Pocket Oxygen Tension in Smokers and Non‐Smokers With Periodontal Disease

BACKGROUND: Smoking is associated with destructive periodontal disease. Pocket oxygen tension (pO2) is likely to be a major environmental determinant of the subgingival microflora, which is a primary etiological factor of the disease. This study aimed to compare the pocket pO2 in smokers and non-smokers with periodontal disease. METHODS: Pocket oxygen tension was compared in 27 smokers and 34 non-smokers by considering 2 confounding factors, probing depth and oxygen saturation of hemoglobin (S(O2)), in the gingiva. The pO2 was determined using oxygen microelectrode by polarographic method with an electronic compensation circuit for subgingival temperature. Gingival S(O2) 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 pO2 was significantly 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 consistent when the confounding factors were considered. Correlation between the PO2 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). Correlation of the PO2 to the gingival S(O2) was highly significant in non-smokers (r = 0.57, P = 0.0005), but no association was found in smokers (r = -0.08, P= 0.6975). CONCLUSIONS: These findings indicate that pO2 is lower in smokers than in non-smokers, and that the pO2 in smokers is not influenced by gingival oxygen sufficiency. The present study may provide the basis of understanding environmental factors possibly associated with microbial flora in the pockets of smokers.