Orthognathic surgery case of metal allergy applied orthodontic appliances made of organic polymer

This case report presents a case that underwent orthognathic treatment with non-metallic appliances made of organic polymer. The patient was a 19-year-old female with mandibular protrusion and maxillary anterior crowding. The overbite was +3.0 mm, and the overjet ?3.0 mm. She was allergic to nickel (Ni³⁺), cobalt (Co³⁺) and cobalt–chrome (Co–Cr³⁺). The pre-surgical orthodontic treatment included the extraction of the maxillary right-and-left second premolars and mandibular right third molar. An orthodontic appliance made of organic polymer was employed. Orthognathic surgery with bilateral sagittal split ramus osteotomy was carried out. After 32 months pre-surgical orthodontic treatment, the left and right sides were set back 9 and 7 mm, respectively. Rigid fixation of the splitted mandible was employed using two absorbency screws in each side, and the inter-maxillary fixation was performed with elastic threads for 8 days. Total treatment period was 42 months. For retention, a non-metal retainer was employed for the upper and lower dentition. The consistent non-metal treatment on orthognathic case of metal allergy was attained successfully. However, the maxillary molars and the mandibular anterior teeth appeared elongated. This was considered to be caused by the low rigidity of a plastic material.