Impact of Subgingival Lactobacillus reuteri Probiotic Therapy on Clinical Outcomes and Porphyromonas gingivalis Quantification in Peri-Implant Disease: A Prospective RT-PCR-Based Clinical Study

Peri-implantitis is a biofilm-induced inflammatory disease that compromises peri-implant tissues, adversely affecting human health and implant survival. As an infectious disease, its management through mechanical debridement alone is often limited by persistent microbial burden. Adjunctive probiotic therapy, grounded in contemporary medicine, has therefore been proposed to improve peri-implant health and oral wellbeing, with potential relevance to broader public health outcomes. The aim of the study was to evaluate the clinical and microbiological effects of subgingival probiotic delivery as an adjunct to mechanical debridement in the non-surgical management of peri-implantitis. A prospective clinical study was conducted involving 52 systemically and periodontally healthy individuals aged 30-60 years with peri-implantitis. Participants were randomly divided into two groups (n = 26 each). Group 1 received mechanical debridement alone, while Group 2 received mechanical debridement combined with subgingival application of Lactobacillus reuteri probiotic. Clinical parameters (PI, GI, PPD, and CAL) and Porphyromonas gingivalis levels were assessed at baseline and three months. RT-PCR was used for microbiological evaluation. Data were analyzed using paired and independent t-tests, with P < 0.05 considered significant. Both groups showed significant intra-group improvements in clinical and microbiological parameters (P < 0.05). However, Group 2 exhibited significantly greater reductions in PI, GI, PPD, CAL, and P. gingivalis levels compared with Group 1 (P = 0.00), demonstrating the superior effectiveness of probiotic therapy. Adjunctive probiotic therapy significantly improves clinical outcomes and reduces microbial load in peri-implantitis patients, offering a beneficial addition to mechanical debridement.