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Modified Lind method. i:incisal (occlusal in premolar and molar teeth) level, a: apical level, Rt: root height, Cr h :
Source publication
Statement of the Problem: Determining the crown-root ratio is crucial in many dental clinical decisions. There are no reliable data presented for Iranian population.
Purpose: The aim of this study was to assess the root-crown ratio of permanent teeth with regards to the relationship of gender and jaw type using panoramic radiographs. The reliabili...
Contexts in source publication
Context 1
... the cemento-enamel junction (CEJ) level is not clearly visible on panoramic radiographs for measuring the crown height and root length of each tooth, modified Lind technique was adopted to determine the midpoint of crown and root, therefore, the length of each tooth could be measured accurately. [4] Based on this technique, the midpoint of a straight line that connects the points of intersection between the outer contours of root and crown was se- lected as point M (Figure 1). In addition, an occlusal reference line for incisors or molars was placed to follow the incisal edge or to connect the buccal cusps. ...
Context 2
... The present study revealed that panoramic radiog- raphy was reproducible and reliable in determining root length. The intra-observer reproducibility and the inter- observer reproducibility, as shown in Figure 1 and 2, were neither scale nor observer dependent and no sub- stantial outliers were presented. These reassure the reli- ability of the method. ...
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Due the importance of diagnosis precocious of osteoporosis, this study carried out the comparison of two conventional radiological methods for the evaluation of bone density in postmenopausal women. X-ray images of panoramic and carpal were selected, corresponding to 68 women between 49 and 80 years old, obtained at the Clinic of Dental Radiology,...
Citations
... In the Malay population, R/C ratios for males and females were similar but were significantly different to that of the antagonist teeth [14]. The range of R/C ratios in the Korean population also was found to vary between males and females, [15] while in the Iranian population, the R/C ratios were similar [16]. These studies show that while there may be less variations between males and females, the variations in R/C ratio may vary within the arch and between a single type or group of teeth. ...
... In the current study, the means R/C ratios varied from 1.59 to 2, which was higher than the result reported among the Korean population, which varied from 1.29 to 1.89 [15]. However, the result of the current study was less than the result reported among White, Malay, and Iranian populations [11,14,16] ...
Background
The ratio between a tooth root and its crown is an essential diagnostic parameter that determines treatment options. This radiographic study used panoramic dental radiographs or orthopantograms to measure the mean root (R)-to-crown (C) ratios (R/C) of the permanent teeth in 81 Saudi adults.
Material/Methods
A total of 81 panoramic radiographs of Saudi adult patients (40 males and 41 females) previously treated in the College of Dentistry, Saudi Arabia, aged 16–35 years, were selected. The crown height and root length for each tooth were measured on the digital panoramic radiographs. The correlation coefficient (intra-class) was calculated to assess the intra-examiner reproducibility and a good agreement was achieved (ICC=0.79–0.89).
Results
For both males and females, the highest mean R/C ratio was for maxillary canine (1.91) and for mandibular second premolar (2.0) while the lowest R/C ratio was for maxillary first molar (1.64) and for mandibular central incisor (1.59). Except for the maxillary second premolar, no significant differences in R/C ratios were observed for maxillary arch. In the mandibular arch, the R/C ratio for lateral incisor, both premolars, and molars differed significantly (P<0.05). Among males, statistically significant differences between teeth existed in R/C ratios for central and lateral incisors, second premolar, and both molars (P>0.05). For females, significant differences between teeth in R/C ratios were observed for both premolars and both molars (P>0.05).
Conclusions
This study supports the findings from previous studies that orthopantograms can be used to calculate root/crown ratios, which varies between males and females and the dental arch among Saudi adults.
... In the Malay population, R/C ratios for males and females were similar but were significantly different to that of the antagonist teeth [14]. The range of R/C ratios in the Korean population also was found to vary between males and females, [15] while in the Iranian population, the R/C ratios were similar [16]. These studies show that while there may be less variations between males and females, the variations in R/C ratio may vary within the arch and between a single type or group of teeth. ...
... In the current study, the means R/C ratios varied from 1.59 to 2, which was higher than the result reported among the Korean population, which varied from 1.29 to 1.89 [15]. However, the result of the current study was less than the result reported among White, Malay, and Iranian populations [11,14,16] ...
