9,10 One clinical study found the incidence of zirconia crown loosening to be twice as high with zinc-phosphate cement as with self-adhesive resin cement. Several laboratory and clinical studies have demonstrated the superiority of self-adhesive resin over conventional cements, such as zinc phosphate, for definitive insertion of high-strength ceramic crowns and bridges. They handle like conventional cements but provide good bond strengths to the restorative material and tooth structures.
5-8Įase of use and peace of mind are the main reasons for the popularity of self-adhesive resin cements. Probably the most frequently used, effective, and successful such monomer is 10-methacryloyloxydecyl dihydrogen phosphate (MDP). A ceramic primer that contains special adhesive monomers is necessary because conventional silane coupling agents cannot bond to metal-oxide ceramics. 7,8 Air-particle abrasion with Al 2O 3 is both effective and practical to provide long-term durable bond strengths to high-strength ceramics. In-vitro studies and systematic reviews are in strong agreement that a combined micromechanical and chemical pretreatment is necessary for long-term durable resin bonds to zirconia. However, in situations of limited mechanical retention and for restorations that rely on resin bonding (eg, resin-bonded fixed partial prostheses, bonded inlays/onlays, or laminate veneers), cementation even with self-adhesive resin cements may not be sufficient. Zirconia-based crowns and bridges with adequate retention and ceramic material thickness can, therefore, be cemented conventionally without many technique-sensitive bonding steps. High-strength, metal-oxide-based ceramics, such as alumina and zirconia, are considered cementable, due to their high flexural strength. 6 Silica-based ceramics (eg, feldspathic, leucite-reinforced, and lithium silicate) should always be resin-bonded and treated with acid-etching and silane coupling-agent application. 6 Clinical and laboratory bonding protocols depend on the type, composition, and properties of the ceramic. Adhesive bonding with composite resins and proper treatment of the abutment tooth and the ceramic bonding surface increase fracture resistance of ceramic restorations, improve retention, and reduce microleakage.
Excessive forces and surface damages may lead to fractures and cracks. 5 The larger amount of cubic-phase particles offers significantly greater light transmission but lower physical strength than conventional zirconia.ĭue to inherent brittleness, the behavior of ceramics in the oral cavity under functional stress is very different from metals. Pre-shaded, multi-layer, high-translucent zirconia materials (eg, Katana ™ STML and Katana ™ UTML, Kuraray Noritake Dental, ) provide a wide range of esthetic possibilities, specifically for anterior teeth and partial-coverage restorations such as onlays and laminate veneers. Zirconia traditionally has been used as a coping and framework material veneered with matching veneering porcelains however, newer, more esthetic formulations and especially high-translucent products have contributed to the popularity of monolithic full-contour zirconia restorations that do not require veneering with porcelain. Zirconia (zirconium dioxide), used in dentistry predominantly as yttria-stabilized tetragonal zirconia polycrystals (Y-TZP), is applied for a large variety of clinical indications, from single crowns to full-mouth implant-supported rehabilitations, with high clinical success.
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Blatz, DMD, PhD Julian Conejo, DDS, MScĪs zirconia is progressively considered the material of choice for indirect all-ceramic restorations, the question of how to cement and bond zirconia becomes increasingly important. Sign up today!Ĭementation and Bonding of Zirconia Restorations
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