DUAL APPLICATION OF DENTIN BONDING AGENTS - MEET ON BOND STRENGTH

Purpose: To evaluate the effect of a dual application of dentin bondin g agents (DBA) on their shear bond strength on dentin with intermediat e application of a provisional cement. Materials and Methods: Freshly prepared flat dentin surfaces of human teeth were coated with a first layer of one of various dentin bonding agents (All-Bond 2, ART Bond, S yntac or an experimental DBA called P-Bond). After curing the DBA, a p rovisional cement (Temp Bond, Freegenol or Fermit, a soft provisional diacrylate) was applied to the bonded dentin surface. After 24 hours, the provisional cement was removed and the dentin surface scrubbed wit h pumice. A second application of the same DBA together with a composi te cylinder followed. After curing and 1,500 thermal cycles with const ant imitation of intrapulpal pressure, shear bond strengths were measu red. Results: Compared to a single application of dentin bonding agent s following Temp Bond treatment (SBS in MPa: Syntac: 0.86 +/- 1.75, AR T Bond: 0.26 +/- 0.47, P-Bond: 14.90 +/- 4.51) application of DBAs pri or to use of Temp Bond as well as after its removal seems to be very b eneficial to shear bond strength values (SBS in MPa: Syntac:13.36 +/- 4.70, ART Bond: 16.34 +/- 5.02, P-Bond: 19.04 +/- 2.01). Independent f rom the provisional cement, the values after serial application of P-B ond provided consistently high bond values which were not statisticall y different (Kruskal-Wallis, P>0.05) from values of P-Bond on fresh de ntin (18.19 +/- 2.29 MPa). The only exception from these findings in t he present study was All-Bond 2. Regardless of the provisional materia ls used, the bond strength values of All-Bond 2 remained low (maximum SBS with Fermit as intermediate provisional cement: 4.63 +/- 2.91 MPa) .