| Abstrakt: |
The purposes of this study were to evaluate the viscosities, physical properties, adaptability and water absorption of a new silicone-based material mixed with crystallized quartz fillers for sports mouthguards. Physical properties, adaptability and water absorption were compared with a room-temperature and a microwave-oven vulcanized material. Furthermore, we describe a step-by-step procedure to fabricate mouthguards with the new silicone-based material for clinical use. However, the physical properties after vulcanization by microwave irradiation have not yet been studied. An automatic rheometer Physica MCR101®(Anton Paar, France)was used for examination of viscosity. Regarding the physical properties, each specimen was made for a hardness test as specified by the JIS K6253 standard, and for tear strength test as prescribed by the JIS K6252 standard. For the shock-absorbing test, a hand-made ball-drop test apparatus was used and seven specimens each were made for the test. The results showed that the viscosity of silicone 20% mixed with quartz fillers was higher than that with a low content. Hardness showed a significant difference between microwave-oven and room-temperature vulcanized material. However, the tear strength of the microwave-oven vulcanized material was not higher than that of the room-temperature vulcanized silicone. From the results of the adaptability and water absorption tests, the silicone-based material showed good performance. Although the application of crystallized quartz fillers increased the viscosity and other physical properties, only the tear strength was not good. It is considered that the size and shape of fillers would differ, and the adhesive strength between the fillers and silicone would be weak regardless of the mixing ratio. On the other hand, the use of a microwave oven for rapid vulcanization of silicone-based material for fabricating sports mouthguards reduced the fabrication time by 2 to 4 hours compared with room-temperature vulcanization. In addition, the use of a mixing cartridge to fill in the plaster mold using the improved silicone material after eliminating the wax was effective. It seems that the most convenient mixing ratio of fillers is 10% for both physical properties and handling in clinics. [ABSTRACT FROM AUTHOR] |
