Acquired acid resistance of human enamel treated with laser (Er:YAG laser and Co(2) laser) and acidulated phosphate fluoride treatment: An in vitro atomic emission spectrometry analysis

BACKGROUND: Dental caries is essentially a process of diffusion and dissolution. If the aspect of dissolution can be curtailed some degree of prevention can be achieved. AIMS: The present study was carried out to evaluate and compare the effect of Er:YAG laser and Co(2) laser irradiation combined with acidulated phosphate fluoride treatment on in vitro acid resistance of human enamel. DESIGN: An in vitro study was carried out on 30 human premolars to evaluate the enamel's acid resistance using an atomic emission spectrometry analysis. MATERIALS AND METHODS: A total of 60 enamel specimens were prepared from 30 human premolars and were randomly assigned to 6 groups: (1) Untreated (control); (2) 1.23% acidulated phosphate fluoride (APF) gel application alone for 4 min; (3) Er:YAG laser treatment alone; (4) Co(2) laser treatment alone; (5) Er:YAG laser + APF gel application; (6) Co(2) laser + APF gel application. The specimens were then individually immersed in 5 ml of acetate buffer solution (0.1 mol/L, pH 4.5) and incubated at 37°C for 24 h, and the acid resistance was evaluated by determining the calcium ion concentration using the atomic emission spectrometry. STATISTICAL ANALYSIS: An ANOVA model was constructed (P value of 0.05), followed by Tukey's test for multiple pair wise comparisons of mean values. RESULTS: Significant differences were found between the control group and the test groups (P < 0.001). CONCLUSIONS: Combining acidulated phosphate fluoride with either Er:YAG or Co(2) laser had a synergistic effect in decreasing the enamel demineralization more than either fluoride treatment or laser treatment alone.