¹ Clinical Associate professor, NYU College of Dentistry, United States

The emergence of blue laser technology — particularly wavelengths of 405 nm and 445 nm — represents a significant advancement in modern dental practice. Unlike traditional infrared and near-infrared laser systems, blue laser light operates through distinct photobiological mechanisms that offer broad versatility across multiple dental disciplines. This comprehensive review synthesizes current evidence on the mechanism of action of blue laser light in dentistry, encompassing its intrinsic antimicrobial properties via endogenous photosensitization, its role in antimicrobial photodynamic therapy (aPDT) with exogenous photosensitizers (curcumin, riboflavin, methylene blue), photobiomodulation effects on host tissues, surgical applications, composite resin polymerization, tooth bleaching activation, caries detection, and gingival depig mentation. Comparative analyses with established wavelengths — including 635 nm, 660 nm, 810 nm, 940 nm, 980 nm diode lasers, Er:YAG, Er,Cr:YSGG, Nd:YAG, and CO₂ lasers — are presented through structured evidence tables. Current evidence indicates meaningful antimicrobial activity against key oral pathogens including Streptococcus mutans, Porphyromonas gingivalis, Enterococcus faecalis, and Candida albicans, while simultaneously providing photobiomodulatory benefits on fibroblast proliferation, tissue healing, and microcirculation. Clinical applications in periodontics, endodontics, oral surgery, orthodontics, restorative dentistry, and implantology are critically reviewed. The evidence supports blue laser technology as a multifunctional, minimally invasive, and promising tool for the contemporary dental clinician, with a favorable safety profile and expanding therapeutic indications.