Physicomechanical properties of cobalt-chromium removable partial denture palatal major connectors fabricated by selective laser melting
Document Type
Article
Publication Date
9-1-2022
Abstract
Statement of problem. Additive manufacturing by selective laser melting (SLM) has been claimed to be less challenging than conventional casting of cobalt-chromium (Co-Cr) removable partial dentures (RPDs), providing significant improvements. However, how the physicomechanical properties of Co-Cr RPDs fabricated by SLM compare with those fabricated by conventional casting is unclear. Purpose. The purpose of this in vitro study was to evaluate the physicomechanical properties of CoCr RPD palatal major connectors fabricated by SLM compared with those fabricated by conventional casting. Material and methods. A master die simulating a maxillary arch of Kennedy class III modification 1 was scanned to create a virtual 3-dimensional (3D) cast. Two groups of 5 Co-Cr RPD major connectors were fabricated. In the 3D printing group, the Co-Cr major connector was virtually designed and exported for direct SLM 3D printing. For the conventional group, Co-Cr major connectors were constructed conventionally. The Co-Cr major connectors were virtually superimposed with the master die for surface adaptation analysis. Additional comparative analyses of surface roughness, relative density, microhardness, and microstructure of the 2 groups were performed. Data were analyzed by using independent t tests (alpha=.05). Results. The overall volumetric and linear discrepancies were significantly higher (P<.05) in the 3D printing group. Significant differences in the surface roughness (P<.05) and microhardness (P<.05) were observed, with the 3D printing group having higher surface roughness and microhardness than the conventional group. Unlike conventional connectors, the microstructure of 3D-printed connectors showed fine homogeneous granules. Conclusions. Compared with the conventional casting technique, SLM 3D printing enabled the fabrication of Co-Cr RPD major connectors with higher microhardness and fine homogenous microstructure. However, the surface adaptation and surface roughness of SLM 3D printing Co-Cr connectors were worse than those produced conventionally. Both techniques showed similar relative densities. (J Prosthet Dent 2022;128:530.e1-e7)
Keywords
CR DENTAL ALLOYS, ERRORS, ACCURACY
Divisions
oralmax,restoreden
Publication Title
JOURNAL OF PROSTHETIC DENTISTRY
Volume
128
Issue
3
Publisher
MOSBY-ELSEVIER
Publisher Location
360 PARK AVENUE SOUTH, NEW YORK, NY 10010-1710 USA