Vertical growth pattern as a determinant of mandibular asymmetry

Objectives: To determine normal mandibular linear values in three vertical groups, to compare right and left side to highlight a prevalent pattern towards mandibular asymettry.

Methods: This is a descriptive cross sectional study in which pre-orthodontic treatment panoramic radiographs and lateral cephalograms of 224 patients (between 18 to 34 years) undergoing treatment in Orthodontic Department of Bahria University Medical and Dental College were used and traced on an acetate sheet. There were 74 patients in high angle,76 and 78 in low angle and normal angle group respectively based on their vertical growth pattern using SNMP angle. Condylar height (CH) and Ramal height (RH), and condylar plus ramal height (CH+RH) measurements were done as previously described by Habets.

Results: There was no statistically significant difference between the three groups as determined by one way ANOVA. Condylar height and Gonial angle showed statistically significant difference when right and left side was compared, with increased values on the right side.

Conclusion: There was no statistically significant difference in condylar, ramal, and total asymmetry index between different vertical groups. Between the right and left sides, condylar height and gonial angles were significantly increased on the right side. However, Ramal height showed no significant difference. Ramal index has a strong linear correlation with total asymmetry index.