Influence of thermal and mechanical load cycling on the microtensile bond strength of self-etching adhesives.

Autor:	Abdalla AI; Department of Restorative Dentistry, Faculty of Dentistry, University of Tanta, Tanta, Egypt. aliebraheem01@yahoo.com, El Zohairy AA, Aboushelib MM, Feilzer AJ
Jazyk:	angličtina
Zdroj:	American journal of dentistry [Am J Dent] 2007 Aug; Vol. 20 (4), pp. 250-4.
Abstrakt:	Purpose: To evaluate the influence of thermal and mechanical load cycling on the microtensile dentin bond strength of two self-etching and one total-etch adhesives. Methods: The adhesive materials were: a two-step self-etch adhesive (Clearfil SE Bond), a one-step self-etch adhesive (Hybrid Bond), and a total-etch one-step adhesive (Admira Bond). Sixty freshly extracted human third molars were used. In each tooth, a Class I cavity (4 x 4 mm) was prepared in the occlusal surface with the pulpal floor extending about 1 mm into dentin. The teeth were divided into three groups (n=20). Each group was restored with the resin composite Clearfil APX using one of the adhesives. After restoration, 10 teeth in each group were thermocycled between 5 degrees C and 55 degrees C, (dwell time 3 minutes, 5,000 cycles). The same teeth were then mounted in a fatigue loading machine to receive an intermittent load of 125 N at 52 cycles/minute for 4,000 cycles. Subsequently, each tooth was sectioned longitudinally, bucco-lingually and mesio-distally to get rectangular slabs 1-1.2 mm in thickness for the microtensile test. Each slab was then placed in a universal testing machine and tensile load was applied at a cross-head speed of 0.05 mm/minute. Results: Without loading procedures, there was no significant difference in the bond strength of the tested adhesives. In contrast to Admira Bond and Clearfil SE Bond, fatigue loading resulted in a significant reduction of the bond strength for Hybrid Bond when compared to the unloaded restorations.
Databáze:	MEDLINE
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