The Effect of Phosphoric Acid Present in Soda Pop on Tooth Decay

This experiment was conducted to determine how the phosphoric acid found in soda pop affects tooth decay. The phosphoric acid, or H3PO4, found in soda pop is corrosive to teeth and causes a loss of tooth mass because it erodes the enamel of the tooth. Titration was used to determine the molarity of phosphoric acid present in Coca-Cola Classic. In order to conduct the titration, a Coca-Cola and tap water solution was created with a 1:4 ratio in milliliters. Phenolphthalein indicator solution was added to the Coke-water solution; the indicator turned the Coca-Cola and tap water solution pink when the acid was neutralized. Solid sodium hydroxide, NaOH, pellets and tap water were used to create a sodium hydroxide solution of 0.1 M. The NaOH solution was then placed in a 50 mL glass burette and titrated into the Coca-Cola and tap water solution. Once the Coke-water solution turned rosy pink, the acid in the soda pop was neutralized. The results obtained from the titration suggested that the molarity of H3PO4 is 0.069 M in Coca-Cola Classic. Next, the experiment to discover the effect of phosphoric acid on teeth was conducted. Twenty-nine sterilized teeth were obtained and after an initial massing, each tooth was placed in an individual test tube filled with 10 mL of 0.069 M H3PO4solution. After five days of submersion in the H3PO4 solution, the teeth were massed again and the total change in tooth mass was found. A matched pairs one sample t test was used to yield the results for the total change in tooth mass. The results obtained from these calculations found that the average change in tooth mass was a loss of 0.03 g per tooth.

Research Done By:

Laura Kuznia
L'Anse Creuse High School

Tara Meldrum
South Lake High School