Long-term effects of orthodontic interceptive expansion treatment : A retrospective study.

Purpose: The aim of this retrospective cohort study was to evaluate the long-term effects of interceptive orthodontic treatment with a removable expansion plate, based on transversal, sagittal, and vertical parameters.

Methods: A total of 90 patients needing interceptive treatment due to a crossbite or space deficiency were included. Records consisting of clinical photos, radiographs, and digital dental casts were collected for evaluation at two time points: the start of interceptive treatment (T0) and the start of comprehensive treatment (T1). Molar occlusion, overjet, overbite, presence and type of crossbite, mandibular shift, and transversal measurements were recorded for comparison.

Results: After expansion with removable appliances, a significant increase in intermolar width was achieved and could be maintained over the observation period (p < 0.001). However, no significant changes regarding overjet, overbite, or molar sagittal occlusion were observed. Crossbite correction was successful in 86.9% of patients with unilateral crossbite and in 75.0% of patients with bilateral crossbite (p < 0.001).

Conclusion: Early expansion with a removable expansion plate is a successful method to correct crossbites and increase intermolar width in the early mixed dentition phase. Results remain stable until the start of comprehensive treatment in the permanent dentition.