Fit accuracy of removable partial denture metal frameworks produced by CAD-CAM – a clinical study

Abstract

Objectives: To assess the effect of a CAD-CAM protocol fabrication on the clinical fit accuracy of removable partial denture metal frameworks to abutment teeth. Methods: Fifteen patients with partial edentulism were selected to participate in this clinical study, and twenty dental arch rehabilitations were planned. For each dental arch (n=20), two cobalt-chromium frameworks were produced through two protocols: CAD-CAM production (experimental group); and conventional lost-wax casting technique (control group). Clinical fit accuracy was assessed using an indirect quantitative method to evaluate the gap between the framework occlusal rest and the corresponding rest seat. A silicone mold of that gap was obtained, digitized, and analyzed by micro-computed tomography. The two silicone molds obtained for each occlusal rest were overlapped and evaluated for thickness and volume. Data were analyzed with the paired t test for silicone thickness results and the Wilcoxon test for silicone volume results (α= 0.05). Results: Considering the two dependent variables under study, no statistically significant (p=0.441 for silicone thickness and p=0.204 for silicone volume) differences were found between groups. Conclusions: The results of this study suggest that the CAD-CAM protocol applied is a viable method for the production of removable partial denture metal frameworks. (Rev Port Estomatol Med Dent Cir Maxilofac. 2021;62

Mechanical and surface properties of a 3D-printed dental resin reinforced with graphene

“…Developments in computer technology and software applications are a relevant part of the groundswell of technological change that has led additive manufacturing technique -3D printing -to where it is today. [5][6][7][8][9] 3D printers based on vat photopolymerization, namely stereolithography (SLA) and digital light projection (DLP), were the first commercially available and are still among the most used. 10,11 The emergence of these new technologies led to the development of new suitable materials.…”

Comparison between digital superimposition and microcomputed tomography methods of fit assessment of removable partial denture frameworks

“…For the digital superimposition method, the metal framework was coated with scanning spray (Zirko Scanspray; Zirkonzahn GmbH), and the definitive stone cast and the combination were digitized with an image assembly software program (Modellier; Zirkonzahn GmbH) installed in a scanner system (Arti S600; Zirkonzahn GmbH), producing 3 individual standard tessellation language (STL) files. 37,39 Each file was positioned with the best-fit tools of a software program (Geomagic Control X, v2018; 3D Systems Inc) by using the combined image as a reference (Fig. 3).…”

“…19,32,34 Furthermore, image capture digital techniques, such as microcomputed tomography (mCT), have been used as high-precision and high-resolution techniques in various fields of biomedical analysis. 30,31,[35][36][37] The development of high-resolution scanners and computer-aided engineering software programs for dental laboratories has allowed new methods of directly measuring 3-dimensional (3D) discrepancies, such as digital superimposition, without an intermediate substrate. 29,31,32,[38][39][40][41][42][43][44] However, studies validating the digital superimposition method of measuring the fit accuracy of RPD frameworks are sparse.…”

Environmental sustainability practices in portuguese dental clinics

“…The most implemented practice in this category was intraoral scanning techniques, with a high percentage of implementation (93.9%), contrary to other studies from the last decade, which mention that its low implementation was due to the high cost of intraoral scanning equipment. 17,28 This change may result from the current digital revolution in the prosthodontic field that led to strong competition in the digital equipment market, making it more available for dental clinics 29 and laboratories.…”