Strengthening of tooth enamel by a remineralizing toothpaste after exposure to an acidic soft drink

The effect of remineralizing and conventional toothpaste treatments on the hardness of intact and acid soft drink-etched enamel were assessed in a lab oratory study. The remineralizing toothpaste (Enamelon(R) Toothpaste) used in the study contains NaF, and simultaneously provides dissolved calcium, p hosphate and fluoride ions. The conventional toothpaste contains NaF in a s ilica base. Sound extracted maxillary human incisors, mounted in epoxy resi n with the facial incisal two-thirds exposed, were polished with 0.3 mu alu mina. Groups of ten teeth were exposed to either twenty 5-minute treatments with an acid soft drink (pH 2.4), remineralizing or conventional fluoride toothpaste, or to twenty alternating cycles of a 5-minute protective treatm ent with either the remineralizing or conventional toothpastes, followed by 5-minute exposures to the acid soft drink, or to 20 five-minute exposures to the acid soft drink followed by 20 five-minute restorative treatments wi th the remineralizing or conventional toothpastes. Knoop Hardness measureme nts were made before and after treatment using a 500 g load and 15-second d well lime. Acid soft drink exposure produced a 15.4% drop in hardness compa red with 4.9% and 1.6% hardness increases due to treatments of intact ename l with the remineralizing and conventional toothpastes, respectively. Prote ctive treatments using the remineralizing and conventional toothpastes sign ificantly reduced the drop in hardness due to acid soft drink exposure to 3 .3% and 6.2%, respectively Restorative treatments by the remineralizing and conventional toothpastes significantly increased the hardness of the acid soft drink-weakened enamel by 12.1% and 7.38, respectively. Both toothpaste s were effective in inhibiting damage due to acid soft drink exposure, but the remineralizing toothpaste was more effective in hardening intact and de calcified enamel than the conventional toothpaste (p < 0.05).