Shear Bond Strength of Several Dental Cements

Purpose: To compare the shear bond strength (SBS) of various cements when bonded to zirconia, e.max crowns, titanium, stainless steel, and dentin using a universal testing machine. Materials and Methods: Products tested were: Group 1: ACTIVA™ BioACTIVE Cement without DenTASTIC™ UNO™ (Pulpdent) (AB), Group 2: Rely X™ Unicem 2 Automix (3M) (RelyX), Group 3: Ceramir® Crown & Bridge (Doxa) (CeraCB), Group 4: FujiCEM™ 2 Cement (GC America) (FCEM), and Group 5: ACTIVA BioACTIVE Cement with DenTASTIC UNO (Pulpdent) (ABD). The cement Groups 1-4 (n=25) were tested against five substrates, and ABD (n=5) was tested against dentin and was not tested against the other four substrates. ABD used five caries-free human molar teeth were mounted in acrylic resin with the long axis of the tooth perpendicular to the surface and flattened using 240 grit silicon paper. Each cement was bonded to their appropriate substrate using cylindrical molds, with an internal diameter of 2.38 mm and height of 2 mm. All samples were cured (Translux® Wave, Heraeus Kulzer) and placed in water at 37ºC for 24 hours prior to testing to ensure complete polymerization of the material. A universal testing machine (Instron® 5566A) was used to test the SBS with 1 mm/min crosshead speed. Results: AB showed statistically significant superior bonds for SBS when compared to CeraCB and FCEM for all five substrates, and only for zirconia when compared to RelyX. There was no statistical significant difference for SBS when comparing dentin bonding between AB and ABD. RelyX showed statistically significant superior SBS when compared to CeraCB and FCEM for all substrates, except dentin. CeraCB and FCEM did not show any statistical significance except when bonded to e.max (p=00079). Conclusion: AB compared to ABD showed no significant difference in terms of dentin bonding. The addition of a primer to the original product did not produce additional adhesive cementation on dentin testing. However, AB and ABD, showed better SBS for dentin compared to RelyX, CeraCB and FCEM. Based on this study, AB and RelyX appear to be appropriate cements for all substrates tested.