The computer-aided design and rapid prototyping fabrication of removable partial denture frameworks

TLDR

Removable partial dentures are designed to retain artificial replacement teeth in the oral cavity. The study investigates using CAD/CAM to electronically survey a scanned dental cast for producing sacrificial patterns of a removable partial denture metal alloy framework. A patient’s dental cast was digitally scanned, converted to a 3D file, and designed in CAD software to generate an STL file, which was then fabricated via rapid prototyping and cast in chromium‑cobalt alloy. The results show that CAD/CAM enables accurate electronic analysis, preparation, and design of RPD frameworks, and that rapid‑prototyped patterns can be cast conventionally to yield satisfactorily fitting frameworks.

Abstract

This study explores the application of computer-aided design and manufacture (CAD/CAM) to the process of electronically surveying a scanned dental cast as a prior stage to producing a sacrificial pattern for a removable partial denture (RPD) metal alloy framework. These are designed to retain artificial replacement teeth in the oral cavity. A cast produced from an impression of a patient's mouth was digitally scanned and the data converted to a three-dimensional computer file that could be read by the computer-aided design (CAD) software. Analysis and preparation were carried out in the digital environment according to established dental principles. The CAD software was then used to design the framework and generate a standard triangulation language (STL) file in preparation for its manufacture using rapid prototyping (RP) methods. Several RP methods were subsequently used to produce sacrificial patterns, which were then cast in a chromium-cobalt alloy using conventional methods and assessed for accuracy of fit. This work demonstrates that CAD/CAM techniques can be used for electronic dental cast analysis, preparation, and design of RPD frameworks. It also demonstrates that RP-produced patterns may be successfully cast using conventional methods and that the resulting frameworks can provide a satisfactory fit.