conchae. The inferior concha may be notched or have a curved convex surface. The chapter also describes the infraorbital foramina. The infraorbital canal issues a small branch on its lateral face close to its midpoint to allow the anterior superior alveolar nerve to pass. In one skull the zygomatic process of the maxilla and the zygomatic process of the temporal bone articulated directly on the temporal surface of the zygomatic bone. There can be several nasal bones or only one. Internasal bones have been found at the edges of the nasal bones in the upper corner of the piriform aperture, lying on the anterior tip of the perpendicular plate of the ethmoid.
... This tendency agrees with other investigations, showing the importance of the MC border for MC visibility. 12,21,22 The superior medial and superior distal parts of the MC border had visibility score 3 in 22.0% and 24.7% of the It is interesting to know that anatomically trabeculated MC walls tend to be denser in the upper part than the lower part, but MC visibility does not have a similar tendency, according to our study and to that of Wadu et al. 21 The last-mentioned sources supplement the statement that radiographic identification of the superior MC border cannot directly relate to MC border density and cannot have a prognostic value for MC damage during implant surgery. ...
Objectives:
To assess the visibility of the mandibular canal (MC) morphology in different jaw dental segments (JDSs) in relation to morphometric and densitometric parameters on digital panoramic radiographs (DPRs).
Methods:
32 DPRs (155 JDSs) were selected randomly after retrieval. MC visibility in conjunction with superior and inferior border visibility was scored on a 5-point scale in four places on the JDS-that is, for the medial, distal, superior, and inferior MC parts. Morphometric and densitometric analyses were made horizontally and vertically in the JDS region. Descriptive statistics, Fisher's exact test, Mann-Whitney U test, and additional tests were performed.
Results:
There was no significant difference in MC visibility for the superior, inferior, medial, and distal parts of the JDSs. Statistically significant (p < 0.05) differences were identified between particular visibility scores of the superior and inferior MC borders. In 22.0-24.7% of JDSs the superior MC border was not visible, more than twice as often as the inferior MC border was not visible (9.1-10.2%). The visibility of superior and inferior MC borders in JDSs was not related to the morphometric or densitometric assessment parameters, or to age, gender, JDS location, condition, or the visibility of neighbouring MC parts or contralateral JDSs.
Conclusions:
DPRs failed to provide MC visibility based on a single factor. Particular differences were identified between the levels of visibility of the superior and inferior MC borders. More advanced radiological investigation methods could be required for the evaluation of about 25% of JDSs when superior MC border identification is obligatory.
... It was found to be a useful and accurate method to detect bifid mandibular canals, anterior loop of inferior alveolar canal, and mandibular incisive canals [27][28][29]. In addition, CBCT showed superior visibility of mental foramen and accessory mental foramen compared to panoramic radiographs [30,31]. This implicates the use of CBCT compared to panoramic radiographs, especially in cases where the 3D images would be beneficial for treatment. ...
... It was found to be a useful and accurate method to detect bifid mandibular canals, anterior loop of inferior alveolar canal, and mandibular incisive canals [27][28][29]. In addition, CBCT showed superior visibility of mental foramen and accessory mental foramen compared to panoramic radiographs [30,31]. This implicates the use of CBCT compared to panoramic radiographs, especially in cases where the 3D images would be beneficial for treatment. ...
Background: Understanding the anatomical variations in the position of the mental foramen is significant for different dental procedures. This study identified the position of the mental foramen among a Saudi population in the western region of Saudi Arabia.
Methods: A total of 950 panoramic radiographs (PAN) were selected from a total of 1195 radiographs. The mental foramen location was determined by drawing imaginary lines parallel with the long access of the lower premolars and mesial root of the first molar on the same side. The mental foramen location was then classified into six classes (Class I-VI).
Results: In the Saudi population, more than half of the mental foramina were located between the lower premolars (Class III, 57.89%), followed by class IV (41.70%) of the mental foramen was located under the second premolar apex. None of the radiographs showed that the mental foramen was located in front of the first premolar (Class I).
Conclusion: For successful and secure mental nerve blocking, the anesthetic solution should be injected between the first and second premolars or under the lower 2nd premolar in the Saudi population. Additionally, caution should be taken when operating close to these areas to avoid mental nerve injury.
Anatomical variations of the jaw bones have been identified in three-dimensional images in dentistry since CBCT was developed. Unfortunately, it is still difficult to find detailed descriptions of such anatomical variations in regular dental textbooks although many studies have been published in the scientific literature. In this review, common anatomical variations of the mandible which are detected on CBCT images, i.e., accessory mental foramina, retromolar foramina, and lingual foramina, are reviewed and discussed from anatomical, radiological, and clinical anatomy perspectives. It is important for clinicians to “know” the anatomical variations before interpreting CBCT images. We believe that a knowledge of anatomical variations can improve clinicians' ability to interpret CBCT images.
