Machining Accuracy of CAD/CAM Ceramic Crowns Fabricated with Repeated Machining Using the Same Diamond Bur

Abstract

The purpose of this study was to investigate the effect of repeated machining up to 51 times using the same diamond bu: on machining accuracy of inner and outer surfaces of CAD/CAM (computer-aided designing and computer -aided manufactur ing) machined ceramic crowns. The surface topography of machined crowns was examined using photographs . It was fount that machining accuracy was not affected by the number of machining times . In all measuring points, the inner surface wa; machined to a dimension larger than the die model (i.e., increased gap) , whereas the outer surface was machined to a dimen sion smaller than the crown model (i.e., smaller crown) . Photo observation showed that cervical contour was machined it a clear, rounded form from 1st to 11th crowns.

A review of dental CAD/CAM: current status and future perspectives from 20 years of experience

“…Furthermore, even if the advantage of production using a computer was emphasized by the developer, essential quality data such as the fit of the restorations were lacking at presentations and in publications. Therefore, we established the following development strategies and started the development of a small and integrated CAD/CAM machine for a dental use [25][26][27][28][29][30][31][32] . 1) Developing an operator-friendly CAD/CAM system as a supplemental tool for dental laboratories.…”

Marginal and Internal Fit of All-ceramic Crowns Fabricated with Two Different CAD/CAM Systems

“…In particular, the porcelain firing cycle can cause a negative effect on the marginal fit of all-ceramic crowns 3) , and hence the success of the restorations 4,5) . All-ceramic crowns can be fabricated using two types of computer-aided design/computer-aided manufacturing (CAD/CAM) systems [6][7][8] : a doublelayer type which has a high-strength core, and a single-layer type without core (the entire crown is fabricated by a CAD/CAM system). The addition of porcelain to the copings of double-layer type may cause a negative effect on the fit of the crowns 3,9) .…”

Effects of coloring agents applied during sintering on bending strength and hardness of zirconia ceramics

“…If restoration materials are used in compliance with demand from patients, metal-free crowns and bridges will have wider application. In addition, technological developments based on computer-aided design/computer-aided modeling (CAD/CAM) systems can lead to higher quality restoration devices, standardized processing accuracy, a simplified production process, and an improved laboratory environment for dental technicians 21,22) . Although it has been difficult to reproduce natural tooth color on frameworks because of high luminosity (white color) and flexibility, elaborate shades can be produced by staining the surface of the framework with coloring agents, achieving high esthetic quality even for the anterior teeth 23,24) .…”