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Objective: To compare the marginal gap of the crown coping fabricated from three different materials by the same CAD-CAM system.
Materials and Methods: Thirty crown copings were fabricated from three different types of materials, Zirconia (Ceramill ZI®, AmannGirrbach, Austria), PMMA (Ceramill PMMA®, AmannGirrbach, Austria) and Wax (Ceramill WAX®, AmannGirrbach, Austria) by the same CAD-CAM system (Ceramill, AmannGirrbach, Austria). The crown copings were milled without fully sintered shrinkage compensation. The crown copings were evaluated the marginal gap by the replica technique using low viscosity silicone. The replicas were cut in mesio-distal and bucco-palatal direction. The gap was measured using optical light microscope at 50X magnification. The marginal gap data from four positions of cutting were averaged as one datum and statistically analyzed by one-way ANOVA and Game-Howell post-hoc test (∝=0.05).
Results: The mean of marginal gap was 67.2±19.1 μm for zirconia, 514.3±55.1 μm for PMMA, and 44.9±14.1 μm for wax. The statistical analysis showed that the marginal gap of wax was significantly smaller than zirconia, while PMMA showed the largest gap (p<0.05).
Conclusion: It is concluded that the crown copings that were fabricated from the three different materials milled by the same CAD-CAM system showed a significant statistical difference in their average marginal distance or gap. PMMA showed the worst in marginal gap.
Miyazaki T, Hotta Y, Kunii J, Kuriyama S, Tamaki Y. A review of dental CAD-CAM: current status and future perspectives from 20 years of experience. Dent Mat J. 2009; 28: 44-56.
Edward A. Mclaren DAT. CAD-CAM Systems, Materials, and Clinical Guildelines for All-Ceramic crowns and Fixed Partial Dentures. Compendium. 2002; 23: 637-52.
Baig MR, Tan KB, Nicholls JI. Evaluation of the marginal fit of a zirconia ceramic computer-aided machined (CAM) crown system. J Prosthet Dent. 2010; 104: 216-27.
Borba M MJW, Cesar PF, Griggs JA, Della Bona A. Evaluation of the adaptation of zirconia-based fixed partial dentures using micro-CT technology. Braz Oral Res. 2013; 27: 396-402.
Herrera M CA, Flores M, Martínez A. Marginal discrepancy and microleakage in crown copings fabricated by three CAD-CAM systems: An in vitro study. Open J Stomatol. 2012; 2: 163-9.
Karatasli O, Kursoglu P, Capa N, Kazazoglu E. Comparison of the marginal fit of different coping materials and designs produced by computer aided manufacturing systems. Dent Mat J. 2011; 30: 97-102.
Schwartz IS. A review of methods and techniques to improve the fit of cast restorations. J Prosthet Dent. 1986; 56: 279-83.
Holmes JR BS, Holland GA, Sulik WD. Considerations in measurement of marginal fit. J Prosthet Dent. 1989 62: 405-8.
Andersson M, Razzoog ME, Oden A, Hegenbarth EA, Lang BR. Procera: a new way to achieve an all-ceramic crown. Quintessence Int. 1998; 29: 285-96.
Boening KW, Wolf BH, Schmidt AE, Kastner K, Walter MH. Clinical fit of Procera AllCeram crowns. J Prosthet Dent. 2000; 84: 419-24.
Jacobs MS, Windeler AS. An investigation of dental luting cement solubility as a function of the marginal gap. J Prosthet Dent. 1991; 65: 436-42.
Nawafleh NA, Mack F, Evans J, Mackay J, Hatamleh MM. Accuracy and reliability of methods to measure marginal adaptation of crowns and FDPs: a literature review. J Prosthodont 2013; 22: 419-28.
McLean JW, von Fraunhofer JA. The estimation of cement film thickness by an in vivo technique. Br Dent J. 1971; 131: 107-11.
Copper TM, Christensen GL, Laswell HR, Baxter R. Effect of venting on cast gold full crowns. J Prosthet Dent. 1971; 26: 621-6.
Koleva M. Poly methyl methacrylate. Injection Moulding Materials 2014; 2: 1-5.
Craig RG, Eick JD, Peyton FA. Strength properties of waxes at various temperatures and their practical application. J Dent Res. 1967; 46: 300-5.
Sabau AS, Viswanathan S. Material properties for predicting wax pattern dimensions in investment casting. Mater Sci Eng A 2003:125-34.