Introdução: Os exames radiográficos são essenciais na Odontologia para diagnosticar lesões, anomalias e/ou variações anatômicas na região maxilo-mandibular. Objetivo: Este estudo avaliou por meio de radiografias panorâmicas (RP) e tomografia computadorizada de feixe cônico(TCFC) a prevalência e possíveis variações anatômicas do canal da mandíbula além de sua relação com os terceiros molares. Metodologia: Foram interpretadas imagens de TCFC e RP pertencentes ao banco de imagem da Faculdade Herrero. Os seguintes dados foram coletados a partir da interpretação das radiografias panorâmicas e TCFC: presença de variações do canal da mandíbula e suas classificações de acordo com a literatura: Classificação de Langlais e Naitoh; Presença de proximidade de relação entre terceiro molar e canal da mandíbula, de acordo com a Classificação de Winter e Pell e Gregory. Resultados: RP: A amostra total foi composta por 509 pacientes, 351 (68,95%) do sexo feminino e 158(15,29%) do sexo masculino, cujas radiografias panorâmicas foram avaliadas bilateralmente. A média de idade foi 45 anos. TCFC: A amostra foi composta por 37 imagens, sendo 24 (64,8%) do sexo feminino, enquanto 13 (35,13%) do sexo masculino. Não foram observadas variações anatômicas no canal da mandíbula Conclusão: A prevalência de canal da mandíbula bífido foi baixa (4,72%), com predominância do lado direito e do tipo I. A maioria dos dentes inclusos estavam em posição mesioangulada, segundo classificação de Winter (48,12%). De acordo com a classificação de Pell & Gregory, foi observado predominância da classe A e III (138 casos 73,79%; e 110 casos 58,82% respectivamente).
Background: Determining the incidence and anatomic features of accessory mental foramen (AMF) in the Iranian population is of vital importance. This study investigated the prevalence and anatomic characteristics of AMF using cone-beam computed tomography (CBCT) in a selected Iranian population. Methods: A total of 853 CBCT images from 440 women and 413 men were examined in this cross-sectional retrospective study. The images were evaluated by two independent observers using reconstructed 3-dimensional, cross-sectional, and panoramic views. Several parameters were assessed, including the location of AMF relative to mental foramen (MF), size and the point of canal bifurcations, and the distance between the main and accessory canals. Finally, statistical differences in the AMF prevalence in terms of gender and direction and its location were evaluated by the Mann-Whitney U test (P<0.05). Results: The prevalence of AMF was 10.55%, which was more frequently located in the posterior inferior area relative to the main MF, and its nerve was more frequently originated from the anterior loop (P=0.001). There were no statistically significant differences in gender (P=0.26) and direction (P=0.4). The mean distance of AMF was 7.62 mm. The mean height of MF and the AMF vertical height were 13.65 mm and 52.12 mm in those with AMF on one side, respectively, and this difference was statistically significant (P=0.001). The sizes of the MF and AMF were 3.2 mm (large diameter), 2.3 mm (small diameter), and 1.4 mm (large diameter), and 1.1 mm (small diameter), respectively. Conclusions: Based on the findings of the present study, the prevalence of AMF according to hemi-mandibular was 5.80% in the selected Iranian population. Thus, AMF might branch from any section of the inferior alveolar nerve and the mandibular canal.
It was aimed to evaluate the frequency of accessory mental foramen (AMF) and accessory infraorbital foramen (AIOF) and analyse the correlation between these two foramina using cone‐beam computed tomography (CBCT). The retrospective study reviewed the CBCT images of 1020 patients. The rates of AMF and AIOF were evaluated according to sex and age distributions. Correlations between the localizations of AMF and AIOF in the right and left jaws and the correlations between the occurrences of these foramina were evaluated. In the CBCT images of the 1020 patients, AMFs were detected in 48 patients, among which 14 were in the right half jaw, and 34 were in the left half jaw. AIOFs were detected in 143 patients, among which 65 were in the right half jaw, and 78 were in the left half jaw. Recognising and detecting AMF and AIOF with CBCT is important in terms of preventing complications that may occur in surgical procedures.
Background and Aim: Recognizing the position of the Mental Foramen (MF) is essential in numerous cases, such as anesthesia injection and periapical surgeries in the anterior region of the mandible. Furthermore, the diversity in the location and position of MF can develop problems during surgery in this region.
Methods & Materials: The present study examined anatomical landmarks based on panoramic radiographic images obtained in Bandar Abbas City, Iran. In total, 450 panoramic radiographic images of men and women were assessed. All explored images were converted to JPEG format and entered in real size in Auto CAD software (2014). The collected data were analyzed in SPSS by one-way Analysis of Variance (ANOVA), Student’s t-test, and Chi-squared test.
Ethical Considerations: This study was approved by the Ethics Committee of Hormozgan University of Medical Sciences (Code: IR.HUMS.REC.1394.189).