Background: The ratio between a tooth root and its crown is an essential diagnostic parameter that determines treatment options. This radiographic study used panoramic dental radiographs or orthopantograms to measure the mean root (R)-to-crown (C) ratios (R/C) of the permanent teeth in 81 Saudi adults. Material/Methods: A total of 81 panoramic radiographs of Saudi adult patients (40 males and 41 females) previously treated in the College of Dentistry, Saudi Arabia, aged 16-35 years, were selected. The crown height and root length for each tooth were measured on the digital panoramic radiographs. The correlation coefficient (intra-class) was calculated to assess the intra-examiner reproducibility and a good agreement was achieved (ICC=0.79-0.89). Results: For both males and females, the highest mean R/C ratio was for maxillary canine (1.91) and for mandibular second premolar (2.0) while the lowest R/C ratio was for maxillary first molar (1.64) and for mandibular central incisor (1.59). Except for the maxillary second premolar, no significant differences in R/C ratios were observed for maxillary arch. In the mandibular arch, the R/C ratio for lateral incisor, both premolars, and molars differed significantly (P<0.05). Among males, statistically significant differences between teeth existed in R/C ratios for central and lateral incisors, second premolar, and both molars (P>0.05). For females, significant differences between teeth in R/C ratios were observed for both premolars and both molars (P>0.05). Conclusions: This study supports the findings from previous studies that orthopantograms can be used to calculate root/crown ratios, which varies between males and females and the dental arch among Saudi adults.
... In the Malay population, R/C ratios for males and females were similar but were significantly different to that of the antagonist teeth [14]. The range of R/C ratios in the Korean population also was found to vary between males and females, [15] while in the Iranian population, the R/C ratios were similar [16]. These studies show that while there may be less variations between males and females, the variations in R/C ratio may vary within the arch and between a single type or group of teeth. ...
... In the current study, the means R/C ratios varied from 1.59 to 2, which was higher than the result reported among the Korean population, which varied from 1.29 to 1.89 [15]. However, the result of the current study was less than the result reported among White, Malay, and Iranian populations [11,14,16] ...
Background: The ratio between a tooth root and its crown is an essential diagnostic parameter that determines treatment options. This radiographic study used panoramic dental radiographs or orthopantograms to measure the mean root (R)-to-crown (C) ratios (R/C) of the permanent teeth in 81 Saudi adults. Material/Methods: A total of 81 panoramic radiographs of Saudi adult patients (40 males and 41 females) previously treated in the College of Dentistry, Saudi Arabia, aged 16-35 years, were selected. The crown height and root length for each tooth were measured on the digital panoramic radiographs. The correlation coefficient (intra-class) was calculated to assess the intra-examiner reproducibility and a good agreement was achieved (ICC=0.79-0.89). Results: For both males and females, the highest mean R/C ratio was for maxillary canine (1.91) and for mandibular second premolar (2.0) while the lowest R/C ratio was for maxillary first molar (1.64) and for mandibular central incisor (1.59). Except for the maxillary second premolar, no significant differences in R/C ratios were observed for maxillary arch. In the mandibular arch, the R/C ratio for lateral incisor, both premolars, and molars differed significantly (P<0.05). Among males, statistically significant differences between teeth existed in R/C ratios for central and lateral incisors, second premolar, and both molars (P>0.05). For females, significant differences between teeth in R/C ratios were observed for both premolars and both molars (P>0.05). Conclusions: This study supports the findings from previous studies that orthopantograms can be used to calculate root/crown ratios, which varies between males and females and the dental arch among Saudi adults.
... A gyermekfogászatban a gyökér-korona hányados ismeretében a fogfejlődési anomáliákat el tudjuk különíteni a normálvariációktól [1]. A fogszabályozásban a kezelési terv elkészítéséhez kell ismernünk a gyökér-korona arányokat [2][3][4]: a horgonylat elemzéséhez, valamint a kezelés közben alkalmazott fogszabályozási erőrendszerek tervezéséhez [1], majd a kezelés közben előforduló apicalis gyökérreszorpció meghatározása céljából értékeljük ezt a paramétert [5][6][7]. ...
