Chemical Factors that Influence Erosive Tooth Surface Loss

The term “chemical factors” is used to describe parameters inherent to erosive beverages, food, or other products. The three main parameters are:

  1. pH and Buffering Capacity: In general, the greater the buffering capacity of an edible item, the longer it will take for saliva to neutralize the product’s acid. So a beverage with a higher buffering capacity will be more erosive than others within the same pH class. Even if a product is at a low pH, it is possible that other factors are strong enough to prevent erosion. Similarly, it is also possible that a less acidic product can cause erosion because it has the capacity to complex calcium, pulling the mineral out of the tooth surface to cause demineralization. While pH is an important factor, there is no specific pH of a product below which damage will occur.2
  2. Acid Type: The erosive character of lactic and citric acid in products is higher than that of acetic, maleic, phosphoric, and tartaric acids.24
  3. Calcium, Phosphate, and Fluoride Concentration: Solutions oversaturated with respect to dental hard tissue will protect against dental surface softening.25,26 A low degree of undersaturation with respect to enamel or dentin leads to a very initial surface demineralization which is followed by a local rise in pH and increased mineral content in the liquid surface layer adjacent to the tooth surface. This layer will then become saturated with respect to enamel and will not demineralize further. A high degree of undersaturation with respect to dental tissue will demineralize the tooth surface considerably more.25,26

Studies have shown that a drink which contains citric acid that was supplemented with calcium, phosphate, and fluoride reduced the erosive potential of the solution.27 The same was true when acidic carbonated drinks were modified with these three minerals.2,28 Yogurt, which is acidic with a pH of 4 hardly has any erosive effect due to its high calcium and phosphate content, which makes it supersaturated with respect to the hydroxyapatite in enamel.2

Other parameters to consider are the calcium-chelating properties of the product being consumed, and the stickiness of the product being consumed, with more sticky products generally being linked to higher erosion risk.2