the risk of damaging ceramic restorations. Crown tractors are quite effective in removing crowns luted with temporary cements. Sticky sweet method or Richwill crown and bridge remover A thermoplastic pliable resin is softened in warm water then placed on the occlusal surface of the crown to be removed. The patient is then asked to bite down, compressing the resin block to two-thirds of its original thickness. The patient is then asked to open the mouth quickly, which should generate enough force to displace the restoration. This method however, is not very effective and has a risk of damaging restorations on or accidentally extracting the opposing tooth. Therefore, before using this method, it is important to look at the state of the opposing tooth. Tapping and pneumatic tools Sliding hammers work by using a tip to engage the crown margin and sliding the weight along the shaft and tapping this to loosen the restoration. Several versions are available. Some are weighted, others are spring loaded. This system is uncomfortable for the patient and is not always successful. It is also contraindicated for periodontically involved teeth, as it can cause unwanted extractions. This system can also damage the ceramic margins. Wedging devices A slot is cut using the side of a long tapered bur, normally on the buccal surface of the crown, all the way into the cement lute. A flat plastic instrument, straight Warrick James, Couplands elevators or dedicated systems such as the WamKey, is inserted into the slot created to wedge the crown apart from the tooth. Metalift crown and bridge removal system Based on the "jack-screw" principle, the Metalift system works by drilling a precision channel through the occlusal surface of a cast restoration, then with a special bur, the area around the periphery of the hole is undermined before a threaded screw is wound into the space. As the screw comes in contact with the core of the restoration, the continued rotation of the screw results in a jacking force that displaces the crown from the preparation. This system can be used to remove both all metal crowns and metal-ceramic crowns, although, with metal-ceramic crowns care should be taken to remove enough ceramic from the area where the hole created to reduce the chances of fracture. The minimum thickness of metal required for the lifting action is approximately 0.5mm. The damage can repaired with a plastic filling material.