Effect of conditioner on microtensile bond strength of self-adhesive resin cements to dentin.
OBJECTIVE
Evaluate, in vitro, the microtensile bond strength (µTBS) of RelyX ARC conventional resin cement and RelyX Unicem and Maxcem self-adhesive resin cements to dentin, and the influence of polyacrylic acid pretreatment on the µTBS.


METHODS
Flat dentin surfaces were obtained in 15 third molars which were randomly divided into 5 groups: Group 1 - RelyX ARC (control); Group 2 - RelyX Unicem; Group 3 - Maxcem Elite; Group 4 - 22.5% polyacrylic acid and RelyX Unicem; Group 5 - 22.5% polyacrylic acid and Maxcem Elite. A block of composite resin was built over the resin cements. The samples were sectioned to obtain beams, and 20 specimens for each group were submitted to µTBS on a universal testing machine. Failure modes were analyzed by scanning electron microscopy.


RESULTS
According to ANOVA and Tukey test, the highest µTBS mean (MPa) was obtained with RelyX ARC (21.38), which did not differ statistically from Maxcem Elite with polyacrylic acid pretreatment (19.22) and RelyX Unicem with polyacrylic acid pretreatment (17.75) (p>0.05). The latter two groups did not differ statistically from RelyX Unicem (16.98) (p>0.05). The lowest mean was obtained for Maxcem Elite (6.43), which differed statistically from the other groups (p<0.05). All failures were adhesive for Maxcem Elite without polyacrylic acid pretreatment, and mixed failures were predominant in the other groups.


CONCLUSIONS
RelyX ARC achieved higher µTBS to dentin in comparison to the self-adhesive resin cements. Polyacrylic acid pretreatment was effective in improving the µTBS of Maxcem Elite, but did not influence the µTBS for RelyX Unicem.
Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga 6681, Porto Alegre, Rio Grande do Sul, Brazil.
Daniela
D
Tonial
Paula Cristine
PC
Ghiggi
André Amorim
AA
Lise
Luiz Henrique
LH
Burnett
Hugo Mitsuo Silva
HM
Oshima
Ana Maria
AM
Spohr
D000134:Acid Etching, Dental / Q000379:methods*; D000180:Acrylic Resins; D000269:Adhesives; D000704:Analysis of Variance; D001840:Dental Bonding; D003737:Dental Cavity Preparation; D003799:Dental Stress Analysis; D003804:Dentin; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry; D018709:Statistics, Nonparametric; D013718:Tensile Strength
D000180:Acrylic Resins; D000269:Adhesives; D017220:Dentin-Bonding Agents; D019279:Resin Cements; C006903:carbopol 940