Abstract
PURPOSE: This randomized, double-blind, placebo-controlled trial evaluated the clinical efficacy of Lactobacillus reuteri in reducing gingival inflammation and alveolar bone loss in periodontitis by modulating endoplasmic reticulum (ER) stress. MATERIALS AND METHODS: A total of 120 patients (aged 22-47 years) with periodontitis (n = 84) or gingivitis (n = 36) were allocated to receive either L. reuteri (1×10⁹ CFU/day, n = 60) or placebo (n = 60) for 8 weeks. Primary outcomes included ER stress markers (GRP78/CHOP), while secondary outcomes comprised probing depth (PD), clinical attachment level (CAL), inflammatory biomarkers (TNF-α, IL-6, CRP), and radiographic alveolar bone loss (Moffat grading). Statistical analyses utilized ANOVA, Welch's t-test, and ANCOVA, with significance at p 0.05. RESULTS: The L. reuteri group exhibited statistically significant reductions in TNF-α (30.01 ± 5.15 vs 16.57 ± 3.88 pg/ml, -45.3%, p 0.05), IL-6 (25.84 ± 3.11 vs 14.35 ± 2.16 pg/ml, -45.2%, p 0.05), and CRP (6.41 ± 1.18 vs 2.68 ± 1.04 mg/L, -57.8%, p 0.05) compared to placebo. Gingival pain (VAS) decreased by 48.5% (5.22 ± 0.51 to 2.69 ± 0.20, p 0.001). ER stress markers GRP78 and CHOP declined by 37.6% (p 0.01) and 35.2% (p 0.01), respectively. PD improved by 35.8% (4.92 ± 1.13 vs 3.12 ± 0.37 mm, p 0.05), with 68.3% of patients achieving ≥2 mm PD reduction (vs 13.3% in controls, p 0.001). Radiographic bone loss improved to mild Moffat grades in 66.7% of test patients (vs 33.3% in controls, p 0.001). CONCLUSIONS: L. reuteri statistically significantly alleviates periodontitis by inhibiting ER stress and inflammatory pathways, demonstrating clinically meaningful reductions in PD, CAL, and alveolar bone loss. These findings underscore its therapeutic potential as an adjunctive intervention.