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Impaction and an abnormal eruption of a second molar occur because of a lack of retromolar space, premature eruption of the mandibular third molar, and ankyloses. The prognosis must be carefully considered when extracting a damaged permanent tooth. In addition to extraction for orthodontics, this enables the establishment of an effective force syst...
Context in source publication
Context 1
... maxillary and mandibular incisors were lingually inclined (SN-U1, 97.8 ; IMPA, 79.5 ) (Table). Root resorption was suspected on the distal surface of the mandibular first molars and maxillary left lateral incisor; thus, confirmatory cone-beam computed tomography (CBCT) images were taken (Fig 4). CBCT showed severe external root resorption of the maxillary left lateral incisor. ...
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Purpose:
Prior to cone-beam computed tomography (CBCT), orthodontic competence included radiological interpretation. Nevertheless, maxillary impacted canines (MICs), because of their position and adjacent complex anatomy, have been challenging to interpret, particularly with regard to root resorption. Although CBCT cross-sectional reconstructions...
Citations
... [11][12][13] However, some researchers argue that the position of the MdM3 above the MdM2 can obstruct the eruption pathway of the MdM2, and indicate the extraction of the MdM3. 14,15 Three months after extracting the MdM3s in the present case ( Figure 2B, Figure 4B), an unexpected effect was observed. The crowns of the bilateral MdM2s drifted upwards, indicating that the MdM2s could erupt. ...
Surgery combined with orthodontic uprighting of impacted mandibular second molars requires sequential treatment procedures. This article presents a rare case of horizontally impacted bilateral mandibular second molars accompanied by dental crowding. The patient’s mandibular second molars were fully embedded in bone with overlying mesially-impacted mandibular third molars and the mandibular first molars were inclined distally. The treatment involved staged bilateral extraction of the second premolars and mandibular third molars, followed by the surgical implantation of micro-implants for anchorage in the mandibular ramus. At a subsequent stage, the mandibular second molars were successfully orthodontically uprighted, leading to a favourable treatment outcome.
... However according to case studies, the average uprighting treatment time ranged from 2 weeks to 15 months. 7,21,28,29 Angle Orthodontist, Vol 00, No 0, 0000 ...
Objectives: To evaluate and compare the efficiency of orthodontic treatment and surgical uprighting of first and second mandibular molars.
Materials and Methods:
An electronic literature search in PubMed, Science Direct, Embase, Scopus, Web of Science, Cochrane Library, LILACS, and Google Scholar, as well as a hand search was conducted by two independent researchers to identify relevant articles up to January 2022. In addition, a manual search was done that included article reference lists, grey literature, and dissertations. The risk of bias of the included prospective and retrospective studies was assessed with the Risk Of Bias Tool In Non-randomized Studies of Interventions (ROBINS-I) assessment tool.
Results:
A total of six nonrandomized clinical trials (non-RCT) evaluating the efficiency of mandibular molar orthodontic and/or surgical uprighting were included. The quality analysis showed certain defects of the Non-RCTs included and, according to the criteria used, the majority of the articles were judged to be of moderate quality.
Conclusions:
Based on the evidence, orthodontic and surgical uprighting appear to be effective treatment methods for mandibular molars. Surgical uprighting may be associated with more complications than orthodontic uprighting. However, the existing literature on the subject is limited, heterogeneous, and methodologically limited. Therefore, the outcomes should be interpreted carefully.
... Consequently, the eruption space of MM2 was smaller in impacted groups. As some ndings [15,16] showed that early extraction of uneruped MM3 would lower the risk of the impacted MM2 and increase the eruption space of MM2. Furthermore, the incident pathology of MM2 such as distal caries and periodontal diseases could be avoided. ...
Objectives
To investigate the morphological differences of localized mandible between patients with impacted mandibular second molars (MM2) and non-impacted patients through mandibular measurements in three dimensions.
