Development of Metal-resin Composite for Dental Magnet Keepers. Part 1: Effects of Filler and 4-META Contents on Setting and Flexural Properties

Abstract

Nine kinds of experimental soft magnetic resin composites containing SUS447J1 stainless steel particles as filler were prepared. A UDMA/MAA resin with an MAA mole fraction of 0.67 was used as a matrix resin. The effects of three levels of 4-META content and three levels of filler content on the setting and flexural properties were studied. Working time and setting time significantly increased with increase of 4-META and filler contents. Flexural strength significantly increased with increase of 4-META content but with decrease of filler content. Elastic modulus simply increased with increase of both 4-META and filler contents. Although the flexural strength obtained was low, results were considered promising being the first step of this novel development.

Development of metal-resin composite for dental magnet keepers, Part 2: Optimum 4-META content

“…This was thought to be caused by the inclusion of a coupling material independent of the setting reaction. The working time and setting time extremely rose with increased amounts of 4-META, and it was impossible to prepare flexural specimens at 12% of 4-META when 1% BPO and 0.7% DMPT were used as in our previous study 10) . Therefore, the BPO and DMPT contents had to be increased with a rise in the 4-META content to adjust the working time and setting time.…”

“…In our previous study 10) , the working time and setting time significantly rose with the increase of 4-META up to 1% in the base resin. For example, the setting time of the experimental magnetic resin composite samples with 1.0% 4-META increased by 21.6 s compared to that with 0.5% 4-META when the filler content was 90% 10) . This was thought to be caused by the inclusion of a coupling material independent of the setting reaction.…”

“…Therefore, level 5 was judged to be optimum. As in our previous study 10) , a UDMA/MAA resin with an MAA mole fraction of 0.67 was selected as the matrix resin, because a strong and tough matrix resin as well as some interaction between the matrix resin and SUS447J1 filler particles were expected. A complex composed of UDMA and MAA based on noncovalent bonds such as hydrogen bonds or an electrostatic interaction between the imino group of UDMA and the carboxyl group of MAA may be formed, then the resultant matrix resin may become strong and tough 12) .…”

“…Our previous study 10) revealed that flexural strength and elastic modulus of experimental magnetic resin composite material rose significantly with the increase of 4-META (4-(2-methacryloyloxyethoxycarbonyl)phthalic acid anhydride) content in the base resin. 4-META is thought to improve the bond between the stainless steel filler particles and resin matrix.…”

“…UDMA/ MAA resin with an MAA mole fraction of 0.67 was used as the matrix resin. The effects of six levels of 4-META content (2,4,6,8,10, and 12 mass%) on the setting and flexural properties were studied. The metal filler content in each paste was 90 mass%.…”