Searching for predictors of long-term stability

The purpose of this investigation was to evaluate a unique sample of orthodontically treated subjects (N = 114; post-retention = 11.97 years). All subjects were treated by one clinician utilizing a consistent diagnostic and treatment protocol. Subjects were grouped into two distinct groups according to the lower incisor irregularity: group 1, “moderate change” and group 2, “minor change.” Statistical analyses were performed at a level of r ≥0.6, p < 0.01. Satisfactory long-term stability was achieved in 79% of the subjects; moreover, no subject exhibited severe incisor irregularity post-retention. Similar to previous studies, no individual or single predictor for long-term change could be identified. However, different to most studies, useful predictors of the post-retention incisor alignment included the relationship of the lower incisor to the A-Pogonion plane at the end of treatment (at T2), posterior face height (at T2), the mandibular plane angle SN-GoGn (at T2), anterior crowding (at T2), and starting age (at T1). It is clearly noted that the vertical dimension features in the equation.