Aim: This in vitro pilot study was undertaken to investigate the effects of Neodymium: Yttrium Aluminium Garnet
(Nd:YAG), Erbium: Yttrium Aluminium Garnet (Er:YAG) and Helium Neon (HeNe) laser radiation on dentine surfaces in
extracted human teeth.
Material and Methods: Instrumented root surfaces and etched and unetched dentine discs were irradiated with a
Nd:YAG laser operating at 3.5, 3.75 or 4W or an Er:YAG laser operating at 60, 80, 100mJ or with a HeNe laser. Results:
The Nd:YAG laser produced melting and resolidification of dentine on all surfaces while the Er:YAG laser produced
craters with closed tubules in root surfaces, but open tubules in dentine discs. The HeNe laser produced no apparent
surface alteration. Both lased and unlased control surfaces were compared using Scanning Electron Microscopy (SEM).
Conclusions: Irradiation with the Nd:YAG and Er:YAG lasers caused significant disruption of the dentine surfaces
on both root surfaces and also on dentine discs. Nd:YAG radiation produced irregular melting and resolidification of the
dentine surface with some occlusion of open dentine tubules. Er:YAG radiation caused ablation of dentine and produced
craters with open tubules in the dentine discs, but closed tubules on most root surfaces. Irradiation using a HeNe laser
produced no noticeable surface effect
