Oxygen tension (pO2) in untreated human periodontal pockets

The purpose of this study was to assess the oxygen tension in untreated human periodontal pockets and test the hypothesis that the subgingival environmental is anaerobic in nature. Twenty-six patients with advanced chronic inflammatory periodontal disease participated. A total of 111 untreated pockets, 5 to 10 mm in depth, were selected for the pO2 measurements. Pocket depths, Plaque-Index and Gingival-Index were recorded. The pO2 at the base of the 111 pockets ranged from 5 to 27 mm Hg, with an average of 13.3 mm Hg (1.8% O2). Mean pocket depth was 6.9 mm. Moderately deep pockets (5-6 mm) had a mean pO2 of 15.0 mm Hg, whereas deep pockets (7-10 mm) showed a significantly lower pO2 of 11.6 mm Hg. No correlation was found between the pO2 and the Plaque-Index. Higher Gingival-Index scores tended to be associated with higher pO2 values. The pO2 in untreated periodontal pockets was low. However, it does not represent a completely anaerobic environment. Deep pockets contained less oxygen than moderately deep sites.