In vitro evaluation of new restorative systems

Abstract

Bonding to dentin and enamel involve multiple steps including acid conditioning, rinsing, priming, drying, etc. A new experimental product, a self-priming conditioner (PCC, Dentsply), attempts to simplify the process. Used in lieu of a conventional primer, it does not require rinsing or use of an additional primer. This study evaluates this new self-priming conditioner for its effect on adhesion to dentin and enamel in vitro. The hypothesis of this study is that PCC produces comparable bond values to bonding systems which use phosphoric acid as conditioner. Two hundred seventy-five human teeth were embedded and prepared to reveal dentin, ground enamel, or intact enamel. PCC was compared to 34% phosphoric acid. Two restorative resins, TPH Spectrum and Dyract AP (Dentsply) were bonded to the surfaces, which were first coated with an adhesive (Prime & Bond 2.1, Dentsply). Bond strength values were measured in shear mode. One way ANOVA and Student-Newman-Keuls tests revealed that PCC produced bond strengths to dentin, comparable to those produced by phosphoric acid. Drying the PCC after application reduced the bond strength on dentin by 50%. Air- vs. blot-drying the enamel after conditioning with PCC or phosphoric acid did not influence the bond strengths. The highest values of bond strength (25.6 ± 5.6 MPa) were observed on enamel with rinsed and air-dried phosphoric acid conditioning. PCC produced clinically acceptable bond strength values on both dentin and enamel.