Comparison of flexural strength of resin-infused hydroxyapatite interpenetrating phase composites
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Interpenetrating phase composites (IPC) microstructure, due to their three-dimensional interconnected network, may have enhanced mechanical properties. This microstructure is composed of two phases in which one phase is a porous matrix and infiltrated by using resin as a second phase. The aims of this study were: (1.) to fabricate a resin-infused ceramic with the use of hydroxyapatite as the first phase and resin as the second phase material, (2.) to reinforce heat-cured resin composite with silica for the IPC and (3.) to investigate the effects of particle size of silica powder on properties of the IPC. The study consisted of 3 parts. Part I examined silica dispersed into resin. Part 2 examined of the properties of the IPC. Part 3 investigated the characteristics of epoxy resin in search of a better processing method for the IPC. Two series of composites were examined to determine the effect of silica concentration and particle size on selected properties. Both series were prepared by dispersing silica particles into heat-cured 30% by weight poly(methyl-methacrylate) (PMMA) resin and 70% by weight methyl-methacrylate (MMA) resin. One series had a silica particle size of 0.007[mu]m with concentrations of 1% and 5% by weight. The second series contained 0.011 [mu]m particles in amounts of 1% and 5% by weight. Cured resin was cut into bars (2.0mm x 4.0mm x 25.0mm) and evaluated with a 4-point bending test. For interpenetrating phase properties, a hydroxyapatite bar made by 3-D printing was used as a porous matrix. The porous matrix received silane treatment and was infused with different resins. Sintered and infused specimens were tested for flexural strength with an Instron testing machine at 0.5mm/min crosshead speed. SEM micrographs and X-ray analysis were used to study the microstructure of the resin-infused hydroxyapatite specimens. For resin bars, the strength varied from 57.2 to 74.6 MPa for PMMA only. For resin-infused HA bars, the strength varied from 54.2 to 71.O MPa for small particles (0.0077[mu]m silica), and 27.5 to 67.6 MPa for larger particles (0.011 [mu]m Silica). Flexural strengths of the infused specimens that contained silica powder of particle sizes 0.011 [mu]m and 0.0077 [mu]m decreased as the percent of silica increased.
PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact firstname.lastname@example.org.Thesis (M.S.D.)--Boston University, Henry M. Goldman School of Dental Medicine, 2003 (Prosthodontics).Includes bibliographical references (leaves 81-85).
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