Clinical and computerized assessment of mandibular asymmetry

The aim of this study was to investigate assessment of mandibular asymmetry by clinicians and to evaluate a new computerized system. Eight experienced clinicians (four maxillofacial surgeons and four orthodontists) assessed 1 2 standardized facial photographs of patients selected to provide a range, from normality to marked mandibular asymmetry. Photographs were taken under standardized conditions; analysis of photographs repeated after one month showed close agreement. The computerized system used four different methods for quantifying asymmetry based on right/left differences in perimeter, ar ea, compactness, and centre of area ratios. Good agreement (kappa = 0.77) was achieved by the clinicians in assessing t he likelihood of treatment need; however, when assessing an 'acceptable' le vel of asymmetry, agreement was moderate (kappa = 0.46). Differences in per imeter ratios did not compare well with clinical assessment, but those for both area and compactness showed 100 per cent sensitivity and specificity t o clinical assessment at ratio differences of 0.05 and 0.03 (deviation from 1), respectively. A centre of area difference ratio greater than 1 showed 75 per cent sensitivity and 85 per cent specificity to clinical assessment. These parameters could prove useful in quantifying change in asymmetries b rought about by growth, treatment, or any subsequent relapse.