In this study, the feasibility of using the microbond test (MBT) to probe the durability of the bond between a dental resin with differently silanized E-glass fibers was investigated. The E-glass fibers were silanized with equivalent amounts of two types of acrylic-silane coupling agents: 3-methacryloxypropyltrimethoxysilane (MPTMS) and 10-methacryloxydecyltrimethoxysilane (MDTMS), a more hydrophobic silane coupling agent; unsilanized E-glass fibers were used as the control. Microdroplets of the photo-activated resin were applied on the fiber and photocured with visible light irradiation (470 nm). Subsequently, the specimens were tested in shear after 24 h storage in air at 23 C. The mean interfacial shear strength, τ, and the standard deviation in MPa for the three systems (n > 7) were: 33.8 (10.1), 34.7 (8.9) and 15.3 (4.2) for the MPTMS silanized, MDTMS silanized, and unsilanized fibers, respectively. When the three types of fibers were first exposed to 60 C water for 24 h prior to having the microdroplets bonded to them, the strength values of the MDTMS silanized fibers and the control fibers remained essentially unchanged at (n > 7) 31.8 (7.7) and 17.5 (4.9) MPa respectively; the MPTMS specimens showed a significant decrease to 15.8 (4.8) MPa. Similar trends were observed when the fibers had droplets bonded to them prior to exposure. These results indicate that the MDTMS silanized fibers exhibited enhanced resistance to degradation from exposure to water, presumably because of the enhanced hydrophobicity of the interface derived from MDTMS. In this study, the microbond test has shown itself to be sensitive enough to measure changes at the interface between a dental resin and variously silanized E-glass fibers.
Citation: Dental Materials Congress
Issue: No. 6
Pub Type: Journals
adhesion, dental composites, dental resin, glass fibers, interface, interfacial shear strength, microdrop test