Results: The obtained data revealed that the mean distance from the MF to the lower edge of the mandible on the right and left was 10.53 mm and 10.51 mm, respectively. The mean distance from the MF to the posterior side of the mandible equaled 49.36 mm on the right and 48.72 mm on the left. Moreover, the mean distance of MF to the midline of the lower jaw on the right and left was calculated as 27.16 and 26.27 mm, respectively. Furthermore, in most cases, the anterior-posterior position of MF was symmetrical concerning anatomical landmarks. The anterior-posterior distance of MF to mandibular midline was significantly different between the explored males and females (P
Introduction:
This study aimed to perform a systematic review and meta-analysis on accessory mental foramen (AMF) research using cone-beam computed tomographic (CBCT) imaging.
Methods:
A systematic review was performed in PubMed, Embase, Thomas Reuter's Web of Science, Scopus, and ScienceDirect databases according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement. Articles focusing on AMF prevalence and location using CBCT imaging were selected without language restrictions. Studies reporting pooled results only or presenting any pathology in the area surrounding the mental foramen (MF) were excluded. A meta-analysis using random effects was performed.
Results:
The present meta-analysis included a total of 46 articles involving 21,761 subjects. The overall pooled AMF prevalence was 7.87% (95% confidence interval [CI], 6.69-9.24) in subjects and 4.75% (95% CI, 3.79-5.95) in hemimandibles (n = 31,158). AMF presence was most commonly unilateral, reaching 90.15% (95% CI, 82.98-94.49). AMFs were significantly more frequent in right hemimandibles (χ2 = 5.20, P < .05) and were most commonly located posterior and inferior to the MF. However, AMFs superior to the MF were also observed in 47.43% (95% CI, 38.45-56.58) of cases. The studies conducted over the last 3 years showed significantly higher AMF prevalence levels (χ2 = 5.12, P < .05).
Conclusions:
Our meta-analysis demonstrates that AMF prevalence is considerable and should not be underestimated. AMFs are most frequently located in right hemimandibles. The presence of AMFs superior to the MF is frequent. Around 3% of people present superior AMFs. This fact puts those patients at greater risk for injury when performing periapical surgery in this area.
Purpose. The aim of this systematic review is to assess whether the anatomy of mental foramen is precisely evaluable with cone beam computed tomography (CBCT) before implantation in humans. Methods. A systematic review was carried out to evaluate the anatomy of mental foramen (size, position, symmetry, anterior loop, and accessory mental foramen or multiple mental foramina). According to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, an electronic search of three databases (Medline, Web of Science, and Cochrane Library) was undertaken until June 2020 and was supplemented by manual searching. Two reviewers will independently perform the processes of study inclusion, data extraction, and quality assessment. Systematic reviews, studies about children, and case reports were excluded. Only studies using CBCT to do preoperative evaluation were selected. Results. From 728 potentially eligible articles, 72 were included in the qualitative analysis and quantitative synthesis. This systematic review provided an assessment of the anatomy of the mental foramen. The mental foramen was located mostly between the two premolars (between 50.4% and 61.95%) or apically to the second premolar (from 50.3% to 57.9%). The mean diameter of the mental foramen was bigger in males than in females; the difference between them could reach 0.62 mm. The anterior loop seemed to be longer in males (between 0.87 ± 1.81 and 7.25 ± 2.02 mm) than in females (between 0.81 ± 1.18 and 6.52 ± 1.63 mm) and with the presence of teeth (from 0.91 ± 1.18 to 2.55 ± 1.28 for dentate people and from 0.25 ± 0.61 to 2.40 ± 0.88 mm for edentate population). The anterior loop and the accessory mental foramina were detected more frequently with CBCT than panoramic X-ray: only between 0.0 and 48.6% AMFs detected with CBCT were also seen with panoramic images. Clinical Significance. The mental foramen (MF) is an important landmark for local anesthesia and surgical and implantology procedures. Its location, morphology, and anatomical variations need to be considered to avoid mental nerve injury. The aim of this review is to evaluate the mental foramen using CBCT through a systematic literature review to improve knowledge of this complex area for the clinician.
1. Introduction
The mental foramen (MF) is a strategically important landmark during implantology procedures. Its location, morphology, and anatomical variations need to be considered before surgery to avoid mental nerve injury [1].
Mental foramen is located on the mandible, a median and symmetric bone, which constitutes the low part of the face and the chin skeleton. The inferior alveolar nerve (IAN) progresses into the mandibular canal in the mandibular body on each side of the mandible. This canal opens posteriorly by the mandibular foramen and anteriorly by the mental foramen. Sometimes, small foramina in the surrounding area of the mental foramen are identified as accessory mental foramina (AMFs). This way, anteriorly, the IAN spreads into two branches: the mental nerve which goes out of the mandible through the mental foramen and enables the sensibility of the chin and the inferior lip while the incisive nerve stays into the mandible and enables the innervation of homolateral incisors and canine [2].
The mental nerve has different ways to reach the mental foramen. Solar et al. present a classification of intraosseous part of the mental nerve with three different types (Figure 1) [3].
Purpose
It is necessary to correlate cancellous bone patterns with cone beam computed tomography (CBCT) images, but this has not been done to date. The goal of this study was to establish how the superior wall of the mandibular canal (MC) on CBCT images correlates with the cancellous bone around the MC on gross anatomical findings.
