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ePaper created 2017-09-29, 09:04:12 | version 1.38.0
literature review _ CAD/CAM material and systems Materials and systems for all ceramic CAD/CAM restorations A review of the literature Authors_Drs Christian Brenes, Ibrahim Duqum & Gustavo Mendonza, USA _Introduction Dental crowns have been used for decades to restore compromised, heavily restored teeth, and for aesthetic improvements. New CAD/CAM (Computer Aided Design/Computer Aided Manu- facturing) materials and systems have been de- veloped and evolved in the last decade for fabri- cation of all-ceramic restorations. Dental CAD/CAM technology is gaining pop- ularity because of its benefits in terms of time consuming, materials savings, standardisation of the fabrication process, and predictability of the restorations. The number of steps required for the fabrication of a restoration is less compared to traditional methods (Fig 1). Another benefit of CAD/CAM dentistry includes the use of new ma- terials and data acquisition, which represents a non-destructive method of saving impressions, restorations and information that is saved in a computer and constitutes an extraordinary com- munication tool for evaluation. The incorporation of dental technology has not only brought a new range of manufacturing meth- ods and material options, but also some concerns about the processes involving restorations’ fit, quality, accuracy, short and long-term prognosis.1 The purpose of this document is to provide a review of the literature regarding the different materials and systems available up until 2015 in the USA. _CAD/CAM materials _Glass ceramics The first in-office ceramic material was Vita- block Mark I (Vident); it was a feldspathic-based ceramic compressed into a block that was milled into a dental restoration. After the invention of the Mark I block, the next generation of materials for CAD/CAM milling fabrication of all-ceramic restorations were Vita Mark II (Vident) and Celay, which replaced the original Mark I in 1987 for fine feldspathic porcelains primarily composed of silica oxide and aluminum oxide.2, 3 Mark II blocks are fabricated from feldspathic porcelain particles embedded in a glass matrix and used for single unit restorations available in polychro- matic blanks nowadays. On the other hand, Cel- ay ceramic inlays have been considered clinically acceptable by traditional criteria for marginal fit evaluation.4 Dicor-MGC was a glass ceramic material composed of 70 percent tetrasilicic fluormica crystals precipitated in a glass matrix; but this material is no longer available on the market.5 Studies from Isenberg et al. suggested that inlays of this type of ceramics were judged as clinically successful in a range from 3–5 years of clinical service.6–8 In 1997, Paradigma MZ100 blocks (3M ESPE) were introduced as a highly filled ultrafine silica ceramic particles embedded in a resin ma- trix; the main advantage of this material is that it can be use as a milled dense composite that was free of polymerisation shrinkage but can not be sintered or glazed.9 In early 1998, IPS ProCAD (Ivoclar Vivadent) was introduced as a leucite reinforced ceramic, which was similar to IPS Empress but with a finer particle size; this material was designed to be use with the CEREC system (Sirona Dental) and was available in different shades.2 More recently, the introduction of IPS Empress CAD (Ivoclar Viva- 16 2_2017