Tensile bond strength to primary dentin after different etching times.
OBJECTIVE
The purpose of this study was to assess in vitro the effect of etching time on tensile bond strength to primary dentin.


METHODS
Forty crowns of sound primary molars were embedded in acrylic resin (N=40). Dentin was exposed in the buccal surfaces, and the specimens were randomly assigned into 4 groups (N=10), according to the etching time with 35% phosphoric acid gel: G1=7 seconds; G2=10 seconds; G3=15 seconds; G4=20 seconds. A 3-mm diameter bonding site was demarcated, the adhesive system was applied, and resin composite cones were built up. After 24 hours, tensile bond strength tests were performed. Data were submitted to statistical analysis using one-way analysis of variance and the Tukey test.


RESULTS
Means (+/-SD) were (MPa): (1) G1=10.04 (+/-3.30); (2) G2=7.78 (+/-4,49); (3) G3=8.78 (+/-2.96); (4) G4=7.60 (+/-1.91).


CONCLUSIONS
Although no statistically significant difference among the times used was found, the 7-second etching time promoted the highest bond strength mean and can be used in primary dentin. Additionally, this lower etching time reduces chair time, which is a significant benefit when treating children.
Torres
Carolina Paes
CP
Department of Pediatric Clinics, Preventive and Social Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, São Paulo, Brazil. carolptorres@hotmail.com
Chinelatti
Michelle Alexandra
MA
Gomes-Silva
Jaciara Miranda
JM
Borsatto
Maria Cristina
MC
Palma-Dibb
Regina Guenka
RG
D000134:Acid Etching, Dental / Q000379:methods*; D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins; D001840:Dental Bonding; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D003804:Dentin; D003806:Dentin Permeability; D017220:Dentin-Bonding Agents; D006801:Humans; D008963:Molar; D010756:Phosphoric Acids; D019279:Resin Cements; D013718:Tensile Strength; D013997:Time Factors; D014094:Tooth, Deciduous
D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; D010756:Phosphoric Acids; D019279:Resin Cements; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate; C030242:phosphoric acid