Methods
Twenty sides from ten dry mandibles derived from six females and four males were used for this study. In order to observe the MC distally, the specimen was prepared by the method used in our previous study. The cancellous bone around the MC was observed and classified into three types: type I (trabecular pattern), type II (osteoporotic pattern), and type III (dense/irregular pattern). The mandibles were examined with CBCT and the superior wall of the MC on CBCT was scored as visible or non-visible. Finally, the scores (visible or non-visible) were compared to the type by gross observation.
Results
For gross observation, a total of 80 areas were available for this study. The data were added to those from our previous study. As a result, 155 areas on 40 sides were analyzed. In dentulous sections, types I, II, and III were found in 55.8%, 20.9%, and 23.3%, respectively. In edentulous sections, the corresponding percentages were 25.0%, 41.1%, and 33.9%, respectively. The dentulous sections was more likely than edentulous to have a type I mandible in both sexes. More females than males had type II (osteoporotic) mandibles. When the superior wall of the MC was non-visible on CBCT, the cancellous bone was type II in 80%.
Conclusions
We believe the results can easily be applied to preoperative diagnosis with not only radiological but also anatomical evidence. This classification now necessitates clinical trials for further evidence.
The morphological variations of the mental foramen (MF) and mandibular foramen (MBF) have been studied for several years, and the prevalence and morphometric characteristics of double and triple foramina have been reported. The objective of this study was to establish the prevalence of variations in the MF and MBF, and to carry out a morphometric analysis of a Chilean population using digital panoramic radiographs. The study included 927 radiographs; the observed prevalence of double MF was 2.58 %, while the prevalence of double MBF was 1.51 %. No cases of triple foramina were found. In men, double MF was found more frequently in the left hemiarch (64.28 % of cases), while in women it was more frequent in the right hemiarch (80 %). Double MBF was found more frequently in the right hemiarch in women (80 % of cases), while the distribution between left and right in men was even. The mean area, width and height of the double MF were 5.46 mm2, 2.77 mm and 2.57 mm respectively. The means of the same morphometric measurements in double MBF were 6.37 mm2, 2.27 mm and 3.19 mm respectively. In both foramina, statistically significant differences were only found between the height of the foramen and the age of the subjects, with the observation that the greater the subject's age, the smaller the height. Dental surgeons must take these anatomical variants into consideration in clinical and surgical actions; timely diagnosis by radiograph is important to avoid possible complications.
Statement of problem:
The presence of an anterior loop (AL), accessory mental foramen (AMF), or lateral lingual foramen (LLF) adds complexity to the mental foraminal region, and consequently, implant placement in this region can damage the nerves and blood vessels if the structures are not carefully identified.
Purpose:
The purpose of this retrospective study was to evaluate the characteristics of the AL, AMF, and LLF to provide recommendations for surgeons operating in the mandibular mental foraminal region.
Material and methods:
Reconstructed cone beam computed tomography (CBCT) images in 306 Southern Chinese patients were retrospectively analyzed. The prevalence of the anterior loop was assessed, and the anterior loop length (ALL) was measured from the most anterior point of the mental foramen to the most mesial part of the anterior loop. The prevalence, location of the AMF as related to the mental foramen, and adjacent teeth were analyzed. Additionally, the distance from the mental foramen to AMF centers were measured. The prevalence, diameter, and location of the LLF were evaluated. The chi-square test was used for prevalence analysis (α=.05).
Results:
Anterior loops were identified in 67.8% of the 612 hemimandibles, with a mean length of 3.3 ±1.2 mm, ranging from 1.2 to 7.3 mm. A total of 5.56% of the hemimandibles had an ALL ≥5 mm, and male patients had a statistically longer loop length (P=.006). The ALL on the right side was found to be statistically longer than that on the left side (P=.002). No statistically significant differences in the ALL were found among different age groups (P=.124). AMFs were observed in 10.5% of the patients, with most located in the posterosuperior position of the mental foramen. The mean distance between the center of the AMF and the mental foramen was 5.1 ±1.4 mm. LLFs presented in 69.9% of patients, with 74.0% located in the premolar region. The mean vertical diameter of the LLF was 0.9 ±0.3 mm, and the mean distance from LLF to the mandibular inferior border was 7.1 ±1.9 mm.
Conclusions:
This study revealed that ALs, AMFs, and LLFs occurred often in the Southern Chinese population. Identifying the presence of the AL, AMF, and LLF is important before surgery in the mental foraminal region.
The mental foramen (MF) is the exit of the mandibular canal and a critical structure for implant surgery, periodontal surgery, periapical surgery, and local anesthesia. The mental neurovascular bundles emerge from the mental foramen, and dentists have to avoid injuring these anatomical structures. Therefore, determining the position of the mental foramen can help to preclude iatrogenic complications during the aforementioned procedures. Several textbooks and scientific papers have described the normal anatomy of the mental foramen; however, there are many variations that must be noted for better clinical practice so that unnecessary complications can be avoided. In this chapter, the normal anatomy and the variations of the mental foramen are reviewed, and their clinical relevance is discussed.
