Three-dimensional evaluation of dimensional and positional changes in the mandibular condyle following miniscrew-assisted rapid maxillary expansion

Objective: This thesis aimed to three-dimensionally compare the effects of miniscrew-assisted rapid palatal expansion (MARPE) supported by two versus four miniscrews on the skeletal structures of the maxilla and the temporomandibular joint (TMJ) in young adult individuals. Materials and Methods: This retrospective study was conducted using clinical and radiological archive records of patients treated with MARPE at the Department of Orthodontics, Faculty of Dentistry, İnönü University. A total of 30 young adult individuals (19 females, 11 males) were included and divided into two groups according to the number of miniscrews used: two miniscrew-supported MARPE (n = 15) and four miniscrew-supported MARPE (n = 15). Three-dimensional analyses were performed to evaluate skeletal maxillary expansion using various transverse measurements. TMJ-related changes were assessed by analyzing the position of the mandibular condyle within the glenoid fossa, condylar angulations, and joint space dimensions. All measurements were carried out using 3D Slicer software (version 5.8.1; Surgical Planning Laboratory, Brigham and Women's Hospital, Boston, MA, USA). Results: Both MARPE groups demonstrated statistically significant skeletal maxillary expansion after treatment (p<0.05). Significant differences were observed between the two- and four-miniscrew-supported MARPE groups in most skeletal parameters (p<0.05). However, no statistically significant differences were found in the majority of TMJ-related parameters between the groups (p>0.05). The change in the articular condylar angle was significantly greater in the two-miniscrew-supported MARPE group compared to the four-miniscrew-supported group (p<0.05). Conclusion: MARPE is an effective treatment method for correcting transverse maxillary deficiency in young adults. Greater skeletal expansion observed in both anterior and posterior regions in the four-miniscrew-supported group suggests that the number of miniscrews plays an important role in the amount and pattern of maxillary expansion. Both treatment protocols produced similar TMJ responses, and the observed condylar changes were adaptive and within physiological limits. Keywords: CBCT, MARPE, Miniscrew, RME, TMJ