Study Of Dental Materials Prepared By Spark Plasma Sintering (SPS)

Spark Plasma Sintering (SPS) technology is a new preparation technology and has special sintering mechanism. Many mechanisms, including a direct current pulse discharges, plasma activates and pressurizing, etc. cowork in the course of sintering. It can reduce largely the sintered temperature. SPS has conspicuous advantages on preparation of dentistry biomaterial. Implant and restoration are primarily two parts of the dentistry biomaterials. The research that implant material concentrates to activate with the surface of the metal or alloy and the ceramics material of the high performance, the point further satisfies the bonding strength and bioactivities request. Along with people to continuously increasing of the tooth esthetics request, and the application of Computer Auxiliary Design / Computer Auxiliary Machining (CAD/CAM) in the dentistry restoration technology, all porcelain restorable materials with machinability become the study focus. This paper mainly focuses on the implant of Titanium metals with HA active coating and the feldspathic porcelain restoration by SPS technology. The SPS technology was applied to prepare the hydroxyapatite (HA) active coating on the Titanium surface in this paper for the first time. The effect of preparation technique of composite materials with HA/Ti biologic activation and the composing and thickness of coating to the bonding strength between the coating and the basal body were studied. Prepared the implant of Titanium stick with HA active coatings using the method of addition between implant and die. As a result, the bonding strength increased when the thickness of coating decreased; the grade coating can improve the bonding strength of coating and base body. Especially the sample was sintered after the passivation, whose bonding strength between the active coating and base body improved notably. Its value of bonding strength had reached 64MPa at most, which has exceeded the International standard of implant material of biological coating used at present (15 MPa). The SPS technology was applied to prepare the dental feldspathic porcelain material in this paper for the first time. The sintering mechanics and various kinds of physics and chemistry performance of feldspathic porcelain were studied. The result shown: The SPS technique can sinter the compact feldspathic porcelain within 10 minutes. Compared with the materials which were sintered by ordinary methods, the dental ceramic by SPS was more compact and the fracture toughness was better. Its fracture toughness had reached to 1.5±0.3MPa·m1/2 from 1.0±0.2MPa·m1/2, which exceeded the fracture toughness range of glass ceramics. The transitions from ceramic to glass phase under the pressure can be realized by SPS. The effect of additives on sintering technics was discussed in this paper and performance of feldspathic was prepared by SPS. The result show that: HA avoid the problem that the feldspathic porcelain sample is apt to darken effectively, it can improve fracture toughness in a certain extent and make the fractograph of feldspathic porcelain level up which is favorable to the improvement of machinability; ZrO2 reduced transmission rate and the sample is looked too white; K2CO3 and glass ceramics (GC) can reduce the sintering temperature of feldspathic porcelain greatly. In addition, they had certain influence on the color and transmission rate, but their capability of improving the fracture toughness of feldspathic porcelain was limited. The fracture toughness of feldspathic porcelain with 5%K2CO3 and 20%GC can reach to 1.59±0.16MPa·m1/2. The sintering processing of feldspathic porcelain preparation by SPS is a kind of liquid-phase sintering. The heat energy comes from combination of heat transfer of mould. The sintering energy depends on the electric discharge on the surface of the particle. Particle superficial discharge produces instantaneously high temperature, which results in melt during sintering. After sintered to be compact ceramic, heat energy only comes from heat transfer of the mould, and the temperature of the sample tends to unanimity, which is a steady stage within a certain range of certain temperatures. Internal crystalline phase after sintered was the remaining phase...