Összefoglaló. Bevezetés: A maradó fogak gyökér-korona arányának meghatározása nagy jelentőséggel bír a fogászati kezelési terv kialakításában és későbbi módosításában. Célkitűzés: Egészséges magyar, német és japán fiatalok maradó fogai gyökér-korona arányának meghatározása és összehasonlítása. Módszer: Hölttä módszerét alkalmaztuk. A mérés 95 magyar, 104 japán és 110 német fiatal páciens 2001 és 2006 között készült panorámaröntgen-felvételén történt. Eredmények: A gyökér-korona arány különbsége a nemek között nem szignifikáns, az egymásnak megfelelő antagonista fogak között sok esetben, de nem mindig, szignifikáns. A legnagyobb gyökér-korona arányt mindhárom populációban az alsó szemfogakon és az alsó második praemolaris fogakon mértük; a felső molarisok esetén a legkisebb az arány. A három nemzetet összehasonlítva szignifikáns különbséget (p≤0,001) nem találtunk egyetlen fogtípus esetében sem. A japán és a német populáció között minden fogtípus esetén szignifikáns volt a különbség a gyökér-korona arányokban. A japán és a magyar populáció összehasonlításakor a fogtípusok felénél találtunk szignifikáns különbséget. A magyar és a német populációt összehasonlítva nagyon kevés fogtípusnál találtunk szignifikáns különbséget. Megbeszélés: Az alsó állcsont fogainak gyökér-korona arányértékei nagyobb mértékben térnek el a populációk között, mint a felső állcsont fogainak esetében. A gyökér-korona arány átlagértéke a német populációban a legnagyobb. A második legnagyobb arányértékkel a magyar populáció rendelkezik, utána pedig a japán, néhány fogtípus kivételével: felső kismetszők, felső szemfogak és felső első molarisok. Következtetés: A legnagyobb gyökér-korona arány különbséget a német és a japán populáció között, a legkisebbet a magyar és a német populáció között találtuk. Cikkünk megmutatja az egyes fogtípusok gyökér-korona arányának normálértékét fiatal, egészséges magyar, német és japán populációban. Orv Hetil. 2021; 162(46): 1848-1855.
Summary:
Introduction:
Defining the root-crown ratio of the permanent teeth is important in making or changing proper treatment plans in dentistry.
Objective:
To define and compare the root-crown ratios of the permanent teeth of healthy, young Hungarian, German, and Japanese populations.
Method:
We adapted Hölttä's method. 95 Hungarian, 104 Japanese and 110 German young patients' panoramic X-rays (made between 2001 and 2006) were involved in the investigation.
Results:
Difference between the genders was found non-significant; between the corresponding antagonists many times, but not all significant. The highest root-crown ratios were found in all investigated populations by the lower canines and premolars, the lowest by the upper molars. P≤0,001 was not found among the three populations. Significant differences were found between Japanese and German populations by all tooth-types; between Japanese and Hungarian populations by near half of the tooth-types; between Hungarian and German populations by only a few tooth-types.
Discussion:
More significant differences were found in root-crown ratios in the lower jaw among the populations. The mean value of the root-crown ratios was the highest in the German population; medium in the Hungarian population; and the least in the Japanese population, with a few exceptions: upper lateral incisors, canines and first molars.
Conclusion:
The biggest differences were found between the German and Japanese populations; the least between the Hungarian and the German populations. Our paper describes the control values of the root-crown ratios of the tooth types in young, healthy Hungarian, German, and Japanese populations. Orv Hetil. 2021; 162(46): 1848-1855.
... In radiographic studies, it is better to measure the Root-Crown ratio rather than the absolute linear measurements as the values remain stable with cants in antero-posterior and vertical dimensions upto some extent. Furthermore, the R/C values as measured on OPGs are not affected by the different angulations or magnifications of different X-Ray machines, providing with a distinct advantage [9]. ...
... To date, various studies measuring the R/C values in the non-orthodontic sample have been conducted to establish normal baseline R/C values for particular ethnic background [8][9][10][11][12]. But R/C ratio has not been used as a tool to measure root resorption after orthodontic treatment on OPGs. ...
... For maxillary molars, the R/C ratio was 1.78 and it was 2.33 for mandibular molars. The comparison with the mean R/C ratio reported in the previous studies [9][10][11] shows wide variation depending on the ethnicity. The mean R/C crown ratio found in the study in Indian Population was different from those reported in Finnish and Korean populations, though the values of this study were closer to Korean population [11] as compared to the Finnish population [10]. ...
Purpose: External Apical Root Resorption (EARR) is an undesirable but unavoidable side effect of orthodontic treatment. The various methods proposed for its evaluation, e.g. Intraoral Periapical (IOPA) X-ray and Orthopantomogram (OPG) x-rays use linear measurements which have errors due to magnification and angulations of x-rays. Root-crown ratio as measured on digital OPGs, which are essential diagnostic records for all orthodontic patients were used for the first time to assess root resorption.
