The objectives of the present study are to: 1) Study the antimicrobial, regenerative and stimulating effect of Er:Cr:YSGG and diode laser on cells and tissues of dental origin; 2) Evaluate the antimicrobial effect of high-energy lasers, regarding S.mutans and L.acidophilus in the course of minimally-invasive treatment of dentinal caries; 3) Conduct a comparative in vitro study of gap formation and microleakage in proximal cavity preparation with high-energy Er:Cr:YSGG laser, ultrasonic tips and conventional burs, applied with or without air abrasion; 4) Investigate the change in the mineral density of dentin and evaluate the volume of removed hard dental tissue after atraumatic removal of a carious lesion with enzyme excavation, laser and conventional cavity preparation; 5) Evaluate the volume changes of Bulk-fill composite materials by micro-CT examination; 6) Study the abilities of DIAGNODENT pen, micro-CT and digital photometric and colorimetric analysis to diagnose initial carious lesions. 7) Investigate the in vitro effect of different remineralizing agents with or without the aid of lasers on tooth enamel by the application of DIAGNOdent pen, DIAGNOcam and digital photometric and colorimetric analysis; 8) Create and approve a methodology for digital photometric and colorimetric analysis of carious lesions in enamel. The project proposal is in line with the objectives of the National Strategy for the Development of Scientific Research by initiating and stimulating a comprehensive process of modernization in scientific research units and ensuring higher research quality. The development of a modern scientific infrastructure will enable scientific breakthroughs, knowledge gap analysis and design studies to support planning and decision making in the field of dentistry.