OBJECTIVES: To investigate the effect of daily use of a lozenge containing arginine and probiotics for 10-12 months on caries increment, gingivitis- and plaque occurrence in children aged 5-9 years.

METHODS: In this placebo-controlled, double-blinded, parallel-grouped randomized clinical trial, 343 children were randomly assigned to one of the study arms (1:1). The intervention group (n= 172) received a lozenge containing Lacticaseibacillus rhamnosus, LGG® (DSM33156), Lactobacillus paracasei subsp. paracasei, L. CASEI 431® (DSM33451) and prebiotic (arginine 2%). The placebo group (n= 171) received an identical lozenge without arginine or probiotics. Primary canines and molars, and permanent first molars were examined clinically (d/D= ICDAS 1-6) and radiographically (d/D= R 1-6) at baseline and follow-up. Missing (m/M), sealed (s/S), and filled (f/F) surfaces (-s/-S) in both dentitions were also included. Utilizing clinical and radiographic scorings, caries experience was classified as d ICDAS1-6msf-s (primary teeth), D ICDAS1-6MSF-S (permanent teeth), d/D ICDAS1-6m/M-s/S-f/F-s/S (mixed dentition). A weighted and an unweighted score system was applied.

RESULTS: The study was completed by 288 children. The dropout rate was 15%. The increase in ∆mean d ICDAS3-6msf-s and ∆mean d/D ICDAS3-6m/M-s/S-f/F-s/S was lower in the intervention group (p= 0.007). No differences were found for gingivitis- and plaque occurrence. No product-related side effects were reported. This study followed ICH-GCP including monitoring.

CONCLUSION: Daily intake of combined prebiotic arginine and two strains of probiotics lozenges showed statistically significantly reduced caries increment but no effect on the mean plaque or gingivitis in children. The use of the lozenge has a promising potential as a supplementary tool for future management of caries. www.

CLINICALTRIALS: gov (NCT03928587).

CLINICAL SIGNIFICANCE: The combination of prebiotic arginine and probiotics shows clinical potential as a supplementary approach to toothbrushing with fluoride toothpaste in managing caries increment in children.