Blood flow in healed and inflamed periodontal tissues of dogs

The objectives of this study were to determine if increased blood flow associated with gingivitis would decrease following resolution of gingival inflammation in dogs with periodontitis; if increased blood flow in inflamed gingiva was associated with changes in the blood flow of alveolar bone, and if blood flow in gingiva and alveolar bone increased if periodontitis was reactivated by ligating teeth. Regional blood flow was measured in dogs with pre‐existing periodontitis, using radioisotope‐labelled, plastic microspheres. In the first experiment on 4 adult Beagle dogs, teeth in the left jaws were treated to resolve the periodontitis, while teeth in the right jaws were not treated. Gingival and bone blood flow were measured after 12 wk. Blood flow was significantly (p<0.05) lower in non‐inflamed healed gingiva (32.1±2.7 ml/min/100 g) than in inflamed gingiva (46.1±5.3 ml/min/100 g). No differences in the blood flow of alveolar bone underlying inflamed or non‐inflamed gingiva were present. In the second experiment, the right mandibular teeth of 5 dogs were treated to resolve periodontitis while teeth in the other quadrants were ligated for 4, 10 or 12 wk. The duration of ligation did not alter blood flow. Gingival blood flow around ligated maxillary and mandibular teeth was comparable and approximately 54% higher than around non‐ligated teeth (p±0.03). The difference in blood flow between gingiva with G.I. ± 1 and gingiva with G.I.±2 was significant (p±0.04). Blood flow in bone was not altered by changes in the inflammatory status of the overlying gingiva. The findings suggest that changes in blood flow associated with inflammation are reversible and that blood flow in alveolar bone is regulated independently of gingival blood flow.