Materials and methods
The 222 subjects who underwent cone-beam computed tomography (CBCT) were included and divided into three groups. Group 1 (G1) comprised 64 patients with unilaterally impacted MM2, group 2 (G2) was composed of 54 patients with bilaterally impacted MM2, and group 3 (G3) was made up of 104 age- and sex-matched controls. 24 measurements were selected, including 21 linear measurements and 3 angular measurements.
Results
The width of mandibular first molar (MM1), the length and width of MM2, the angle between MM1 and MM2, the angle between MM2 and ascending mandibular ramus (MR) were higher in G1 and G2 than in G3 (P < 0.05). Also, the length of MM1 and MM2, the angle between MM1 and MM2 were statistically higher in the impacted side than in the non-impacted side for G1. There was positive correlation between impacted MM2 and the length, the width of MM2, the angle between MM2 and MR, but the length between MM1 and MR, the length of alveolar bone for eruption of MM2 had negative effects.
Conclusions
The crown of MM1 and MM2 were larger in the patient of impacted MM2. The eruption space of MM2 was insufficient, while the width of mandibular arch were not affected in impacted patients.
Clinical Relevance
Impacted mandibular second molars are more common in clinic.
... Consequently, the eruption space of MM2 was smaller in impacted groups. As some ndings [15,16] showed that early extraction of uneruped MM3 would lower the risk of the impacted MM2 and increase the eruption space of MM2. Furthermore, the incident pathology of MM2 such as distal caries and periodontal diseases could be avoided. ...
Objectives
To investigate the morphological differences of localized mandible between patients with impacted mandibular second molars (MM2) and non-impacted patients through mandibular measurements in three dimensions.
Materials and methods
The 222 subjects who underwent cone-beam computed tomography (CBCT) were included and divided into three groups. Group 1 (G1) comprised 64 patients with unilaterally impacted MM2, group 2 (G2) was composed of 54 patients with bilaterally impacted MM2, and group 3 (G3) was made up of 104 age- and sex-matched controls. 24 measurements were selected, including 21 linear measurements and 3 angular measurements.
Results
The width of mandibular first molar (MM1), the length and width of MM2, the angle between MM1 and MM2, the angle between MM2 and ascending mandibular ramus (MR) were higher in G1 and G2 than in G3 (P < 0.05). Also, the length of MM1 and MM2, the angle between MM1 and MM2 were statistically higher in the impacted side than in the non-impacted side for G1. There was positive correlation between impacted MM2 and the length, the width of MM2, the angle between MM2 and MR, but the length between MM1 and MR, the length of alveolar bone for eruption of MM2 had negative effects.
Conclusions
The crown of MM1 and MM2 were larger in the patient of impacted MM2. The eruption space of MM2 was insufficient, while the width of mandibular arch were not affected in impacted patients.
Clinical Relevance
Impacted mandibular second molars are more common in clinic.
... This approach is most indicated in an adolescent patient in whom the third molar is still developing distal to the impacted second molar. In an adult patient where the third molar may have erupted mesially and may be lying on top of the second molar, the extraction of the third molar or orthodontically uprighting it to provide access to the second molar, would be necessary [9,38,39,41,56]. ...
Mesially impacted mandibular second molars are a common occurrence in orthodontic practices, especially those using the lingual arch or lip bumper for alleviating anterior crowding. Horizontally impacted second molars, on the other hand, occur so infrequently that most practitioners have limited experience in treating such a patient. Because of this there is little consensus on the management of these cases. As opposed to vertically impacted molars that may be associated with ankylosis or other factors preventing eruption, the mesially angulated, horizontally impacted mandibular second molar usually has eruption potential, because its impaction is more commonly due to lack of space and/or abnormal eruption path. Hence, orthodontic uprighting shows the most promise and can commonly be done without extracting the third molar or surgically exposing the impacted second molar. Modern clinicians have at their disposal a myriad of biomechanical choices that can be used to successfully reposition these teeth and enable finishing with an optimal occlusion.
