Class III subdivision malocclusion associated to unilateral posterior crossbite and dentoalveolar biprotrusion – corrective treatment of Pattern I in young adult

Vol. 15 – Number 58 – 2022 Case report Page 56-66 Class III subdivision malocclusion associated to unilateral posterior crossbite and dentoalveolar biprotrusion – corrective treatment of Pattern I in young adult João Paulo Schwartz¹ Taisa Boamorte Ravelli¹ Dirceu Barnabé Ravelli¹ Abstract Adult individuals with posterior crossbite malocclusion show poor prognostic for Rapid Palatal Expansion (RPE), when not associated to temporary skeletal anchorage devices or surgery. This study aimed to analyze the effects of orthodontic corrective treatment of Pattern I individual with Class III left subdivision malocclusion associated to unilateral posterior left side crossbite and dentoalveolar biprotrusion in young adult patient. The correction of unilateral posterior left side crossbite was obtained by midpalatal suture opening, being performed the RPE with Haas appliance, that caused palatal ulceration and was replaced by Hyrax appliance. Immediately after the expander appliance removal, pre-adjusted orthodontic appliance was installed for alignment and leveling. The correction of dentoalveolar biprotrusion was performed by extraction of four first premolars, using orthodontic mechanics for retraction of anterior teeth and spaces closure. The cephalometric, occlusion and face results were evaluated. The correction of Class III left subdivision malocclusion, unilateral posterior left side crossbite and dentoalveolar biprotrusion provided Class I normal occlusal relationship with normal overjet and overbite, as well as improvement of patient facial profile. Therefore, it was concluded that RPE, without temporary skeletal anchorage devices or surgery, was effective in correcting posterior crossbite malocclusion in young adult, as well as the pre-adjusted orthodontic appliance associated to the extraction of four first premolars for the treatment of dentoalveolar biprotrusion. The accurate diagnostic, treatment plan, orthodontic mechanic and retention allowed a Class I relationship, treated normal occlusal at the end of the treatment, as well as stability two years after the end. Descriptors: Malocclusion, necrosis, tooth extraction, Angle Class III malocclusion, Orthodontics. ¹ Department of Children’s Clinic – UNESP-FOAr. DOI: 10.24077/2022;1558-0195366