LAUSR

Treatment of the total edentulous patient can be a real challenge for the clinician. Dental implants have been utilized with a high degree of success to solve functional difficulties associated with edentulous jaws; they can offer to the patient what almost every patient would prefer the opportunity of having a fixed reconstruction [1]. The implant-supported fixed dental restorations can be screwretained or cement-retained. The type of retention for these restorations remains an important decision factor for the clinician due to the advantages and limitations of both screwand cement-retained restorations [2, 3]. The decision of which type of restoration should be used is largely determined by the experience of the clinician and clinical aspects. The patients are not showing any preference for either retention system, but despite this, there are some relevant clinical and technical differences between the two types of restorative connections [4]. The screw-retained restorations can be removed whenever the clinician considers is applicable, and gives the patient the opportunity to a better hygiene. The presence of suppuration, fistula, the peri-implantitis due to the impossibility (inability) to remove all the cement, are some of the outcomes of the cement-retained restorations [5]. Fixed dental implant restorations can be fabricated from many combinations of materials such as metal alloy-acrylic, metal alloy-composite, and metal alloy-ceramic. There is extensive evidence of the excellent long-term result from conventional metal-ceramic and metal-resin implantsupported fixed dental prostheses [6-8]. Conventionally metal-ceramic restorations have the drawback of difficulty in fitting when full-arch implant-supported restorations are required, wear of opposing surfaces, ceramic chipping, difficulty in shade matching of acrylic and pink ceramic and extensive work for repair after framework breakage have encouraged dentists to look for other material options. Metal-acrylic restorations have more disadvantage by accelerated wear and loss of sheen, including fractured or debonded acrylic resin teeth, which can adversely impact esthetics. In recent years, fixed dental restorations based on yttria-stabilized tetragonal zirconia polycrystals (Y-TZP)