A Predictive Model of "Favorable" Versus "Unfavorable" Growth For Orthodontic Treatment Planning

. Purpose The purpose of this study was to use longitudinal cephalometric data to identify cephalometric characteristics associated with “favorable” and “unfavorable” craniofacial growth patterns in adolescents. Materials and Methods This retrospective longitudinal study included 226 untreated adolescent subjects, ages 10-15. Subjects were grouped as “favorable” and “unfavorable” based on the horizontal relationships of the maxillary and mandibular skeletal bases, defined by ANS and Pg. They were grouped based on these relations at 10 and 15, as well as on the changes that occurred between 10 and 15. Statistical analyses, including paired t-tests, bivariate correlations, and multiple regressions, were used to determine the associations. Discriminant analysis was used to predict group membership at age 15. Results Horizontal maxillomandibular relationships of females, but not males, worsened between 10 and 15 years of age. The majority (58%) of the subjects with favorable horizontal relationships at 10 maintained their favorable horizontal relationships. Relationships at 15 were most closely associated with changes or relationships between T1 and T2. Multiple regression showed that the Y-axis, ANS-N-Pg and symphysial angle explained approximately 60% of the variation in horizontal relationships at age 15. Discriminant function, using these three variables, correctly predicted “favorable” or “unfavorable” relations at age 15 77.4% of the time. Conclusions While most horizontal relationships are stable, individual variability is great. To determine an individual’s relationship at 15, information about their relationships at 10 and the changes between 10 and 15 are needed, with the changes beting the most important. Horizontal relations at age 15 are able to be predicted using the variables of Y-axis, ANS-N-Pg, and symphysial angle. Using these variables it is possible to predict if a subject will have favorable or unfavorable relations with over 75% accuracy