Reliability and validity of clinical assessments of malocclusion

The purpose of this research was to determine the reliability and validity of selected clinical judgments of malocclusion, including general evaluations of occlusal status and more specific aspects of dentofacial malrelations. Study casts of twenty-one adolescents planning orthodontic treatment and twenty-nine not planning treatment were examined and rated. The examiners were five dentists in an orthodontic specialty-training program. They completed ratings on six dimensions: (1) need for treatment, (2) degree of malocclusion, (3) potential for tissue loss, (4) negative effect on occlusal stability, (5) negative effect on dental-facial attractiveness, and (6) negative effect on masticatory function. Six weeks later the same five rates scored the fifty casts, using the standardized Treatment Priority Index (TPI). Three weeks later, or 9 weeks after the initial ratings, the casts were again rated on the two general dimensions: need for treatment and degree of malocclusion. Correlations among all the measures were examined. Inter-rater reliability was highest for the ratings of impact on dental-facial attractiveness (r = 0.88). The two general assessments also yielded relatively high rater reliabilities, and the second rating yielded stability coefficients of 0.84 for both of these ratings. Correlations with total TPI scores were 0.70 for the dental-facial attractiveness measure and 0.65 and 0.64, respectively, for assessments of need for treatment and degree of malocclusion. The data indicate that clinical evaluations of the severity of malocclusions are comparable to objective measures in terms of inter-rater reliability. Clinical evaluations are also relatively stable over time. Correlations with the TPI scores also provide evidence of the concurrent validity of clinical judgments.