ABSTRACT
Around the year 2000, zirconia was introduced in dentistry. It is a material with great strength and attractive aesthetic properties, such as translucency and colour. Recent advances in digital dentistry are aimed at veneering the supporting structure ofzirconia with a layer of glass ceramics by means of an automated process. With the Primero process, a transparent outer layer of glass ceramic is applied directly onto the zirconia core, milled in the green stage and sintered. Because the restorations produced in this way have a two-layer structure like natural teeth, they obtain an aesthetic look similar to natural dental elements. The aim ofthis prospective study was to evaluate fit, marginal adaptation, contact with antagonists and neighbouring dental elements, aesthetics and colour. Clinical performance of Primero restorations were evaluated over a period of6 months and the results were compared with a previous study of CAD/CAM copings which were produced with the same method, but were veneered by hand in the traditional way.
