Effect of temporary cements on the shear bond strength of luting cements

Abstract

ObjectiveThe purpose of this study was to evaluate, by shear bond strength (SBS) testing, the influence of different types of temporary cements on the final cementation using conventional and self-etching resin-based luting cements.Material and MethodsForty human teeth divided in two halves were assigned to 8 groups (n=10): I and V (no temporary cementation); II and VI: Ca(OH)2-based cement; III and VII: zinc oxide (ZO)based cement; IV and VIII: ZO-eugenol (ZOE)-based cement. Final cementation was done with RelyX ARC cement (groups I to IV) and RelyX Unicem cement (groups V to VIII). Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level.ResultsMeans were (MPa): I - 3.80 (±1.481); II - 5.24 (±2.297); III - 6.98 (±1.885); IV - 6.54 (±1.459); V - 5.22 (±2.465); VI - 4.48 (±1.705); VII - 6.29 (±2.280); VIII - 2.47 (±2.076). Comparison of the groups that had the same temporary cementation (Groups II and VI; III and VII; IV and VIII) showed statistically significant difference (p<0.001) only between Groups IV and VIII, in which ZOE-based cements were used. The use of either Ca(OH)2 based (Groups II and VI) or ZO-based (Groups III and VII) cements showed no statistically significant difference (p>0.05) for the different luting cements (RelyXTM ARC and RelyXTM Unicem). The groups that had no temporary cementation (Groups I and V) did not differ significantly from each other either (p>0.05).ConclusionWhen temporary cementation was done with ZO- or ZOE-based cements and final cementation was done with RelyX ARC, there was an increase in the SBS compared to the control. In the groups cemented with RelyX Unicem, however, the use of a ZOE-based temporary cement affected negatively the SBS of the luting agent used for final cementation.

Effect of temporary cements on the bond strength of a resin cement to a pre-hybridized dentin

“…Provy is a eugenol-containing temporary cement; a substance which is known to be a strong inhibitor of polymerization of resinbased materials (FIORI-JÚNIOR et al, 2010) and also able to reduce bond strength FIORI-JÚNIOR et al, 2010). Once in contact with water in the dentinal tubules, eugenalate in temporary cement is hydrolyzed, a process that releases eugenol (CARVALHO et al, 2007).…”

“…Once in contact with water in the dentinal tubules, eugenalate in temporary cement is hydrolyzed, a process that releases eugenol (CARVALHO et al, 2007). This substance tends to protonate free radicals generated during the polymerization reaction (FIORI-JÚNIOR et al, 2010). As the amount of free radicals available decreases, a hybrid layer with a low degree of conversion is generated, which impairs adhesion.…”

“…Although there is conflicting evidence regarding the effect of temporary cement on adhesion (FIORI-JÚNIOR et al, 2010;SCWARTZE et al, 2007), most studies indicate that residues of temporary materials can affect cementation of indirect restorations CARVALHO et al, 2007). Contaminants in temporary cements can impair wetting of the substrates, which impacts the bond strength of final cementation (TAKIMOTO et al, 2012).…”

“…However, after tooth preparation for a fixed restoration, the prepared tooth is covered with a provisional restoration, which is coated with temporary cement. The contamination of dentin with temporary cement has been reported to significantly reduce the bond strength values of resin cements with dentin (RIBEIRO et al, 2011;SILVA et al, 2011;FIORI-JÚNIOR et al, 2010;CARVALHO et al, 2007).…”

Removal of temporary cements following an immediate dentin hybridization approach: a comparison of mechanical and chemical methods for substrate cleaning

“…For example, provisional cements or sealing agents containing eugenol (a chemical component used as a catalyst) are known to reduce bond strength of definitive restorations to previously contaminated substrates [4]. Eugenol has an high-diffusion capacity into dentin, and relatively small amounts might produce interferences with contemporary adhesive techniques [6]. Moreover, the use of eugenol-free temporary materials was also found to reduce bond strength to dentin, when compared to fresh or surface-treated substrates [7]; the negative effect may not be caused by eugenol itself but by the presence of residual particles of cement [8].…”