MODERN CAD/CAM COMPOSITE MATERIALS: MATERIAL PROPERTIES AND LUTING STRATEGIES 22-03-2016 Dr. Ralf Böhner First publication in ZMK (32) 3/2016, 112118, Spitta Verlag, Germany
BRILLIANT Crios The latest generation of Reinforced Composite Blocs.
Composite-based CAD/CAM materials have been marketed as „composite ceramics or hybrid ceramics“ to underscore their longevity. The latest generation of reinforced composite blocs demonstrates excellent material properties, which are in part even superior to the properties of ceramics. Comparative studies have provided interesting insights into the flexural strength and abrasion resistance of these innovative restoration materials. Digital production is becoming increasingly popular in the fabrication of dental restorations. In this process, the restorations are ground to their final shape using digital data sets. Numerous computer-guided modelling systems are commercially available that can generate the shape of the restoration via a direct digital impression taken in the mouth or by digitalising of an impression or a tooth model. The important pioneers of this technology were Duret and Mörmann/Brandestini [1], among others. Whereas Duret favoured materials made of fibre-reinforced composite, Mörmann preferred ceramic materials. Mörmann‘s CAD/CAM system prevailed on the market as „Cerec“. Over time, the CAD/CAM ceramic blocks were optimised and today are divided into two material categories: 1) feldspar or leucite ceramics which do not necessarily have to be fired after the grinding process of the restoration, and 2) lithium disilicate or zirconium oxide ceramics which must be subjected to a firing process after grinding [2]. Although these ceramic materials have good aesthetics and resist abrasion, they also have drawbacks that include a relatively high modulus of elasticity, a tendency to chip, and abrasion of the antagonist. Modifying or repairing ceramics intraorally is also quite an elaborate procedure. Therefore, there is a need for composite materials for use with the CAD/CAM method in addition to light-curing composites for permanent restorations. In contrast to light-curing composites, CAD/ CAM composite materials can be manufactured on an industrial scale with excellent mechanical properties achieved. One of the first products in this category was marketed by the 3M Espe company under www.coltene.com
the name Paradigm, and this was followed by Lava Ultimate, Cerasmart (GC) and Shofu Block HC (Shofu). COLTENE, the Swiss dental specialist, is currently introducing BRILLIANT Crios, a novel and versatile CAD/CAM composite material with high performance.
COMPOSITE OR HYBRID CERAMIC? A composite is generally described as a material consisting of two or more different components that are bonded to each other. CAD/CAM composites consist of a matrix of polymerised methacrylates, which, depending on the product, contain different fillers (glass or ceramic). Although this is a composite in terms of material design, some companies market their products as hybrid ceramics due to the use of ceramic fillers. These products include the following: • Composite ceramic based on nano-ceramic technology (Lava Ultimate) [3] • CAD/CAM bloc made of hybrid ceramic (Cerasmart) [4] • Highly aesthetic ceramic-based material (Shofu Block HC) [5] Another CAD/CAM block material, Vita Enamic (Vita Zahnfabrik), differs from both ceramic materials and composites, as it is a polymer-infiltrated porous ceramic. This material is suitable for minimally invasive reconstructions, posterior crowns for teeth [7], and other uses. According to the manufacturer, Lava Ultimate is indicated for inlays, onlays and veneers [3]. The CAD/CAM composite bloc materials BRILLIANT Crios, Cerasmart and Shofu Block HC are also approved for single crowns [4–6]. Composites must not be confused with purely ceramic CAD/CAM materials or treated as such. For example, as composite materials should not be fired, their processing procedure is considerably easier. In addition, adhesive luting is adapted to the composite. Similar to light-curing filling materials, composite-based CAD/CAM materials are easy to modify and polish. Furthermore, their repairs can be performed intraorally. In general, the luting strategy of CAD/CAM fabricated restorations is crucial for the success of treatment.