Lasers are continuous to be an important tool in dentistry for providing comfort to the patients. Recently ultrafast lasers open the possibility for damage free treatment. In this book the processing of hard dental tissues (enamel and dentin) in vivo using excimer laser radiation is described. The influence of laser processing parameters such as radiation fluence and number of pulses on morphology, structure and chemistry of the tissues has been explained. Possible applications of excimer laser processing including dental hypersensitivity and restorative dentistry have also been discussed. The electron microscopy images of the treated tissue surfaces would be useful for dentists and researchers to understand the laser tissue interaction mechanisms.