Oxygen sufficiency in the gingiva of smokers and non-smokers with periodontal disease

Background: Epidemiological studies have demonstrated deteriorating effects of smoking on periodontal tissue. The aims of this study were to compare o xygen saturation of hemoglobin in the gingiva (GSo(2)) of smokers and non-s mokers and to evaluate the chronic effect of smoking on gingival oxygen suf ficiency. Methods: GSo(2) was determined using tissue reflectance spectrophotometry i n 110 papillary gingival sites of 62 smokers and 100 sites of 60 non-smoker s. Results: No significant difference was found in GSo(2) between smokers and non-smokers. In the model of ANOVA with covariates, age (P = 0.0048) and pr obing depth (P = 0.0012) had significant effects on GSo(2). No significant effect was found in either smoking status (P = 0.3557) or the modified ging ival index (MGI) (P= 0.3824). The interaction effect between smoking status and the MGI was highly significant (P = 0.0003) indicating that the effect of smoking status on the GSo(2) should be compared at each level of the MG I score. GSo(2) in healthy gingiva was significantly lower in smokers than non-smokers (P = 0.0014), while smokers showed higher GSo(2) than non-smoke rs in moderately inflamed gingiva (P = 0.0356). The GSo(2) in inflamed ging iva was significantly decreased compared with healthy gingiva in non-smoker s (P = 0.0044), while smokers showed no significant difference between heal thy and inflamed gingiva (P = 0.2772 to 0.8665). GSo(2) in smokers was cons istently and significantly lower than that of healthy gingiva of non-smoker s (P = 0.0391 to 0.0004). Conclusions: Smokers exhibit possibly lower function of oxygen sufficiency in healthy gingiva and reduced ability to adapt the function in inflamed gi ngiva than non-smokers. This suggests that smokers have functional impairme nts in the gingival microcirculation.