Reliability of Universal Adhesives’ Bond Strength Applied by Various Operators

Objectives: To evaluate and compare the dentin bond strength of a universal adhesive when applied by various operators in comparison to three-step etch and rinse adhesive.
Methods: Four hundred and eighty sound dentin specimens were embedded in resin. Four dentists with at least ten years of experience in general dentistry and four pre-doctoral dental students without any dental experience applied Adhese Universal (IvoclarVivadent) and Optibond FL (Kerr Sybron) adhesives on wet, moist and dry dentin surfaces (n=10/group). Subsequently, composite restorations (Tetric Evoceram Bulkfill, Ivoclar Vivadent) were applied using Ultradent shear bond strength testing jig. Shear bond strength test was conducted using a universal testing machine (Instron, Canton, MA, USA). A general linear mixed-model was employed to look at the effect of adhesive (etch and rinse vs universal), and operator (dentists vs student).
Results: A significant difference in dentin bond strength was found between universal adhesive and etch and rinse (1, N = 480) = 83.17, p< 0.001, variance explained = 83.2%. Universal adhesive possessed 7.49 +/- 0.82 greater dentin bond strength (MPa) than three-step etch and rinse adhesive (Figure 1). However, no significant difference in dentin bond strength for both adhesives systems was found when applied by variant operators,(1, N = 480) = 0.16, p= 0.685, variance explained = 0.16%.
Conclusions: The tested universal adhesive performed significantly better than the three-step etch and rinse adhesive. Operator experience did not influence dentin SBS values.