RT Journal Article SR Electronic T1 Effects of nicotine on bone during orthodontic tooth movement in male rats JF Saudi Medical Journal JO Saudi Med J FD Prince Sultan Military Medical City SP 1127 OP 1135 DO 10.15537/smj.2016.10.15159 VO 37 IS 10 A1 Bakathir, Manal A. A1 Linjawi, Amal I. A1 Omar, Samia S. A1 Aboqura, Ahad B. A1 Hassan, Ali H. YR 2016 UL http://smj.org.sa/content/37/10/1127.abstract AB Objectives: To investigate the effects of nicotine on orthodontic tooth movement and accompanying histological and immunohistochemical changes in rats.Methods: An experimental study conducted at King Abdulaziz University, Jeddah, Saudi Arabia between 2013 and 2014. Thirty-two rats randomly divided into 4 groups. Three were experimental, received daily nicotine injections: group A: 0.37 mg/kg, group B: 0.57 mg/kg, and group C: 0.93 mg/kg. The control group (group D) received a daily injection of 0.5 mL saline. All rats were subjected to 30 g of orthodontic force on the maxillary left first molars and incisors using a nickel-titanium closed-coil spring. The distance between the 2 teeth was assessed before and after 14 days of force application. Histological, immunohistochemical, and histomorphometric assessments were performed on sections from groups C and D.Results: Groups C (p<0.001) and D (p<0.001) showed the significantly greatest and least amounts of tooth movement . The results were statistically dose-dependent. Unbalanced resorption-apposition bone remodeling patterns and increased osteoclast cell distribution were observed in the nicotine group with significantly smaller percentages of bone surface areas mesially and distally (p<0.05). Immunohistochemical stains showed low alkaline phosphatase activity and intense tartrate-resistant acid phosphatase activity in the nicotine group.Conclusions: Nicotine accelerated orthodontic tooth movement with unbalanced bone resorption and apposition patterns around the moving teeth.