COMPREHENSIVE EVALUATION OF FACTORS LEADING TO CLASS III SUBDIVISION MALOCCLUSION USING 3-D CBCT

Introduction:Several studies have been conducted to assess skeletal and dental asymmetry on Class II subdivision cases but no studies have yet been published to assess such asymmetries for patients with Class III subdivision malocclusion. The purpose of the study was to assess the maxilla-mandibular dimensional and positional asymmetry along with asymmetry at glenoid fossa level and to find out true dental asymmetry at molar and canine level in class III subdivision malocclusion.

Materials and Methods: A split mouth prospective study was conducted on Angles Class III subdivision malocclusions (n=15) and CBCT scans were analyzed with 3-D Dolphin software.

3-D and 2-D measurements were recorded to assess asymmetry between class I and class III sides. 2-D measurements were recorded to assess the position of glenoid fossa, joint spaces and condyle dimension, position and their angulation.

Results: Statistically significant differences were found in glenoid fossa depth, position of the maxilla, mandible, as well as in gonial angle. Statistically significant dental differences were also found for the position of the mandibular first molars and canines along with total asymmetry (combined skeletal and dental) in maxilla and mandible.

Conclusions: The components contributing to Class III subdivision malocclusion were multifactorial involving glenoid fossa asymmetry, positional asymmetry in maxilla and mandible. Mandibular dimensions were more on class III side but it was not statistically significant. True dental asymmetry was also foundin mandible along with total asymmetry in maxilla and mandible.