Objective: This study aimed to investigate the frequency and characteristics of accessory mental foramina (AMFs) and their bony canals in a selected Chinese population using cone-beam computed tomography (CBCT).
Materials and methods: Reconstructed CBCT images of the mandible in 784 Chinese patients (305 males and 479 females) were retrospectively analysed to identify the AMF. The presence, dimension and location of the AMF as well as the origin and course of the associated bony canal were evaluated and classified. Variations in these characteristics were analysed according to gender, side and age.
Results: A total of 66 AMFs were found in 57 (7.3%) of the 784 patients. The frequency of AMFs was significantly influenced by gender and side of the mandible (p < .05). Most AMFs were located apically between apices of the first and second premolars. The high-position AMFs (above the mental foramen) accounted for 54.5% of the total. The mean horizontal and vertical diameters of the AMF were 1.38 ± 0.47 and 1.23 ± 0.37 mm, respectively. Two typical types of the bony canal leading to the AMF were identified according to their bifurcation site from the mandibular canal. Most bony canals originated from the anterior loop of the mental canal (56.1%) and coursed posterosuperiorly (36.3%). The mean length of the bony canals was 5.78 ± 2.31 mm.
Conclusions: This study presents a considerable frequency of AMFs in a Chinese population. The high-position AMF and the associated bony canal coursing in the oblique upward direction appear frequently. Thus, clinicians should be alert to the presence of the AMF to avoid neurovascular complications especially when dental procedures require periosteum detachment and implant insertion in the mental region.
Introduction: The knowledge of precise location of various mandibular anatomical landmarks is mandatory to obtain the desired surgical outcome. Damage to the nerve can be caused by perforation of the nerve canal during different surgical procedures. Accessory mental foramen (AMF) is a relevant anatomic structure with widespread importance as its presence may cause failure to achieve adequate level of anesthesia using conventional nerve block technique. Aim: To assess the inferior alveolar nerve canal position and accessory mental foramen using CBCT. Objective: 1) To assess the linear relationship of the alveolar nerve canal (ANC) to buccal and lingual cortex, bone crest to canal on both sides of mandible. 2) To identify the occurrence and location of AMF as a rare anatomical variation on both side of mandible. Materials and methods: A total 178 mandibular CBCT scans were examined for AMF and the linear relationship ANC to buccal and lingual cortex, bone crest to canal in both side of mandible was evaluated in cross-section. Result: Out of the studied population, 13 AMF were detected in 12 subjects (9 Males, 4 Females). Gender wise comparison of the linear measurement of the study population in buccal cortex, lingual cortex, cortical width, total width through centre of inferior alveolar nerve canal (IANC) and diameter of inferior alveo-lar nerve canal (IANC) shows no statistically significant variance (P > 0.05). Conclusion: The presence of anatomical variations is frequently neglected. To get rid of iatrogenic injuries during the surgical procedures, it is important to identify these variations by presurgical imaging examination which permits more accurate planning and contributes more successful treatment.
Introduction:
The purpose of this study was to investigate the relationships between the location of the mental foramen (MF) and the mandibular canal (MC) and the surgical access line (SAL) of the mandibular posterior teeth using cone-beam computed tomographic (CBCT) scans.
Methods:
CBCT scans of 204 subjects ranging in age from 18-76 years old were evaluated. The vertical and horizontal distances from the MF to the SAL of the mandibular premolars and first molars and the vertical distance from the MC to the SAL of the second premolars and first molars were measured via CBCT scans.
Results:
The average vertical distance between the MF and the SALs showed significant increases sequentially from the first premolars to the distal roots of the first molars, and the shortest average distance of 2.74 mm was obtained for the first premolars. The SALs of the second premolars were the closest to the MF in the horizontal direction with an average distance of 1.5 mm. In 19.9% of the cases, the vertical and horizontal distances between the MF and the SALs of the second premolars were less than 2 mm. In addition, the MF was located superior to the root apices in 6.62% of the cases. The majority of the SALs were located at a vertical distance from the MC that was more than 2 mm. Men and women exhibited significant differences in both the horizontal distance from the MF to the SALs of the first premolars and the vertical distance from the MC to the SALs of the second premolars.
Conclusions:
To improve the success of endodontic microsurgery, adequate knowledge of the anatomic relationships between the location of the MF and MC and the SAL of the mandibular posterior teeth is indispensable to surgeons.
Objective:
To investigate the incidence of bifid mandibular canals (BMC), and analyze the types, courses, and anatomic features of the variant canals in the adult population in Sichuan Province.
Methods:
Five hundred patients (1 000 hemimandibles) underwent cone beam computed tomography (CBCT) were included in this study. The incidence, bifurcate types and courses of the BMC were evaluated.
Results:
The incidence of BMC was 13.8% (69/500) in the study, 9.2% in terms of total hemimandibles. The most frequently type was retromolar canals, followed by the dental and buccolingual type, meanwhile the lowest was the forward type. The mean diameter of the accessory canals was 0.90 mm and the mean length was 9.39 mm.
