Mandibular Third Molar Impaction in Skeletal Class I Individuals With Different Vertical Patterns: A Cross-Sectional Study Publisher

Summary: Can facial type predict third molar impaction? A study found no significant links between facial types and impaction rates in a sample of Iranians. 45.9% had impacted molars. #DentalResearch #OralHealth

Mojtahedi H ; Tanbakuchi B ; Dehshiri E ; Bolandparva F ; Kharazifard MJ ; Safari F
Source: Iranian Journal of Orthodontics Published:2025

Abstract

Aim: This study assessed the relationship between different skeletal facial types and the position of impacted mandibular third molars in an Iranian population. By clarifying this important relationship, it may be possible to predict the likelihood of third molar impaction based on skeletal facial type, thereby improving the focus of preventive interventions. Methods: In this study 122 individuals with skeletal Class I relationships and different vertical skeletal facial types were examined radiographically. According to SN-GoGn and FMA angles, the subjects were categorized into three groups: mesofacial, brachiofacial, and dolichofacial. The angular position of third molars was classified on the panoramic x-ray according to Winter’s classification, which evaluates the beta angle, defined as the angle formed by the long axes of the second and third mandibular molars, categorized as vertical, mesioangular, distoangular, or horizontal. The position of the third molar relative to the occlusal plane and the cervical level of the second molar was categorized based on the Pell and Gregory classification into position A (the third molar aligned with the occlusal plane of the second molar), position B (the third molar situated between the occlusal plane and cervical area of the second molar), and position C (the third molar located below the cervical region of the second molar).The Chi-square and ANOVA tests were performed for statistical analyses. P<0.05 was considered as significant. Results: This study showed mandibular third molar impaction rate was 45.9%, with a slight female predilection. The most common angulation was vertical (63.5%), and the predominant occlusal level was position A (50%). Distoangular impactions, the least frequent, were mainly observed in the dolichofacial group. Dolichofacial group indicated the highest incidence of at least one impaction, followed by the mesofacial and brachiofacial groups at 43%, 30% and 26% respectively. No significant associations were found between skeletal facial type and either the angulation (P=0.41) or level (P=0.49) of third molars. Conclusion: This study found no significant relationship between facial type and the position or impaction rate of lower third molars. These findings suggest that vertical facial patterns do not significantly predict mandibular third molar impaction. © 2025, Author(s).