The near red-pulsed erbium, chromium:yttrium-scandium-gallium-garnet laser hydrokinetic system, or Er,Cr:YSGG laser HKS, is effective in cutting dental hard tissues. In this longitudinal study, the authors studied the continuously erupting open-apex incisors of New Zealand albino rabbits and the constricted apex teeth of beagles to determine the effects of HKS-produced lesions at various energy levels and of preparations produced by a tapered fissure bur on dental pulp. No pulpal inflammatory responses could be identified either immediately or 30 days after surgery in HKS preparations that removed enamel and dentin without pulp exposure.