International Journal of Academic Health and Medical Research (IJAHMR) ISSN: 2643-9824 Vol. 4 Issue 9, September -2020, Pages: 22-40 www.ijeais.org/ijahmr 22 Evaluation of Marginal Gap and Internal Adaptation of All-Ceramic Coping Fabricated With CAD/CAM and Press-Laboratory Technique; an In Vitro Study Ayman M. Musleh, , Bassel S. AbuNasser, Ahmad J. Faraj, Ahmed Awwad, Yousef J. Hamad, Fatema Al Hour, Amjad Elshanti Department of Dentistry, Faculty of Medicine and Health Sciences, University of Palestine Abstract: This study aims to evaluate marginal gap and internal adaptation of zircon reinforced lithium disilicate copping fabricated by conventional press-laboratory and CAD/CAM systems. Methods: Tooth #14 was prepared per standard specification to receive the zircon reinforced lithium disilicate copping. For press-laboratory technique fifty type IV gypsum dies tooth #14 were duplicated and divided into two groups (n=25). CAD/CAM technique (Group A) copping was fabricated with the CEREC CAD/CAM system according to manufacturer's instructions. Within press-laboratory made copping, impressions were taken on the region area with one-step impression techniques with light and putty consistency Polyvinyl siloxane. Impressions were sent to two independent dental laboratories (Groups B and C) for fabricating the press copping. Tooth #14 was optically scanned and zircon reinforced lithium disilicate blocks were used to fabricate copping using CAD/CAM technique. The marginal and internal gap of the copping was assessed by the silicone replica technique which use optical microscope at 160× magnification to comparison between results of replica. Eight sections of each replica were obtained, four section were used to measured internal gap and each section was evaluate at four points: cervico-axial (CA), mid axial wall (AW), axio-occlusal edge (AO) and Centro-occlusal wall (CO), and other four section used to measured marginal gap and each section was evaluate at one points: middle buccal, middle palatal, middle mesial and middle distal using an image analyzing software. Statistical analysis was performed using t-test. Result: there was a significantly differences in marginal (t=11.17, P-value=0.000), and internal gap cervically (t=2.79, P-value=0.007), middle (t=3.42, P-value=0.001) and occlusally (t=3.42, P-value=0.001) of press-laboratory technique and the CAD/CAM technique. Keywords: Marginal Gap, Internal Adaptation, Ceramic Coping, CAD/CAM, Vitro Study 1. Introduction The aim of prosthodontics is to replace missing teeth and restore those that are mutilated. The fixed prosthodontics have many steps start with examination, planning, preparation of the tooth, impression making, restoration try-in and end with cementation of restoration. Success of fixed restorations depends on functional, esthetic and biological requirements, with the focus on the last one which depends to a large extent on the fit between crown and prepared tooth structure. The adaptation of a crown to the abutment tooth can be one of the most important factors that affects crown prognosis, so the marginal gap is defined as the vertical distance from the internal surface of the abutment crown to prepared tooth surface closed to the prepared finish line, and the internal adaptation is defined as the width of the cement space between the tooth and the restoration. The marginal gap was evaluated clinically by Mclean and von Fraunhaufer that concluded to 120 μm was the maximum tolerable maximum opening (1). And as reported by Fransson et. al said theoretically, the internal space necessary of cement is 20 to 40μm (2) and other study concluded to the practical range for clinical acceptability of internal fit seems to be approximately 50 to 100μm (3). Other factors such as margin configuration, impression making, material of the restoration, type of cement used, cementation technique, die spacer thickness, wax pattern fabrication, investment and casting are also affecting the prognosis of an adapted crown. One of the most critical aspects of providing marginal gap and internal adaptation of a crown is fabrication technique. There are many techniques of fabrication ceramic crown that used in dentistry, in this study we will use CAD/CAM and Press-laboratory techniques. CAD/CAM is generally standing for computer aided design and computer aided manufacturing numerical control respectively, designing usually starts with CAD software where the actual drawing of part to be machined is made which is followed by generating tool paths on CAM software. In other hand press-laboratory techniques is a method in which it fabricates crown using the lost wax ingots of ceramic material which heat pressed into mold with ceramic furnace to obtain desired shape after burn out This study guides dentists in selecting the most adaptation and less marginal of fixed restoration.