In Vitro Adhesive Bond Strength of Three Universal Enamel-Dentin Bonding Agents

Objectives: Bonding techniques and bonding agents are the main source of retention of a restoration. This study compared the shear bond strength of Optibond™XTR(OP) Kerr™, Scotchbond™Universal(SBU) 3M™ and AdheSE™Universal(AU) Ivoclar™ bonded to dentin and enamel at 15 minutes and 24 hours
Methods: One hundred and forty-four human extracted teeth were collected, sectioned and mounted in acrylic blocks followed by exposing and finishing the enamel or dentin surfaces with 240 and 600 grit silicon carbide papers. Six groups for dentin and enamel were made (N=12). Each group was bonded following manufacturer recommendations, placed on the Ultradent bonding jig (2.38mm), filled with Herculite^® Ultra (Kerr) and polymerized for 20s using a Demi™ Plus curing light. Samples were either stored for 24-hours at 100% humidity and tested or tested 15 minutes after the bonding procedure using an Instron^® universal testing machine at 1mm/min crosshead speed and expressed in MPa’s. The nature of the failure was observed with a 10X stereo microscope (Leica–GZ6). Statistical analysis was done using ANOVA.
Results: See Tables 1 and 2. No statistically significant difference was observed between groups in either the enamel-bonded or the dentin-bonded cohort using ANOVA testing (15-min, Enamel:F(2,27)=1.83, p=0.179; 15-min, Dentin:F(2,27)=3.30, p=0.052; 24-hour, Enamel:F(2,27)=2.23, p=0.127; 24-hour, Dentin:F(2,27)=0.38, p=0.686).
Conclusions: Despite variation in mean bond strengths between AU, OP, and SBU, no statistical difference was observed. Further clinical testing is needed.