Rapid manufacture of removable partial denture frameworks

Abstract

This work was part of a long-term research project undertaken by the Medical Applications Group of PDR into the application of advanced design techniques to the needs of the dental technology industry, in particular the design and manufacture of Removable Partial Denture Frameworks (RPDs).

These frameworks are traditionally made in wax by hand in a highly-skilled, laborious and time consuming process. Previous research carried out by MAG had established that advanced design techniques including three-dimensional scanning and computer-aided design (CAD) could be used to develop accurate designs for custom-fitting RPD devices (see Williams outputs). This research suggested that digital processes could yield benefits in productivity and repeatability. However, the multiple steps required to produce sacrificial patterns and castings did not fully exploit the potential advantages of computer-aided manufacture.

This article reported on the exploitation of a new layer-additive manufacturing technique called Selective Laser Melting (SLM). SLM manufactures metal parts of almost any shape directly from computer designs. This research required experimentation to establish design parameters for the successful manufacture of RPD frameworks using SLM, including design considerations, build strategies, optimum orientation and support generation. Assessment of the RPD frameworks produced by SLM in both Cobalt-Chrome alloy and 316L Stainless Steel demonstrated that the finished items were fit for purpose and compared favourably to frameworks made by traditional techniques. Subsequent research has demonstrated that the devices produced fit patients as required and further work is being undertaken to enable commercial and technical benefits to be realised (see Williams output 4).

This work reports the world’s first successful production of an RPD framework using a computer-aided design and direct layer-additive manufacturing process.