Effects of Er:YAG and Nd:YAG lasers on dentin permeability in root surfaces: a preliminary in vitro study.
OBJECTIVE
This in vitro study evaluated the effects of Nd:YAG and Er:YAG lasers on reducing dentin permeability by sealing opened tubules.


BACKGROUND
According to hydrodynamic theory, dentine hypersensitivity occurs when dentin is exposed with tubules opened. Consequently, a painful sensation occurs due to an intensification of the dentinal permeability. Treatment, therefore, should be based on a decrease of this permeability, achieved by the obliteration of dentinal tubules. The Nd:YAG laser is known for its capacity to seal dentinal tubules; however, few studies concerning treatment with Er:YAG laser are available.


METHODS
The Nd:YAG laser was used, based on two parameters: (A) 1.0 W, 10 Hz, and (B) 1.5 W, 15 Hz. The Er:YAG laser was used at 60 mJ, 2 Hz, four applications of 20 sec each, at 6 mm from the surface. After irradiation, all samples were immersed in 1% Rodamine B dye solution, in order to evaluate the penetration of the dye solution and observe the decrease/increase of dentinal permeability after the laser treatment.


RESULTS
The laser conditions used in the present study decreased the permeability as follows: (a) when using the Er:YAG laser at 60 mJ, 2 Hz in 26.05%, and (b) when using the Nd:YAG laser at 1.5 W, 15 Hz in 19.03%--with no statistical difference between them. Additionally, the Nd:YAG laser at 1.0 W, 10 Hz, decreased permeability in 4.59%, with a smaller effect.


CONCLUSIONS
According to the results of this in vitro study, the Er:YAG laser at 60 mJ, 2 Hz, and the Nd:YAG laser at 1.5 W, 15 Hz are useful for decreasing dentin permeability.
Aranha
Ana Cecília Corrêa
AC
Department of Restorative Dentistry, School of Dentistry, University of São Paulo, São Paulo, Brazil.
Domingues
Fernanda Baudichon
FB
Franco
Vanessa Ormeni
VO
Gutknecht
Norbert
N
Eduardo
Carlos de Paula
Cde P
D000704:Analysis of Variance; D003786:Dental Pulp Cavity / Q000528:radiation effects*; D003806:Dentin Permeability / Q000528:radiation effects*; D003807:Dentin Sensitivity / Q000517:prevention & control; D004871:Erbium; D005069:Evaluation Studies as Topic; D006801:Humans; D066298:In Vitro Techniques; D053685:Laser Therapy; D008963:Molar / Q000528:radiation effects; D009354:Neodymium; D011336:Probability; D012016:Reference Values; D012390:Root Canal Therapy / Q000295:instrumentation* / Q000379:methods; D012494:Sampling Studies; D012680:Sensitivity and Specificity
D009354:Neodymium; D004871:Erbium