Association of the Vertical and Sagital Growth Paterns of Jaws with the type of Third Molar Impactions:: A Radiological Analysis

Abstract

Objective: To evaluate if the jaw growth paterns are associated with third molar impactions. Design: Cross-sectional study. Study seting: Orthodontics Department, Islamic International Dental Colege & Hospital Islamabad, Jan to Jun 2018. Methods: We analysed the records of 300 mandibular and maxilary third molars with specific criteria. Orthopantomogram Xrays were used to identify impactions and were classified by Pel and Gregory (P&G) and Winter lines. In addition, lateral cephalograms were assessed for sagital classes and vertical growth paterns. Results: Angles of impaction (Winter lines) of mandibular M3s were significantly associated with sagital growth paterns (p=0.021), with most mesioangular impactions found in Classes I and i. High-angle subjects resulted in the highest impactions in the vertical growth paterns. High angle was folowed by low angle and normal angle in mandibular M3s and normal angle and low angle in maxilary M3s. Levels of maxilary M3s (P&G) and vertical paterns showed a significant association (p=0.016), with the highest M3s at level C. The maximum number of impacted M3 coexisted with P&G Class- i and level B for both jaws. Conclusion: Significant associations were found between mandibular M3 angles, sagital paterns, and levels of maxilary M3s and vertical paterns. Results conclude that facial growth paterns and M3 impactions are not completely independent and may help predict impaction status in adolescence and aid in orthodontic treatment.