Effect of Er:YAG laser irradiation combined with fluoride application on resistance of primary and permanent dental enamel to erosion

Erosion is an important cause of tooth mineral loss. The combined use of lasers and fluoride has been introduced as a novel modality for the prevention of enamel demineralization. This study aimed to assess the effect of Er:YAG laser combined with fluoride application on primary and permanent enamel resistance to erosion.

Eighty enamel specimens of permanent (n=40) and primary (n=40) molars were prepared and randomly assigned to four groups:  C —control (no pretreatment), F—acidulated phosphate fluoride (APF) gel, FL—APF gel application followed by Er:YAG laser irradiation, and LF—Er:YAG laser irradiation followed by the application of APF gel . The specimens were then submitted to pH cycling using Coca-Cola (pH=2.4). Enamel micro-hardness was measured using the Vickers micro-hardness tester before pretreatment and after the erosive process. The collected data were analyzed using the Kolmogorov-Smirnov test, two-way ANOVA and repeated measures ANOVA.

The micro-hardness of both permanent and primary enamel significantly decreased after the erosive process (P<0.05). In the permanent enamel specimens, the greatest reduction in micro-hardness was noted in groups C and F, while the least reduction was noted in group FL. However, these differences were not statistically significant (P>0.05). In the primary enamel specimens, the greatest reduction in micro-hardness was noted in groups C and LF, while the least reduction was noted in group F. These differences were not statistically significant (P>0.05).

Within the limitations of this study, Er:YAG laser irradiation combined with fluoride application could not prevent erosion in permanent and primary enamel during the erosive process.