Marginal and Internal Precision of Zirconia Four-Unit Fixed Partial Denture Frameworks Produced Using Four Milling Systems

Karl Martin Lehmann; Michael Weyhrauch; Monika Bjelopavlovic; Herbert Scheller; Henning Staedt; Peter Ottl; Peer W Kaemmerer; Stefan Wentaschek

doi:10.3390/ma14102663

Marginal and Internal Precision of Zirconia Four-Unit Fixed Partial Denture Frameworks Produced Using Four Milling Systems

Materials (Basel). 2021 May 19;14(10):2663. doi: 10.3390/ma14102663.

Authors

Karl Martin Lehmann¹, Michael Weyhrauch¹, Monika Bjelopavlovic¹, Herbert Scheller¹, Henning Staedt², Peter Ottl^{2

3}, Peer W Kaemmerer⁴, Stefan Wentaschek¹

Affiliations

¹ Department of Prosthodontics and Materials Science, University Medical Center of University of Mainz, Augustusplatz 2, 55131 Mainz, Germany.
² Department of Prosthodontics and Materials Science, University of Rostock, Strempelstr. 13, 18057 Rostock, Germany.
³ Department Life, Light & Matter, University of Rostock, Albert-Einstein-Straße 25, 18059 Rostock, Germany.
⁴ Department of Oral- and Maxillofacial Surgery, University Medical Center of University of Mainz, Augustusplatz 2, 55131 Mainz, Germany.

Abstract

Background: CAD/CAM systems enable the production of fixed partial dentures with small and reproducible internal and marginal gaps.

Purpose: The purpose of this study was to evaluate the reproducibility of the marginal and internal adaptations of four-unit fixed partial denture frameworks produced using four CAD/CAM systems.

Materials and methods: Prepared dies of a master model that simulated the loss of the first left molar were measured. Fifteen frameworks were manufactured using four CAD/CAM systems (A-D). The internal fit was determined by the replica technique, and the marginal gap was determined by microscopy. ANOVA was carried out to detect significant differences, and the Bonferroni adjustment was performed. The global level of significance was set at 5%.

Results: The mean gap size ranged from 84 to 132 µm (SD 43-71 µm). The CAD/CAM systems showed significant variance (p < 0.001), and system A (VHF) showed the smallest gaps. The smallest gaps for each system were in the molar part and in the marginal region of the frameworks (p < 0.001).

Conclusions: The CAD/CAM systems showed significantly different gap sizes, particularly between premolars and molars and among the marginal, axial and occlusal regions. All of the systems are suitable for clinical application.

Keywords: CAD/CAM; FPD; internal fit; marginal fit; zirconia.