PRO—biotics? Are pre- and probiotics a valuable adjunct to fluoridated toothpaste in the battle against dental decay?
Authors: Mughal Rhyanna 
Published: January 2024

Abstract
Design
An investigator and participant masked, parallel-group randomised control trial examining the tooth surfaces of 288 children aged 5–9 years (n = 141 in the intervention group, n = 147 in the control group). Children in the intervention group were provided a daily lozenge containing 2% arginine (prebiotic), Lacticaseibacillus rhamnosus and Lactobacillus paracasei subsp. paracasei (probiotics).
Children in the control group were provided with a placebo lozenge. Parents of participants were also provided with 1450 ppm fluoride toothpaste and advised to brush their children’s teeth twice daily. Clinical and radiographic examinations were undertaken at baseline and 10–12 months assessing caries activity, progression and regression at a tooth surface level. A modified ICDAS and radiographic scoring system were used to record presence and extent of carious lesions.

Case selection
Of 343 children who met the inclusion criteria, 21,888 tooth surfaces were examined in 288 low caries risk children aged between 5–9 years. Fifty-four participants withdrew consent (n = 31 for intervention group, n = 24 for control group) and 1 child was excluded as they were pre-cooperative for their dental examination. Participants were recruited from four municipalities in Denmark. To be eligible to participate, children had to be medically healthy, cooperative for clinical and radiographic examination, and able to ingest a daily lozenge.

Data analysis
The primary outcome for this study was relative risk reduction (RRR) of caries activity, progression and regression. Although not present in this study, the main study broadly showed equality between the two groups in terms of their social demographic, dietary, oral health-related factors. The authors used modified Poisson regression to determine any surface level differences between the intervention and placebo groups. The threshold for statistical significance was set as follows: p < 0.05 was considered statistically significant. The authors describe that a power calculation was undertaken for the main study. However, none of the outcomes in this study were powered for.

Results
19,950 tooth surfaces were included in the final analysis. There was no significant difference in change in caries activity between the two groups. There was a trend towards reduction in relative risk in the intervention group, with fewer active lesions (RRR: 15.3%; −6.0%, −32.4%), more caries regression (RRR: 0.3%; −0.4%, −1.0%) and reduced caries progression (RRR: 13.6%; −8.0%, −30.9%) observed than in the control group.

Conclusions
The use of a probiotic and prebiotic daily lozenges as an adjunct to 1450 ppm fluoride toothpaste and oral hygiene instruction did not result in a significantly reduced relative risk of change in caries status compared to placebo. Further research over an increased intervention time with a higher caries risk population may identify potential advantages of adjunctive pre- and probiotics fluoride toothpaste in the prevention, arrest and regression of dental caries.