• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.6
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• pp.505-511
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• 2011

Purpose: This study evaluated correlation and risk factors between position of the mandibular third molars and mandibular angle fractures using clinical and radiographic findings. Methods: Medical records and panoramic radiographs of 188 patients with mandibular fractures were retrospectively reviewed. The presence and position of the third molars were assessed for each patient and were related to the occurrence of mandibular angle fractures. Results: The incidence of mandibular angle fracture was found to be greater when a lower third molar was present, particularly at the occlusal plane positioned on the $2^{nd}$ molar occlusal surface (by Archer system) and the third molar is impacted in mandibular ramus (by Pell & Gregory system). Of the 192 sites with a lower third molar, 32 (16%) had an angle fracture. Of the 184 site without lower third molars, 16 (8%) had an angle fracture. Conclusion: This study confirmed an increased risk of angle fractures in the presence of a lower third molar as well as variable risk for angle fracture, depending on positioning of the third molar.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.5
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• pp.349-354
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• 2011

Introduction: Mandibular third molar extraction is one of the most common procedures performed in oral and maxillofacial surgery units. Although the overall complication rate is low with most complications being minor, mandibular third molar removal is so common that the population morbidity of complications might be significant. Therefore, efforts to limit intraoperative or postoperative complications might have a significant impact in terms of enhancing the patient outcome. The aims of this study were to identify the position and angulation associated complications after mandibular third molar extractions. Materials and Methods: This study surveyed 568 patients who had a mandibular third molar extracted, showed clinical complications and underwent a radiographic measurement of the available space, depth and spatial relationship. Results: The results obtained were as follows: 1. The complications were a dry socket, nerve injury, root rest, infection, bleeding, hamatoma, and adjacent teeth injury. 2. There were no significant differences between the complication and ramus relationship (available space) of the mandibular third molar. 3. There were no significant differences between the complications and depth of the mandibular third molar. 4. There were no significant differences between the complications and spatial relationship of the mandibular third molar. Conclusion: There were no significant differences in the complication rate, ramus relationship, depth and spatial relationship of the mandibular third molar. This suggests that the position and angulation of the mandibular third molar may not have an impact on the complications. The relationship between the position and angulation of the mandibular third molar, and complications deserves a further study using longitudinal data.

• Imaging Science in Dentistry
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• v.38 no.3
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• pp.163-167
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• 2008

Purpose : The purpose of this study is to evaluate the position of the mandibular canal in relation to the mandibular third molar by cone beam CT in cases showing a close relationship between the third molar and the mandibular canal on the panoramic radiograph. Materials and Methods : The panoramic images and cone beam CT scans of 87 impacted mandibular third molars in 60 patients were evaluated to assess the tooth relationship to the mandibular canal. The clearness of the canal wall and the vertical depth of the lower third molar were evaluated on panoramic radiographs. The lower third molars were assessed using cone beam CT to determine the proximity and position of the canal relative to the roots. Results : In the 66 cases where the canal wall was unclear on the panoramic radiographs, 58 (87.9%) of the third molars had contact between the canal and root; 34 (51.5%) canals were showed an inferior position and 22 (33.3%) showed a linguoinferior position on cone beam CT. Conclusion : Interruption of the canal wall on panoramic radiographs was highly predictive of contact between the mandibular canal and the third molar. Cross sectional CT may be indicated for localization of the mandibular canal in such cases.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.48 no.1
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• pp.63-67
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• 2022

Controversies exist regarding the need for prophylactic extraction of mandibular third molars in patients who plan to undergo orthognathic surgery. An 18-year-old male patient was diagnosed with mandibular prognathism and maxillary retrognathism with mild facial asymmetry. He had a severely damaged mandibular first molar and a horizontally impacted third molar. After extraction of the first molar, the second molar was protracted into the first molar space, and the third molar erupted into the posterior line of occlusion. The orthognathic surgery involved clockwise rotation of the maxillomandibular complex as well as angle shaving and chin border trimming. Patients who are missing or have damaged mandibular molars should be monitored for eruption of third molars to replace the missing posterior tooth regardless of the timing of orthognathic surgery.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.6
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• pp.492-498
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• 2009

We sought to evaluate the relationship between the mandibular canal and impacted mandibular third molars by using dental cone beam computed tomograph(CBCT) for third molar surgery. A total of 111 patients(177 teeth) offered the images through CBCT and panoramic radiography for the extraction of the mandibular third molars. In CBCT, the accurate relationship between the third molar and the mandibular canal were evaluated. In panoramic radiographies, we evaluated the impacted level and superimposition sign of the mandibular third molar with the mandibular canal, and also, the radiopacity of the white line in the canal. Data were statistically analyzed and estimated by $X^2$-test. In CBCT finding, high prevalence of contact between the mandibular canal and roots occured in the deep impacted third molars, narrowing mandibular canals, bending mandibular canals and cases where the radiopacity of white line of canals were "absence" on panoramic images. It showed statistical significance (P<0.05). When evaluating the mandibular canal and the roots through the panoramic radiography for third molar extraction, it could be difficult to diagnosis accurately. Thus, it is required to have an accurate diagnostic approach through CBCT that could evaluated the location between mandibular canal and root.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.3
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• pp.207-213
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• 1998

