Methods: Forty human premolars painted with an acid resistant nail varnish except for a buccal surface window were stored for four weeks in artificial saliva. The samples were divided into four groups and subjected to testing solutions 3 times a day for 5 minutes during weekdays. Erosive properties of orange juice (Tesco value), cola (Coca-Cola) and sugar-free cola (Diet Coke) were tested against a negative control mineral water (Volvic). Twice a week the samples were photographed using QLF and at the end of the experiment TMR analysis was performed.
Results: With QLF there was a significant correlation between exposure time and fluorescence loss (ΔQ) for orange juice (r = 0.93, p < 0.001) and sugar-free cola (r = 0.68, p = 0.043), while cola and water groups had no significant correlation (r = 0.24, p > 0.05). Direct measurement of mineral loss using TMR demonstrated that all three acid containing drinks developed artificial erosive lesions. Mineral loss (ΔZ) for cola was 3991.8 ± 434.6, for sugar-free cola – 1690.4 ± 257.1, for orange juice – 922.5 ± 237.0 and mean delta Z value recorded on the surface of teeth exposed to mineral water was 224.3 ± 67.0 with significant difference between all groups (ANOVA and Tukey post hoc, p < 0.001). Mean depth of the crater of the lesion as a percentage of the whole lesion depth was 36.1, 74.1 and 59.3% for orange juice, cola and sugar-free cola respectively (ANOVA and Tukey post hoc, p < 0.001).
Conclusion: Among all three acid containing drinks, cola had the greatest erosive potential. Using sugar substitutes significantly reduced the erosive properties of carbonated cola.