Skeletal, dentoalveolar, and buccal bone changes using hybrid and tooth-borne expanders for RME and SARME in different growth stages

Abstract Objective To compare the skeletal, dentoalveolar and buccal bone thickness of tooth–bone-borne (Hybrid-H) and tooth-borne (TB) maxillary expanders used for rapid maxillary expansion (RME) in early and late adolescents and for surgically-assisted RME (SARME) in young adults. Materials and methods: This two-centre clinical study included initial and 6 months post-retention CBCT records of 60 patients (27 males, 33 females; mean age 15.7 ± 3.75 years). The cohort was divided into two groups according to the expander type (H or TB) and subdivided into a further three groups determined by cervical vertebrae maturation stages: early adolescents (EA), late adolescents (LA), and young adults (A). EA and LA patients underwent RME and young adults received a SARME. Results: The hybrid-designed appliance increased the internal skeletal maxillary width and nasal width more than the TB-designed appliance anteriorly in EA and posteriorly in SARME young adults. The TB expanders tipped and expanded the first premolars more than the Hybrid SARME expanders in young adults and caused a greater reduction in buccal alveolar bone thickness at the level of the first premolars and molars at the three growth stages. Conclusion The hybrid expanders, with relatively greater skeletal and nasal widening potential and fewer dentoalveolar side effects, were a favourable alternative to tooth-borne expanders for RME in the early and late adolescents, and for SARME in young adults.