The effect of mandibular repositioning appliances on regenerative remodeling of condylar bone in patients with disc displacement: a systematic review

To investigate the effects of mandibular repositioning appliances on regenerative bone remodeling in temporomandibular joint (TMJ) with disc displacement (DD). Following the PRISMA guidelines, six databases were searched until March 2026. Studies assessing the condylar bone remodeling of DD patients receiving mandibular repositioning appliance were eligible. The methodological quality was evaluated using MINORS. A qualitative synthesis was performed. 10 studies were included. The MINORS scores ranged from 10 to 11 for non-comparative studies and 18 to 22 for comparative studies. 8 studies evaluated the proportion of joints demonstrating positive bone remodeling following the mandibular repositioning appliance, ranging from 8.6% to 69.2%: 2 studies clearly claimed no differences between disc displacement with reduction (DDwR) and without reduction (DDwoR); 4 studies included exclusively adolescent patients, occupying the second to fifth positions in the ranking of positive remodeling efficacy. 5 studies assessed condylar quantitative changes, 2 of which reported superior positive remodeling in DDwR compared to DDwoR. Despite considerable heterogeneity among included studies, the available evidence suggest that mandibular repositioning appliances could promote varying degrees of positive condylar bone remodeling in a subset of DD patients. Adolescents and DDwR patients might show better positive bone remodeling outcome after mandibular repositioning appliance therapy, though high-quality studies are very much needed to confirm treatment-induced repair and spontaneous repair.