Nd:YAG laser influence on sound dentin bond strength.
OBJECTIVE
In the present study, the authors evaluated tensile bond strength of composite resin to dentin treated with Nd:YAG laser before and after bonding procedures.


BACKGROUND
Lasers have been widely used in dentistry and have contributed to the development of new technologies. Adhesive systems have been indicated for most dental procedures and have produced good results. Studies concerned with the combined use of this adhesive system was the subject of this study.


METHODS
Thirty noncarious human anterior teeth, freshly extracted, for periodontal reasons, were used. After grinding the buccal dentinal surface until its exposition, specimens were separated into three groups and received the following treatments: (group 1) control--acid etching plus primer plus bond; (group 2) laser plus acid etching plus primer plus bond; (group 3) acid etching plus primer plus bond plus laser. Specimens of composite resin (Z100, 3M, Saint Paul, MN) were constructed on an inverted truncated 3-mm diameter cone mold. Tensile bond strength was performed using Inströn Universal machine, at 0.5 mm/min speed.


RESULTS
Analysis of variance (ANOVA) (p < 0.05) determined that the type of dentinal treatments used had an influence on tensile bond strength. Tukey's test, however, showed that group 1 (15.46) and 3 (15.67) had similar results both of which were higher than group 2 (4.57).


CONCLUSIONS
Based on the results obtained, one can conclude that group 1 (without laser) and group 3 (laser after bonding) had similar results, both higher than those observed for group 2 (laser before bonding). These results indicate that more research is needed about how a hybrid layer is formed when laser radiation is used.
Matos
A B
AB
University of São Paulo, School of Dentistry, Operative Dentistry Department, São Paulo, Brazil. p-bona@siso.fo.usp.br
Oliveira
D C
DC
Kuramoto
M
M
Eduardo
C P
CP
Matson
E
E
D003804:Dentin / Q000528:radiation effects*; D006801:Humans; D007834:Lasers