ABSTRACT
RESUMEN: Introducción: La confección de restauraciones indirectas ha sido tradicionalmente realizada mediante técnicas convencionales de laboratorio, la cual involucra la realización de una serie de pasos y la necesidad de que el paciente asista a varias sesiones clínicas. En las últimas décadas ha sido incorporada la técnica CAD/CAM, la cual ha simplificado la confección de restauraciones indirectas. Es necesario comparar el desempeño clínico de ambas técnicas. Métodos: Realizamos una búsqueda en Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante el cribado de múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, analizamos los datos de los estudios primarios, realizamos un metaanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. Resultados y conclusiones: Identificamos tres revisiones sistemáticas que en conjunto incluyeron ocho estudios primarios, de los cuales, cinco corresponden a ensayos aleatorizados. Concluimos que la técnica CAD/CAM probablemente aumenta la falla de la restauración y la pérdida de retención. Por otra parte, podría disminuir levemente la pérdida de vitalidad y tener nula o poca diferencia en el riesgo de extracción dentaria, riesgo de caries secundaria y cambio de color superficial, pero la certeza de la evidencia es baja.
ABSTRACT: Introduction: Conventional laboratory techniques for indirect restoration involve multiple stages and several clinical sessions for patients. In the last decades, the CAD/CAM technique has been incorporated in clinical practice, simplifying the fabrication process of indirect restorations. A comparative assessment of the clinical performance of both techniques is required. Methods: We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. Results and conclusions: We identified three systematic reviews including eight studies overall, of which five were randomized trials. We conclude that CAD/CAM technique probably increase the risk of restoration failure and loss of retention. On the other hand, CAD/CAM technique may slightly reduce the risk of loss of vitality and may make little or no difference to the risk of tooth extraction, risk of secondary caries and superficial color change, but the certainty of the evidence is low.
Subject(s)
Humans , Computer-Aided Design , Dental Restoration, Permanent/methodsABSTRACT
STATEMENT OF PROBLEM: Delamination of veneering porcelain from underlying ceramic substructures has been reported for zirconia-ceramic restorations. Colored zirconia cores for esthetics have been reported that their bond strength with veneered porcelain is weaker compared to white zirconia cores. PURPOSE: This study aimed to investigate the shear bond strength by manufacturing the veneering porcelain on the colored zirconia core, using the layering technique and heat-pressing technique, and to evaluate the clinical stability by comparing the result of this with that of conventional metal ceramic system. MATERIAL AND METHODS: A Metal ceramic (MC) system was tested as a control group. The tested systems were Katana zirconia with CZR (ZB) and Katana Zirconia with NobelRondo Press (ZP). Thirty specimens, 10 for each system and control, were fabricated. Specimen disks, 3 mm high and 12 mm diameter, were fabricated with the lost-wax technique (MC) and the CAD-CAM (ZB and ZP). MC and ZB specimens were prepared using opaque and dentin veneering ceramics, veneered, 3 mm high and 2.8 mm in diameter, over the cores. ZP specimens were prepared using heat pressing ingots, 3 mm high and 2.8mm in diameter. The shear bond strength test was performed in a Shear bond test machine. Load was applied at a cross-head speed of 0.50 mm/min until failure. Mean shear bond strengths (MPa) were analyzed with the One-way ANOVA. After the shear bond test, fracture surfaces were examined by SEM. RESULTS: The mean shear bond strengths (SD) in MPa were MC control 29.14 (2.26); ZB 29.48 (2.30); and ZP 29.51 (2.32). The shear bond strengths of the tested systems were not significantly different (P > .05). All groups presented cohesive and adhesive failures, and showed predominance of cohesive failures in ceramic veneers. CONCLUSION: 1. The shear bond strengths of the tested groups were not significantly different from the control group (P > .05). 2. There was no significant different between the layering technique and the heat pressing technique in the veneering methods on the colored zirconia core. 3. All groups presented cohesive and adhesive failures, and showed predominance of cohesive failures in ceramic veneers.