In vitro evaluation of two adhesive systems used with compomer filling materials

To evaluate and compare the in-vitro shear bond strength, microleakage and dentine-restorative interface of a self-etching/self-priming dentine bonding agent with a three-component dentine-bonding agent.

For shear bond strength (SBS) testing 30 non-carious human molars were used of which 15 were tested with Non-Rinse Conditioner (NRC)/Prime&Bond NT (PBNT) and Dyract AP and 15 were tested with Scotchbond Multi-Purpose Plus (SBMP) and F2000. For the microleakage evaluation cavity preparations were made on the facial surfaces of 30 non-carious human premolars of which 15 were restored with NRC and PBNT with Dyract AP and 15 were restored with SBMP and F2000. The dentine-restorative interface was examined through a confocal scanning laser microscope (CSLM).

The mean SBS of PBNT and SBMP were 12.8 and 18.1 MPa, respectively. The microleakage scores showed NRC/PBNT leaked on the dentine side in 13 of the 15 specimens examined. On the enamel side two of the 15 specimens showed microleakage. With SBMP no microleakage was observed on either enamel or dentine sides. The CSLM images show clear resin tag and hybrid layer formation for both the materials examined although SBMP showed better and deeper penetration into the dentine with longer resin tags. SBMP showed resin tags measuring about 150 mm while the hybrid layer measured about 5 mm. The length of the resin tags as well as the thickness of the hybrid layer for PBNT were 20 mm Pounds and 2 mm Pounds, respectively.

The acid-etch technique of SBMP produced higher bond strength and no microleakage when compared with the self-etching/self-priming 'non-rinse technique' of NRC with PBNT. Thus it can only be speculated that SBMP should be the superior in the clinical situation.