Conclusions:
CBCT used in this study has shown that the incidence of BMC assessed by CBCT was significantly higher than panoramic radiography. Furthermore, CBCT can depict the position, course, size and the branches of the mandibular canals.
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The mental foramen and mental nerve are clinically relevant structures both for surgical and nonsurgical interventions in dentistry. Although the mental foramen is usually visible on conventional periapical or panoramic radiographs and can easily be located after flap elevation in the mandibular premolar areas, caution must be exercised to avoid damage to the mental nerve. Anatomical and neurovascular features of the mental foramen are presented in detail in this chapter.
A multidimensional image navigation and display software was designed for display and interpretation of large sets of multidimensional and multimodality images such as combined PET-CT studies. The software is developed in Objective-C on a Macintosh platform under the MacOS X operating system using the GNUstep development environment. It also benefits from the extremely fast and optimized 3D graphic capabilities of the OpenGL graphic standard widely used for computer games optimized for taking advantage of any hardware graphic accelerator boards available. In the design of the software special attention was given to adapt the user interface to the specific and complex tasks of navigating through large sets of image data. An interactive jog-wheel device widely used in the video and movie industry was implemented to allow users to navigate in the different dimensions of an image set much faster than with a traditional mouse or on-screen cursors and sliders. The program can easily be adapted for very specific tasks that require a limited number of functions, by adding and removing tools from the program's toolbar and avoiding an overwhelming number of unnecessary tools and functions. The processing and image rendering tools of the software are based on the open-source libraries ITK and VTK. This ensures that all new developments in image processing that could emerge from other academic institutions using these libraries can be directly ported to the OsiriX program. OsiriX is provided free of charge under the GNU open-source licensing agreement at http://homepage.mac.com/rossetantoine/osirix.
The location and configuration of the mandibular canal are important in surgical procedures involving the mandible. Previously,
we reported that bifid mandibular canals could be classified into four types: retromolar, dental, forward, and bucco-lingual
canals, using cone-beam computed tomography (CBCT). Herein we report three Japanese patients with a bony canal in the mandibular
ramus, which was independent of the mandibular canal, using CBCT images. A CBCT unit with a flat panel detector and exposure
volume of 102mm in diameter and 102mm in height was used. Two-dimensional (2D) and three-dimensional (3D) images in the
mandibular ramus region were reconstructed using 3D visualization and measurement software packages. Three bony canals in
two patients were considered to correspond to a temporal crest canal, which was raised from the mandibular notch, and reached
the antero-inferior region of the coronoid process. One bony canal in one patient, ran bucco-lingually in the mandibular ramus.
It is important for variations in the mandibular and bony canals to be carefully observed, by use of CBCT images, in surgical
procedures involving the mandible.
KeywordsMandibular canal-Temporal crest canal-Retromolar foramen-Mandibular ramus-Cone-beam computed tomography
The most common diagnostic imaging modalities for cross-sectional imaging in dental implant planning are currently cone-beam computed tomography (CBCT) and multislice CT (MSCT). However, clinical differences between CBCT and MSCT in this task have not been fully clarified. In this investigation, the detection of fine anatomical structures in the mandible was assessed and compared between CBCT and MSCT images.
The sample consisted of 28 patients who had undergone CBCT and MSCT. The bifid mandibular canal in the mandibular ramus, accessory mental and buccal foramina, and median and lateral lingual bony canals were observed in 2-D images, and the findings were compared between CBCT and MSCT.
Four of 19 canals observed in CBCT were not observed in MSCT images. Three accessory mental foramina in 2 patients and 28 lateral lingual bony canals in 18 patients were observed consistently using the two methods.
Depiction of fine anatomic features in the mandible associated with neurovascular structures is consistent between CBCT and MSCT images.
The location and course of the mandibular canal and multiple mental foramina are important in dental implant insertion and any surgical procedures involving the mandible. The purpose of the present investigation was to assess buccal foramen presence in the mandible using cone-beam computed tomography (CBCT) images.
A total of 84 patients were enrolled in this investigation. Buccal foramen presence in the mandibular body, which was defined as a buccal bone defect of the bony canal penetrating through the buccal cortical bone, was assessed using two- and three-dimensional CBCT images.
Buccal foramen presence, located from the median to molar regions, was observed in 44% of patients. There was no significant difference among gender and age. Also, a buccal foramen showing continuity with the mandibular canal was observed in 7.1% of patients.
Buccal foramen presence in the mandibular body could be assessed in detail using CBCT images.
Some variations of the mandibular canal (so-called bifid mandibular canal) have been reported using various radiography techniques; however, the occurrences of bifid mandibular canal were less than 1% according to panoramic radiographic surveys. The purpose of the present investigation was to clarify the rate and type of bifid mandibular canal in the mandibular ramus region, as observed using cone-beam computerized tomography (CBCT) images.
