Evaluation of the relationship between gonial angle and impacted mandibular third molar teeth

  • Oğuzhan DemirelEmail author
  • Aslıhan Akbulut
Original Article


Mandibular third molar teeth have the highest impaction frequency for several reasons such as lack of space which may be related to the direction of facial growth. Gonial angle is used for the definition of facial growth pattern with some other measures such as mandibular plane angle. Winter and Pell–Gregory classifications are used for defining the level and pattern of mandibular third molar impaction. The aim of this study is to define the relationship between mandibular third molar impaction pattern and gonial angle; also to evaluate relationship between mandibular third molar roots and inferior alveolar canal. Study included 90 patients who had undergone cone beam computed tomography assessment for mandibular third molar impaction. Impacted teeth were grouped according to Pell–Gregory depth (A, B, C) and ramus (1, 2, 3) classification and sub-groups were composed. Winter classification was used for angulation of third molars and their relationship between with inferior alveolar canal was recorded. Gonial angle was measured on panoramic radiographs. Of the evaluated 90 impacted third molars, mesioangular position was the most frequent (34.4%), followed by vertical, horizontal and distoangular positions. Nearly 77% of the impacted third molar roots were related to inferior alveolar canal. While no correlation was determined between gender, age, third molar angulation and gonial angle, C2 sub-group of Pell–Gregory classification showed statistically significant higher gonial angle values. Although no significance was found, gonial angle was higher in level C group. In conclusion, gonial angle is higher in patients with C2 impaction level. Also, although statistically insignificant, Pell–Gregory C group had higher gonial angle averages.


Cone beam computed tomography Gonial angle Panoramic radiography Third molar Tooth impaction 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

For this study, ethical approval was taken from İstanbul Medipol University Ethics Committee (No.: 329/2019).

Statement of clinical relevance

Gonial angle, which is one of the measures of facial growth pattern, can be evaluated on panoramic radiographs. Gonial angle may be related to third molar impaction estimation and impaction of third molars may affect orthodontic treatment modalities.


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Copyright information

© Japanese Association of Anatomists 2019

Authors and Affiliations

  1. 1.Department of Dentomaxillofacial Radiology, School of Dental MedicineBahçeşehir UniversityIstanbulTurkey
  2. 2.Department of Dentomaxillofacial Radiology, Faculty of Dentistryİstanbul Medipol UniversityIstanbulTurkey

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