Smoking cessation rescues tooth movement delays caused by tobacco smoke components

ABSTRACT Purpose: Smokers who receive orthodontic treatment occasionally require longer treatment periods. Nevertheless, it is unclear whether delayed tooth movement can be recovered by encouraging smoking cessation. The study was designed to examine whether tooth movement rates can be recovered by a period of smoking cessation in rats treated with a comprehensive mixture of tobacco smoke components (TSCs). Materials and methods: Nine-week-old Wistar male rats were divided into no treatment, sham, TSCs, and TSCs cessation groups. The rats in the no treatment and sham groups drank distilled water, whereas those in the TSCs group and the TSCs cessation groups received TSCs in their drinking water. A smoking cessation period of 10 days was set for rats in the TSCs cessation group before the three groups underwent tooth movement. Tooth movement distance was measured using micro-computed tomography, and osteoclast differentiation was evaluated histologically. Results: There was significantly greater tooth movement in the sham and TSCs cessation groups than in the TSCs group. However, the TSCs cessation group showed lesser osteoclast differentiation than the sham group. Conclusion: Our results indicate that delayed tooth movement caused by smoking was recovered by smoking cessation treatment; this recovery seems to be partially due to the increase in osteoclasts, although the number of osteoclasts was still less than that in the sham group.