Cementation TECHCERAM Techceram now has eleven years of clinical feedback experience, with single unit alumina ceramic restorations. The most successful cementation materials for Techceram all-ceramic restorations, are the dual/self-cure resin cements. In anterior positions glass ionomer cements have also been used successfully. LAVA AND CERCON For Lava and Cercon multiple unit bridge restorations Techceram recommend that dual/self-cure resin cements are used, as they will optimise long term function and biocompatibility. PROCEDURE • Restoration should be checked on the production model. • Clean prepared tooth surface and try restoration on (dry) for marginal integrity and fit. • Carefully clean restoration in a solvent such as acetone or alcohol. • Clean tooth with oil free pumice and water. Wash and dry. • Occlusal check should ideally be conducted after cementation. • Heavy occlusal forces at the try-in stage can result in fracture of the restoration. • Apply suitable bonding agent/cement (see below). • When seating the restoration, use a gentle vibrating motion. Light finger pressure should be applied until the cement is set or resin cured. • Any necessary adjustment may be made using a fine diamond bur and water spray and subsequently polished. RECOMMENDED DUAL / SELF-CURE RESIN CEMENTS: 1. Rely X Unicem (3M ESPE) 2. Panavia F, X or 21 (Kuraray) 3. Nexus 2 (Kerr) 4. Variolink II (Ivoolar) 5. Calibra (Dentsply) Rely X Unicem incorporates its own etching and bonding agent and thus does not necessarily involve the extra steps of etching an bonding, normally associated with the adhesive bonding technique. Some clinicians do however still prefer to etch any exposed enamel, in order to optimise the bond achieved in the marginal area. Use of light pressure intra-oral alumina grit blasting also acts to enhance the bond achieved between the tooth tissue and the cement. CONTRAINDICATED CEMENTS • Fuji Plus (GC) • Rely X Luting (3M ESPE) • Dyract-cem (Dentsply) • Embrace (Pulpdent) At present Resin-modified Glass lonomer and Compomer cements are contraindicated for bonding Techceram Lava and Cercon all-ceramic restorations. These cements contain HEMA resin which is hydrophilic and can result in post-set expansion. This may cause delayed fracture in an all-ceramic restoration. Examples of such cements are given above. OPTIMISATION OF ADHESIVE BOND TO RESTORATION FIT SURFACE Techceram, Lava and Cercon restorations have their inner fitting surface grit blasted with 50/100 micron alumina, following porcelain build-up, to provide a micro-retentive surface, to optimise "physical bonding"   It is however advisable to also optimise the opportunity for "chemical bonding", using the 3M ESPE Cojet system. Applied using a conventional hand held microblast unit, at the surgery, the inner fitting surface of the restoration is impregnated with a silicatized layer.   The system is particularly advantageous for "Veneer" type restorations which have had trial pastes applied to assess correct shade of cement.   If a traditional resin cement is used for cementation, the silicatized layer should be treated with silane (included in the Cojet kit) prior to cementation.   If Rely X Unciem is used, silane treatment prior to cementation is not necessary Note 1: The Cojet treatment should only be conducted on a clean, dry surface and immediately prior to cementation. Note 2: The Cojet kit can also be used for the intra-oral repair of chipped metal-ceramic and all-ceramic restorations, using modern day composite materials such as Filtek Supreme and HFO.