Influence of calcinable cylinders cast in cobalt-chromium alloy on the passivity of implant-supported frameworks

• Published in: Revista odonto ciência Vol. 24; no. 2
• Main Authors: Fernandes Triches, Diego, Rizzo Alonso, Fernando, Disconzi Seitenfus, Daniela, Carlos Pinheiro Beck, João, Mayumi Hirakata, Luciana, Rolim Teixeira, Eduardo
• Format: Journal Article
• Language: English
• Published: Porto Alegre EDIPUCRS 01-04-2009
• ISSN: 0102-9460; 1980-6523

Purpose: This study aimed to determine the effect of using calcinable cylinders on the passivity of a framework that simulates a three-unit fixed partial prosthesis on two implants. Methods: Two 3.75×10 mm external hex implants were used, with their abutments set on a steel base forming the master model. Ten cobalt-chromium alloy frameworks were manufactured by the induction casting technique. Two groups were established: Group 1 used premachined cylinders to cast five frameworks; Group 2 used plastic calcinable cylinders to cast five frameworks. Passivity evaluation was accomplished by using strain gauges placed in the cervical and occlusal regions of the framework pontics. The measurement was performed during screwing of the second prosthetic screw with a torque of 10 Ncm. Data were analyzed by Student's t test (?=0.05). Results: The mean (standard deviation) values were 39.16 (24.74) mV/V for Group 1 and 43.76 (21.13) mV/V for Group 2. There was no statistically significant difference between groups (P=0.815). Conclusion: The results suggest that the use of calcinable cylinders had a similar degree of passivity compared to the use of premachined prosthetic cylinders.