Effect of CO2 Laser and 1.23% Acidulated Phosphate Fluoride on Acid Resistance and Fluoride Uptake of Human Tooth Enamel: An In Vitro Assessment

Abstract

To evaluate the effectiveness of CO2 laser treatment before applying 1.23% acidulated phosphate fluoride (APF), through topically applied 1.23% APF solution, and after applying 1.23% APF on acid resistance and fluoride uptake of the enamel. Sixty non-carious human premolars were extracted due to the orthodontic reason and stored in distilled water solution under refrigeration. Using a water-cooled diamond disc, enamel slabs of 4 mm × 4 mm × 1.5 mm were cut from the buccal surface of each tooth. Sixty samples were randomly divided into one control group and five test groups of 10 premolars each. Solution was prepared for wet chemical analysis followed by fluoride analysis that was carried out using a fluoride ion selective electrode (Thermo Scientific Orion 4-Star Plus ISE Meter). The weight of enamel (WE) was determined from the amount of calcium (Ca) etched away considering the fact that the Ca content of the human enamel is 37.4 wt%. The subgroups were statistically analyzed using ANOVA for fluoride determination and evaluation of acid resistance. There was a significant increase in acid resistance of enamel slabs when treated individually or in combination of a low-power CO2 laser and 1.23% APF solution. Application of 1.23% APF solution after low-power CO2 laser treatment showed maximum increase in acid resistance. Application of a low-power pulsed CO2 laser through topically applied 1.23% APF solution resulted in a detrimental effect of the human tooth enamel with resultant decrease in acid resistance. High fluoride uptake does not necessarily indicate increased acid resistance. The present study provides evidence that a low-power CO2 laser can be used effectively in combination with topically applied 1.23% APF solution in order to make the enamel more resistant to acid attack, thereby helping in controlling dental caries.