Numerical Analysis Of Stress Distribution On Artificial Hip Joint Due To Jump Activity

Due to degenarative disorder of articular cartilage, hip joint need to be replaced with an artificial hip joint. Currently, the modular design of artificial hip joint become popular in the procedure because the modular type’s provide flexibility for the surgeon. But, there were several report about the failure of modular version, and the failure was likely to happen on the neck part. The main focus of this research was to ensure the design safety of present artificial hip joint using FEM (Finite Element Method). The present artificial hip joint was loaded with force that occurred due to jump activity, and there were 3 type of materials that used in this research (Titanium Alloy (Ti-6Al-4V), Cobalt - Chrome alloy, and stainless steel (SS) 316L). The result is maximum stress that occurred on Ti-6Al-4V, Co-Cr alloy, and SS316L were 296.13 MPa, 294.02 MPa, and 294.51 MPa, respectively. The Ti-6Al-4V perform the best among the others with the safety factor of 2.7.

Effect of the action of diamond burs with high speed on the tensile strength of cores cemented with zinc phosphate at different preparation times

Objective: To know the finishing effect, in order to be able to safely proceed with the cores preparation in the daily clinic, without compromising the prosthetic restoration longevity. Methods: This study used 48 human single-rooted premolars, which after the section of its crowns, were endodontically treated, and its root canal prepared 8 mm deep to receive cores casting in cobalt-chrome alloy. Cementing was made with zinc phosphate and the tensile test performed at different preparation times: G1 - without re-preparation after cementation (control); G2 - re-prepared 24 hours after cementation, and G3 - re-prepared 15 minutes after cementation. Results: Statistical analysis showed no significant difference in the tensile strength values in the different groups (p = 0.233), in other words, the core re-preparation 15 minutes or 24 hours after the cementation caused no significant reduction in tensile strength between the core and the root remaining when using the zinc phosphate cement. Conclusion: The metallic core re-preparation cast 15 minutes or 24 hours after cementation caused no significant reduction in tensile strength between the cast metallic core and the root remaining, although in absolute values there was an important difference.