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

Area of Science:

• Dentistry
• Oral and Maxillofacial Surgery
• Orthodontics

Background:

• Mandibular third molars exhibit high impaction rates, influenced by facial growth patterns and anatomical landmarks like the gonial angle.
• Classifications such as Winter and Pell-Gregory define impaction levels and patterns, crucial for surgical planning.
• Understanding the relationship between impaction and facial morphology aids in predicting and managing complications.

Purpose of the Study:

• To investigate the correlation between mandibular third molar impaction patterns and the gonial angle.
• To assess the relationship between impacted third molar roots and the inferior alveolar canal.
• To analyze how different impaction classifications relate to facial growth indicators.

Main Methods:

• Cone beam computed tomography (CBCT) was used for 90 patients with impacted mandibular third molars.
• Impaction patterns were classified using Pell-Gregory (depth A, B, C; ramus 1, 2, 3) and Winter (angulation).
• Gonial angle was measured from panoramic radiographs; root proximity to the inferior alveolar canal was recorded.

Main Results:

• Mesioangular impaction was most frequent (34.4%), followed by vertical, horizontal, and distoangular.
• Approximately 77% of impacted third molar roots showed proximity to the inferior alveolar canal.
• The Pell-Gregory C2 sub-group demonstrated a statistically significant higher gonial angle; Level C impactions trended towards higher gonial angles.

Conclusions:

• A higher gonial angle is observed in patients with C2 impaction level, suggesting a link to specific facial growth patterns.
• While not statistically significant, a trend of higher gonial angles was noted in Pell-Gregory Level C impactions.
• The high prevalence of root proximity to the inferior alveolar canal underscores the need for careful surgical assessment.