Introduction Microimplant-assisted rapid palatal expansion (MARPE) has recently been offered to adult patients for correcting maxillary transverse deficiency. However, there is limited information in the literature on the success of this appliance and its skeletal and dental effects on skeletally matured patients. The purpose of this study was to investigate the immediate skeletal, dentoalveolar, and periodontal response to MARPE appliance using cone-beam computed tomography in a skeletally matured patient as assessed by the cervical vertebral maturation method. Materials and Methods Eight consecutively treated patients (2 females, 6 males; mean age of 21.9 ± 1.5 years) treated with a maxillary skeletal expander were included in the study. Measurements were taken before and after expansion to determine the amount of midpalatal suture opening, upper facial bony expansion, alveolar bone bending, dental tipping, and buccal bone thickness (BBT). Data were analyzed using a one-way ANOVA and matched-pair t-test (α = 0.05). Results Midpalatal suture separation was found in 100% of the patients with no dislodged microimplants. Total maxillary expansion was attributed to 41% skeletal, 12% alveolar bone bending, and 48% dental tipping. Pattern of midpalatal suture opening was found to be parallel in both the coronal and axial planes. On average, the absolute dental tipping ranged from 4.17° to 4.96° and the BBT was reduced by an average of 39% measured at the premolars and molars. Conclusions The MARPE appliance can be a clinically acceptable, nonsurgical treatment option for correcting mild to moderate maxillary transverse discrepancies for skeletally matured adult patients with a healthy periodontium.

Introduction: Microimplant-assisted rapid palatal expansion (MARPE) has recently been offered to adult patients as a treatment option for correcting maxillary transverse deficiency. However, there is a lack of information in the literature on the effects of this newer expansion technique specifically related to skeletal maturity. The purpose of this study was to investigate the immediate skeletal, dentoalveolar, and periodontal response to MARPE in skeletally matured patients, as assessed by the cervical vertebral maturation (CVM) method, using cone-beam computed tomography. Experimental Design and Methods: Eight patients (2 females, 6 males; mean age of 21.9 ± 1.5 years) treated with the maxillary skeletal expander (MSE), a particular type of MARPE appliance, were included in the study. Measurements before and after MARPE of midpalatal suture opening, upper facial bony expansion, aveolar bone bending, dental tipping, and buccal bone thickness were compared using one-way ANOVA or matched-pair t-test (α = 0.05). Results: Midpalatal suture separated in 100% of subjects with no dislodged microimplants. Contribution to total expansion include 41% skeletal, 12% alveolar bone bending, and 48% dental tipping. Pattern of midpalatal suture opening was parallel in both coronal and axial view. On average, absolute dental tipping ranged from 4.17 o to 4.96 o and buccal bone thickness reduced by 0.27 mm to 0.68 mm, which may be improved overtime with orthodontic uprighting. Conclusion: MARPE can be a clinically acceptable, nonsurgical treatment option for correcting mild to moderate maxillary transverse discrepancies, less than 7 mm, in skeletally matured adult patients with a healthy periodontium. iii ACKNOWLEDGEMENTS AND DEDICATIONS "The best kind of people are the ones that come into your life, and make you see the sun where you once saw clouds. The people that believe in you so much, you start to believe in you too. The people that love you, simply for being you. The once in a lifetime kind of people." I would like to acknowledge several individuals for their contributions to this thesis. Dr. Peter Ngan, for his endless encouragement, support and guidance throughout the entire process. Dr. Tung Nguyen, for dedicating his valuable time to educate me on color map superimpositions and assisting me with the related data analysis. Dr. Fernanda Angelieri, for also offering her precious time to help me assess the individual midpalatal suture maturation. Dr. Tim Tremont and Dr. Chris Martin, for their encouragement and advice throughout the process. Dr. Gerry Hobbs for his help with the statistical analysis. I dedicate this thesis to my wonderful family, particularly my parents. Thank you for giving me life and for always encouraging and supporting me to do what makes my heart smile. I also dedicate this thesis to my lifelong friends. Thank you for playing a role in shaping me into the person I am today. I feel truly blessed to have been gifted with the loving family and friends that I have in this lifetime.