Manufacture of ceramic-based dental brackets

Dental brackets, which can be applied to every young and old patient, are used in orthodontic treatment for aesthetic or health correction of tooth deformities. In this study, the production of ceramic tooth brackets produced by ceramic injection molding (CIM) method which is one of the powder injection (PM) methods, which corrects the perpendicularity, skewness and curvature of the teeth used in orthodontic treatment, has been studied. In this context, the mold which was manufactured according to the metal injection molding method was revised by adapting it according to the ceramic injection molding method, production process, making the ceramic product after production and post-production tests were performed. In the first stage of the study, the necessary revisions were determined by checking the product figure in the mold by making trial prints of the ceramic powder raw material. Mold practice, polishing, gating puller arrangement, widening of gating entries, determination of the processes to be applied after production and tests and controls to be applied after printing were performed. It was decided to work with Al2𝑂3 raw material which is one of the raw material types used in the production of ceramic brackets. The production was realized by making the mold revision in accordance with powder injection as 4 cavity considering the shrinkage factor (Z) value of the raw material to be used for the brackets and the dimensional decreases in the binder removal and sintering processes. The process parameters for injection molding were investigated in accordance with the raw materials. Alumina loaded into the feed raw material is transferred to the extruder, by means of the heating resistors on the extruder, the raw material becomes fluidized and injected into the mold coldly at 1500 bar pressure at a rate of 25 cm3 / s in a total of 15 seconds. Binding removal process was applied to ceramic brackets after forming. This process was carried out at 35 °C in water for 32 hours to remove the binder. The brackets that were unbonded were subjected to sintering. Sintering process, heat-insulated electric industrial furnace, (starting temperature 0° accepted) Increased by 600 °C per hour, 2 hours, 10 minutes to 1300 °C, 1300 °C for 3 hours after 45 minutes to 1600 °C and increased After waiting 2 hours at 1600 °C, the lid did not open and was allowed to cool naturally for 10 hours. Microstructure, pore, hardness, density, dimensional analysis and SEM-EDS analysis tests of the brackets were performed after production. In this experimental study. The process parameters in mold printing, binder removal, sintering and post-production measurement tests were applied and values that could shed light on the transformation of the product to commercial status were determined. Keywords: Orthodontic tooth bracket, Mold, Powder metal injection, Ceramic injection molding, tooth bracket production