M Hashimoto1, H Ohno, M Kaga, H Sano, F R Tay, H Oguchi, Y Araki, M Kubota. 1. Department of Operative Dentistry and Endodontics, School of Dentistry, Iwate Medical University, Morioka, Iwate 020 8505, Japan. masanori-h@mue.biglobe.ne.jp
Abstract
OBJECTIVES: The purpose of this study was to determine (1) the weakest zone of resin-dentin bonds and (2) the relation between bond strength and failure mode to clarify the effect of demineralized dentin. METHODS: Human premolars were sectioned to expose the dentin surfaces, and the dentin surfaces were conditioned with phosphoric acid for 15, 60, 120, or 180s. Resin-dentin bonded specimens were produced using two adhesives: One-Step (Bisco) and OptiBond Solo (Kerr). Each sample was sectioned to produce a beam (adhesive area: 0.9mm(2)). Microtensile bond tests were then conducted, and the mean bond strengths (n=12 for each group) were statistically compared using two-way ANOVA and Duncan's multiple-range test (p<0.05). The fractured surfaces of all specimens were examined using SEM, and the areas of failure were measured using an image analyzer. RESULTS: For One-Step, the bond strength decreased with increase in acid-conditioning time (15s: 50.7+/-9.7, 60s: 40.8+/-11.0, 120s: 23.6+/-4.9 and 180s: 12.1+/-4.6MPa) (p<0.05). For OptiBond Solo, the bond strength in the case of 15s acid-conditioning time (42.6+/-7.9MPa) was significantly greater than that for the other times (60s: 31.9+/-10.3, 120s: 31.8+/-14.4 and 180s: 31.8+/-7.4MPa) (p<0.05). Fractography showed that the area percentage of the hybrid layer increased with increase in etching time for both systems. CONCLUSIONS: The integrity of the hybrid layer, especially the top part, has an effect on bond strength.
OBJECTIVES: The purpose of this study was to determine (1) the weakest zone of resin-dentin bonds and (2) the relation between bond strength and failure mode to clarify the effect of demineralized dentin. METHODS:Human premolars were sectioned to expose the dentin surfaces, and the dentin surfaces were conditioned with phosphoric acid for 15, 60, 120, or 180s. Resin-dentin bonded specimens were produced using two adhesives: One-Step (Bisco) and OptiBond Solo (Kerr). Each sample was sectioned to produce a beam (adhesive area: 0.9mm(2)). Microtensile bond tests were then conducted, and the mean bond strengths (n=12 for each group) were statistically compared using two-way ANOVA and Duncan's multiple-range test (p<0.05). The fractured surfaces of all specimens were examined using SEM, and the areas of failure were measured using an image analyzer. RESULTS: For One-Step, the bond strength decreased with increase in acid-conditioning time (15s: 50.7+/-9.7, 60s: 40.8+/-11.0, 120s: 23.6+/-4.9 and 180s: 12.1+/-4.6MPa) (p<0.05). For OptiBond Solo, the bond strength in the case of 15s acid-conditioning time (42.6+/-7.9MPa) was significantly greater than that for the other times (60s: 31.9+/-10.3, 120s: 31.8+/-14.4 and 180s: 31.8+/-7.4MPa) (p<0.05). Fractography showed that the area percentage of the hybrid layer increased with increase in etching time for both systems. CONCLUSIONS: The integrity of the hybrid layer, especially the top part, has an effect on bond strength.
Authors: Mohamed M Awad; Feras Alhalabi; Mohamed Bamuqadm; Abdulmalik Alhoti; Abdulilah Almasaad; Ali Robiaan; Ahmed Almahdy; Ali Alrahlah; Mohammed H Ahmed Journal: Odontology Date: 2022-09-29 Impact factor: 2.885
Authors: Leila Soares Ferreira; Christian Apel; Carlos Francci; Alyne Simoes; Carlos P Eduardo; Norbert Gutknecht Journal: Lasers Med Sci Date: 2009-08-06 Impact factor: 3.161