RESUMEN
Maxillofacial prostheses have traditionally been manufactured by pouring silicone into molds. However, the development of computer-aided design and computer-aided manufacturing (CAD-CAM) systems allows the virtual planning, design, and manufacture of maxillofacial prostheses through the direct 3-dimensional printing of silicone. This clinical report describes the digital workflow as an alternative to the conventional method of restoring a large midfacial defect in the right cheek and lip. In addition, the approaches were nonblinded evaluated in relation to outcomes and time efficiency, while marginal adaptation and esthetics, including patient satisfaction, were assessed for both prostheses fabricated. The digital prosthesis had acceptable esthetics and fit with improved patient satisfaction, especially in terms of efficiency, comfort, and speed of the digital workflow.
RESUMEN
PURPOSE: The aim of this study was to compare the marginal fit of cobalt-chromium crowns fabricated using conventional casts and computer-aided design/computer-assisted manufacturing (CAD/CAM) techniques at three stages of production: metal coping, after porcelain firing, and after cementation. MATERIALS AND METHODS: A total of 80 metal-ceramic crowns were fabricated using four different techniques: lost wax casting, milling, laser sintering, and milling of a presintered metal block. Marginal fit was measured at each manufacturing stage. RESULTS: The porcelain firing stage improved marginal fit. CAD/CAM techniques resulted in better marginal fit than did conventional casting techniques at all manufacturing stages. CONCLUSION: CAD/CAM techniques improve marginal fit.
Asunto(s)
Diseño Asistido por Computadora , Coronas , Adaptación Marginal Dental , Diseño de Prótesis Dental , Cromo , Cobalto , Técnica de Colado Dental , Humanos , Técnicas In Vitro , Aleaciones de Cerámica y MetalRESUMEN
To treat a patient who needed a replacement for a maxillary obturator prosthesis, a new obturator prosthesis was fabricated from polyetheretherketone (PEEK), a material often used in medicine but seldom in dentistry. This material provided the patient with a better-adjusted, more functional, and lighter prosthesis.
Asunto(s)
Materiales Biocompatibles/química , Diseño de Prótesis Dental , Cetonas/química , Obturadores Palatinos , Polietilenglicoles/química , Resinas Acrílicas/química , Adhesivos/química , Benzofenonas , Bases para Dentadura , Diseño de Dentadura , Dentadura Parcial Removible , Femenino , Humanos , Metacrilatos/química , Metilmetacrilatos/química , Persona de Mediana Edad , Enfermedades Nasales/terapia , Fístula Oral/terapia , Polímeros , Fístula del Sistema Respiratorio/terapiaRESUMEN
PURPOSE: The purpose of this study was to evaluate the marginal adaptation of zirconium dioxide crowns in preparations with two different finish line configurations before and after porcelain firing cycles, after a glaze cycle, and after cementation. MATERIALS AND METHODS: Twenty human molar teeth were prepared to receive full crowns; ten were prepared with a 90° round shoulder and another ten with a 45° chamfer finish line. Zirconium dioxide copings were fabricated using CAD/CAM technology (Lava™ system). They were then veneered with a low-fusing glass-ceramic (IPS e.max® Ceram). Finally, they were glazed and cemented with a resin-composite cement (RelyX™ Unicem, Aplicap™). Measurements for marginal adaptation using stereomicroscopy (40×) were performed at four stages: copings (S1), after porcelain firing cycles (S2), after glazing (S3), and after cementation (S4). One-way ANOVA was used to assess the influence of the finish line design on the marginal adaptation in each stage. Two-way ANOVA with repeated measurements was performed to assess the influence on the marginal adaptation of the porcelain firing cycles, glaze firing cycle, and cementation. RESULTS: The measured marginal gap mean values for the shoulder group (µm) were: 50.13 (S1), 54.32 (S2), 55.12 (S3), and 59.83 (S4). The values for the chamfer group were: 63.56 (S1), 71.85 (S2), 74.12 (S3), and 76.97 (S4). When comparing marginal gaps between specimens with two different finish lines, differences were noticed at the four studied stages (p = 0.0165, p = 0.0027, p = 0.0009, and p = 0.0009, respectively). No differences were manifested in the marginal gap measurements of the shoulder group at the different stages of fabrication (p = 0.4335); however, in the chamfer group, differences were noticed between S1 and S3 (p = 0.0042). CONCLUSIONS: Marginal adaptation was influenced by the finish line design. The firing cycles significantly affected the chamfer group; nevertheless, the marginal gap was within the range of clinical acceptability.