Impact of Scar Contracture on Miniscrew-Assisted Rapid Palatal Expander Efficacy in Unilateral Cleft Lip, Alveolus, and Palate: A Finite Element Analysis

Abstract

Objective This study investigates the impact of scar contracture on displacement of the maxillary segments during miniscrew-assisted rapid palatal expansion (MARPE) in unilateral cleft lip, alveolus, and palate (UCLAP) using finite element analysis (FEA). Methods A finite element model was constructed from a 3-dimensional maxilla model derived from a CT scan of a patient with UCLAP, incorporating scar tissue along with a 3-dimensional MARPE model. Simulations were conducted with (MARPE + s) and without (MARPE − s) scar tissue forces from the palatal tissue and upper lip, with the same MARPE expansion force applied in both conditions. Displacement was observed at 16 reference points on the palate and teeth along the x - (transverse), y - (vertical), and z- (sagittal) axes. Results Both simulations exhibited lateral, inferior, and anterior displacement along the x -, y -, and z -axes. Notably, the minor segment showed slightly greater displacement than the major segment along the x - and z -axes, whereas the major segment showed slightly greater displacement along the y -axis. Slightly lower displacement values were observed in the MARPE + s simulation compared with the MARPE − s simulation across all 3 axes. Conclusions Both simulations produced generally comparable displacement patterns, with only minimal reductions observed in the presence of scar tissue forces. These findings suggest that scar tissue may have only a limited biomechanical influence on MARPE expansion under the modeled conditions.