خرید و دانلود نسخه کامل کتاب Thin veneers in feldspar ceramics, composites and lithium dislicate (dental lab techonology articles Book 3)

The use of veneers has become quite common thanks to the excellent results obtained, both aesthetic and functional alike. They can be fashioned in composites (direct or indirect), or ceramics (only indirect).Ceramic veneers first made their appearance at the start of the 80s through Charles Pincus, a Californian dentist, in order to promptly modify the smiles of actors.For many years, for what concerns veneer crafting, both the dentist and the dental technician made use of feldspar ceramic, which provides exceptional aesthetic yield, but lacks satisfactory mechanical properties, especially in regards to flexibility. These veneers are applied to fabricated dental elements: Indeed, the minimum ceramics thickness had to be 0.7/0.8mm that increased to 1.3/1.5 mm around the incisal margins. Given the abive mentioned thicknesses, preparation often concerned the top surface portion of dentine aside from the layer of enamel. The veneers then underwent surface treatment with fluorhydric acid at 1% (Simonsen and Calamia, 1982) and were applied to the teeth thanks to cement adhesion techniques.However, the introduction of further advanced materials modified the protocol stated above; both for what concerns cementing (substantial increase of adhesive strength) and the realization of the veneers themselves thanks to the introduction of highly aesthetic materials with excellent mechanical properties such as lithium disilicate.These aspects have made it possible to craft veneers using less material (0.3-0.4 mm in the lab that can undergo further reduction while in the dentist chair with finishing procedures); thereby, greatly reducing the sacrifice of hard dental tissue, which is one of the leading reasons behind therapy refusal. This veneer is known as “thin-veneer” and constitutes the latest frontier of cosmetic dentistry. According to the manufacturers, there is minimal reduction of dental material to application of the thin veneers. Yet, excellent aesthetic and functional results can be obtained even without preparation of the dental elements simply by increasing surface roughness or, at most, softening any sharp edges. This procedure, so-called additive, is made possible by adhesive systems that stick to unfavorable substrates. (such as enamel in the near proximity of the cementoenamel junction) and by the ability of the operator that always seek to obtain top results that last in time, always raising the bar on the limits of the materials at hand.Keywords: veneer, lithium, disilicate, feldspar, ceramics