Methods: A two-step method was used, first to check the v alidation of OPG measurement with IOPA x rays. The first step involved the measurement of Root-crown ratio on digital OPG and IOPA by 5 independent examiners on IC measure software. The second step involved the measurement of root resorption as Root-crown ratio on pretreatment and post-treatment OPG X rays of 32 treated orthodontic patients all of which were treated by a single orthodontist. Digital OPG images of all patients were traced in Picassa software. In both steps, root-crown ratio was assessed by modified Lind method.
Results: The results of first step did not show any significant differences in examiners to read the IOPA and OPG x rays. The results of the second step showed 11.8% root resorption in maxillary central incisors and 4% root resorption in lateral incisors. Similarly, maxillary and mandibular molars showed 1.6% and 5.1% resorption, respectively. The resorption in mandibular molars was significantly more compared to pretreatment value. There was apparently no effect of extraction treatment or treatment time on the amount of resorption.
Conclusion: The study concluded that root-crown ratio can be used as an effective and efficient alternative method to quantify root resorption on OPG X rays and possibly alleviate the need for taking IOPA x rays in orthodontic patients thereby reducing the radiation exposure.
... Earlier studies have successfully used panoramic radiographs to assess the R/C ratios of permanent dentition in Finnish, Korean and Iranian populations. [13][14][15] However, reference values are not available for all ethnic groups and no comparisons of the R/C ratios have been made among different ethnicities. ...
... Radiographic measurements of dental hard tissues are typically evaluated from panoramic, periapical, or Cone Beam Computed Tomography (CBCT) images. 13,17 Most studies of the R/C ratios use panoramic radiographs, which are relatively inexpensive, accessible, and a part of most new patient exams. [13][14][15]18 Although panoramic radiographs may have some limitations in terms of the accuracy of measurements compared with CBCT, they provide adequate information and are more practical for the assessment of changes in large number of teeth without additional exposure to radiation 18 . ...
... 13,17 Most studies of the R/C ratios use panoramic radiographs, which are relatively inexpensive, accessible, and a part of most new patient exams. [13][14][15]18 Although panoramic radiographs may have some limitations in terms of the accuracy of measurements compared with CBCT, they provide adequate information and are more practical for the assessment of changes in large number of teeth without additional exposure to radiation 18 . While the F I G U R E 2 Method used to measure the root and crown lengths. ...
Objective
Root resorption due to orthodontic tooth movement may adversely affect the root‐crown (R/C) ratios of permanent teeth, especially in patients with Short Root Anomaly (SRA), a poorly understood disorder affecting root development. Evaluation of SRA R/C ratios to normal dentition would facilitate diagnosis and orthodontic treatment planning. However, reference values are not available for all ethnicities. Our goal was to determine R/C ratios of permanent teeth and their relationship to gender and ethnicity.
Setting/Sample
A retrospective study of 333 patients (109 Caucasians, 112 African Americans and 112 Hispanics) from the University X School of Dentistry.
Materials/Methods
Root lengths and crown heights were measured from panoramic radiographs of 6,241 teeth using modified Lind's method. A linear mixed model was used to compare the R/C ratios of teeth among subgroups (gender, ethnicity).
Results
The mean R/C ratios varied from 1.80‐2.21 for the maxillary teeth and 1.83‐2.49 for the mandibular teeth. Gender differences in R/C ratios were found to be significant only for the lower central incisors (P<0.05). Hispanics showed significantly lower ratios for most teeth compared to the other two groups (P<0.05). There were significant differences in R/C ratios between African Americans and Caucasians in the upper lateral incisors, lower central incisors and lower first premolars (P<0.05).
Conclusion
Our results suggest that ethnicity is an important factor in determining the R/C ratios of permanent teeth. Therefore, when diagnosing developmental conditions such as SRA, ethnic group‐specific reference values should be considered.
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... The root-to-crown ratio is the ratio of the length of the root to the length of the crown. After normal tooth development extrinsic factors like external root resorption or dental trauma can cause reduction of the root length [14,15]. However, disturbances of root development can be due to both genetic and extrinsic factors [14,15]. ...
... After normal tooth development extrinsic factors like external root resorption or dental trauma can cause reduction of the root length [14,15]. However, disturbances of root development can be due to both genetic and extrinsic factors [14,15]. Because root development follows crown development, disturbances of the root development will more frequently be found in patients treated at an older age [5,8,13]. ...
