A cross-sectional cohort study of gingival crevicular fluid biomarkers in normal-weight and obese subjects during orthodontic treatment with fixed appliances

Objectives: To investigate the effects of obesity on biomarker levels within lower incisor gingival crevicular fluid (GCF) in subjects undergoing routine fixed appliance orthodontic treatment. Materials and Methods: This was a cross-sectional clinical cohort study. GCF was collected from normal-weight and obese subjects at completion of alignment at least 1 month after placement of 0.019 x 0.025-inch stainless-steel archwires. The primary outcome was the difference in GCF biomarker levels between groups. Secondary outcomes included differences in clinical parameters of plaque and gingival indices, unstimulated whole-mouth saliva, and GCF flow rates. Results: Thirty-eight subjects (18 male, 20 female) with a mean age of 25.6 (SD, 6.3) years and mean body mass index (BMI) of 22.6 (1.6) in normal-weight and 32.4 (2.2) kg/m(2) in obese groups were investigated. Apart from BMI (P < .0001), there were no statistically significant differences in essential demographics between groups. Significantly increased levels of the adipokine leptin (P < .009) and the tissue-remodeling biomarker matrix metalloproteinase-9 (MMP9; P < .020) were identified in the obese cohort. For the remainder of the biomarkers, including the RANKL bone-remodeling marker and several inflammatory markers, there were no significant differences between groups. No correlation was observed between plaque index or gingival index for any GCF biomarker for either group (P = .07-1.00). Conclusions: This study investigated the GCF biochemical profile of obese and normal-weight subjects undergoing fixed-appliance orthodontic treatment. Significantly increased levels of the adipokine leptin and the tissue-remodeling biomarker MMP9 were identified in the obese group. These data provide evidence of differences in GCF biochemistry between obese and normal-weight subjects undergoing fixed appliance orthodontic treatment.