Semirapid Maxillary Expansion and Mandibular Symphyseal Distraction Osteogenesis in Adults: A Five-Year Follow-up Study

The aim of this study was to evaluate the long-term effects of semirapid maxillary expansion (SRME) and mandibular symphyseal distraction osteogenesis (MSDO) on dentofacial structures in adult patients. The sample comprised posteroanterior cephalograms of 14 patients, with an age range between 15.8 and 25.01 years (mean, 20.09 ± 2.36 years) at the start of treatment. Records were obtained before treatment (T1, day 0), at the end of SRME and MSDO retention (T2, 4.57 ± 0.65 months), at the end of orthodontic treatment (T3, 22.14 ± 4.69 months between the end of SMRE/MSDO retention of SRME/MSDO and end of orthodontic treatment), and after a 5-year follow-up period (T4, 4.99 ± 1.00 years, between the end of orthodontic treatment and follow-up). Data were analyzed statistically by using the repeated measure analysis of variance and paired t test. Statistically significant changes were observed in the lower nasal, bimaxillary, upper molar, upper incisors, lower molar, and lower incisors at the end of the retention period (P < 0.001). The following changes were statistically significantly changed from T1 radiograph to the T4 radiograph: upper and lower nasal widths, nasal angle, bimaxillary width, upper and lower molar width, upper and lower incisor intercrown widths, and upper and lower incisor interapex widths. The following changes were not statistically significantly changed from the T1 to the T4: orbital width, zygomatic width, bicondylar width, bigonial width, biantegonial width, and ramal angle. SRME and MSDO efficiently increased mandibular skeletal and dental arch widths; therefore, it is an efficient nonextraction treatment alternative for patients with maxillomandibular transverse deficiencies.