Archive for February 2014
Case 1:Vita Enamic, 2M2T shade
The patient presented with large pinned amaglam restoration on tooth 46 with failing margins and recurrent decay. A full coverage restoration was recommended and the patient decided to proceed with a Cerec crown restoration.
The decay was excavated from the tooth and the remaining tooth structure was prepared for the Cerec crown. Hemostasis was achieved in subgingival areas using the Waterlase iPlus.
An Enamic 2M2T block by Vita was chosen for this restoration - a very durable and resilient material. The Enamic is a hybrid ceramic material with a composite resin matrix designed to resist the propagation of cracks thus reducing the risk of fracture. The material is quickly milled by the Cerec MCXL milling unit (this particular case took only 4min) and is easily adjusted with finishing burs. A slight increase in proximal contact strength during the design phase was required to achieve the desired intraoral contact strength. The Enamic polished well using a series of soft points, goats hair brushes and a cotton wheel with high shine paste (the polishing time was 10-15min). The crown was bonded using Scotchbond Universal and Rely-X Ultimate (3M ESPE).
The monochromatic nature of the Enamic block creates a very opaque looking crown. To improve esthetics, a lighter shade in combination with intraoral, resin-based stains should be used.
Case 2: Ivoclar Empress A3 MultiCAD
The loose gold onlay was easily removed, the decay excavated and the remaining tooth structure prepared for a full coverage restoration. Shade A3 Empress MultiCAD by Ivoclar was used to match the unrestored first bicuspid and canine. The Empress CAD blocks are a leucite reinforced glass ceramic - the multiCAD blocks have an internal shade gradient with increasing translucency that creates a tough, highly esthetic crown (milling time was 6.5 min with the Cerec MCXL).
The crown was bonded using Scotchbond Universal and Rely-X Ultimate (3M ESPE). The Ceraglaze ceramic polishing system was used create a high shine (approximately 10 minutes). The esthetics of the Empress block is lost in the post operative images due to the overshadowing nature of the surrounding gold onlays. The true nature of this case will be visible following replacement of the failing 35 onlay.