Development and validation of the German version of the Orofacial Esthetic Scale.

Abstract

This study aimed to develop the German version of the Orofacial Esthetic Scale (OES-G) and to assess its psychometric properties. The OES is an eight-item instrument with seven items directly addressing esthetic impacts of the orofacial region and an eighth item for a global assessment. It applies an 11-point ordinal rating scale, with summary scores ranging from 0 (worst) to 70 (best). The original OES items were translated into German using a forward-backward method. A de novo development of German items (n = 21 patients) and a cross-cultural adaptation after pilot testing (n = 15 patients) established content validity. Internal consistency and construct validity (structural, convergent, known-groups) of the OES-G were assessed in a sample of 165 prosthodontic patients. The OES was applied in 42 patients on two occasions, with a temporal distance of 2-4 weeks apart to determine test-retest reliability. Internal consistency of the OES-G was considered as satisfactory (Cronbach's alpha 0.94; average inter-item correlation 0.64). Intraclass correlation coefficient of 0.95 (95 % confidence interval 0.92-0.98) indicated excellent test-retest reliability. Correlation matrix and exploratory factor analysis provided support for unidimensionality of the measured construct. The OES-G summary score was correlated with the patients' global assessment of their esthetics (r = 0.87) and external ratings of the expert group (r = 0.55) and discriminated patients with treatment need (39.4 points) from patients without (58.4 points; p < 0.001) and with a large effect size. The OES-G has good psychometric properties and is a valuable instrument for the assessment of self-perceived orofacial esthetics.