Pocket oxygen tension in smokers and non-smokers with periodontal disease

Background: Smoking is associated with destructive periodontal disease. Poc ket oxygen tension (pO(2)) is likely to be a major environmental determinan t of the subgingival microflora, which is a primary etiological factor of t he disease. This study aimed to compare the pocket pO(2) in smokers and non -smokers with periodontal disease. Methods: Pocket oxygen tension was compared in 27 smokers and 34 non-smoker s by considering 2 confounding factors, probing depth and oxygen saturation of hemoglobin (SO2), in the gingiva. The pO(2) was determined using oxygen microelectrode by polarographic method with an electronic compensation cir cuit for subgingival temperature. Gingival SO2 was determined using tissue reflectance spectrophotometry. Results: No significant difference was found in the modified gingival index and the plaque index between smokers and non-smokers. The pO(2) was signif icantly lower in smokers (21.9 +/- 9.6 mmHg) than in non-smokers (33.4 +/- 8.4 mmHg). The difference was highly significant (P <0.0001) and was consis tent when the confounding factors were considered. Correlation between the pO(2) and probing depth approached statistical significance in smokers (r = -0.36, P=0.0674) and significance in non-smokers (r = -0.41, P=0.0174). Co rrelation of the pO(2) to the gingival SO2 was highly significant in non-sm okers (r = 0.57, P=0.0005), but no association was found in smokers (r = -0 .08, P=0.6975). Conclusions: These findings indicate that pO(2) is lower in smokers than in non-smokers, and that the pO(2) in smokers is not influenced by gingival o xygen sufficiency. The present study may provide the basis of understanding environmental factors possibly associated with microbial flora in the pock ets of smokers.