Dentoskeletal effects of rapid maxillary expander therapy in early mixed dentition patients with different vertical growing patterns without posterior crossbite: A retrospective study

Introduction: This study aimed to analyze the variation of dentoskeletal effects after rapid maxillary expander therapy in subjects with different vertical growth patterns. Methods: The study sample consisted of 94 patients (32 males, 62 females; mean age 8.9 ± 1.5 years) treated with rapid maxillary expander (RME) anchored on first permanent molars. For each subject, lateral cephalograms and maxillary digital dental casts were available before RME, immediately after appliance removal, and 1 year after appliance removal. All the subjects were divided into 3 groups according to their vertical facial patterns (low-angle, normal-angle, and high-angle). Cephalometric analysis was conducted on lateral cephalograms. The virtual 3-dimensional models were used to analyze the torque of the first permanent molars and intercanine and intermolar width. The differences between the vertical facial subgroups were contrasted by analysis of variance multicomparison test (P [removed]