Effects of Adjunctive Synbiotic Supplementation to Non-Surgical Periodontal Therapy on Clinical, Immunological, and Microbiological Parameters in Smokers With Periodontitis

Periodontitis is a chronic inflammatory disease characterized by the progressive destruction of tooth-supporting tissues, leading to periodontal pocket formation, bleeding on probing, clinical attachment loss, alveolar bone loss, and ultimately tooth loss if untreated. During disease progression, periodontal pathogens stimulate the production of proinflammatory mediators such as IL-1β and IL-8, which contribute to tissue destruction and immune cell recruitment. Excessive inflammatory responses increase reactive oxygen species (ROS) production, resulting in oxidative stress and oxidative DNA damage, commonly assessed by 8-hydroxy-2'-deoxyguanosine (8-OHdG).

Smoking is a major risk factor for periodontitis, as it alters the oral microbiota, impairs immune responses, and increases oxidative stress, often reducing the effectiveness of periodontal therapy. Although non-surgical periodontal therapy is the standard treatment for periodontitis, its outcomes may be limited in smokers and in severe cases.

Synbiotics, which combine probiotics and prebiotics, may help restore microbial balance, modulate host immune responses, and reduce oxidative stress. Therefore, adjunctive synbiotic supplementation alongside non-surgical periodontal therapy may enhance periodontal treatment outcomes, particularly in individuals with periodontitis.

There is limited evidence regarding the combined evaluation of the effects of synbiotic supplementation on clinical periodontal parameters, immunological markers, microbiological parameters, and microbiota in smokers with periodontitis. Therefore, the aim of this placebo-controlled, parallel-group, double-blind, prospective clinical study is to evaluate the effects of adjunctive synbiotic supplementation combined with non-surgical periodontal therapy on clinical periodontal parameters, IL-1β, IL-8, and 8-OHdG levels, periodontal pathogens, and gastrointestinal microbiota in smokers and non-smokers with generalized Stage III/IV Grade B/C periodontitis.

Following Ethics Committee approval, patients diagnosed with generalized Stage III-IV Grade B/C periodontitis, without systemic disease, who apply to the Department of Periodontology at Biruni University Faculty of Dentistry and voluntarily agree to participate in the study will be included.