RESUMO
Objective:To study the stress distribution of Magsoft (cushion type) and Magnedisk magnetic attachment. Methods: 2 overdentures were prepared on each of 5 edentulous jaw models. The overdentures were pared and retained with Magnedisk and Magsoft magnetic attachments respectively.Photoelastic analysis was used to study the stress distribution for the implanted complete overdentures. Results: Under the same load, around the implants, the stress under the overdentures retained with Magsoft was lower than that with Magnedisk. Compared with Magnedisk, the stress around the abutments under the overdenture retained with Magsoft were distributed in a more even manner. Conclusion: Magsoft magnetic attachment has better biomechanical characteristic than Magnedisk and can distribute stress more evenly throughout the whole supporting structure for its special cushioned design.
RESUMO
Objective: To evaluate the physical properties of SY-1 silicone elastomer with various ratios of cross-linker to base. Methods: The ratios of cross-linker to base were set at 0.5 %、1 %、 1. 5 %、 2 % 、2. 5 % respectively while other conditions were kept same, then the major physical properties of the elatomer were studied with a tensile tester and ASTMD 2240 method. Results: The elongation(%) due to tension, tensile strength (MPa), laceration strength (kN/m) and hardness (A) of SY-1 silicone elastomer with the ration of 0. 5% of cross-linker to base were 540?47,4. 3?0. 28, 14. 4?2.4 and 18. 0?3. w; those of that with 1% 440 ?54,4.0?0.32,18. 2?3.1 and 24. 0?3. 61 with 1.5% 430?51, 4.1?0. 29, 13.6?2.2 and 25.0?2.1; with 2% 350?46, 2.5?0. 33, 9.0?2.1 and 28.0?1.9; with 2.5% 280?36, 2.0?0. 3, 11.0?2.5 and 29.0? 2.8, respectively. Conclusion: The physical properties of SY-1 silicone elastomer with a ratio of 1% of crosslinker to base are more suitable for prothesis fabrication.