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ment. Although the report did not detail the pos- sible need for crown lengthening or gingivectomy procedures, these were areas of diagnostic concern in this case. However, biological width encroach- ment did not appear to be an issue during cleaning and probing. To address the patient’s concern with the aes- thetic appearance of tooth #13, high-translucency and high-strength, lithium disilicate glass-ceramic would be CAD/CAM processed into a crown. Milled to as thin as 300 µm axially, the lithium disilicate crown would instil a contact lens effect on the gin- gival–facial margin of tooth #13. The crown would then be bonded in place with an adhesive that demonstrates high radiopacity to ensure that excess cement was not inadvertently left behind, specifically in the deep distal margin in this case. The adhesive bonding agent also ensured that cementation was predictable. When complete, the tooth would appear natural and indistinguish- able from the surrounding dentition. Clinicalprotocol After thorough examination and prophylaxis, tooth #13 was prepared for restoration with a CAD/CAM (CEREC MC XL) processed lithium disilicate crown(IPSe.maxCAD)andthetempo- rary material removed. A specialised mouthpiece (Isolite, Isolite Systems) was placed intra-orally to ensure total isolation was achieved (Figs. 3 & 4). Prior to scanning, the tooth #13 preparation, the surrounding denti- tion and the soft tissues were sprayed with a CAD/CAM powder (Fig. 5). The anatomical form of the dentition and soft tissues was then captured using an LED scanning unit (CEREC Bluecam). After scan- ning, 3-D software (CEREC 3D) was used to design the desired crown contours and occlusal relation- ships. A prefabricated high translucency lithium disilicate block (IPS e.max CAD) was then milled chairside (CEREC MC XL) into a crown for tooth #13 (Fig. 6). Lithium disilicate was the material of choice in this case because it demonstrates high strength and lifelike optical properties. The crown was tried in the patient’s mouth over the tooth #13 preparation to evaluate fit, contour and anatomical harmony (Figs. 7 & 8). Upon confir- mationofproperfitandfunction,thecrownwasre- moved, cleaned and dried. Stains were then placed onthecrownsurfacetomimicthetobaccostainson the surrounding dentition. However, it was decided that cervical stains to mimic the decay on the natu- ral dentition would not be placed. After staining, the lithium disilicate crown was crystallised and ready for immediate seating (Fig. 9). The specialised mouthpiece (Isolite) was repositioned in the mouth to isolate the tooth during cementation. Dual-curingluting composite (Multilink Automix, Ivoclar Viva- dent)wasusedtoseat the crown. Indicated for use with metal, all-ceramic, metal- ceramic and compos- ite restorations, the luting composite of- fers a strong hold on all surfaces and is available in transpar- ent, yellow or opaque shades to ensure proper aesthetics are Fig. 11_The crown is seated on the preparation of tooth #13. Fig. 12_Initially, excess cement is removed from the cervical and interproximal areas with a micro-brush. Fig. 13_Pressure is applied with dental forceps to ensure that the crown remains in proper position after initial excess cement removal. Fig. 14_Applying pressure to the crown, excess cement is removed from the interproximal spaces with dental floss. Fig. 15_The crown is cured on the buccal, lingual and distal surfaces with the bluephase LED curing light. Fig. 16_Dental floss is used to remove any remaining cement from the interproximal spaces. Fig. 17_The final restorative result. I case report _ crown fabrication 12 I CAD/CAM 3_2011 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 Fig. 17