Evaluation of Oxidative Stress Biomarkers and Gene Expression Profiles in Saliva Following Orthodontic Application Force

Abstract

Orthodontic treatment applies mechanical forces that induce oxidative stress and inflammatory response within the periodontal tissue, potentially affecting oral health. Non-invasive diagnostic method through saliva offering a promising medium for evaluating oxidative stress biomarkers and gene expression profiles. This cross-sectional study assessed salivary biomarkers and the expression of the IL-1β and IL-8 genes in patients with orthodontic appliances, as these factors are crucial in inflammation, bone resorption, and remodeling during orthodontic treatment. Thirty orthodontic patients with fixed metallic appliances (≥6 months) and thirty matched healthy controls, ages 18 to 35, participated in this cross-sectional study. Salivary biomarkers, such as total protein concentration and oxidative stress markers were measured using standard assays. The expression of target genes was determined through Quantitative Reverse Transcription-PCR and the results were presented as fold change values. Oxidative stress markers demonstrated significant differences between groups, with the case group exhibiting notably higher levels of 8-OHdG (p = 0.0067), MDA (p = 0.0031), TAC (p = 0.0074), and TBARS (p < 0.0001). Orthodontic patients also displayed significantly elevated mean fold changes in IL-1β (p < 0.0001; 4.4) and IL-8 (p < 0.0001; 5.45) gene expression relative to controls. Furthermore, positive correlations were reported between the target genes and oxidative stress indicators, particularly MDA and 8-OHdG. A significant increase in oxidative stress levels and changes in salivary Interleukin-1 beta and Interleukin-8 gene expression have been observed during orthodontic treatment.