Background: Cigarette smoking has long been recognized as a risk factor for periodontal disease. The aim of this study was to perform quantitative and qualitative analyses of bone loss in the furcation region of periodontally healthy rats after daily systemic administration of nicotine or saline solution.
Methods: Thirty adult male Wistar rats were assigned randomly to twice daily subcutaneous injections of saline solution (control, group C) or nicotine (group N). The animals were sacrificed at 37, 44, or 51 days after the first subcutaneous injection. The specimens were processed for serial histologic sections, and the area of bone loss in the furcation region of the second molar was analyzed histometrically.
Results: Greater bone loss was detected in group N compared to group C on day 37 (16.36 +/- 5.84 mm(2) and 7.24 +/- 2.66 mm(2)), day 44 (15.12 +/- 4.57 mm(2) and 7.76 +/- 1.35 mm(2)), and day 51 (18.80 +/- 3.71 mm(2) and 8.74 +/- 2.61 mm(2)), respectively (P <0.05). Extension of bone loss appeared greater in the furcation region of group N where a thinner trabeculae bone was found. After day 37, bone loss did not increase significantly.
Conclusions: Daily systemic administration of nicotine resulted in significantly greater bone loss in the furcation region compared to saline solution. This indicated a close association between nicotine and periodontal morbidity in rats.