Three-dimensional analysis of palatal asymmetry before and after treatment of functional posterior crossbite in mixed and permanent dentition: A retrospective study.

INTRODUCTION

This study aimed to evaluate and compare the palatal dimensional and morphologic characteristics (symmetry or asymmetry) before and after the treatment of functional posterior crossbite (FPXB) in mixed and permanent dentition.

METHODS

Forty-four patients with a diagnosis of transverse maxillary deficiency and FPXB underwent maxillary expansion: 22 in mixed dentition (mixed dentition study group [MD-SG], mean age = 8.6 ± 1.3 years) and 22 in permanent dentition (permanent dentition study group [PD-SG], mean age = 13.3 ± 1.1 years). Two age-matched control groups (mixed dentition control group and permanent dentition control group) were included. Digital models at T0 (baseline) and T1 (12-18 months postexpansion) were analyzed for palatal dimensions, volume, and symmetry. Deviation analysis and percentage matching were performed between the original and the mirrored models. Statistical analyses assessed intragroup, intergroup, and intertiming differences.

RESULTS

At T0, linear and volumetric measurements were greater at the noncrossbite side (nCBs) than the crossbite side (CBs) in patients with FPXB compared with controls (P <0.001). The CBs/nCBs volumetric difference was greater in PD-SG than MD-SG (P = 0.001), whereas surface matching was higher in MD-SG (P = 0.004). At T1, CBs/nCBs dimensional asymmetry decreased in both FPXB groups (P <0.001), and the surface matching improved (P <0.001). However, MD-SG remarkably showed greater posttreatment changes than PD-SG (volumetric data: P = 0.012; surface data: P = 0.009).

CONCLUSIONS

Patients with FPXB in permanent dentition could exhibit greater maxillary asymmetry than in mixed dentition. After reestablishment of normal occlusion, the asymmetry reduced in both MD-SG and PD-SG, though the latter group retained more residual asymmetry, potentially affecting final maxillary morphology.