J Adv Prosthodont.  2020 Dec;12(6):329-337. 10.4047/jap.2020.12.6.329.

Biomechanical behavior of CAD/CAM cobaltchromium and zirconia full-arch fixed prostheses

• Barbin T
• Silva LDR
• Velôso DV
• Borges GA
• Presotto AGC
• Barão VAR
• Groppo FC
• Mesquita MF

• KMID: 2509766
• DOI: http://doi.org/10.4047/jap.2020.12.6.329

Abstract

PURPOSE
To verify the influence of computer-aided design/computer-aided manufacturing (CAD/CAM) implantsupported prostheses manufactured with cobalt-chromium (Co-Cr) and zirconia (Zr), and whether ceramic application, spark erosion, and simulation of masticatory cycles modify biomechanical parameters (marginal fit, screw-loosening torque, and strain) on the implant-supported system.
MATERIALS AND METHODS
Ten full-arch fixed frameworks were manufactured by a CAD/CAM milling system with Co-Cr and Zr (n=5/group). The marginal fit between the abutment and frameworks was measured as stated by single-screw test. Screw-loosening torque evaluated screw stability, and strain analysis was explored on the implant-supported system. All analyses were performed at 3 distinct times: after framework manufacturing; after ceramic application in both materials’ frameworks; and after the spark erosion in Co-Cr frameworks. Afterward, stability analysis was re-evaluated after 10 6 mechanical cycles (2 Hz/150-N) for both materials. Statistical analyses were performed by Kruskal-Wallis and Dunn tests (α=.05).
RESULTS
No difference between the two materials was found for marginal fit, screwloosening torque, and strain after framework manufacturing (P>.05). Ceramic application did not affect the variables (P>.05). Spark erosion optimized marginal fit and strain medians for Co-Cr frameworks (P<.05). Screwloosening torque was significantly reduced by masticatory simulation (P<.05) regardless of the framework materials.
CONCLUSION
Co-Cr and Zr frameworks presented similar biomechanical behavior. Ceramic application had no effect on the biomechanical behavior of either material. Spark erosion was an effective technique to improve Co-Cr biomechanical behavior on the implant-supported system. Screw-loosening torque was reduced for both materials after masticatory simulation.

Keyword

Computer-aided design/computer-aided manufacturing (CAD/CAM); Dental marginal adaptation; Dental stress analysis; Implant-supported dental prostheses; Spark erosion