Master of Science (M.S.) in Dentistry
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College of Dental Medicine
Publication Date / Copyright Date
Nova Southeastern University
Marwa Bawazir. 2019. Reliability of Bond Strength Using Universal Adhesives to Variable Dentin Conditions. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, College of Dental Medicine. (100)
Brief Background: Both three-step etch-and-rinse adhesives and universal adhesives have proven their effectiveness to produce successful bond to dentin. However, there are no studies comparing adhesives’ bond strength when applied by multiple operators, and to variable dentin conditions. Objectives: To evaluate and compare the bond strength of a universal adhesive when applied by multiple operators, and to variable dentin conditions, in comparison to three- step etch-and-rinse adhesive. Methods: Three hundred extracted human teeth were embedded in resin. Five dentists with at least ten years of experience in general dentistry and five pre-dental students applied a universal adhesive (Adhese Universal, Ivoclar Vivadent, Amherst, NY) and an etch-and-rinse adhesive (OptiBond FL, Kerr, Orange, CA) on wet, moist and dry dentin surfaces (n=5/group). Subsequently, composite restorations (Tetric EvoCeram Bulk Fill, Ivoclar Vivadent) were applied using Ultradent shear bond testing jig. After a technique demonstration, the same operators repeated the same bonding procedures. Shear bond strength test was conducted using a universal testing machine (Instron, Canton, MA, USA). Failure mode was evaluated by using scanning electron microscopy (SEM). Results: After calculating the descriptive statistics and pairwise comparisons using a Tukey HSD, a significant difference in dentin bond strength by adhesive was found, p<0.001. Overall universal adhesives possessed 7.38MPa +/-0.73 greater dentin bond strength than etch-and-rinse adhesives. Additionally, a significant difference in dentin bond strength by the operator and surface condition was observed. However, there was no significant difference in dentin bond strength by demonstration. While there was no difference between the dentin surface conditions for the universal adhesive, a significant difference was found with etch-and-rinse adhesive between moist and wet (moist 2.67MPa+/-0.89 greater than wet) (p=0.002), and dry and wet conditions (dry 3.79MPa+/- 0.89 greater than wet) (p<0.001). Further, there was no difference between moist and dry conditions with etch-and-rinse adhesive. Regarding the operators’ variability, expert dentists obtained higher bond strength values (1.65MPa+/-0.73) (p=0.030) than dental students with etch-and-rinse adhesive. However, such a difference was not found with universal adhesive. Conclusion: Universal adhesive showed unaffected to dentin surface condition and operator differences. On the contrary, etch-and-rinse adhesive was influenced by the variability of surface condition and the operator’s expertise. The tested universal adhesive was found to be more reliable as an adhesive system in comparison to the etch-and-rinse adhesives.
Dentin, Etch-and-rinse adhesives, Operator's variability, Shear bond strength, Surface conditions, Universal adhesives
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