OBJECTIVES: To determine how daily consumption of a lozenge combining arginine and two probiotic strains affects the Relative Risk Reduction (RRR) in children regarding dental caries transitions and lesion activity at tooth surface level during 10-12 months.

METHODS: A total of 21,888 tooth surfaces in 288 children were examined. The intervention group (n= 141) received a lozenge containing 2% arginine, Lacticaseibacillus rhamnosus, LGG® (DSM33156), Lactobacillus paracasei subsp. paracasei, L. CASEI 431® (DSM33451). The placebo group (n= 147) received a placebo lozenge. Both groups received 1,450 ppm F - toothpaste. Primary canines, molars, and first permanent molars were examined clinically (ICDAS 0-6) and radiographically (R 0-6) at baseline and follow-up. Sealed, filled, and missing surfaces were included. Caries activity was computed as a sum of each caries lesion's location, color, texture, cavitation, and gingival bleeding. RRRs were computed with cluster effect on surface level. ICH-GCP was followed, including external monitoring.

RESULTS: A total of 19,950 surfaces were analyzed after excluding 1,938 tooth surfaces. No statistically significant differences were found between the groups. The RRRs showed less caries progression (13.6%, p= 0.20), more regression (0.3%, p= 0.44), and fewer active caries lesions (15.3%, p= 0.15) in the intervention group.

CONCLUSION: Daily consumption of a lozenge combining arginine and probiotics for 10-12 months given to 5-9-years-old children characterized being with low caries risk demonstrated a marked, though not statistically significant RRR for caries progression, regression, and number of active lesions in the intervention group compared to the placebo-group.

CLINICALTRIALS: gov (NCT03928587).

CLINICAL SIGNIFICANCE: Since all the RRRs were in favor of the intervention group and the PF of combined arginine and probiotics is high (81.6%) compared to fluoride toothpaste (24.9%) and arginine-fluoride toothpaste alone (19.6%) the combined pre-and probiotics approach may be a future additional tool regarding caries prevention and control.