Efficacy of a Microencapsulated Sugar-Free Probiotic Oral Rinse on Gingival Health and Salivary Matrix Metalloproteinases 8 and 9 in Children With Down Syndrome: A Pilot Randomized Clinical Trial.

backgroundChildren with Down Syndrome (DS) are at heightened risk for oral diseases due to their distinct physiological and immune characteristics. Matrix metalloproteinases (MMPs), particularly MMP-8 and MMP-9, are key mediators of periodontal tissue breakdown. Probiotics may provide a novel, well-tolerated alternative to conventional antiseptics by modulating these biomarkers.

methodsThis single-center, parallel-arm, randomized, single-blind pilot trial compared a sugar-free microencapsulated probiotic oral rinse against a 0.2% chlorhexidine digluconate rinse in children with DS. A total of 118 participants aged 6-14 years were enrolled; following attrition after oral rehabilitation, 40 children (20 per group) were allocated to intervention, and 15 participants per group completed all assessments. After individualized oral rehabilitation and oral health education, participants were randomized (1:1). Group 1 received probiotic rinse and Group 2 chlorhexidine rinse, both administered twice daily for two weeks. Primary outcomes were salivary MMP-8 and MMP-9 levels (enzyme-linked immunosorbent assay). Secondary outcomes were plaque index (PI), gingival index (GI), oral hygiene index-simplified (OHI-S), and bleeding on probing (BOP). Outcomes were assessed at baseline prior to oral rehabilitation (T0), two weeks after completion of oral rehabilitation (T1), two weeks following completion of the rinse protocol (T2), and six months post-rinse (washout period, T3) by blinded examiners.

resultsAll 30 randomized participants completed the trial (15 per group). Both groups showed significant within-group reductions in MMP-8, MMP-9, PI, GI, OHI-S, and BOP at follow-up (p < 0.05). Between-group comparisons showed no significant differences in MMP levels, PI, GI or OHI-S at any interval. At six months, the probiotic group demonstrated a greater reduction in BOP compared with chlorhexidine (median difference -6.0; 95% CI [-9.0, -3.0]; p = 0.001). Given the two-week duration of rinsing, this isolated 6-month difference should be interpreted cautiously. HARMS: No systemic side effects or gastrointestinal symptoms were reported. Mild tooth staining occurred in two participants in the chlorhexidine group; no adverse effects were reported in the probiotic group.

conclusionBoth rinses demonstrated within-group improvements, although no significant between-group differences were observed in the primary biochemical outcomes. The probiotic rinse showed comparable short-term efficacy and better tolerability, but due to underpowering and design limitations, findings remain exploratory. Larger, adequately powered studies are required to determine true clinical effectiveness.

trial registrationThis study was a registered clinical trial with the Clinical Trials Registry of India (CTRI/2023/04/051447). The trial was prospectively registered, adhering to the WHO standards for clinical trial registration to ensure transparency and integrity in reporting health-related outcomes.