elastic impression materials pdf

Be economical. independent responses of elastic impression materials under load and provides a better understanding of their mechanical properties. the material is non-elastic, so cannot be used in undercut areas. Wouldn’t it be high if it is oversized. • • o (fast/short set time > slow): Addition silicone (PVS) > polyether > condensation silicone > polysulfide rubber Working time problems o In lab it takes for ever to set o But in the mouth it all happens faster o May have various layers where they don’t mix / steps Impression concerns o Make sure all the materials get to the mouth and there is no delay o Don’t want material in the tray to start setting without u knowning o May be elastic and may still also be flowing o We may be compressing it but it may recover once you remove it o Set in elastic state à Remove tray à impression rebounds à Might have a short and distorted die o Lab, not a problem, mouth is a problem o Want material freshly mixed and “dead soft” Impression materials o All has to do with rxn conversion o At 50% conversion à they all get rubbery o With PE and PVS very much in a hurry o They all set at different rates factors affection impression / dimensional stability / accuracy o polymerization shrinkage is immediate but … § there is a potential for longterm shrinkage with biproduct o when u remove it gets distored à will it recover elastically? Hydrocolloid impression materials used in dentistry are based on colloidal suspensions of polysaccharides in water. They reproduce an imprint faithfully, providing details of a high deﬁnition despite the presence of undercuts. Once the material has set, the Positioning Screws are loosened, and the impression is removed. The plaster should be mixed with water or an anti-expansion solution in the ratio of 100g to 50-60ml. They could be described as possessing rubbery characteristics. Of particular interest has been the effect of disinfection solutions on the qualities of impressions and the biocompatibility of impression materials. polyvinyl siloxane and polyether? percolation The pumping of oral fluids in and out at the tooth-restoration interface as the restoration contracts and expands with temperature changes. Dentistry and Dental Materials, 2. Elastic impression materials The base and catalyst are either 2 paste substances or a powder and a liquid (which may be water). ELASTIC Impression MATERIALS ABHISHEK KAVLEKAR 3. elastic : susceptible to being stretched, compressed, or distorted and then tending to resume the original shape elastomeric impression material: a group of flexible chemical polymers, which are either chemically or physically cross-linked. Thus, the minimum thickness of the material in the tray should be three to four times more than the largest undercut (Hamalian, T. A. et al., 2011). �-}r�g`��[#Ͼ�-�^��x�^�&Q.��.�@_ NON ELASTIC IMPRESSION. 1. of elastic impression materials. ��n�:d��>$�>2&�\��IW��2�;��o5Ӻ��4�u��ؚxW��aw�g��b?�`�O �S��zd�Y��ʌ��V�xq��;��j��O�=];EZ5�w0"��{:˹yrc$;Ȏ%|��ؾ�Co9��缿�P�~j��Hs^��A|H��ħ5$��H�v�/l#�ZZ�\�eUפ]st�3{��U�߷�;��i�O߄��ۨ��V@k�eC}�&lϛ ��y��ً�0��4��u��U�}ў��F_"XC�8�U�� 04�d""�u%OVY t�\��RF��МF�bh�8);څ��m��i�r>�v��y�xjZ_�sr_�wj_Q��%�紾�j�%�a�v%��70�,@ MATERIALS IN DENTISTRY. he said this in lecture but I don’t understand so I emailed him types of elastomeric impresion material o polysulfide, silicone, polyether, polyvinyl siloxane o these types all polymerize why remove impression quickly from mouth? This textbook covers all aspects of materials science relevant to the practice of dentistry. 5. Elastic and plastic properties W . This paper describes the development of an instrument for determining consistency, working time and setting time of elastomeric impression materials. ELASTIC Material susceptible to being stretched compressed or distorted and then tending to resume the original shape. <> Abstract This study was conducted to evaluate the methods used for measuring the elastic recovery of various elastomeric impression materials. Elastic impression materials are capable of accurately reproducing both the hard and the soft structures of the mouth including the undercut areas and interproximal Tear energy should be between 390 and 1800 J/m^2. Elastic impression materials are capable of accurately reproducing both the hard and the soft structures of the mouth including the undercut areas and interproximal spaces 4. They are essential in daily clinical practice in all dental specialisations: conservative, cosmetic, aesthetic, prostheses, orthodontics, implantology and pediatric dentistry. Elastic impression compositions Download PDF Info Publication number US2359512A. 1. Reproduction of oral detail The rubber impression materials are capable of reproducing detail more accurately than can be transferred to the stone die or cast ELASTICITY Elastic properties of elastomeric impression materials improve with an increase in curing time in the mouth Permanent deformation following strain in compression increases in following order- addition silicone, … Relevant to the practice of dentistry the development of an instrument for determining consistency, working time and time! Medium body or putty materials viz., polysulfide or silicone, the molar crown was... In all dental practices a fixed compressive strain and the impression, use warm water materials viz., polysulfide silicone! Normal ) and polyethers, working time Table I lists brand names and manufacturers.. University of Windsor paste were shorter than those of alginate impression materials composition or properties upon from... 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