Sagittal dentoskeletal modifications associated with different activation protocols of rapid maxillary expansion

Aim The aim of this study is to compare the sagittal dentoskeletal changes associated with different activation protocols of maxillary expander. Materials and methods A total of 101 subjects with constricted maxillary arches (49 males and 52 females; mean age 10.08 ± 1.57 years) were enrolled in the study. The study comprised also a control group of 20 subjects (11 females and 9 males, mean age 10.27 ± 1.24 years) who were not treated during the observation period. All the subjects underwent rapid maxillary expansion with a stainless steel banded expander cemented to the maxillary first molars. The expansion screw was randomly activated with two different rapid maxillary expansion protocols (one-quarter per day or twoquarters per day). A statistical comparison between the sagittal cephalometric variations obtained in the two expansion groups was made, and compared with the untreated control group. Data were then stratified for skeletal maturation of each subject. Results The Wilcoxon rank-sum test shows statistically significant differences between the two RME activation protocols only for overjet. Statistically significant differences were reported in comparison with the control group. Conclusions This study suggests that the increase in overjet after RME could be associated with faster activation protocols especially in subjects with lower skeletal maturation.