Subablative Er:YAG laser effect on enamel demineralization

Objectives: To characterize the cariostatic potential of a low-energy Er:YAG laser treatment. Methods: Twelve sound premolars were selected. Two 2 × 1 mm windows were created on each tooth and randomly assigned to L ₁ and L₂ groups. Three sites in each window were chosen with the middle site as the control and the left and right ones receiving Er:YAG laser treatment of 5.1 J/cm² (L₁) or 2.0 J/cm² (L₂), respectively. The teeth were further subjected to 4-day pH cycling to create caries-like lesions. After mineral quantification using a micro-computed tomography scanner, the preventive effects (ΔML = mineral loss of the control area minus that of the lased area) of L₁ and L₂ treatments were calculated based on the difference in the gray value of the control and lased sites. Results: Significant inhibitory effects of L₁ and L₂ on enamel demineralization were demonstrated (both p ≤ 0.001), with the L₁ treatment having a greater effect (45.2%) than the L₂ treatment (25.2%, p = 0.004). Conclusions: Subablative low-energy Er:YAG laser irradiation can significantly prevent enamel demineralization potentially through the retardation of enamel diffusion. This study confirmed that high-energy laser treatment, which may damage the peripheral and underlying tissues, may not be needed for caries prevention.