Compromised GCF total antioxidant capacity in periodontitis: cause or effect?

Background: Oxidative stress is implicated in the pathogenesis of periodontitis. The total antioxidant capacity (TAOC) of gingival crevicular fluid volume (GCF) and plasma appears compromised in periodontitis, but it is unclear whether this predisposes to, or results from the inflammatory process. Materials and Methods: To investigate longitudinal changes in GCF and plasma TAOC following reductions in periodontal inflammation with successful non-surgical therapy. Results: Two longitudinal studies were run in series on non-smokers with chronic periodontitis (CP). Study-1 (n=17) assessed index sites with mild disease; Study-2 (n=18) investigated deep sites. GCF sampling and clinical measures were performed at baseline and 3 months post-therapy. Plasma and GCF TAOC was determined by enhanced chemiluminescence and 32 age/sex-matched periodontally healthy controls were used. Therapy improved clinical outcomes consistent with the literature. There were no differences in plasma TAOC between periodontitis patients (507 +/- 92 mu MTeq) and controls (520 +/- 100 mu MTeq; p=0.57) at baseline, but GCF TAOC was lower (p < 0.0001) in CP patients (680 +/- 371 mu MTeq) than controls (1129 +/- 722 mu MTeq). Successful periodontal therapy did not alter plasma TAOC (p=0.56), but GCF TAOC increased (by 449 +/- 722 mu MTeq, p < 0.001) to control subject levels (p=0.47) Conclusions: Local total antioxidant capacity in CP appears to reflect increased oxygen radical activity during periodontal inflammation and can be restored to control subject levels by successful non-surgical therapy.