Amalgam sheer bond strength to dentin using single-bottle primer/adhesive systems

Purpose: To evaluate the in vitro shear bond strengths (SBS) of a spherical amalgam alloy (Tytin) to dentin using several single-bottle primer/adhesiv e systems both alone: Single Bond (SB), OptiBond Solo (Sol), Prime & Bond 2 . 1 (PB), One-Step (OS) and in combination with the manufacturer's suppleme ntal amalgam bonding agent: Single Bond w/ 3M RelyX ARC (SBX) and Prime & B ond 2.1 w/ Amalgam Bonding Accessory Kit (PBA). Two, three-component adhesi ve systems, Scotchbond Multi-Purpose (SBMP) and Scotchbond Multi-Purpose Pl us w/light curing (S+V) and w/o light curing (Sf) were used for comparison. Materials and Methods: One hundred eight extracted human third molars were mounted lengthwise in phenolic rings with acrylic resin. The proximal surf aces were ground to expose a flat dentin surface, then polished to 600 grit silicon carbide paper. The teeth were randomly assigned to 9 groups (n=12) , and dentin surfaces in each group were treated with an adhesive system ac cording to the manufacturer's instructions, except for S+V specimens, where the adhesive was light cured for 10s before placing the amalgam. Specimens were then secured in a split Teflon mold, having a 3 mm diameter opening a nd amalgam was triturated and condensed onto the treated dentin surfaces. T wenty minutes after condensation, the split mold was separated. Specimens w ere placed in distilled water for 24 hrs, then thermocycled (300 cycles, be tween 5 degrees C and 55 degrees C, with 12 s dwell time). All specimens we re stored in 37 degrees C distilled water for 7 days, prior to shear streng th testing using a Zwick Universal Testing Machine at a cross-head speed of 0.5 mm/min. Results: The highest to the lowest mean dentin shear bond stre ngth values (MPa) for the adhesive systems tested were: S+V (10.3 +/- 2.3), SEX (10.2 +/- 3.5), PEA, (6.4 +/- 3.6), SOL (5.8 +/- 2.5), SBMP (5.7 +/- 1 .8), S+ (4.8+/-2.3), PB (2.7 +/- 2.6), SE (2.7 +/- 1.1) and OS (2.5 +/- 1.8 ). One-way ANOVA and Duncan's Multiple Range Test indicated significant dif ferences among groups. SEX and S+V produced significantly higher amalgam to dentin shear bond strengths than all other adhesive systems. Bond strength s of amalgam to dentin for the single-bottle adhesives, SOL and PEA were co mparable to the three-component systems, SBMP and S+ and were significantly greater than OS, SE and PB (P < 0.05).