Occlusal Force Changes in Growing Patients Treated with the Three Bite Plane Appliance: A Prospective Study

Objective: To investigate the effects of three-bite plane appliance (TBP) therapy on maximal occlusal force (MOF) in growing patients. Methods: This study included 120 children (aged 9–10 years) diagnosed with Class I, Class II, or Class III malocclusion. All subjects presented with a deep bite and a normodivergent growth pattern. MOF was recorded at baseline (T0) and after 12 months of treatment (T1). A standardized multi-bite protocol was used to improve reproducibility. Paired t-tests or Wilcoxon tests assessed intragroup differences, while Welch’s ANOVA with Games–Howell post hoc testing evaluated intergroup variation. Results: Significant intragroup differences were found for all groups (p < 0.001). Class I subjects demonstrated a reduction in MOF (Δ = −138.3 N; p < 0.001), whereas Class II (Δ = 113.35 N; p < 0.001) and Class III (Δ = 145.6 N; p < 0.001) subjects showed significant increases. Intergroup comparison revealed a significant overall difference in MOF change (F = 41.35; p < 0.001). Post hoc analysis confirmed significant differences between Class I and both Class II and III, while no significant difference was detected between Class II and III. Conclusions: Treatment with a three-bite plane appliance modifies MOF in growing patients, showing malocclusion-specific adaptation patterns. The reduction observed in Class I contrasts with the functional enhancement detected in Class II and Class III subjects.