... The cutoff for measurements was .5 mm. To counteract any vertical deformation, the modified Lind method was used ( Figure 2) [14,15,23]. Both researchers measured each tooth independently. ...
... The root-to-crown ratio is the ratio of the length of the root to the length of the crown. After normal tooth development extrinsic factors like external root resorption or dental trauma can cause reduction of the root length [14,15]. However, disturbances of root development can be due to both genetic and extrinsic factors [14,15]. ...
... After normal tooth development extrinsic factors like external root resorption or dental trauma can cause reduction of the root length [14,15]. However, disturbances of root development can be due to both genetic and extrinsic factors [14,15]. Because root development follows crown development, disturbances of the root development will more frequently be found in patients treated at an older age [5,8,13]. ...
... The cutoff for measurements was .5 mm. To counteract any vertical deformation, the modified Lind method was used ( Figure 2) [14,15,23]. Both researchers measured each tooth independently. ...
To investigate dental development in patients treated with a hematopoietic stem cell transplantation (HSCT), 42 children/young adults who were under 12 years old at time of HSCT were examined for dental agenesis, microdontia and root-crown ratio. Conditioning regimens were total body irradiation (TBI) based in 12 patients, 21 patients received a busulfan based regimen and 9 patients had other chemotherapeutic agents. Sixteen patients were < 3 years old, 9 patients were 3 - 6 years old and 17 patients were 6-12 years old at HSCT. Prevalence of agenesis and microdontia of at least one permanent tooth were respectively 51.3% and 46.2% in the study population and 76.3% had an aberrant root-crown ratio. All these results were highly different from the prevalence in the healthy population. Patients treated before 3 years of age had more microdontia (76.9%) and agenesis (92.3%) compared to patients treated at an older age. In the subgroup of patients treated after 6 years, there was more microdontia when treated with busulfan (50%) compared to treatment with TBI (0%) (P = 0.044).
Conclusion:
patients treated with HSCT had many disturbances in dental development. Age at HSCT and possibly also the conditioning regimen used had an effect on their type and prevalence. Dental follow-up should be incorporated in the multidisciplinary follow-up program of these patients.
... Literature has a surplus mention of studies that have calculated the crown and root lengths of teeth by taking the mean and standard deviation [10,11] but none of these studies have analyzed and compared the ratio among root length and crown length on a single tooth. Since, mean values of root length and crown length are given separately, it was not possible to calculate golden ratio on previously published data and hence comparison with the previous literature was not possible. ...
Aim:
The aim of this study is to find out whether tooth length (crown length + root length) follows the rule of most divine and mysterious phi (ϕ) or the golden ratio.
Methods:
A total of 140 teeth were included in the study. The crown-root ratio was manually calculated using vernier caliper and its approximation to golden ratio or the divine number phi (ϕ) was examined.
Results:
The average root-crown ratio (R/C) for maxillary central incisor was 1.627 ± 0.04, and of its antagonist, mandibular central incisor was 1.628 ± 0.02. The tooth-root ratio (T/R) for the same was 1.609 ± 0.016 and 1.61 ± 0.008, respectively. Similar values were appreciated for lateral incisors where the R/C ratio in the maxillary and mandibular teeth was 1.632 ± 0.015 and 1.641 ± 0.012 and the T/R ratio was 1.606 ± 0.005 and 1.605 ± 0.005, respectively.
Conclusion:
On measuring the tooth length in linear fashion from the cusp tip to the root apex, we found that the tooth was divided into two parts at the cemento-enamel junction in the golden ratio. This information can be exploited in restorative and implant dentistry in future.
... [10]. On the other hand, the R/C ratio of this study was significantly less than the R/C ratio reported by other studies [9,11]. In the Finnish population, Holtta et al. had found the R/C ratio of unrestored dentition to be in the range of 2.11-2.17 ...
... Similarly, Haghanifar et al. had found that the R/C ratio of Iranian population to range from 1.78-2.46 [11]. ...
... Comparison of R/C ratio values by tooth type found premolars exhibited significantly greater R/C ratios than incisors and molars. In general, this corresponds to the reported anatomical R/C ratio of natural teeth, where the premolars R/C ratio was greater than the R/C ratio of the other teeth [9,11]. Likewise, another investigation that had measured the clinical R/C ratio found the premolars R/C ratio exhibited a similar range to what has been reported in this study [10]. ...
