Stereolithography: A new method for processing dental ceramics by additive computer-aided manufacturing.
The aim of this study was to compare the physical and mechanical properties of stereolithography (SLA)- manufactured alumina ceramics of different composition to those of subtractive- manufactured ceramics and to produce suitable dental crown frameworks.



The physical and mechanical properties of a control and six experimental SLA ceramics prepared from slurries with small (S) and large (L) particles (0.46±0.03 and 1.56±0.04μm, respectively) and three dry matter contents (70%, 75%, 80%) were evaluated by dynamic rheometry, hydrostatic weighing, three3-point flexural strength measurements, and Weibull analyses, and by the micrometrics measurement of shrinkage ratio before and after the heat treatments.



S75 was the only small particle slurry with a significantly higher viscosity than L70. The viscosity of the S80 slurry made it impossible to take rheological measurements. The viscosities of the S75 and S80 slurries caused deformations in the printed layers during SLA manufacturing and were excluded from further consideration. SLA samples with low dry matter content had significantly lower and densityflexural strengths. Only SLA samples with a large particle size and high dry matter content (L75 and L80) were similar in density and flexural strength to the subtractive- manufactured samples. The 95% confidence intervals of the Weibull modulus of the L80 ceramic were higher (no overlap fraction) than those of the L75 ceramic and were similar to the control (overlap fraction). The Weibull characteristics of L80 ceramic were higher than those of L75 ceramic and the control. SLA can be used to process suitable crown frameworks but shows results in anisotropic shrinkage.



The hH High particle size and dry matter content of the L80 slurry allowed made it possible to produce a reliable ceramic by SLA manufacturing with an anisotropic shrinkage, and a density, and flexural strength similar to those of a subtractive-manufactured ceramic. SLA allowed made it possible to build up a dense 3D alumina crown framework with controlled shape. Further studies on the marginal adaptation and shrinkage model of alumina crown frameworks will be required to optimize the process.
Department of Prosthodontics, Faculty of Dentistry, University of Lille, Place de Verdun, 59000, Lille, France; LMCPA, Laboratoire des Matériaux Céramiques et Procédés Associés, University of Valenciennes and Hainaut Cambrésis, Boulevard Charles de Gaulle, 59600, Maubeuge, France.
Marion
M
Dehurtevent
Department of Endodontic and Restorative Dentistry, Faculty of Dentistry, University of Lille, Place de Verdun, 59000, Lille, France; LMCPA, Laboratoire des Matériaux Céramiques et Procédés Associés, University of Valenciennes and Hainaut Cambrésis, Boulevard Charles de Gaulle, 59600, Maubeuge, France.
Lieven
L
Robberecht
LMCPA, Laboratoire des Matériaux Céramiques et Procédés Associés, University of Valenciennes and Hainaut Cambrésis, Boulevard Charles de Gaulle, 59600, Maubeuge, France.
Jean-Christophe
JC
Hornez
LMCPA, Laboratoire des Matériaux Céramiques et Procédés Associés, University of Valenciennes and Hainaut Cambrésis, Boulevard Charles de Gaulle, 59600, Maubeuge, France.
Anthony
A
Thuault
Department of Endodontic and Restorative Dentistry, Faculty of Dentistry, University of Lille, Place de Verdun, 59000, Lille, France.
Etienne
E
Deveaux
Department of Prosthodontics, Faculty of Dentistry, University of Lille, Place de Verdun, 59000, Lille, France. Electronic address: pascal.behin@univ-lille2.fr.
Pascal
P
Béhin
D000537:Aluminum Oxide; D002516:Ceramics; D017076:Computer-Aided Design; D003442:Crowns; D003776:Dental Porcelain; D006801:Humans; D008422:Materials Testing; D000076227:Stereolithography; D013499:Surface Properties
D003776:Dental Porcelain; D000537:Aluminum Oxide
Additive technology; CAD/CAM; Ceramics; Dental crown; Stereolithography