Purpose : This study attempted to relate the incidence of fractures at the mandibular angle with the presence and state of eruption of lower third molars, and to find out the real risk factors for angle fractures in the states of lower third molars. Materials and Methods : Medical records and radiographs of 395 patients with mandibular fractures were retrospectively reviewed. The presence and states of third molars were assessed for each patients and related to the occurrence of angle and other mandibular fractures. Results : Of 395 patients with mandibular fractures, 142 had angle fractures. The incidence of angle fractures was found to be significantly greater when partial erupted lower third molars were present and it had a definite role for risk factors for angle fractures. But there were no clear relationship between the incidence of angle fracrtures and states of without, fully erupted lower third molars. Furthermore, the states of patial and unerupted lower third molar had an effect on bony segment displacement. Conclusions : This study provides clinical evidence to suggest that patial erupted third molar teeth weaken the mandibular angle both quantitatively and qualitatively.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.6
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• pp.420-425
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• 2009

Purpose: The aim of this study is to analyze the correlation between incidence of mandibular angle fracture and eruption state of mandibular third molar using clinical and radiographic findings. Materials and Methods: The data were obtained from the clinical and radiographic records of 205 patients who visited the Department of Oral and Maxillofacial Surgery, Chonbuk National University Hospital for treatment of the mandibular fracture. Panoramic radiographies were taken for radiographic examination and the mandibular third molars were classified according to age, gender, position and eruption state. Data were analyzed by a chi-square statistics. Results: In this study, the incidence of mandibular angle fracture had a tendency to be greater when a mandibular third molar was present(p>0.05), but there was not a statistically significant difference. Of the 255 cases with a mandibular third molar, 67 had an angle fractures. Of the 155 cases without a mandibular third molar, 138 had not angle fracture. And the incidence of mandibular angle fracture was high at class BII(by Pell & Gregory system)(p<0.05). Conclusion: Although there was not a statistically significant difference, mandibular third molar was more susceptible to mandibular angle fracture. When the reduction of mandibular angle fracture, it was recommended that mandibular third molar should be extracted especially in case of pericoronitis, periodontitis and other infections.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.5
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• pp.242-245
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• 2013

Impacted mandibular third molars are located between the second mandibular molar and mandibular ramus. However, ectopic mandibular third molars with heterotopic positions are reported in the subcondylar or pterygomandibular space. The usual cause of malposition is a cyst or tumor, and malposition without a pathology is rare. This case report described an impacted mandibular third molar in the pterygomandibular space without any associated pathology.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.40 no.5
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• pp.225-232
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• 2014

Objectives: The purpose of this retrospective study is to find the differentiating characteristics of cystic and cystic-appearing lesions that involve the impacted mandibular third molar by analyzing panoramic radiographs and computed tomography images, and to aid the preoperative diagnosis. Materials and Methods: Eighty-one patients who had a mandibular cystic or cystic-appearing lesion that involved impacted mandibular third molar and underwent cyst enucleation were included in the study. The preoperative panoramic radiograph and computed tomography findings were analyzed in accordance to the histopathologic type. Results: Most of the cystic lesions containing the mandibular third molar were diagnosed as a dentigerous cyst (77.8%). The occurrence of mesio-distal displacement of the third molar was more frequent in the odontogenic keratocyst (71.4%) and in the ameloblastoma (85.7%) than in the dentigerous cyst (19.1%). Downward displacement was primarily observed in each group. Odontogenic keratocyst and ameloblastoma showed more aggressive growth pattern with higher rate of bony discontinuity and cortical bone expansion than in dentigerous cyst. Conclusion: When evaluating mandibular cystic lesions involving the impacted mandibular third molar, dentigerous cyst should first be suspected. However, when the third molar displacement and cortical bone absorption are observed, then odontogenic keratocyst or ameloblastoma should be considered.

• The Journal of the Korean dental association
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• v.57 no.11
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• pp.654-663
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• 2019

This case report describes the management of a 30-year-old woman with hopeless mandibular first molars and right maxillary second premolar. The treatment plan included mandibular second and third molar protraction after extraction of mandibular first molars. Mini-implants were placed between roots of first and second premolar. Sliding mechanics with lever arm was used to prevent inclination of molars. A good functional occlusion was achieved in 38 months without clinically significant side effects. Most of the extraction space of mandibular first molar was closed by protraction of second and third molars. The skeletal Class II pattern was improved by counterclockwise rotation of mandible through reduction of wedge effect. Mandibular molar protraction with orthodontic mini-implants in adequate cases would be a great alternative to prosthetic implant and reduce the financial and surgical burden of patients.