The effects of low-yield nicotine cigarette smoke inhalation on orthodontic tooth movement.

Objective: This study aimed to investigate the effects of low-nicotine cigarette smoke (CS) inhalation on orthodontic tooth movement (OTM) in rats. Methods: Forty 4-week-old male Wistar rats, were randomly divided into four groups: three experimental and one control. Group 1 (control group) had dental impressions taken at week 9. Group 2: OTM group received a continuous mesially directed force applied to the maxillary first molar at week 9 for 4 weeks. Group 3: CS group rats had 9 weeks of CS inhalation; Group 4: CS + OTM group, 9 weeks of CS inhalation and 4 weeks of orthodontic force application. Rats in groups 3 (CS) and 4 (CS + OTM) were exposed to 10 cigarettes for 8 minutes, 3 times per day for 9 weeks. All groups had polyvinyl siloxane impressions taken at week 9 and at the end of the experimental period (week 13). At week 13, all rats were sacrificed under general anesthesia, and their maxillae were dissected and scanned using a TRIOS 2014-1 intraoral scanner. The tooth movements were measured using digital models. Results: A slight increase in tooth movement rate was observed in smokers. However, this difference was not statistically significant. Conclusions: CS inhalation did not increase the rate of OTM in rats.