Post-Pubertal Deepbite Changes in Patients With or Without Previous Early Interceptive Treatment: A Retrospective...

Objectives: To compare overbite changes from the beginning of fixed appliance treatment to the post-pubertal assessment during retention between patients who had previously undergone early interceptive treatment and patients treated without a previous interceptive phase. Methods: This retrospective longitudinal study included 34 patients (13 females and 21 males) with an initial overbite ≥4.5 mm. Seventeen patients had undergone an early interceptive phase (ETG), whereas 17 received fixed appliance treatment without previous interceptive treatment (LTG). T0 corresponded to the beginning of fixed appliance treatment in both groups; in the ETG, T0 followed Phase 1 treatment and an intermediate retention period. T1 was obtained during posttreatment retention at a post-pubertal stage. Overbite was the primary outcome, while the remaining skeletal and dentoalveolar measurements were considered secondary exploratory outcomes. T1-T0 changes were compared between groups using ANCOVA with the corresponding T0 value as a covariate. Results: At T0, the ETG showed a smaller overbite (4.1 ± 1.2 mm vs. 5.6 ± 0.9 mm) and a greater U1-PP angle (111.5° ± 5.1° vs. 104.8° ± 6.7°). During T0-T1, overbite decreased by 0.8 ± 1.0 mm in the ETG and 2.5 ± 1.6 mm in the LTG. After accounting for the corresponding T0 value, the between-group difference in overbite change was 0.8 mm (95% CI, -0.2 to 1.8; p = 0.118). No statistically significant between-group difference in overbite change was detected. No statistically significant between-group differences were detected for the secondary skeletal or dentoalveolar outcomes. Conclusions: Within the limitations of this retrospective study, no statistically significant between-group difference in overbite change was detected. However, the study had limited power to exclude a clinically meaningful difference, and the findings should not be interpreted as evidence of equivalence.