Protraction of a mandibular second molar into the adjacent atrophic first-molar extraction site with ridge-split technique through clear aligners: A case report

This case report describes the successful orthodontic management of a 25-year-old female patient presenting with Class II Division 2 malocclusion, moderate maxillary anterior crowding, and a missing mandibular left first molar. Treatment plan involved extraction of two maxillary first premolars to address crowding and protraction of two mandibular left molars, combined with the strategic use of mini-implants for precise tooth movement control. Ridge-split surgery was adopted to manage alveolar ridge resorption in the edentulous area. This procedure was essential for widening the narrow alveolar ridge, thereby reducing resistance and facilitating the mesial movement of two mandibular left molars. Lingual and labial biomechanics, including linguoincisal elastics and a cantilever system, were utilized to optimize torque control and molar protraction. Clear aligners were employed throughout the treatment phases, navigating challenges such as the closure of extraction spaces and achieving stable buccal interdigitation. The treatment spanned 4 years, using a total of 175 aligners. The initial phase required 66 aligners to close maxillary extraction spaces and the mandibular edentulous space, followed by 52 aligners in the first refinement and 57 aligners in the second refinement phase. Posttreatment evaluations demonstrated successful alignment of dental arches, correction of malocclusion, and enhancement of facial aesthetics. This case highlights the efficacy of integrated orthodontic techniques in achieving comprehensive functional and aesthetic outcomes in complex orthodontic cases.