Application of the Millon Adolescent Personality Inventory in evaluating orthodontic compliance.

Lack of adolescent patient compliance is a significant problem in orthodontics. The purpose of this study was to examine the feasibility of using a commercially available adolescent personality test to predict the behavior of adolescent patients in an orthodontic practice. Specifically, this study tested (1) the use of the Millon Adolescent Personality Inventory (MAPI) as an appropriate instrument for an adolescent orthodontic population and (2) the correlation between MAPI test results and orthodontic compliance. The MAPI was administered to 104 13- to 18-year-old orthodontic patients who were blindly evaluated for orthodontic compliance after 2 years of treatment. Twenty modified MAPI scales with high internal consistencies (coefficient alpha = 0.66 to 0.87) were developed. Factor analytic results demonstrated that the modified scales had a dimensionality that was similar to that of the original test. Seven of 20 test scales and gender were found to be significantly correlated with orthodontic compliance. These eight variables contribute to a predictive model that accounts for 24% of the variance in assessing orthodontic compliance. We conclude that the MAPI has potential as a useful instrument in assisting the management of adolescent patient behavior in an orthodontic practice.