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

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? 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. 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

尽管相较于十年前，全瓷冠（full ceramic crowns）的应用已成为牙科临床中一项成熟的诊疗常规，但进口铸造式金属烤瓷冠（porcelain-fused-to-metal, PFMs）的使用仍较为普遍。进口PFMs的应用常受经济因素驱动；然而，牙医在订购此类冠修复体时，无法对其真实的合金成分进行检测。为此，我们提出如下疑问：相较于国产PFMs，价格更为低廉的进口PFMs是否存在更显著的合金成分偏差？
本研究共纳入62件金属烤瓷冠：其中41件产自挪威，21件为进口产品。研究采用能量色散X射线光谱（Energy Dispersive X-ray Spectroscopy, EDX）与扫描电子显微镜（Scanning Electron Microscope, SEM）对其合金成分开展无损检测。结果表明，进口PFMs的成分偏差幅度显著高于国产PFMs。不同合金中的关键金属元素（钨（W）、铟（In）、钯（Pd）、银（Ag））均存在显著偏差。其中，钨与铟等关键元素的检测偏差，可能会对PFMs的临床使用寿命产生影响。上述研究发现或引发国际学界的广泛关注。