Pipop Saikaew1, A F M Almas Chowdhury2, Mai Fukuyama2, Shinichi Kakuda2, Ricardo M Carvalho3, Hidehiko Sano2. 1. Department of Restorative Dentistry, Division of Oral Health Science, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan. Electronic address: pipop045@den.hokudai.ac.th. 2. Department of Restorative Dentistry, Division of Oral Health Science, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan. 3. Department of Restorative Dentistry, Division of Oral Health Science, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan; Department of Oral Biological and Medical Sciences, Division of Biomaterials, University of British Columbia, Faculty of Dentistry, 2199 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada.
Abstract
OBJECTIVE: This study evaluated the effects of surface preparation and the application time of adhesives on the resin-dentine bond strengths with universal adhesives. METHODS: Sixty molars were cut to exposed mid-coronal dentine and divided into 12 groups (n=5) based on three factors; (1) adhesive: G-Premio Bond (GP, GC Corp., Tokyo, Japan), Clearfil Universal Bond (CU, Kuraray Noritake Dental Inc., Okayama, Japan) and Scotchbond Universal Adhesive (SB, 3M ESPE, St. Paul, MN, USA); (2) smear layer preparation: SiC paper ground dentine or bur-cut dentine; (3) application time: shortened time or as manufacturer's instruction. Fifteen resin-dentine sticks per group were processed for microtensile bond strength test (μTBS) according to non-trimming technique (1mm(2)) after storage in distilled water (37 °C) for 24h. Data were analyzed by three-way ANOVA and Dunnett T3 tests (α=0.05). Fractured surfaces were observed under scanning electron microscope (SEM). Another 12 teeth were prepared and cut into slices for SEM examination of bonded interfaces. RESULTS: μTBS were higher when bonded to SiC-ground dentine according to manufacturer's instruction. Bonding to bur-cut dentine resulted in significantly lower μTBS (p<0.000). Shortening the application time resulted in significantly lower bond strength for CU on SiC and GP on bur-cut dentine. SEM of fractured surfaces revealed areas with a large amount of porosities at the adhesive resin interface. This was more pronounced when adhesives were bonded with a reduced application time and on bur cut dentine. CLINICAL SIGNIFICANCE: The performance of universal adhesives can be compromised on bur cut dentine and when applied with a reduced application time.
OBJECTIVE: This study evaluated the effects of surface preparation and the application time of adhesives on the resin-dentine bond strengths with universal adhesives. METHODS: Sixty molars were cut to exposed mid-coronal dentine and divided into 12 groups (n=5) based on three factors; (1) adhesive: G-Premio Bond (GP, GC Corp., Tokyo, Japan), Clearfil Universal Bond (CU, Kuraray Noritake Dental Inc., Okayama, Japan) and Scotchbond Universal Adhesive (SB, 3M ESPE, St. Paul, MN, USA); (2) smear layer preparation: SiC paper ground dentine or bur-cut dentine; (3) application time: shortened time or as manufacturer's instruction. Fifteen resin-dentine sticks per group were processed for microtensile bond strength test (μTBS) according to non-trimming technique (1mm(2)) after storage in distilled water (37 °C) for 24h. Data were analyzed by three-way ANOVA and Dunnett T3 tests (α=0.05). Fractured surfaces were observed under scanning electron microscope (SEM). Another 12 teeth were prepared and cut into slices for SEM examination of bonded interfaces. RESULTS: μTBS were higher when bonded to SiC-ground dentine according to manufacturer's instruction. Bonding to bur-cut dentine resulted in significantly lower μTBS (p<0.000). Shortening the application time resulted in significantly lower bond strength for CU on SiC and GP on bur-cut dentine. SEM of fractured surfaces revealed areas with a large amount of porosities at the adhesive resin interface. This was more pronounced when adhesives were bonded with a reduced application time and on bur cut dentine. CLINICAL SIGNIFICANCE: The performance of universal adhesives can be compromised on bur cut dentine and when applied with a reduced application time.