Influence of the CAD-CAM Systems on the Marginal Accuracy and Mechanical Properties of Dental Restorations

Roberto Padrós; Luís Giner; Mariano Herrero-Climent; Carlos Falcao-Costa; José-Vicente Ríos-Santos; Francisco Javier Gil

doi:10.3390/ijerph17124276

Influence of the CAD-CAM Systems on the Marginal Accuracy and Mechanical Properties of Dental Restorations

Int J Environ Res Public Health. 2020 Jun 15;17(12):4276. doi: 10.3390/ijerph17124276.

Authors

Roberto Padrós¹, Luís Giner², Mariano Herrero-Climent³, Carlos Falcao-Costa^{3

4}, José-Vicente Ríos-Santos⁵, Francisco Javier Gil^{2

6}

Affiliations

¹ Barcelona Dental Institute, 08034 Barcelona, Spain.
² Faculty of Dentistry, International University of Catalonia, Josep Trueta s/n, 08195 Barcelona, Spain.
³ Porto Dental Institute, 4150-518 Porto, Portugal.
⁴ Faculty of Health Sciences, Fernando Pessoa University, 4200-150 Porto, Portugal.
⁵ Department of Periodontology, University of Seville, 41009 Seville, Spain.
⁶ Bioengineering Institute of Technology, International University of Catalonia, Josep Trueta s/n, 08195 Barcelona, Spain.

Abstract

The aim of this study was to compare the quality of different computer-assisted-design and computer assisted manufacturing systems (CAD-CAM) generated by only one scanner, focusing on vertical fit discrepancies and the mechanical properties. A master model was obtained from a real clinical situation: the replacement of an absent (pontic) tooth, with the construction of a fixed partial denture on natural abutments with three elements. Nine scans were performed by each tested and 36 copies were designed using a dental CAD-CAM software (Exocad). The frameworks were manufactured using three-axis and five-axis, with the same batch of the chrome-cobalt (CrCo) alloy. The frameworks were not cemented. A focus ion beam-high resolution scanning electron microscope (FIB-HRSEM) allowed us to obtain the vertical gap measurements in five points for each specimen. Roughness parameters were measured using white light interferometry (WLI). The samples were mechanically characterized by means of flexural tests. A servo-hydraulic testing machine was used with a cross-head rate of 1 mm/min. One-way ANOVA statistical analysis was performed to determine whether the vertical discrepancies and mechanical properties were significantly different between each group (significance level p < 0.05). The overall mean marginal gap values ranged: from 92.38 ± 19.24 µm to 19.46 ± 10.20 µm, for the samples produced by three-axis and five-axis machines, respectively. Roughness was lower in the five-axis machine than the three-axis one, and as a consequence, the surface quality was better when the five-axis machine was used. These results revealed a statistically significant difference (p < 0.005) in the mean marginal gap between the CAD-CAM systems studied. The flexural strength for these restorations range from 6500 to 7000 N, and does not present any statistical differences' significance between two CAD-CAM systems studied. This contribution suggests that the number of axes improves vertical fit and surface quality due to the lower roughness. These claims show some discrepancies with other studies.

Keywords: CAD-CAM; Cr-Co alloy; dental prosthesis; marginal fit; mechanical properties.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Computer-Aided Design*
Denture Design
Denture, Partial, Fixed
Materials Testing
Surface Properties
Zirconium

Substances

Zirconium