Comparison of microtensile bond strength of universal adhesives utilizing various application methods: an in vitro study

Abstract

Purpose: To investigate�microtensile bond strength (?TBS)�of a conventional three-step etch and rinse, and universal adhesive systems with etch and rinse mode utilizing various application methods at�24 hour�and after 6 month�water-?storage.
 
 Material and methods: Seventy-?two extracted human third molars were cut to expose a flat dentin surface. Optibond FL (OFL; Kerr, USA), Single Bond Universal (SU; 3M ESPE, USA), Clearfil Universal Bond Quick (CU; Kuraray Noritake Dental Inc., Japan), G-?Premio BOND (GP; GC�Corporation, Japan), Prime&Bond Universal (PB; Dentsply, Germany) were used in etch and rinse mode following the manufacturers' instruction and double application method. Subsequently, composite resins were constructed on prepared dentin and then sectioned into 1x1x8 mm3 stick to be tested after 24 hours and 6 months of water-?storage by microtensile bond strength (?TBS) testing. The data of universal adhesives were analyzed with two-?way ANOVA (p�= 0.05). Additionally, the ?TBS values were obtained and analyzed with one-?way ANOVA followed by a Tukey Post Hoc test and a Pair T-?test.
 
 Results: The ?TBS of universal adhesives were not significantly increased when using double application method compared to manufactures' instruction at 24 hr (p = 0.652) and after 6 month water storage (p = 0.173).�In contrast, kind of adhesives had statistically significant influence on ?TBS at 24 hr (p < 0.001) and after 6 month water storage (p < 0.001).�Optibond FL, Single Bond Universal Adhesive when applied in double application methods, G-Premio BOND�when following the manufacturer's instruction, and appling in double application method had�statistically significantly decreased ?TBS after 6 month water-storage.�
 
 Conclusions: Double application of universal adhesives did not improve the bond strength of tested universal adhesives at 24 hours and after 6 months of water storage. Single Bond Universal used following manufacturer's instruction, Clearfil Universal Bond Quick and Prime&Bond Universal used both following manufacturer's instruction and modified double application method, had stable dentin microtensile bond strength, while Optibond FL and G-Premio Bond used both techniques had deceased bond strength after 6 months of water storage.