The preventative effects of black and green tea on remineralisation of enamel caries lesions under cariogenic challenge in vitro

Aim: To investigate the remineralising efficacy of green tea, black tea and black tea plus milk on artificial enamel caries-like lesions under cariogenic challenge in vitro, using QLF analysis. Materials and methods: A total of 150 bovine enamel slabs, with artificial subsurface caries-like lesions, were allocated randomly to five different groups (black tea, green tea, black tea plus milk, 5.0 ppm and 0 ppm F water), with n=30 slabs per group. A 28-day pH-cycling regime was then carried out, in which the enamel samples were subjected to one of the treatment groups, acetic acid and artificial saliva. Throughout the cycling regime, temperature, pH, acid titratability, amount of tea in tea bags and fluoride concentration were analysed. Additionally, tea stains were controlled by polishing the enamel slabs at the end of the cycling period. Quantitative Light–Induced Fluorescence (QLF) system was used to analyse the enamel subsurface lesions under standardised environmental conditions at three different time points (at baseline, following the pH-cycling and after implementing the stain removal method). Results: All study groups showed regression of early enamel lesions in comparison to baseline, though the extent of this was less in the 0 and 5.0 ppm F water groups compared with the tea groups. Further, Bonferroni’s multiple comparison tests were used to determine inter-group differences. In terms of remineralisation efficacy, the results indicated statistically significant differences (p<0.01), in favour of the test groups (green tea, black tea and black tea plus milk) over the control groups (5.0 ppm and 0 ppm F water). Another statistical significance was observed in favour of the 5.0 ppm F water group over the 0 ppm F water group (p<0.05). However, when comparing between the three tea groups, no significant differences were observed. Conclusions: Green tea, black tea and black tea plus milk groups demonstrated high efficacy in remineralising artificial enamel caries-like lesions under cariogenic challenge in vitro.