One hundred twenty-two patients who had undergone preoperative imaging of dental implant treatment using CBCT were enrolled in the investigation. Two-dimensional (2D) images of various planes in the mandibular ramus region were reconstructed on a computer using three-dimensional visualization and measurement software. The course of the mandibular canal was observed and the length of the bifid canal was measured.
Bifid mandibular canal in the mandibular ramus region was observed in 65% of patients and 43% of sides. Bifid mandibular canal can be classified into four types: retromolar, dental, forward, and buccolingual canals.
Bifid mandibular canal was observed at a high rate using CBCT.
Volumetric CT using a cone beam has been developed by several manufacturers for dentomaxillofacial imaging. The purpose of this study was to measure doses for implant planning with cone beam volumetric imaging (CBVI) in comparison with conventional multidetector CT (MDCT).
The two CBVI systems used were a 3D Accuitomo (J. Morita), including an image-intensifier type (II) and a flat-panel type (FPD), and a CB MercuRay (Hitachi). The 3D Accuitomo operated at 80 kV, 5 mA and 18 s. The CB MercuRay operated at 120 kV, 15 mA, 9.8 s. The MDCT used was a HiSpeed QX/i (GE), operated at 120 kV, 100 mA and 0.7 s, and its scan length was 77 mm for both jaws. Measurement of the absorbed tissue and organ doses was performed with an Alderson phantom, embedding the radiophotoluminescence glass dosemeter into the organs/tissues. The values obtained were converted into the absorbed dose. The effective dose as defined by the International Commission on Radiological Protection was then calculated.
The absorbed doses of the 3D Accuitomo of the organs in the primary beam ranged from 1-5 mGy, and were several to ten times lower than other doses. The effective dose of the 3D Accuitomo ranged from 18 muSv to 66 muSv, and was an order of magnitude smaller than the others. In conclusion, these results show that the dose in the 3D Accuitomo is lower than the CB MercuRay and much less than MDCT.
The purpose of the present study was to assess the accessory mental foramen using cone-beam computed tomography (CBCT) images.
A total of 157 patients were enrolled in this investigation. The mental and accessory mental foramina, which show continuity with the mandibular canal, were assessed using axial and cross-sectional, 2-dimensional CBCT images. The sizes of the mental and accessory mental foramina were measured and statistically analyzed. Also, the distance between the mental and accessory mental foramina was measured.
The accessory mental foramen was observed in 7% of patients. There was no significant difference regarding the sizes of the mental foramen between accessory mental foramen presence and absence. Also, the mean distance between the mental and accessory mental foramina was 6.3 mm (SD: 1.5 mm).
The accessory mental foramen, which shows continuity with the mandibular canal, could be observed in 7% of the subjects using CBCT.
We examined the range of the accessory mental foramen [AMF] and its accessory mental nerve in three Japanese cadavers. The diameters of the AMF were relatively small: 0.74 mm, 0.80 mm and 0.89 mm. The distances between the mental foramen and AMF were: 0.67 mm, 2.1 mm and 5.74 mm. The distribution of the accessory mental nerve was different in the three cases. These nerves communicated with the branches of the facial and buccal nerves.
A child's mandible retrieved from a North American archaeological site had an anomalous canal 2 mm in diameter and 10 mm long, opening posteriorly behind the temporal crest and anteriorly in the retromolar fossa. Radiographic analysis revealed a second canal passing down from the temporal crest canal (TCC) toward the molar roots. A survey of retromolar variants in a large skeletal series (N2391) revealed TCC present in 1.7% of all persons on average, ranging up to 23% in certain population samples. It appeared to be more common in males than in females and in native Americans than in other racial groups. From its location and orientation, TCC was inferred to have conveyed all or part of the buccal nerve. The clinical significance of this variant is that pain fibers from the molar roots joining the nerve as it runs in this canal would exit the bone behind the temporal crest, thus escaping anesthetization in routine injections for inferior alveolar and buccal nerve block.
The purpose of this study was to identify and classify specific anatomic variations of the mandibular canal for which we have suggested the term "bifid mandibular canals." A total of 6,000 panoramic radiographs were studied, and those that contained these canals were identified. A classification of bifid mandibular canals was developed from this material. In addition, as the different variations of these bifid mandibular canals may present a number of problems in clinical practice, some solutions to these problems are presented. In our sample, there were 57 bifid mandibular canals, an incidence of 0.95%. These results suggest that the presence of bifid mandibular canals is not a rare finding. If panoramic equipment is not available, the lateral jaw view may be taken to study the mandible for the anesthetic, surgical, and prosthetic problems.
Failure to achieve complete mandibular anesthesia is a problem that often occurs. The explanations include faulty anesthetic solutions, faulty technique, and anatomic or physiologic variations. Bifurcation of the mandibular nerve, rarely mentioned in the literature, may be a cause of inadequate anesthesia in a small percentage of cases.
