Smoking affects the self-healing capacity of periodontal tissues. A histological study in the rat.

This study aimed to evaluate in rats the impact of cigarette smoke inhalation (CSI) and nicotine administration (NA) on a periodontal healing model in the absence of a plaque biofilm. Wistar rats (n = 42) were assigned to three groups: Group 1, control (n = 14); Group 2, NA (3 mg kg(-1)) (n = 14); and Group 3, CSI (n = 14). Thirty days after CSI and NA exposure, fenestration defects were created buccally to the distal root of the first mandibular molar. The animals were killed 21 d later and their mandibles were processed for histological examination. The percentage of bone fill and the density of newly formed bone were assessed histometrically. Intergroup analysis demonstrated that compared to the control and NA groups, CSI was associated with a reduced rate of bone repair. No new cementum had been formed along the root surface in any of the three groups. It is concluded that cigarette smoke reduces the self-healing capacity of periodontal tissues.