Clinical evaluation of CAD-CAM made translucent monolithic restorations and double-layered restorations

The aim of this study was to evaluate the clinical success of translucent monolithic zirconia and double-layered restorations with 2 year clinical follow-up. 18 patients who had absence of molar tooth in both jaws and required treatment with included this study. In this split-mouth randomised-controlled clinical study, zirconia restorations were prepared with two different methods. One of the half jaw was restorated with translucent monolithic zirconia (ZenoStar, Wieland, Pforzheim, Germany) and the other one was restorated with double-layered restorations. Totally 40 fixed partial dentures (n=40) were applied to patients. Restorations were cemented with adhesive resin cement (Multilink Speed, IvoclarVivadent). Marjinal and internal adaptation of the restorations were determined with silicone-replica method. Replicas were sectioned and get pictured by light microscope (Leica Cambridge Ltd., Cambridge, England) and various parts of light body silicone was measured. Restorastions clinical success was evaluated with modified USPHS criteria in clinical Follow-up periods of 0, 6, 12 and 24 months. To investigate the wear behavior of the restorations, plaster models obtained by basis of Ivoclar Wear Protocol in follow-up periods of 0 and 24 months. Models were digitalised by 3-dimensional scanner (Omnicam, Sirona Dental Systems, GmbH, Bensheim, Almanya). Models were overlapped in CAD-CAM software programme Cerec 4.4, Sirona) and measurements were made. All zirconia restorations were demonstrated clinically acceptable success in 2 year follow-up period. There was no significant difference between clinical performance of translucent monolithic restorations and double-layered restorations (p>0.05). Double-layered restorations yielded significantly better marjinal and internal fit (p<0.05). Degree of antagonistic tooth wear of translucent restorations was significantly lower than double-layered restorations (p<0.05).