To treat smooth surface and proximal non-cavitated caries lesions, a modified and commercially developed German technique called "resin infiltration" has been used to infiltrate the porosities of enamel lesions with a low-viscosity resin, establishing a diffusion barrier within the lesion without selecting any material on the enamel surface. Thus, resin infiltration can delay the time for restoration placement. Hydrochloric acid erodes the lesion surface, and a low-viscosity resin is infused into the intercrystalline spaces of hypocalcified or demineralized enamel from the back. Previously filled with air (RI = 1.00) or water (RI = 1.33), the porous enamel now has a resinous material infiltrating it, which has a refractive index (RI) (1.52) closer to hydroxyapatite (1.62). The Icon-Infiltrant (DMG America) is a highly fluid, unfilled resin with a high penetration coefficient that will be carried into the porosities of the lesion by capillary action, and once there, it will be light cured, occluding the microporosities, and stopping the demineralization process. Resin infiltration is a nonsurgical, effective, and permanent therapy option. Patients may get therapy in as little as a few minutes without needing a local anesthetic or removing healthy tooth structure, and they can anticipate permanent, irreversible effects.