In Vitro Study of the Influence of Dentin Desensitizing and Sealing on the Shear Bond Strength of Two Universal Resin Cements

Purpose: To test whether or not dentin desensitizing or sealing methods influence the bond strength of universal resin cements. Materials and Methods: The bond strength of two universal resin cements (RelyXUnicem, Self-adhesive Prototype Cement) to human dentin was assessed after different dentin surface treatments (test). A conventional resin cement (Panavia 21) served as control. The influence of the following pretreatment methods was tested and compared to freshly ground dentin: dentin desensitizing by means of glutaraldehyde-containing primers (Gluma Desensitizer, Syntac Primer/Adhesive), or dentin sealing by means of bonding agents (Heliobond, ClearfilSE Bond). Additionally, the influence of provisional cement (Freegenol) was analyzed after its application and subsequent mechanical removal. Bond strength after thermocycling was measured in a shear test (n = 10). Data were analyzed with one-way ANOVA, followed by a post-hoc Tukey test (p 0.05). Results: Both test cements exhibited significantly lower bond strength to freshly ground dentin than the control cement. The desensitization methods did not affect the bond strength of the test cements. Furthermore, the sealing methods significantly increased the bond strength of both test cements as compared to freshly ground dentin. The application and subsequent removal of the provisional cement only had a minor influence on the bond strength of the test cements. The contamination with provisional cement, however, significantly affected the bond strength of the control cement compared to the values achieved on freshly ground dentin. Conclusion: Desensitization or sealing of dentin have a beneficial effect on the bond strength of universal resin cements. The application of a provisional cement prior to adhesive cementation exhibits no significant influence on the bond strength of the universal resin cements. Parole chiave: resin cements, universal resin cements, shear bond strength, desensitization, dentin sealing