Effects of lithium on extraction socket healing in rats assessed with micro-computed tomography

Abstract

Objective. Lithium is an activator of β-catenin signaling and β-catenin plays an important role in regulating bone formation and remodeling. The purpose of this study was to investigate the effects of lithium on bone repair in tooth extraction sockets in rats. Material and methods. Twenty male Wistar rats were subjected to maxillary left second molar extraction. The animals received a daily injection of lithium chloride (LiCl) or the same dose of sodium chloride (NaCl) starting 7 days before tooth extraction until sacrifice 14 days after extraction. Rats were randomly divided into: (1) a pre-treated group that received LiCl injection from 7 days before to 3 days after tooth extraction; (2) a post-treated group that received LiCl injection starting 4 days after tooth extraction; (3) a continuously treated group that received LiCl injection for the entire 21 days; and (4) a control group that received NaCl injection only. The volume of new bone and the bone density in the extraction socket were quantified by micro-computed tomography. Results. The percentage of new bone formation in the extraction socket was as follows: 63.2 ± 13.4% (pre-treated group), 53.9 ± 9.8% (post-treated), 23.8 ± 8.0% (continuously treated) and 37.5 ± 4.2% (control). The difference in percentage was statistically significant between each pair of groups. Pre- and post-treated groups also showed a significant increase in the density of new bone. Conclusions. Lithium enhances bone repair in extraction sockets when delivered before or after tooth extraction. Tooth extraction during lithium treatment may impair bone healing.