RANK/RANKL/OPG gene polymorphisms and loss of orthodontic mini-implants.

Objective: To investigate the association of genetic polymorphisms (tagSNPs type) of RANK/RANKL/OPG genes with the loss of orthodontic mini-implants (MIs).

Setting And Sample Population: One hundred and thirty-five patients of both sexes, with mean age of 48.7 ± 10 (20-76 years), were studied. The control group was composed of 104 patients, with no MI lost and functioning for at least 6 months and the case group, of 31 patients with at least one MI lost.

Materials And Methods: Cells were obtained by mouthwash with 3% glucose solution for 1 minute and scraping the buccal mucosa with sterilized spatula. DNA was extracted from buccal epithelial cells with 10 M ammonium acetate and 1 mM EDTA. Genotyping was performed by the real-time polymerase chain reaction (PCR) technique. Univariate and multivariate analyses were performed (P < .05).

Results: No markers were associated with MI loss after Benjamini and Hochberg false discovery rate correction of Univariate tests. In the multivariate analysis, the variables that associated with MI loss were the number of MIs installed (P < .000) and the polymorphism rs8086340 in the RANK gene (P = .018).

Conclusion: A higher number of MIs installed (P < .000) and polymorphism rs8086340 in the RANK gene (P = .018) were associated with loss of orthodontic MIs after multivariate analysis.