PURPOSE To evaluate the dimensional accuracy of several impression methods including agar alginate combined impression in vivo; the marginal accuracy of stone dies was determined using a new electroformed master crown technique. MATERIALS AND METHODS Cast cores with knife-edge and chamfer margins and electroformed master crowns were fabricated for 3 patients. Five impressions were taken of ea...

PURPOSE The aim of this study was to compare the precision of optical impression (Trios, 3Shape) versus that of conventional impression (Imprint IV, 3M-ESPE) with three different margins (shoulder, chamfer, and knife-edge) on Frasaco teeth. MATERIALS AND METHODS The sample comprised of 60 zirconia half-crowns, divided into six groups according to the type of impression and margin. Scanning el...

Feature correspondence is an important step in image registration. Chamfer matching is a process of establishing the feature correspondence of an object (subimage) in an image where both the subimage and the image are binary. Chamfer matching establishes correspondence based on low level features. It is the process of locating the template within the image by shifting the template within the im...

The sealing performance of the rubber packer is vital importance for subsea retractable connector, and cross-sectional shape one most important factors affecting it. compression distance increased by 19.54% utilizing established two-dimensional numerical model. In addition, a new parameter called anti-shoulder extrusion variable was defined in this paper. Shoulder will not occur when using as c...

Chamfer distances are discrete distances based on the propagation of local distances, or weights, defined in a mask. The medial axis, i.e. the centers of maximal balls (balls which are not contained in any other ball), is a powerful tool for shape representation and analysis. The extraction of maximal disks is performed in the general case by testing the inclusion of a ball in a local neighborh...

Consider a binary image containing one or more objects. A signed distance transform assigns to each pixel (voxel, etc.), both inside and outside of any objects, the minimum distance from that pixel to the nearest pixel on the border of an object. By convention, the sign of the assigned distance value indicates whether or not the point is within some object (positive) or outside of all objects (...

The aim of this study was to evaluate the marginal adaptation of Turkom-Cera all-ceramic crowns compared to In-Ceram and Procera AllCeram systems. The influence of finish line design (chamfer or shoulder) on the marginal adaptation of Turkom-Cera all-ceramic crowns was also investigated. Thirty human premolars were prepared with chamfer margins and assigned to either the Turkom-Cera, In-Ceram, ...

With improvement in material properties of ceramic restorative materials, these materials have been used as the definitive restoration material instead of the dental alloy, even in the posterior region. The incomplete fit of full crown restorations remains a critical problem for dentists, leading many researchers to study this problem. The distribution and magnitude of stress at any point can b...

STATEMENT OF THE PROBLEM Although all-ceramic restorations are broadly used, there is a lack of information concerning how their fit is affected by fabrication procedure and marginal configuration. PURPOSE The purpose of this study was to evaluate the marginal fit of zirconia CAD/CAM ceramic crowns before and after porcelain firing. The influence of finish line configuration on the marginal f...

in this investigation the thickness of enamel in the gingival, middle, and incisal thirds of the labial surface of the anterior teeth were measured regarding preparation of the teeth for porcelain laminate veneers.part one, 20 extracted intact human maxillary central and lateral incisors ten of each were selected. the teeth were imbedded in autopolimerize acrylic resin. cross section was prefor...