Effect of additional acid etching on bond strength and structural reliability of adhesive systems applied to caries-affected dentin .
OBJECTIVE
To evaluate the effect of additional acid etching on the microtensile bond strength (μTBS) and Weibull modulus (m) of two adhesive systems applied to caries-affected dentin.


METHODS
Ninety human molars with coronal carious lesions were sectioned to produce flat coronal surfaces containing caries-affected (CAD) and sound dentin (SD). The teeth were allocated to 6 groups: SB-CT: Control - Single Bond applied according to the manufacturer's instructions; SB+15: Single Bond with additional 35% phosphoric acid etching for 15 s; SB+30: Single Bond with additional etching for 30 s; CF-CT: Control - Clearfil SE Bond applied according to the manufacturer's instructions; CF+15: Clearfil SE Bond with additional 35% phosphoric acid etching for 15 s; CF+30: Clearfil SE Bond with additional etching for 30 s. Composite crowns were incrementally built up. The teeth were sectioned after 24 h in order to produce 2 to 3 slices involving each dentin substrate. The slices were trimmed into hourglass-shaped specimens (n = 30) and tested in tension at a crosshead speed of 1 mm/min. Data were analyzed by three-way ANOVA, Tukey's test (p < 0.05) and Weibull statistics.


RESULTS
The μTBS to CAD was lower than to SD, except for SB+30. The additional etching increased the μTBS to CAD. The μTBS to SD increased with CF, but decreased with SB. CAD produced lower values of m with both adhesive systems. SB resulted in lower m in sound dentin than CF. The additional etching did not affect the m.


CONCLUSIONS
The additional etching increases the μTBS to CAD, but not enough to reach the μTBS values obtained in SD. The structural reliability of the bond to CAD is not affected by the additional etching.
Zanchia
Cesar Henrique
CH
Department of Restorative Dentistry, Federal University of Pelotas, Pelotas, Brazil. chzanchi@gmail.com
D'Avila
Otavio Pereira
OP
Rodrigues-Junior
Sinval Alberto
SA
Burnett
Luiz Henriques
LH
Demarco
Flavio Fernando
FF
Pinto
Marcia Bueno
MB
D000134:Acid Etching, Dental / Q000379:methods*; D000704:Analysis of Variance; D001840:Dental Bonding; D003731:Dental Caries / Q000473:pathology*; D003738:Dental Cements; D003799:Dental Stress Analysis; D003804:Dentin / Q000473:pathology*; D006801:Humans; D008422:Materials Testing; D008963:Molar; D019279:Resin Cements; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D013718:Tensile Strength
C554641:Adper single bond 2; C438313:Clearfil SE Bond; D003738:Dental Cements; D019279:Resin Cements