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. 2020 Feb 11;7(1):41-49.
doi: 10.1080/26415275.2020.1724512. eCollection 2020.

Discrepancy in alloy composition of imported and non-imported porcelain-fused-to-metal (PFM) crowns produced by Norwegian dental laboratories

Håvard Jostein Haugen  1 , Brandon Michael Soltvedt  1 , Peter N Nguyen  1 , Hans Jacob Ronold  2 , Gaute Floer Johnsen  1
Affiliations

Discrepancy in alloy composition of imported and non-imported porcelain-fused-to-metal (PFM) crowns produced by Norwegian dental laboratories

Håvard Jostein Haugen et al. Biomater Investig Dent. .

Abstract

Purpose: Even though the use of full ceramic crowns have become a well-established practice in dental clinics compare to the last decade, the use of imported casted porcelain-fused-to-metal (PFMs) crowns is still prevalent. The use of imported PFMs is often economically driven; however, when dentists order PFMs, they do not have capabilities to examine its true alloy content. Therefore, we raise the questions whether cheaper imported PFMs have more discrepancies in alloy content compared to domestically produced PFMs? Materials and Methods: This study included 62 porcelain-fused-to-metal crowns: 41 produced in Norway and 21 imported. Their alloy-composition was determined non-destructively by EDX and SEM. Results and Conclusions: Imported PFMs demonstrated larger deviations compared with non-imported PFMs. Significant deviation was found in key metallic elements in the different alloys (W, In, Pd, Ag). The detected deviations in key element such as Wolfram and Indium could influence the PFMs service time. These finding may be of international concern.

Keywords: Dental crown; metal ceramic alloys; metal ceramic restorations; porcelain-metal alloys.

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Conflict of interest statement

No potential conflict of interest was reported by the author(s).

Figures

Figure 1.
Figure 1.
Number of base-metal crowns sorted in categories according to degree of deviation (A: all base metals, B: Predominantly base metal base metal only C: noble metal base metal only.) No deviation: Minor deviations in major constituents (elements that comprises >20 wt. %) and slight deviations in additional elements that comprise <10 wt.%. Small deviation: <5 wt. % concerning major constituents and/or deviations >1 wt. % in additional elements that comprise <10 wt.%. Large deviation: >5wt. % concerning major constituents and missing and/or additional elements.
Figure 2.
Figure 2.
Whisker diagrams depicting distribution of data concerning alloy content deviation. Alloys ‘Noble’ (D) had large variations, hence the outliers in several of the constituents, whereas d.SIGN53 (B) showed little variation. *Noble metal diagram includes both Noble metal 1 and 2; these two alloys are both from Lab D and were termed Noble metal, however with slight differences in wt. % of each element. #statistically significant difference between the mean of the sampled population and the hypothesized population mean (p < .05).
Figure 3.
Figure 3.
Information provided by the seven different dental laboratories showing level of ‘incorrect content’, ‘unspecified content’ and ‘specified content’.
See this image and copyright information in PMC

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