Association Between Angulation of Mandibular Third Molar Impactions With Facial Skeletal Types and Cephalometric Landmarks

Abstract

OBJECTIVE: To determine the association of impacted mandibular third molar with skeletal facial types and different anatomical and cephalometric landmarks.
 METHODS: This cross-sectional study was conducted at Rehman College of Dentistry and Khyber College of Dentistry, Peshawar, Pakistan from October to December 2020. Panoramic and lateral cephalometric radiographs of 800 patients (aged 22-35 years) were retrieved from the records. Third molar impaction was classified by Winter’s classification using IC Measure software. The skeletal facial type was determined by measuring Point A Nasion Point B angle using Viewbox software. An association of third molar impaction with skeletal facial types, cephalometric and anatomical variables was evaluated.
 RESULTS: The most common mandibular tooth impactions type was Mesioangular impaction (81.3%) and skeletal facial type was skeletal class-I (47.5%). Comparative analysis among different impaction types using One-way ANOVA showed that although these impaction types did not differ significantly in terms of skeletal facies (p=0.07), significant difference in terms of age (p=0.028), Maxillary Mandibular Plane Angle (MMPA) (p=0.007), depth (p=0.000), ramus relation (p=0.000) and inferior dental nerve (ID) canal (p=0.001) were observed. ID canal was found to be positively but weakly correlated (r=0.2) with impaction types. Contrariwise, depth and ramus relation showed moderately negative correlation (r=-0.40 and r=-0.30, respectively) with impacted tooth angulations.
 CONCLUSION: Although it is difficult to predict the impaction type in patient based on their skeletal facies, associations between other anatomical and cephalometric variables were observed which may help in predicting the degree of difficulty that may be encountered during the surgical procedures.