Page 89 - SPONDYLOARTHRITIS IN COLOMBIA -

The presence of periodontitis and its severity were defined according to the criteria established by the Center for Disease Control and Prevention-American Academy of Periodontology (CDC-AAP) 16. According to these criteria, the definitions were based on measures of CAL and PD at the four interproximal sites per tooth. Periodontitis was defined as ≥2 interproximal sites with CAL ≥4 mm or ≥2 interproximal sites with PD ≥5 mm (not on same tooth). Severe periodontitis was defined as ≥2 interproximal sites with CAL ≥6 mm (not on same tooth) or ≥1 interproximal sites with probing depth ≥5 mm.
Laboratory testing
The protocol employed for the detection of IgG1/IgG2 antibodies against Porphyromonas gingivalis (P. gingivalis) has been previously standardized 7. To detect these antibodies an indirect ELISA was performed in-house in 96-well plates. Each well was coated with 5 mg of a sonicated preparation of whole P. gingivalis ATCC33277 and W83 strains. For bacterial identification the following procedure was performed: after removing supragingival plaque with curettes and previous relative isolation with cotton rolls, a tip of sterile paper (caliber 40-NewStetic) was placed in the gingival sulcus for 20 seconds in 6 of the deepest sites of each patient. The paper tips of each site were placed in a sterile tube and processed for bacterial by quantitative polymerase chain reaction 17. The results for plaque samples were projected on the standard curve generated with P. gingivalis (ATCC 33277), T. denticola (ATCC 35405) and T. forsythia (ATCC 43037) and transformed to Log10.
Statistical analysis
Descriptive analyses were used to calculate means (SD) for continuous data and percentages for categorical data. The frequencies of periodontitis, severity, periodontal variables, IgG1/IgG2 antibodies against P. gingivalis and bacterial identification were established. Comparisons of periodontal characteristics between SpA patients and control individuals were performed using univariable analyses. For variables with a normal distribution, parametric t tests were used. For variables with a non-normal distribution, differences between cases and controls were compared by McNemar test for categorical variables or Wilcoxon signed test for continuous variables. A logistic regression analysis was performed with the diagnosis of periodontitis as a dependent
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