Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2017-02-21, 16:08:16 | version 1.38.0
literature review _ CAD/CAM material and systems to 45 percent leucite reinforced glass ceramic with a fine particle size.10 To overcome aesthetic prob- lems of most CAD/CAM blocks having a mono- chromatic restoration, a different version was de- veloped as a multicoloured ceramic block, which was called VITA TriLuxe (Vident) and also IPS Em- press CAD Multiblock; the base of the block is a dark opaque layer, while the outer layer is more translucent; the CAD software allows the clinician to position or align the restoration into the block for the desired outcome of the restoration.11,12 In 2014, the Enamic (VITA) material was re- leased as a ceramic network infi ltrated with a reinforcing polymer network that has the benefi ts of a ceramic and resin in one material, but no clinical data are available.14 _Alumina-based ceramics Alumina blocks (Vitablocs In-Ceram Alumi- na, VITA) are available for milling with the CEREC system (Sirona Dental) and now compatible with other milling machines as well. Due to the opacity of alumina-based ceramic materials, the In-Ce- ram Spinell (VITA) blocks were developed as an alternative for anterior aesthetic restorations; it is a mixture of alumina and magnesia. Its fl ex- ural strength is less than In-Ceram Alumina, but veneering with feldspathic porcelain for a more aesthetic result could follow it after the milling process.14,15 Nobel Biocare developed Procera material; for its fabrication high purity aluminum oxide is compacted onto an enlarged die that is fabricated from the scanned data.16 The enlarged fabricated core shrinks to the dimensions of the working die when sintered at 1,550 °C; this material offers a very high strength core for all-ceramic resto- rations; the crown is fi nished with the application of feldspathic porcelain.17 More recently, In-Coris AL (Sirona Dental) has been introduced as a high- strength aluminum oxide block with similar me- chanical properties as Procera.18 Fig. 1 Fig. 1_Number of steps comparison between traditional methods of all- ceramic restorations and CAD/CAM restorations. _Lithium disilicate Lithium disilicate is composed of quartz, lith- ium dioxide, phosphor oxide, alumina, potassium oxide and other components. According to Saint- Jean (2014) the crystallisation of lithium disilicate is heterogenous and can be achieved through a two or three stage process depending if the glass ceramic is intended to be used as a mill block (e-max CAD) or as a press ingot (e-max press). Lithium disilicate blocks (Fig. 3) are partially sin- tered and relatively soft; they are easier to mill and form to the desired restoration compared to ful- ly sintered blocks; after this process the material is usually heated to 850 °C for 20 to 30 minutes Fig. 2 Fig. 3 Fig. 2_Vita Mark II block. Fig. 3_In-house milled crown. 17 dentistry1_2017cosmetic