Combined Effect of Nicotine and Caffeine on Orthodontic Tooth Movement in Rats

Background: The individual effects of nicotine and caffeine have been reported in previous studies but their combined effect on tooth movement needs to be elucidated. The objective of this study was to evaluate the combined effect of nicotine and caffeine on the magnitude of orthodontic tooth movement (OTM) in rats. Material and Methods: This experimental study was conducted on Sprague-Dawley rats (Animal House and Pathology Laboratory; Post Graduate Medical Institute, Lahore) in the department of Orthodontics, de’Montmorency College of Dentistry, Lahore from 8th July 2014 to 8th January 2015. Forty male Sprague-Dawley rats were divided into four equal groups: Control group (CR), nicotine group (NT), caffeine group (CF) and combined nicotine and caffeine group (CNC). Closed coil nickel titanium (NiTi) spring was placed between incisor and maxillary molar. Nicotine group (NT) was treated by intraperitoneal injections of nicotine. Caffeine was given to caffeine group and Combined nicotine and caffeine group (CNC) was treated in the same way as individual nicotine and caffeine groups daily for 14 days. All the rats were sacrificed on 15th day. Magnitude of the orthodontic tooth movement was measured using digital Vernier caliper. Means and standard deviation were calculated for orthodontic tooth movement. One-way ANOVA was used to determine the mean difference in OTM. Post hoc Tukey test was used for multiple comparisons among the groups. Results: The mean orthodontic tooth movement (OTM) was 0.32 mm ± 0.05 in control group, 0.56 mm ± 0.04 in nicotine group, 0.52 mm ± 0.034 in caffeine group and 0.8 mm ± 0.06 in combined NC group, respectively. The difference between mean OTM among the groups was statistically significant (P-value