Lithium Disilicate
An excellent alternative to traditional all-ceramic restorations when a metal-free restoration is indicated, Lithium Disilicate is milled from lithium disilicate instead of zirconia. Finished with a ceramic veneer over its glass-ceramic base, Lithium Disilicate restorations feature lifelike translucency and brightness without sacrificing durability.
Lithium Disilicate is indicated for full anterior or posterior crowns. Lithium Disilicate press is indicated for full anterior or posterior crowns and three-unit bridges having only one pontic with the second bicuspid as the most distal abutment. Veneers can also be indicated and are recommended when combining with adjacent Lithium Disilicate crowns or bridges, provided ample reduction is achieved. Otherwise, Lithium Disilicate CAD would be indicated for veneers, inlays and onlays.
Contraindications
Lithium Disilicate should not be used on patients with malfunctional occlusion such as bruxers or clenchers. Lithium Disilicate should not be used as abutments for cast partials. Lithium Disilicate should not be used in situations when preparation requirements cannot be achieved. Lithium Disilicate is not indicated for Maryland-type bridges.
Anterior full-coverage crowns require a chamfer or shoulder margin. A circular shoulder is prepared with rounded inner edges or a chamfer at an angle of 10-30°: the width of the shoulder/chamfer is approx. 1 mm. Facial reduction is 1.5 – 2 mm; 1 – 1.5 mm lingual contact clearance. Incisal reduction is 1.5 – 2 mm with rounded internal line angles, and an incisal edge at least 1mm wide to permit optimum milling of the incisal edge during CAD/CAM processing.
Posterior full-coverage crown requires a chamfer or shoulder margin. A circular shoulder is prepared with rounded inner edges or a chamfer at an angle of 10-30°: the width of the shoulder/chamfer is approx. 1 mm. Occlusal reduction is 1.5 – 2 mm: axial reduction (buccal, lingual and interproximal) is 1.5 mm with rounded internal line angles.
For greatest strength, and where preparation allows for dry field (supra-gingiva margins), it is recommended to use adhesive bonding, such as VarioLink II (Ivoclar Vivadent) or similar dual cure materials (Insure, Cosmedent; Nexus, Kerr; Choice, Bisco, Inc.; Lute-It, Pentron).
For areas subgingival, or when a dry field cannot be achieved, Ivoclar Vivadent recommends a hybrid glass ionomer cement system with less than 0.5 percent expansion. (NOTE: Resin-reinforced glass ionomers (Advance, Vitremer) are not indicated for any all-ceramic restoration.)
Some recommended resin cements:
- Vivaglass (Ivoclar Vivadent)
- GC Fuji (GC America)
- Ketec Cem (3M ESPE)
- Panavia F (J. Morita)
- C&B Metabond
- Variolink (Ivoclar Vivadent)
If adjustment is required on the ceramic, ALWAYS CEMENT OR BOND INTO PLACE BEFORE PROCEEDING, then use a fine diamond with water to keep the crown cool. To contour the crown, polish with a porcelain polishing wheel ( Brassler, Shofu and Vident) and diamond polishing paste.
Caution: Do NOT attempt to fire porcelain. IPS e.max ceramic requires specific stains and glaze, as well as precisely calibrated ovens at specific temperatures and vacuum settings.For best results, return crown for re-glaze firing to lab.
- D2740 Crown
- D2610 Inlay for 1 surface
- D2620 Inlay for 2 surfaces
- D2630 Inlay for 3 surfaces
- D2962 Labial Veneer
- D2783 Crown 3/4 Porcelain Ceramic (does not include veneers)