Associations between Salivary Cytokines and Periodontal and Microbiological Parameters in Patients undergoing Fixed Orthodontic Appliance Treatment

Background: Orthodontic treatment can lead to microbial-induced gingival inflammation and aseptic periodontal inflammations. The aim of this study was to investigate the relationship between salivary pro-inflammatory cytokines levels with gingival health status and oral microbe loads among patients undergoing fixed orthodontic appliance treatment (FOAT). Methods: This was a cross-sectional study among a sample of 111 consecutive orthodontic patients (mean age 18.4 ± 4.4 years). Clinical examinations were conducted to assess the gingival health status employing the Modified Gingival Index (MGI), Gingival Bleeding Index (GBI) and Plaque Index (PI). Salivary microbiological assessments of total aerobic and anaerobic bacteria count, streptococci count and lactobacilli count were undertaken. Salivary immunological assessments included Interleukin-1Beta (IL-1β) and macrophage migration inhibitory factor (MIF) ELISA assays. Results: The mean ± standard deviation (SD) of salivary IL-1β was 83.52 ± 85.62 pg/ml and MIF was 4.12 ± 0.96 ng/ml. Positive significant correlations between salivary IL-1β levels and salivary bacteria counts (r=0.380~0.446, P<0.001), and between salivary MIF levels and total salivary aerobic and anaerobic bacteria counts (r=0.249~0.306, P<0.01) were observed. A significant positive correlation was found between salivary IL-1β levels and BI (r=0.216, p<0.05). Conclusions: The levels of salivary IL-1β and MIF correlate with oral bacterial load among patients undergoing fixed orthodontic therapy. This has implications in understanding gingival inflammation/ aseptic periodontal inflammation during orthodontic therapy.