Supervisor : Ehab El-Sayed Mosleh, Hanaa Hassan Zaghloul.El Gendy, Mennatalla Ahmed Emad,2022-01-182022-03-272022-01-182022-03-272019.EG-CaMIUThs297https://iorep.miuegypt.edu.eg/handle/20.500.13071/94DISSERTATION NOTE-Degree type M.Sc.DISSERTATION NOTE-Name of granting institution Misr International University, Faculty of Oral and Dental MedicineIncludes Arabic Summary.Includes bibliographic references (pages 71-90)`The increased demand for esthetic dentistry and the rising question regarding the biocompatibility of dental alloys lends to the introduction of new esthetic materials. Ceramic materials are nowadays an attractive alternative to metal based restorations. With greater success and reliability, the applications of metal-free ceramic restorations have been extended due to the introduction of zirconia in dentistry. Because of the introduction of CAD/CAM system, the production of zirconia restorations has become a fully digitalized process which is faster and more accurate. Zirconia restorations suffer of decreased translucent properties. However; this problem could be overcome by esthetic optimization of veneered restorations with pronounced anatomic structure. However, research reports have documented ceramic veneer fractures (chipping) and fractures of the zirconia substructure as well. To overcome these problems of veneered zirconia fractures, the full contoured monolithic zirconia “translucent zirconia” was introduced as an alternative approach. Translucent zirconia offers improvement in esthetics. Moreover, this restoration is defined by a significantly reduced material thickness in comparison with veneered restorations or other monolithic materials. As the restoration can be colored individually prior to sintering, followed by staining and characterization, good esthetic could be achieved. Bonding to zirconia is challenging as it tends to be difficult to etch with hydrofluoric acid due to the absence of glassy matrix. However, bonding to zirconia ceramic can be improved via many surface treatments such as selective infiltration etching technique, laser etching, alumina Introduction 2 coating, tribochemical silica coating, silica ceramic coating and airborne particle abrasion. 1–4 The airborne particle abrasion with alumina has been used for mechanical interlocking claiming that a durable strong zirconia based ceramic bond could be achieved. The type of luting agent, biocompatibility, insolubility and resistance to degradation contributes to the long term success of fixed dental prosthesis. Different cementing agents have been produced and only those containing organophosphate ester monomer groups have shown a significant durable bond to zirconia.5 Aging and thermo-cycling are two significant factors to be considered in the bond strength tests. It was found that the minimum number of thermal cycles for metal/resin bond is 5000 cycles. This is based on ISO 10477.6 Adhesive ability can predict the longevity of a restoration which can be measured by bond strength testing. An accurate and clinically reliable bond strength test must be less technique sensitive and it should involve the use of relatively inexpensive protocol. A newly introduced calcium aluminate based cement, referred to its bioactive properties, with claims to form hydroxyapatite, as well as the release and recharge of calcium, phosphate and glass ionomer. It would be worthy however, to investigate the micro-shear bond strength of air-abraded translucent zirconia cemented with bioactive cement after thermocycling.97 pages : illustrations, photo ; 30 cmtextapplication/pdfengFixed Prosthodonticstext