Assessed facial normality after Twin Block therapy

Abstract

The first aim of this study was to identify any difference in the perception of facial normality between orthodontists and lay people of patients with the initial presentation of a Class II division 1 malocclusion, the second is to investigate whether there was an identifiable facial change following Twin Block (TB) therapy, and lastly, the relationship between identifiable facial change and clinical measurements was explored. Animated laser scans of 16 randomly selected adolescent patients, nine males aged 12-14 years and seven females aged 11-13 years with Class II division 1 malocclusions before and after TB therapy, were assessed on a visual analogue scale (VAS) by 34 orthodontists and 35 lay people. The 'Mark and Measure' and 'Orientated' techniques were used to determine soft tissue dimensions. Overjet was also recorded. Non-parametric statistical analyses were employed, including Mann-Whitney, Wilcoxon signed value, and Spearman's rank-order correlation tests. There was no statistically significant difference in facial normality scores of adolescents before TB therapy when assessed by orthodontists (46.2 mm) and lay people (50.9 mm; P = 0.120). However, TB therapy significantly improved the assessment score of the orthodontists (54.8 mm) and lay people (57.8 mm; P = 0.000). Using a 5 per cent threshold in categorization of change in VAS scores, the majority of assessors perceived an overall 'improvement' (87.0 per cent). An increase in soft tissue lower face height (ST LFH) and overjet reduction was strongly correlated with the higher assessments of lay people (r = 0.515) and orthodontists (r = -0.505), respectively. Although orthodontists and lay people assess facial normality of patients with Class II division 1 malocclusions similarly, following TB therapy an increase in ST LFH with lay people and overjet reduction with orthodontists were most closely related to improved facial normality.