Evaluation of the Efficacy of a Dentifrice Tablet to Prevent Dental Caries: A Microbial Study

Background/Objectives: Dentifrice tablets are a new over-the-counter dentifrice form that are gaining global interest. The aim of this microbial study was to investigate the effectiveness of dentifrice tablet (DT) containing nanohydroxyapatite (nHAP) to prevent tooth demineralization. Methods: 120 bovine tooth blocks were randomly assigned to four treatment groups (30/group): Nanohydroxyapatite DT (5% nHAP), placebo DT (Placebo), NaF toothpaste (1100ppm Fluoride), and no-treatment (Control). Blocks were subjected to 7-day demineralization by plaque growth in a mixed-organism Microbial Caries Model. Toothpaste was made into slurry (1 toothpaste:3 water), while DT was thoroughly crushed and homogenized with water (1 tablet:3 water) to slurry. Both slurries were applied twice daily for 2 minutes on each occasion. Demineralization was assessed using Surface Microhardness (SMH) testing before and after plaque exposure. Change (ΔSMH) and percentage change (%∆SMH) in SMH (percentage demineralization [%Dem]), and % demineralization inhibition (%Dem-Inhibition) in each group were calculated. Intra-group (SMH) comparison (paired t-test) and intergroup (%∆SMH) comparison (ANOVA/Tukey’s test) were conducted (α=0.05). Results: Paired t-test indicated significant difference (p<.001) between pre-treatment and post-treatment SMH in all groups. Intergroup comparison based on their %Dem using ANOVA/Tukey’s test showed that Control (29.93±5.58) had significantly (p<.05) higher %Dem than Placebo (22.81±7.47, p<.05), nHAP (13.93±11.31, p<.001), and Fluoride (14.44±10.65, p<.001). Placebo had significantly (p<.01) higher %Dem than nHAP and Fluoride. No significant difference between nHAP and Fluoride. Intergroup comparison based on their %Dem-Inhibition (calculated relative to the control) using ANOVA/Tukey’s test, nHAP (51.74±40.05, p<.01) and Fluoride (50.56±37.21, p<.05) had significantly higher %Dem-Inhibition than Placebo tablet (21.86±5.55). No significant difference in %Dem-Inhibition between nHAP and Fluoride. Conclusions: The present study demonstrated that dentifrice tablets containing 5% nanohydroxyapatite are as effective as NaF toothpastes containing 1100 ppm fluoride in preventing tooth demineralization.