The influence of retention hole and adhesive systems on the shear bond strengths of resin composite to amalgam

Abstract

The aim of the study is to evaluate the influence of surface-treatment methods with and without the use of a retention hole on the shear bond strength of a resin composite adhered to amalgam using an adhesive system. Amalgam specimens were divided into six groups. Group 1 (Bur) specimens were roughened with a diamond bur, Group 2 (Al2O3) specimens were sandblasted with a 50 m aluminum oxide powder, Group 3 (CoJet (R)) specimens were sandblasted with 30 mu m CoJet (R) Sand, Group 4 (Bur + Rh) specimen surfaces were prepared with a retention hole 1 mm in diameter and 1 mm deep and roughened with a diamond bur, Group 5 (Al2O3 + Rh) specimens were also prepared with a retention hole and sandblasted with 50 mu m aluminum oxide powder, and Group 6 (CoJet (R) + Rh) surfaces were prepared with a retention hole and sandblasted with 30 mu m CoJet (R) Sand. Resin composite cylinders were bonded onto the amalgam surfaces using Xeno (R) IV, Optibond (TM) All-In-One, Clearfil (TM) SE Bond, Adper (TM) Single Bond Plus, and Scotchbond (TM) Multi-Purpose adhesive systems. In addition, silane (Monobond S) was used for Groups 5 and 6. The shear bond was determined and statistically analyzed using two-way analysis of variance and post hoc Tukey's tests (p <= 0.05). The surface treatment significantly affected the shear bond strengths of the adhesive systems. The shear bond strengths of Optibond (TM) All-In-One (2.661 +/- 0.48 MPa) in Group 1 and Scotchbond Multi-Purpose (3.818 +/- 0.98) in Group 4 were significantly higher than those of the other adhesive systems. Silica coating of the amalgam surface significantly improved the shear bond strength of the resin composites. The addition of a retention hole on the amalgam affects the bonding strength of the composite adhesion.