Postoperative bleeding tendency as a risk factor in Actinobacillus actinomycetemcomitans-associated periodontitis

Frequent bleeding on probing (BOP) has been considered a risk factor for recurrence of periodontitis. In the present study, 29 patients with Actinobacillus actinomycetemcomirans-associated periodontitis were enrolled in a carefully performed recall system. At 6 sites per tooth, periodontal probing depth (PPD), gingival index (GI), plaque index (PII) and BOP was assessed 6 weeks, 6 months, 1 and 2 years after comprehensive therapy. Professional toothcleaning and subgingival scaling at sites with PPD ≥ 5 mm and BOP was carried out every 2nd or 3rd month. Subgingival samples from 2 sites, a pooled subgingival sample, check mucosa, saliva and tongue samples were selectively cultivated for A. actinomycetemcomitans after 2 years. Following active therapy, 8 % sites had a PPD of ≥ 4 mm, whereas 21 % sites bled on probing. After 2 years, respective figures were 12 and 27 %. During maintenance, frequent BOP (≥3 times at 4 visits) had a predictive value of 0.133 to indicate an increase in PPD of ≥ 2 mm and a negative predictive value of 0.947. The predictive value of no bleeding to indicate a stable site was 0.972, the negative predictive value 0.078. There was evidence for heterogeneity of associations between increase in PPD of ≥ 2 mm and ≥ 3 times BOP among patients (X²₍₂₈₎ = 41.45, p < 0.05). Significant sources for the variation of weighted In-transformed estimates of individual odds ratios (range -0.83 to 6.21, median 1.52) were relative numbers of A. actinomycetemcomitans-positive samples 2 years after therapy, age, and mean % of PII 2 (R² =0.439, p<0.001). No association between increase in PPD and BOP was found in patients where A. actinomycetemcomitans was not recovered from any sample (X²_MH = 1.96), but A. actinomycetemcomitans-positive subjects still had inconsistent associations (X²_MH = 37.65. p < 0.01). Ignoring patient characteristics may be misleading in the search for risk factors for recurrence of the disease.