Texas). It is possible for the 3D image to originate from conventional casts which have been poured up in stone/plaster. The model is scanned and the 3D image is uploaded onto the software. Next, the restoration can be designed, by the software programme, on the virtual casts. Once confirmed, the milling process can begin. The milling process uses pre-fabricated blocks of restorative material, e.g. lithium disilicate or composite reinforced ceramic, to produce the end product. Finally, the restoration is sintered/glazed chair side. Lost wax technique There are two ways in which wax can be used to produce cast metal/ceramic indirect restorations, these are known, firstly, as the indirect wax technique using Type 1 inlay wax and, secondly, the direct wax technique using Type 2 inlay wax. For technique 1, a wax pattern is designed on the die from the cast impressions and for technique 2 the wax is packed into the tooth preparation in the mouth and adapted the shape of the cavity. Inlay wax is chosen due to its brittleness – it breaks upon removal from undercut of a cavity, either on the die or in the mouth. In this case, this is a beneficial character as it helps us to identify the presence of an undercut which then can be removed. Once the wax pattern is constructed the fabrication of this into the final restoration can begin, a method known as the Lost Wax Technique is used. The wax is embedded into an investment material with a sprue former – this forms a passage for molten metal to be poured through into the cylinder. The investment material must produce enough expansion to compensate for shrinkage of the metal on solidification and should be slightly porous to allow for dissipation of released gases. The container, or casting cylinder, is then placed in a furnace to burn out the wax and what is left is a hollow shape ready for molten metal to be poured into. The metal can be melted using either gas and compressed air, gas and oxygen or electric arc. Casting methods include the use of steam pressure or a centrifugal system. Gold is an example of a material that can be used to produce inlays/onlays. Once cast a layer of oxides are present on the surface, these can be removed by placing the restoration in an ultrasonic bath for 10 minutes. This removes the oxides along