Enamel diffusion modulated by Er:YAG laser: (Part 1)—FRAP

Several studies have demonstrated the caries protective effect of lasers by strengthening enamel crystalline structure. However, the effect of laser on enamel diffusion (ED) remains unclear. Objectives This study aimed to quantify the laser-induced alteration of diffusion coefficients (DC) in enamel using fluorescence recovery after photobleaching (FRAP). Methods Eleven caries-free enamel sections were characterized morphologically using stereomicroscopy, polarized light microscopy and scanning electron microscopy, before and after laser treatment with Er:YAG laser 50 mJ × 5 s × 5 Hz. With 20 μM fluorescein, DCs were measured (n = 11) by FRAP coupled with confocal microscopy. Results The DCs measured were 2.89 ± 0.61 × 10−7 cm2/s and 4.076 ± 0.73 × 10−7 cm2/s, at the lased and unlased areas, respectively (p = 0.001). Conclusions This study has confirmed the reduction of ED as a potential mechanism involved in laser-induced caries prevention. FRAP was demonstrated to be a promising technique for evaluating diffusion-related phenomenon in enamel.