Histometric evaluation of the effect of nicotine administration on periodontal breakdown: an in vivo study

The present study investigated the effect of nicotine administration on per iodontal breakdown resulting from ligature-induced periodontitis in rats. T wenty adult male Wistar rats were used. After anesthesia, a mandibular firs t molar was randomly assigned to receive a cotton ligature in the sulcular area while the contralateral tooth was left unligated. The animals were ran domly assigned to one of the following treatments, of daily intraperitoneal injections: A - saline solution, B - 0.37 mg of nicotine/kg, C - 0.57 mg o f nicotine/kg and D - 0.73 mg of nicotine/kg. Thirty days later, the animal s were sacrificed and the specimens routinely processed for serial decalcif ied sections. Statistical analysis (ANOVA) revealed greater bone loss (p <0 .05) in the ligated teeth of animals which received nicotine (groups B/C/D) thin in the ligated teeth of animals which received saline solution (group A). In addition, a dose-dependent response was observed among the nicotine groups. A negative effect of nicotine was observed in the unligated teeth of the experimental groups (p < 0.05). Therefore, daily administration of n icotine enhanced, in a dose-dependent manner, the effects of local factors in producing periodontal breakdown. Furthermore, the nicotine seemed to hav e a direct deleterious effect on the periodontal tissues.