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

Thaís Barbin; Letícia Del Rio Silva; Daniele Valente Velôso; Guilherme Almeida Borges; Anna Gabriella Camacho Presotto; Valentim Adelino Ricardo Barão; Francisco Carlos Groppo; Marcelo Ferraz Mesquita

doi:10.4047/jap.2020.12.6.329

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

J Adv Prosthodont. 2020 Dec;12(6):329-337. doi: 10.4047/jap.2020.12.6.329. Epub 2020 Dec 28.

Authors

Thaís Barbin¹, Letícia Del Rio Silva¹, Daniele Valente Velôso¹, Guilherme Almeida Borges¹, Anna Gabriella Camacho Presotto¹, Valentim Adelino Ricardo Barão¹, Francisco Carlos Groppo², Marcelo Ferraz Mesquita¹

Affiliations

¹ Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil.
² Department of Physiological Sciences, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil.

Abstract

Purpose: To verify the influence of computer-aided design/computer-aided manufacturing (CAD/CAM) implant-supported 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 10⁶ 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, screw-loosening 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). Screw-loosening 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.

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