| Due to the increasing number of people’s dental health problems,the market demand for denture restorations has increased dramatically.The rapid and personalized preparation of dentures in denture restoration is of great significance.As a new type of rapid prototyping technology,3D printing technology has attracted the attention of the world.When 3D printing directly prepares dentures,due to the particularity of tooth materials,it is impossible to directly 3D shape dentures and traditional preparation materials are wasted.After exploring,3D printed and formed the crown ceramic mold,and poured the metal crown to prepare a denture that satisfies a healthy human body.The research in this paper mainly includes:the construction of the experimental platform,the reconstruction of the dental crown and the static analysis,the determination of the laser vaporization size and the experimental verification and analysis,the shaping of the crown and the performance test,and the results meet the requirements of use.First,the 3D printing principle of the frozen slurry laser selective solidification method is determined,and the experimental system is designed according to the 3D printing method.The whole experimental system consists of laying and printing integrated workbench,freezing device,control device,CO2 laser scanning device and other parts.The left and right camera scanner is used to obtain the crown data,and then to establish the 3D model and casting.The three-dimensional structure of the tooth crown was statically analyzed using finite element analysis software,and the maximum deformation and maximum stress were obtained.The results show that the designed three-dimensional crown structure meets the requirements of normal and healthy human occlusal force.Then,a numerical simulation model is established for the warping of the slurry surface caused by the non-uniform distribution of thermal stress and chemical reaction changes induced by CO2 laser beam when scanning and freezing the uniformly mixed sodium silicate and alumina ceramic slurry.COMSOL Multi-physics field coupling analysis software is used to simulate and analyze the process of laser scanning irradiation of frozen slurry,and the influencing factors of the thermal action zone when laser irradiates are obtained.By analyzing the changes in temperature field and concentration field,the experimental process parameters were preliminarily determined:solid content 50wt%,laser power 50W,scanning speed 600mm/s,scanning distance 0.052mm,paving material thickness 0.298mm.And finally,Aiming at the problem of curing effect and surface holes of frozen ceramic paste after laser selective curing and scanning,the experiment of single-layer sample was investigated by using the control variable method,and the data parameters for good curing quality of the sample are obtained.In view of the surface roughness and bending strength of solidified forming billet body,experimental analysis and exploration were carried out to form the 3D printing method of dental crown casting,and the dental crown casting was printed.White light interferometer is used to measure the roughness,Chebyshev’s law of fitting is used to analyze the flatness,and the three-point bending test is used to obtain the bending strength.The results show that the prepared crown mold meets the requirements of casting mold. |
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