Black tea effect on the pH and salivary buffer capacity

Salivary buffer capacity is the major regulating system of pH changes in oral cavity, maintaining the mineralization demineralization equilibrium. If it is broken (pH fall under 5.5) is when the carious process begins.

Tea has shown to have a favorable effect over the systemic and oral health, without producing significant variations in the oral pH.

Objective:

To describe the effect of black tea on the buffer capacity after a single fall on salivary pH.

Methods:

We selected 10 subjects with high buffer capacity (according to Ericcson's Method) between 23 and 25 years old, without pathologies, etc. To induce the fall on pH and buffer capacity values, we used a soft drink, and to observe the black tea effect, we gave it to drink like an infusion. Temperatures and pH of soft drink and infusion were registered previously, and times of intake were controlled too.

Then, we took 3 consecutive samples of non-stimulated saliva (by 15mins each): 1. Basal, 2. Post-intake of soft drink and 3. Post-intake of black tea to determinate the pH and buffer capacity values in each sample. Results were analyzed with SPSS software through U-Mann Whitney test.

Results:

The basal pH value was 7.12 and 5.84 for buffer capacity. Carbonated drink decreased the basal salivary pH to 6.93 (p=.028) and to 5.27 the buffer capacity (p=.075), and the black tea infusion raised the pH to 7.25 (p=.009) and to 5.94 the buffer capacity (p=.041). About last values, these did not have statistical significance (p=.290 and p=.880 respectively).

Conclusions:

In this study, on the sample of subjects with high buffer capacity, black tea shown a rise on the pH and salivary buffer capacity values subsequent to a slight decrease produced by a soft drink.