Abstract:

BACKGROUND: Studies have shown that the incidence of local adverse effects of gingival and periodontal tissues after fixation of metal-ceramic crowns may relate to the release of metallic elements by the metal-ceramic restorations.
OBJECTIVE: To analyze and summarize the biocompatibilities, cytotoxicities, cell metabolisms and mechanisms in molecular levels of non-noble metal-ceramic and noble metal-ceramic alloys.
METHODS: A search of studies published from January 1990 to January 2012 related to the effects of metal-ceramic alloys on normal physiological metabolism and immunology of cells was performed in PubMed database and Wanfang database using the key words of “dental casting alloys, biocompatibility, cytotoxicity, cytokines” in English and in Chinese, respectively. Articles irrelative to this paper and repetitive studies were excluded. Finally, 39 literatures were chosen to summarize.
RESULTS AND CONCLUSION: The cytotoxicities of five metal-ceramic alloys commonly used in clinical practice are in order of nichrome alloy, titanium alloy, cobalt-chromium alloy, palladium-based alloy, gold alloy. Noble metal-ceramic alloys have good mechanical properties, anti-tarnish and corrosion-resistant properties, good processing properties, and good cytocompatibilities and biocompatibilities. The genotoxicity of gold alloy is superior to nichrome alloy, titanium alloy and cobalt-chromium alloy. Gold alloy can be well used in dentistry based on its good biological properties. For non-noble metal-ceramic alloys, Co-Cr-Mo has the highest biosafety, Ni-Cr-Be has the lowest biosafety, and the biosafety of Ni-Cr is between those of Co-Cr-Mo and Ni-Cr-Be. Noble metal-ceramic alloys are not easy to be porcelain fractured based on their better bond strengths of metal-porcelain compared with non-noble metal-ceramic alloys. Gold coatings can disperse the gathered internal stress to strengthen the bond strength of metal-porcelain through relief the interface stress based on their own elastic yield.