Flávio D Neves1, Célio J Prado2, Marcel S Prudente3, Thiago A P N Carneiro3, Karla Zancopé3, Letícia R Davi2, Gustavo Mendonça4, Lyndon F Cooper4, Carlos José Soares5. 1. Professor, Department of Occlusion, Fixed Prosthesis and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil. Electronic address: neves@triang.com.br. 2. Professor, Department of Occlusion, Fixed Prosthesis and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil. 3. Graduate student, Department of Occlusion, Fixed Prosthesis and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil. 4. Professor, Department of Prosthodontics, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC. 5. Professor and Research Coordinator, Biomechanics Group, Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil.
Abstract
STATEMENT OF PROBLEM: No consensus exists concerning the acceptable ranges of marginal fit for lithium disilicate crowns fabricated with either heat-pressing techniques or computer-aided design and computer-aided manufacturing (CAD/CAM) systems. PURPOSE: The purpose of the study was to evaluate with micro-computed tomography the marginal fit of lithium disilicate crowns fabricated with different chairside CAD/CAM systems (Cerec or E4D) or the heat-pressing technique. MATERIAL AND METHODS: Lithium disilicate crowns were fabricated to fit an in vitro cast of a single human premolar. Three fabrication techniques were used: digital impressions with Cerec 3D Bluecam scanner with titanium dioxide powder, followed by milling from IPS e.max CAD for Cerec; digital impressions with E4D Laser scanner without powder, followed by milling from IPS e.max CAD for E4D; and fabrication from IPS e.max Press by using the lost-wax and heat-pressing techniques. Each crown was fixed to the cast and scanned with micro-computed tomography to obtain 52 images for measuring the vertical and horizontal fit. Data were statistically analyzed by 1-way ANOVA, followed by the Tukey honestly significant difference test (α=.05). RESULTS: The mean values of vertical misfit were 36.8 ±13.9 μm for the heat-pressing group and 39.2 ±8.7 μm for the Cerec group, which were significantly smaller values than for the E4D group at 66.9 ±31.9 μm (P=.046). The percentage of crowns with a vertical misfit <75 μm was 83.8% for Cerec and heat-pressing, whereas this value was 65% for E4D. Both types of horizontal misfit (underextended and overextended) were 49.2% for heat-pressing, 50.8% for Cerec, and 58.8% for E4D. CONCLUSIONS: Lithium disilicate crowns fabricated by using the Cerec 3D Bluecam scanner CAD/CAM system or the heat-pressing technique exhibited a significantly smaller vertical misfit than crowns fabricated by using an E4D Laser scanner CAD/CAM system.
STATEMENT OF PROBLEM: No consensus exists concerning the acceptable ranges of marginal fit for lithium disilicate crowns fabricated with either heat-pressing techniques or computer-aided design and computer-aided manufacturing (CAD/CAM) systems. PURPOSE: The purpose of the study was to evaluate with micro-computed tomography the marginal fit of lithium disilicate crowns fabricated with different chairside CAD/CAM systems (Cerec or E4D) or the heat-pressing technique. MATERIAL AND METHODS:Lithium disilicate crowns were fabricated to fit an in vitro cast of a single human premolar. Three fabrication techniques were used: digital impressions with Cerec 3D Bluecam scanner with titanium dioxide powder, followed by milling from IPS e.max CAD for Cerec; digital impressions with E4D Laser scanner without powder, followed by milling from IPS e.max CAD for E4D; and fabrication from IPS e.max Press by using the lost-wax and heat-pressing techniques. Each crown was fixed to the cast and scanned with micro-computed tomography to obtain 52 images for measuring the vertical and horizontal fit. Data were statistically analyzed by 1-way ANOVA, followed by the Tukey honestly significant difference test (α=.05). RESULTS: The mean values of vertical misfit were 36.8 ±13.9 μm for the heat-pressing group and 39.2 ±8.7 μm for the Cerec group, which were significantly smaller values than for the E4D group at 66.9 ±31.9 μm (P=.046). The percentage of crowns with a vertical misfit <75 μm was 83.8% for Cerec and heat-pressing, whereas this value was 65% for E4D. Both types of horizontal misfit (underextended and overextended) were 49.2% for heat-pressing, 50.8% for Cerec, and 58.8% for E4D. CONCLUSIONS:Lithium disilicate crowns fabricated by using the Cerec 3D Bluecam scanner CAD/CAM system or the heat-pressing technique exhibited a significantly smaller vertical misfit than crowns fabricated by using an E4D Laser scanner CAD/CAM system.
Authors: Franz Sebastian Schwindling; Moritz Waldecker; Peter Rammelsberg; Stefan Rues; Wolfgang Bömicke Journal: Clin Oral Investig Date: 2018-12-04 Impact factor: 3.573
Authors: Fabio Kricheldorf; Cleuber Rodrigo de Souza Bueno; Wilson da Silva Amaral; Joel Ferreira Santiago Junior; Hugo Nary Filho Journal: Eur J Dent Date: 2018 Jan-Mar