Bond strength of self-adhesive resin cements to dry and moist dentin

Abstract

This study evaluated the effects of humidity conditions and evaluation times on the dentin bond strength (DBS) of two self-adhesive resin cements (RC). The RC used were: RelyX Unicem (3M ESPE) and Clearfil SA Cement (Kuraray Med.). One hundred and twenty coronal portions of bovine incisors (n = 10) were used. Buccal surfaces were abraded in order to expose a flat dentinal surface (180-grit SiC) and to standardize the smear layer formation (600-grit SiC). The humidity conditions tested were: dry (air-dried for 10 s), slightly moist (water application with disposable applicator on dried dentin and water excess removed with absorbent paper), and moist (same application without water removal). The RC were used according to the manufacturers' recommendations and were applied to prepolymerized resin discs (2 mm thick; Sinfony, 3M ESPE), which were subsequently bonded to the dentin surfaces. After 24 h, half of the teeth were prepared for the microtensile bond strength test, while the other half were stored in water for 6 months and tested in tension (0.5 mm/min) until failure. A 3-way analysis of variance and the Tukey test were performed (preset alpha of 0.05). No RC showed any reduction of DBS after 6 months, and no significant difference was observed between them. The moist dentin increased the bond strength of Clearfil SA Cement for both periods of time. Humidity conditions can change the DBS; however, the study's results were product-dependent.

Tensile Bond Strength of Self Adhesive Resin Cement After Various Surface Treatment of Enamel

“…These findings showed that the different composition and solvent of selfadhesive resin cements did not affect the bond strength. Similar results were reported by André et al, and Lin et al, in which no significant differences were observed among the different selfadhesive resin cements [23,47]. However, André et al did their studies on dentin [47].…”

Evaluation of long-term bond strength and selected properties of self-adhesive resin cements

“…7,8,9 The self-adhesive properties of these SARCs are attributed to the presence of acidic methacrylate monomers capable of dem i nera l i zi ng a nd infiltrating into the dental substrate, 10,11 resulting in micromechanical interlocking. The first SARC introduced was RelyX Unicem® (3M ESPE, Germany) and the bond strength of RelyX Unicem®, has been evaluated in several studies, 5,9,10,12,13,14,15,16,17,18 with results comparable with those of multi-step luting agents available at present. 10,12,18 However, the long-term storage of these SARCs to show long-term dentin bond effectiveness 12,14,15,17 and mechanical stability 19 has rarely been evaluated.…”

“…The first SARC introduced was RelyX Unicem® (3M ESPE, Germany) and the bond strength of RelyX Unicem®, has been evaluated in several studies, 5,9,10,12,13,14,15,16,17,18 with results comparable with those of multi-step luting agents available at present. 10,12,18 However, the long-term storage of these SARCs to show long-term dentin bond effectiveness 12,14,15,17 and mechanical stability 19 has rarely been evaluated. 12,14,15,17 Mechanical stability is related to high pH-neutralization over time, which in turn renders the polymer more hydrophobic and less prone to hydrolytic degradation.…”

“…10,12,18 However, the long-term storage of these SARCs to show long-term dentin bond effectiveness 12,14,15,17 and mechanical stability 19 has rarely been evaluated. 12,14,15,17 Mechanical stability is related to high pH-neutralization over time, which in turn renders the polymer more hydrophobic and less prone to hydrolytic degradation. 19,20 Nevertheless, to the best of our knowledge, the relationship between bonding longevity and pH-over-time has not yet been evaluated.…”

Durability of the adhesive cementation to the dentin substract

“…The storage in water for 1 year does not decrease the bond strength of self-adhesive resin cements to dentin. Conversely, the humidity conditions can change the bond strength to dentin; however, these results are productdependent 13 .…”