Purpose:
The authors have been using improved superelastic Nickel-Titanium alloy wire (ISW) to close and align extraction spaces simultaneously, instead of separately using rigid wires for closing extraction spaces and Ni-Ti alloy wires for leveling and aligning. ISW has a low stiffness, which makes it challenging to generate sufficient moments. This study aimed to demonstrate the forces and moments exerted on adjacent brackets using an orthodontic simulator (OSIM) attached to a high-precision 6-axis sensor.
Materials and methods:
In experiment 1, a 0.016 × 0.022-inch ISW, stainless steel (SS) wire, and β-titanium wires were ligatured into the two brackets. The 0.018 × 0.025-inch slot self-ligating brackets were bonded to two simulated teeth at the same height, and the experiment was conducted using the high-precision OSIM. The distance between the brackets was 10 mm, the V-bend angles of the installed wires were 10°, 20°, 30°, and 40°, and the apex position was set at the center of the bracket. In experiment 2, 6.0- and 9.0-mm long elastomeric chains were placed on the same brackets as in Experiment 1 to measure forces and moments. The distance between the brackets was increased by 1.0 mm from 6.0 to 15.0 mm. Both experiments were conducted in a 37 °C thermostatic chamber similar to the oral environment.
Results and discussion:
In experiment 1, we measured moments on both sides for all the wires. As the V-bend angle increased, the absolute values of the moments also increased. With a V-bend angle of 10°, there was a significant (p < 0.05) difference in the moment generated in the left and right brackets among the three wire types. In the ISW, -1.67 ± 0.38 N・mm was generated in the left bracket, while 0.38 ± 0.26 N・mm was generated in the right bracket at 10°. At 20°, -1.77 ± 0.69 N・mm was generated in the left bracket, while 2.37 ± 0.94 N・mm was generated in the right bracket. At 30°, -2.98 ± 0.49 N・mm was generated in the left bracket, while 3.25 ± 0.32 N・mm was generated in the right bracket. Moreover, at 40°, -3.96 ± 0.58 N・mm was generated in the left bracket, while 3.55 ± 0.53 N・mm was generated in the right bracket. Furthermore, in experiment 2, the moments increased in proportion to the increase in distance between the centers of the two brackets. Absolute values of the moments were approximately equal for the left and right brackets. The 6.0-mm elastomeric chain generated a minimum force of -0.09 ± 0.05 N in the left direction when the distance between brackets was 6.0 mm, while a maximum of 1.24 ± 0.3 N when the distance between brackets was 12 mm in the right bracket. In the left bracket, minimum and maximum forces of -0.09 ± 0.07 and 1.3 ± 0.4 N were generated in the right direction, respectively. The 9.0-mm elastomeric chain generated a minimum force of 0.03 ± 0.07 N in the left direction when the distance between brackets was 9.0 mm, while a maximum of 1.3 ± 0.1 N when the distance between brackets was 15 mm in the right bracket. In the left bracket, minimum and maximum forces of 0.05 ± 0.06 and 0.98 ± 0.2 N were generated in the right direction, respectively.
Conclusion:
Mechanical data of the ISW have been collected in the study, which was previously difficult to perform owing to the low stiffness of the wire. It is suggested that the ISW can provide sufficient moments with the addition of V-bends to close the space by bodily movement.
Impacted permanent tooth can occur on any tooth in the dental arch. The incidence of retention and impaction of the second molar lies between 0 and 2.3%. It is infrequently found in normal dental patients because most of the second molar impactions are asymptomatic. However, it is a common occurrence in orthodontic practice. The impacted second molar may provoke many pathologic disorders to the adjacent and opposite teeth, eventually malocclusions. There are many treatment modalities in facilitating the eruption of the second molar impaction. Early diagnosis and early treatment are crucial for the successful treatment of mandibular second molar impaction. This article presents an overview of various treatment modalities for an impacted second molar.
