Long-term changes of alveolar buccal bone after rapid maxillary expansion in an adolescent patient

Besides the orthopedic effect of midpalatal suture split, rapid maxillary expansion causes buccal movement of supporting teeth by tipping and bodily translation. The orthodontic effect leads to periodontal changes such as reduction of buccal alveolar bone plate thickness and buccal alveolar crest level. The question that remains is whether any long-term bone regeneration occurs in the buccal bone plate after expansion. This report describes the longitudinal changes in the alveolar crest level of the maxillary posterior teeth after rapid maxillary expansion (RME) in an 11-year-old patient. This patient was included in a sample of a previous publication and initially presented with a unilateral posterior crossbite on the left side in her permanent dentition. After the RME procedure with use of a tooth-tissue-borne Haas-type expander, the patient experienced extensive buccal bone dehiscences in the supporting teeth. After expansion, she underwent comprehensive orthodontic treatment. Approximately 8 years after the expansion, orthodontic follow-up showed that the orthodontic outcomes, including the posterior crossbite correction, remained stable. The patient then underwent cone beam computed tomography (CBCT) for extraction of her third molars. Buccal bone dehiscences remained in the first maxillary premolars and in the mesial roots of the maxillary first molars. Also, gingival recession was observed in many maxillary and mandibular teeth. This case report suggests that alveolar bone dehiscence that develops immediately after RME tends to remain in the long term and predispose gingival recession. Factors related to this variable longitudinal behavior should be elucidated by future studies.