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Tooth Colored Dental Brackets
Project Description :

Dental brackets, scientifically known as orthodontic brackets, are used for correction of irregular and deformable teeth of the people by applying continuous pressure on the teeth to slowly move the teeth in a specific direction over a period of time which helps to make proper teeth alignment. at present, different types of dental brackets are available in the world such as; metallic, gold-plated, sliver coated, plastic, translucent plastic and ceramic. stainless steel brackets find mass usage in our country owing to its cost effectiveness over bio compatible ceramic brackets. problems associated with metallic and plastic brackets are as follows; metallic brackets are notorious for causing stains on the surface of the teeth, some people are allergic towards metal, it irritates tongue and gums of the people and generates uneasiness while drinking hot or cold drinks as the metals are good conductor of heat in general. on the other hand, plastic brackets are esthetically satisfying compared to metallic ones but there are some severe problems exists with them such as, high wear rate during service and failure to deliver sufficient torque because of their low modulus. on the contrary, ceramic brackets provide significantly better mechanical properties, increased transparency and decreased reactivity with the oral environment compared to their metallic and plastic counterparts. whereas, ceramic brackets are similar in colour to human teeth and offers solution to most of the above mentioned problems. so, ceramic brackets offers an unbeatable combination of performance and beauty. however, ceramic brackets are imported to our country and available for a cost of approx. 5 times than its metallic counterparts, which sets the stage for indigenous development of the tooth coloured brackets at a comparable cost to metallic ones. in the present work, micro ceramic injection moulding (µ-cim) process technology is used to develop green compact of tooth coloured alumina dental brackets and afterwards debinding, sintering processes were adopted to arrive at the final shape of the prototype brackets. in summary, the present innovation shows novel net shape, low cost, tooth colored polycrystalline alumina dental brackets, which offers sufficient hardness, bio compatibility within the oral cavity and improved debonding strength/fracture toughness. the tooth colored dental brackets are prepared by micro ceramic injection moulding (µ-cim) technique, which has capability to be used for mass production of dental brackets and alleviates the need of precision machining operations involved in case of other process technology of bracket manufacturing, followed worldwide, such as; press moulding, slip casting, conventional cim etc. alpha alumina powder having average particle size of 0.3-0.4 µm and hdpe based polymeric binder system is used for the preparation of alumina feedstock, having powder loading of 58 vol%. custom built miniature sigma blade mixer having 50cc volumetric capacity has been used here for feedstock preparation. in the present invention, design modifications have been incorporated within the prototype brackets, keeping in view of the manufacturing ease and cost effectiveness. subsequently, multi cavity micro injection mould has been designed and developed, wherefrom eight brackets of similar or different dimensional details can be manufactured from one injection shot. afterwards, alumina feedstock was injected into the bracket mould, followed by thermal debinding and sintering (at 1600oc) of the injection moulded green compact of dental brackets, under air atmosphere, to arrive at the final bracket shape. the tooth coloured alumina dental brackets have been developed in net shape i.e, alleviating the need of any machining, grinding requirements, with average density of approx. 3.8gm/cc (98% of theoretical density of alumina), bimodal grain structure having sizes ranging between 0.8-2 µm, with minimum presence of microporosity, hardness of approx. 2400 vhn, and fracture toughness of 4.2 mpam^1/2. .

 
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Project Details :
  • Date : Oct 24,2018
  • Innovator : Prosenjit Das
  • Team Members : Mrs. Manju Singh ,Mr. Tapan Ray ,Mr. Pinaki Das ,Miss. Moumita Sarkar
  • Guide Name : Self Conceived
  • Submission Year : 2019
  • Category : Mechanical/Textile
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