Shortening of primary dentin etching time and its implication on bond strength.
OBJECTIVE
The aim of this study was to investigate the influence of shortening the etching time on the bond strength of a conventional and a self-etching primer adhesive system used in primary tooth dentin.


METHODS
Flat dentin surfaces were obtained from 24 primary molars, randomly assigned to 4 experimental groups. The adhesive systems Single Bond and Clearfil SE Bond were applied in two groups according to the manufacturers' recommendations. In the other two groups, the adhesives were applied after half-time of acid etching, 7 s for Single Bond and 10 s for Clearfil SE Primer. Resin crowns were built up and after 24 h storage in water at 37 degrees C, the teeth were sectioned to produce beams with cross-sectional area of approximately 0.49 mm2. Specimens were tested in tension at 0.5 mm/min until failure. Fractured specimens were analyzed to determine the failure mode.


RESULTS
Tensile bond strengths for Single Bond in primary dentin were higher than for Clearfil SE Bond. Shortening of acid etching time improved bond strength only for Single Bond, while no statistically significant difference was observed for Clearfil SE Bond when both etching times were compared.


CONCLUSIONS
No detrimental effect on bond strength was observed when the time of acid etching was shortened in 50%. Shortening the time for a procedure in a small child without compromising the quality of the work is a very important finding for the practicing pediatric dentist.
Sardella
Tálita Nogueira
TN
Department of Orthodontics and Pediatric Dentistry, Araraquara School of Dentistry, UNESP. Rua Humaitá, 1680, Araraquara, São Paulo 14801-903, Brazil.
de Castro
Fabrício Luscino Alves
FL
Sanabe
Mariane Emi
ME
Hebling
Josimeri
J
D000134:Acid Etching, Dental / Q000379:methods*; D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000494:pharmacology; D002675:Child, Preschool; D001840:Dental Bonding; D003799:Dental Stress Analysis; D003804:Dentin / Q000187:drug effects*; D003806:Dentin Permeability; D017220:Dentin-Bonding Agents / Q000494:pharmacology*; D006801:Humans; D008422:Materials Testing; D011897:Random Allocation; D019279:Resin Cements / Q000494:pharmacology; D013718:Tensile Strength; D013997:Time Factors; D014094:Tooth, Deciduous / Q000187:drug effects*
C438313:Clearfil SE Bond; D017220:Dentin-Bonding Agents; D019279:Resin Cements; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate