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.