Research on Influence of Metallurgy Factors on the Quality of Metal Components in Metal-Ceramic Prosthetic Restorations
Abstract
The paper summarizes the characteristics of the metal component in the structure of metal-ceramic fixed prostheses and the technological conditions for obtaining it. The paper presents partial results of an experimental study on identifying the causes that favor the generation of defects during the stages of metal melting-casting, defects which in turn may be causes of failure in metal-ceramic restorations. The type of defect identified elucidates both the cause of and effects on the quality of metal-ceramic bond. The study was conducted by light and electron microscopy analysis of samples from two non-noble dental alloys (Co-Cr and NiCr), samples taken from casting network, supply channels and metal crown. Results of the analysis performed with a scanning electron microscope SEM fitted with an energy spectrometer EDAX revealed the presence of oxide inclusions, chemical and structural heterogeneity, alloy solidification shrinkage voids and discontinuities caused by lack of technological discipline in the steps of metallurgical alloy processing, particularly the lack of rigorous assessment of temperature and optimum casting time and exposure of the molten alloy into contact with the atmosphere for a long time.
Downloads
References
[2]. Bratu D., Nussbaum R., Bazele clinice şi tehnice ale protezării fixe, Ed. Medicală, București, 2009.
[3]. Bratu D., Nussbaum R., Bazele clinice şi tehnice ale protezării fixe, cap. 18., p. 981-1006, Ed. Signata, Timişoara, 2001.
[4]. Codruța Nicola, Materiale dentare. Consideratii clinice și tehnologice, Editura Casa Cărții de Știință, Cluj-Napoca, 2009.
[5]. Deliu L., Cercetări privind influența unor factori tehnologici în procesul de realizare a cmponentei metalice pentru coroanele mixte metalo-ceramice, lucrare licenta, FMF, Galati, 2015.
[6]. Christos G., Consideraţii privind legătura maselor ceramice cu infrastructura metalică, teza de doctorat, UMF Bucuresti, 2014.
[7]. Duchaye R., Hastings G. W., Metal and Ceramic Biomaterials, vol. I si II, Ed. Boca Raton Florida, 1998.
[8]. Mackert J. R., Ringle R. D., Parry E. E., The Relationship between Oxide Adherence and Porcelain Metal Bonding, J Dent Res, 67:474, 1988.
[9]. Pătraşcu I., Pătraşcu D., Ciocan L. T., Compatibility of Metal-Ceramics Bond, Romanian Biotechnological Letters, Vol. 5, No. 4, p. 285-290, 2000.
[10]. Dorsch P., Thermal Compatibility of Materials for Porcelain Fused to Metal (PFM) Restorations, Caramic forum International, Ber Dt Keram Ges, 59:1, 1982.
[11]. Pătraşcu I., Ciocan L. T., Frussigniotti S., Evaluation of Metal-Ceramics Interface for Modern Ni-Cr Alloys, “BASS2000” Congress of Balkan Stomatological Society, Thessaloniki, Greece, April 15, 2000.
[12]. Hâncu V., Studii asupra biocompatibilității şi bioeconomiei materialelor utilizate în restaurările protetice metalo-ceramice, la interfața cu structurile dentare, Universitatea Titu Maiorescu, București, 2013.
[13]. Fairhurst C. S., Anusavice K. J., Hashiger D. T., et al., Thermal Expansion of Dental Alloys and Porcelain, J Biomed Mater Res, 14:435, 1980.
[14]. Lubovichi P. A., Goodkindi R. J., Bond strength of ceramicmetal alloys, J. Pros. Dent., 37-288, 1977.
[15]. Pătraşcu I., Ciocan L. T., Ghiorghieş C., Research Regarding the Testing of Metal-Ceramics Bond of Non-Noble Alloys, The Annals „Dunarea de Jos” University of Galati, Fascicula V, p. 43-49, 1999.
[16]. Wen S., Liu Q., High Resolution Electron Microscopy Investigation of Interface and Other Structure Defects in Some Ceramics, Microsc. Res. Tech., Feb. 1, 40(3), p. 177-186, 1998.
[17]. Roland Strietzel, Restaurări protetice fixe și combinate, Dental Press Hungary, 2013.
[18]. Kenneth J., Anusavice-Philip`s Science of Dental materials eleventh edition, Elsevier, Florida, 2011.
[19]. Craig R. G., Restorative dental materials, Mosby, Chicago, 1993.
[20]. Ghiban Brânduşa, Metallic Biomaterials, Ed. Printech Bucureşti, 1999.
[21]. Norina Forna, Protetică dentară, vol. 1, Editura Enciclopedică, 2011.
[22]. Flinn R., Trojan P., Engineering Materials and Their Applications, 3rd edition, Boston, MA, Houghton Mifflin Co., p. 116-169, 1986.