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Effect of electric arc, gas oxygen torch and induction melting techniques on the marginal accuracy of cast base-metal and noble metal-ceramic crowns
پروتزهای دندانی
Prothtodontics
پژوهشي
Research
<p> <strong>Objectives</strong></p><p> The aim of this study was to identify the most appropriate alloy composition and melting technique by evaluating the marginal accuracy of cast metal-ceramic crowns.</p><p> <strong> </strong><strong>Methods</strong></p><p> Seventy standardised stainless-steel abutments were prepared to receive metal-ceramic crowns and were randomly divided into four alloy groups: Group 1: palladium-gold (Pd-Au), Group 2: nickel-chromium-titanium (Ni-Cr-Ti), Group 3: nickel-chromium (Ni-Cr) and Group 4: titanium (Ti). Groups 1, 2 and 3 were in turn subdivided to be melted and cast using: (a) gas oxygen torch and centrifugal casting machine (TC) or (b) induction and centrifugal casting machine (IC). Group 4 was melted and cast using electric arc and vacuum/pressure machine (EV). All of the metal-ceramic crowns were luted with glass-ionomer cement. The marginal fit was measured under an optical microscope before and after cementation using image analysis software. All data was subjected to two-way analysis of variance (ANOVA). Duncan's multiple range test was run for post-hoc comparisons. The Student's t-test was used to investigate the influence of cementation (α=0.05). </p><p> <strong>Results</strong></p><p> Uncemented Pd-Au/TC samples achieved the best marginal adaptation, while the worst fit corresponded to the luted Ti/EV crowns. Pd-Au/TC, Ni-Cr and Ti restorations demonstrated significantly increased misfit after cementation. </p><p> <strong>Conclusions </strong></p><p> The Ni-Cr-Ti alloy was the most predictable in terms of differences in misfit when either torch or induction was applied before or after cementation. Cemented titanium crowns exceeded the clinically acceptable limit of 120μm. </p><p> <strong>Clinical significance</strong></p><p> The combination of alloy composition, melting technique, casting method and luting process influences the vertical seal of cast metal-ceramic crowns. An accurate use of the gas oxygen torch may overcome the results attained with the induction system concerning the marginal adaptation of fixed dental prostheses. </p><hr><p></p><p> <strong>Source: </strong>Journal of Dentistry</p><p> <a href="http://www.jodjournal.com/article/S0300-5712(13)00156-5/abstract" target="_blank"><font color="#0000ff">Full Text</font></a></p>
Gas oxygen torch, Induction, Vacuum-casting, Pressure-differential casting machine, Dental alloy, Marginal fit
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http://idai.ir/browse.php?a_code=A-10-32-2197&slc_lang=fa&sid=1
Pablo
Gómez-Cogolludo
100319475328460010332
100319475328460010332
No
Department of Buccofacial Prostheses, Faculty of Odontology, Complutense University of Madrid (U.C.M.), Pza. Ramón y Cajal, s/n, 28040 Madrid, Spain
Raquel
Castillo-Oyagüe
100319475328460010333
100319475328460010333
Yes
Department of Buccofacial Prostheses, Faculty of Odontology, Complutense University of Madrid (U.C.M.), Pza. Ramón y Cajal, s/n, 28040 Madrid, Spain
Christopher
D. Lynch
100319475328460010334
100319475328460010334
No
Tissue Engineering & Reparative Dentistry, School of Dentistry, Cardiff University, Cardiff, Wales, UK
María-Jesús
Suárez-García
100319475328460010335
100319475328460010335
No
Department of Buccofacial Prostheses, Faculty of Odontology, Complutense University of Madrid (U.C.M.), Pza. Ramón y Cajal, s/n, 28040 Madrid, Spain