Buccal Alveolar Bone changes and upper first molar displacement after maxillary expansion with RME, Ni-Ti leaf springs expander and Tooth- Bone-borne Expander. A CBCT based analysis.

AIM To evaluate the buccal alveolar bone changes and the upper first molar displacement in subjects treated with conventional rapid maxillary expansion (RME), Ni-Ti leaf springs expander (Leaf Expander) and Tooth-Bone-borne Expander (Hybrid Expander) using CBCT scans. METHODS The sample consisted of 52 children treated with RME (n=18), Leaf Expander (n= 17) and Hybrid Expander (n= 17). CBCTs were taken before and after maxillary expansion and the Horos software was used for the analysis. Descriptive statistics and paired t-test were used to assess changes between the pre-treatment and post-treatment measurements. ANOVA test and Tukey's post hoc test with Bonferroni correction was used for between groups comparison. CONCLUSION The Hybrid Expander during preadolescence showed few advantages over the use of tooth-anchored expanders. An expansion approach with mini-screws is not preferable during early mixed dentition to a conventional approach. The differences in dental tipping values were clinically insignificant and the reduction in cortical bone thickness remained less than 1 mm. When possible, the use of second primary molars as anchorage should be preferred.