The large bilateral mandibular retromolar canals were found in a 47-year-old Japanese man. This paper presents the nature and distribution of the elements of nerves and arteries in the left retromolar canal which were able to examined. The left mandibular retromolar canal arose from the bifurcation of the mandibular canal at 18 mm anterior to the mandibular foramen and it opened on the surface of the retromolar fossa at 13 mm posterior to the third mandibular molar. The total length of the retromolar canal from the bifurcation to the retromolar foramen was about 16 mm, and 2.5-2.6 mm in diameter. The radiographic image of this retromolar canal was a liner shadow with thin radiopaque anterior and posterior borders cast on a lateral radiography of the left half of the head. Within the retromolar canal, the artery that was branched from the inferior alveolar artery ran through the canal forwards and joined with the branches of the buccal artery and the facial artery, and then gave off the superior and inferior labial arteries. The nerve (R. retromolaris) in the retromolar canal derived from the inferior alveolar nerve trunk and branched off to the following areas: the third mandibular molar, the mucosa of retromolar triangle, the buccal mucosa, and the buccal gingiva of the mandibular premolar and molar region. The retromolar canals and foramina were found in 8 out of 41 Japanese skulls. Clinically, if the arteries in the retromolar canal become injured, complications may arise such as bleeding, and iatrogenic nerve damage may lead to paralysis.(ABSTRACT TRUNCATED AT 250 WORDS)
This concludes a series of descriptive statistical reports on discrete cranial traits in 81 human populations from around the world. Four variants classified as vessel and nerve related characters were investigated: patent condylar canal, supraorbital foramen; accessory infraorbital foramen; and accessory mental foramen. A significant asymmetric occurrence without any side preference was detected for the accessory mental foramen. Significant intertrait associations were found between the accessory infraorbital and supraorbital foramina in the panPacific region and Subsaharan African samples. The intertrait associations between the accessory infraorbital foramen and some traits classified as hypostotic were found mainly in the samples from the western part of the Old World, and those as hyperostotic traits in the samples from eastern Asian and the related population samples. With a few exceptions. the occurrence of a patent condylar canal and a supraorbital foramen was predominant in females, but the accessory infraorbital and accessory mental foramina were predominant in males. The frequency distributions of the traits showed interregional clinality and intraregional discontinuity. A temporal trend was found in the Northeast Asian region in the frequencies of the accessory infraorbital and accessory mental foramina. The diversity of modern human discrete cranial traits may at least in part be attributable to differential retention or intensification from an ancestral pattern.
To determine the incidence and characteristics of bifid mandibular canals.
A retrospective study was performed using panoramic radiographs of 2012 patients subjected to dental treatment in the Dental Clinic of the Valencia University Dental School (Valencia, Spain) between 1996 and 1999. The goal was to investigate the presence of double mandibular canals.
The extraoral panoramic radiographs revealed a total of 7 images suggestive of bifid canals. Mandibular computed tomography revealed the existence of this anatomic variant in 2 of 3 patients. An analysis was performed on the incidence of this type of image in extraoral panoramic radiography, its possible interpretations, and the clinical implications of bifid mandibular canals.
In this study, 0.35% of canals were bifid. All cases were in women.
The anterior mandible is generally considered a rather safe surgical area, involving few risks of damage to vital anatomic structures. Nevertheless, both neurosensory disturbances and hemorrhages have been reported after implant surgery in that particular area.
With the increasing demand for oral implant placement, the anatomy of the anterior mandible should receive more attention. This review will focus on the anatomic peculiarities of the anterior mandible and the related clinical implications.
The scientific evidence on the anatomic, histologic, physiologic, and clinical aspects of the neurovascularization of the anterior mandible will be reviewed.
Surgical complications may be attributed to the existence of a mandibular incisive canal with a true neurovascular supply. Potential risks may also be related to the presence of the lingual foramen and anatomic variations, such as an anterior looping of the mental nerve.
Preoperative radiographic planning for oral implant placement in the anterior mandible should therefore not only consider all esthetic and functional demands but should also pay particular attention to the anatomic peculiarities of this region to avoid any neurovascular complications.
The location and configuration of mandibular canal variations are important in surgical procedures involving the mandible, such as extraction of an impacted third molar, dental implant treatment, and sagittal split ramus osteotomy. We report 3 Japanese patients with bifid mandibular canals using panoramic radiograph and multi-slice helical computed tomography (CT) images. In 2 of the 5 sides, the bifid mandibular canal was suggested on panoramic radiograph. The bifid mandibular canal had a short and narrow upper canal toward the distal area of the second molar in 4 sides, and a short and narrow lower canal toward the distal area of second molar in 1 side, as revealed on reconstructed CT images. Since the location and configuration of mandibular canal variations are important in surgical procedures involving the mandible, they should be carefully observed using reconstructed CT images.
Observation of bifid mandibular canal using cone-beam computed tomography. The International Jour-nal of Oral & Maxillofacial Implants
- M Naitoh
- Y Hiraiwa
- H Aimiya
- E Ariji
Naitoh, M., Hiraiwa, Y., Aimiya, H. & Ariji, E. (2009a) Observation of bifid mandibular canal using cone-beam computed tomography. The International Jour-nal of Oral & Maxillofacial Implants 24: 155–159.
Temporal crest canal
- Ossenberg