Limited Decalcification/Diffusion of Self-adhesive Cements into Dentin

Abstract

Resin cement diffusion into dentin may differ as a function of the pre-treatment regimen. Since self-adhesive cements do not require substrate pre-treatment for luting, penetration of and interaction with the underlying dentin are questioned. We hypothesized that differences in the resin cement diffusion into dentin may exist among current commercial adhesive cements. Composite cylinders were luted on mid-coronal dentinal surfaces by an etch-and-rinse cement (Calibra), a self-etching system (Panavia F 2.0), and 4 self-adhesive cements (Multilink Sprint, Rely X Unicem, G-Cem, Bis-Cem). Dentin/cement interfacial characteristics were analyzed by a staining technique (Masson's trichrome) and by scanning electron microscopy. Conventional acid etching resulted in partially infiltrated adhesive interfaces differing from those achieved with the application of self-etching primer. No hybrid layer and/or resin tag formation was detectable at the interfaces bonded with self-adhesive cements. Limited decalcification/infiltration was observed for self-adhesive cements into the underlying dentin. Self-adhesive cements were not able to demineralize/dissolve the smear layer completely.

Are self-adhesive resin cements a valid alternative to conventional resin cements? A laboratory study of the long-term bond strength

“…Therefore this cements seem to have technically a potential of decalcification of the dentin. But, neither demineralization nor infiltration of dentin can be shown [10]. In addition, pretreatment of the dentin facilitates to create a real hybrid layer which occurred with PAN but not with RXU [4].…”

“…The failure types on dentin showed only adhesive failures. At conventional resin cements during dentin pre-treatment the dentin tubules are opened and a hybrid layer with resin tags into the dentin can be observed [10] or the smear layer is merely altered and the intertubular collagen only mild demineralised by the bonding agent as in the control group PAN [10]. Measurements of pH values of RXU and GCM after light curing showed values of 5.0 or less [22].…”

“…Handling problems like e.g. contamination of the substrate with saliva or blood significantly reduce the bond strength of the respective polymerizing cement [10,11,12].…”

Evaluation of bond strength of resin cements using different general-purpose statistical software packages for two-parameter Weibull statistics

“…A multistep pretreatment is required to achieve a compound between the cement and the tooth. Therefore, a multistep adhesive system is needed to remove the smear-layer and additionally create a hybrid layer between the tooth and the cement [11]. Adhesive systems show a high sensitivity for user handling errors which results in significantly lower bond strength values on dentin, based on the fact that the surface is contaminated with saliva or blood or when manufacturers recommendations are not fulfilled [12,13].…”

Effect of Storage Time on Microtensile Bond Strength of Self-Adhesive and Multi-Step Resin Cements to Dentin

“…10 On the other hand, self-adhesive cements were unable to demineralize/dissolve the smear layer completely; no decalcification/infiltration of dentin and no hybrid layer and/or resin tag formation was detectable at the bonded interfaces. 11 Many studies have evaluated the performance of immediate dentin bond strength resin cements. 2,8,9,12 Immediate bond effectiveness is adequate to evaluate adhesive ability, whereas long-term clinical trials are the ideal method of assessing the durability of adhesive materials.…”