Figure 5: On the left are two views of the provisional restoration, while on the right are two views of the final restoration. The provisional was used to aid the final color selection of the ceramic. The final crown mimicked the natural tooth and provisional, with a darker shade at the cervical third to impart warmth.
The restoration was waxed up, and the appropriate lithium disilicate ingot (GC Initial LiSi Press, GC America) was selected. The material was chosen based on its multiple indications, stability, and strength (>500 MPa flexural strength, according to the manufacturer). These characteristics result from HDM Technology, which utilizes equally dispersed lithium disilicate microcrystals to fill the entire glass matrix.
The ingot was pressed and divested. Virtually no reaction layer was created during divesting.
The mesial, distal, lingual, and contact areas remained in their monolithic form, and only a facial cutback was performed. Removing the sprues and contouring, in addition to imparting microanatomical details and surface textures, was facilitated by a smooth grinding surface of the material.
The relatively uncomplicated process of characterizing the crown involved applying internal stains (e.g., Opal Grey for layers, White Powder Stain for calcification spots) with GC Initial Lustre Pastes (GC America) and one bake of Enamel 58, followed by contouring and glazing. Although only one bake was required in this case, a benefit of the high-strength HDM material is its color stability, without distortion or a drop in value even after multiple firings (figure 6).