Hydrocolloids were the first elastic materials to be used in the dental field. Jamani materials research laboratory, department of dental prosthetics and. Jamani materials research laboratory, department of dental prosthetics and periodontics, university of birmingham, birmingham, u. One technique for recording impressions of undercut areas, commonly used before the advent of elastic materials, was to allow the impression plaster to set and then to fracture it in order to facilitate removal from the mouth. The determination of elastic recovery of impression materials. Percentage of deviation as a function of time for five elastomeric impression materials with the use of a custom tray. Viscoelastic properties of silicone, polysulfide, and. Jan 01, 2015 chapter 19 elastic impression materials. There are several elastic impression materials available for dental use. Elastic dental impressions pdf free pdf epub medical books. The term elastic as applied to impression materials is fairly unequivocal since the materials which form this group all possess the ability to be stretched or compressed and give a reasonable degree of elastic recovery following strain. Perezalvarez, manuel, the accuracy of elastic impression materials 1977.
In prosthodontics, impression materials are used to record intraoral structures for the fabrication of definitive restorations. It has been accepted for inclusion in masters theses by. Hence impression materials are classified as being elastic or nonelastic. Elastic dental impressions, introduction to elastomers, silicones silicones. Effects of moisture on polyether impression materials core. Engineering stress and strain are defined and their importance in designing devices and systems is explained. The table provides data on three of the most important mechanical properties for four elastomeric impression materials. Elastic impression materials free download as powerpoint presentation. Creep value of all the above mentioned alloys is same e. Viscoelastic properties of elastomeric impression materials. Prosthodontics impression materials nbde part ii youtube. Evaluation of the elastic recovery of polyether impression. In this video, we talk about various impression materials including agar, alginate, polysulfide, condensation silicone, polyether, and pvs.
The greater the strainincompression, the more fl exible is the material. Henkepress application syringe for elastic impression. Synthetic elastomers were developed mainly for industrial applications but their potential in medicine and dentistry was quickly realized and they are now widely used as impression materials. Ppt impression materials powerpoint presentation free to. Elastomeric impression materials addition silicones and polyethers offer high elastic recovery and acceptable flexibility on removal of the impression from the. Both types of silicone rubber have the best elastic properties of any impression material, the recovery of strain being said to be almost instantaneous, but polysulfide materials need 2 min poor elastic recovery like the other elastomers, they have adequate tear resistance. Scribd is the worlds largest social reading and publishing site. The creep compliance and recovery of selected elastic impression materials after application and removal of static loads was reported by goldberg 1974. Nov 26, 2015 elastomeric impression materials offer high elastic recovery and acceptable flexibility on removal of the impression from the mouth. Cresson3 suggested the revision of the testing procedure for compressive strengths of dental elastic impression materials that would apply the load at the rate of 18,000 gm. In the light of these facts, a study was planned to evaluate the elastic recovery of various elastomeric impression materials on autoclaving and comparing it to the. All elastic impression materials absorbed water from the. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
Students calculate stress, strain and modulus of elasticity, and learn about the. Impression materials, that is, the materials used to get an idea about the shape of teeth and the alveolar ridges, can be categorized as nonelastic and elastic materials. The elastic impression materials must then be used, but, as most are actually viscoelastic materials see chapter 1. The material is weak and easily fractured due to its high water powder ratio. The accuracy of elastic impression materials manuel perezalvarez loyola university chicago this thesis is brought to you for free and open access by the theses and dissertations at loyola ecommons. Polymer high shrinkage filled polymer low shrinkage impression during setting shrinkage, distortion of impression is toward tray.
Siliconimpression materials siliconeelastomers can be applied to slightly moist bases and are partly heat resistant up to 200 celsius. Recently, new elastomeric impression materials have been introduced, with the claim of very high elastic recovery and high tear and tensile strengths. Elasticity the material is nonelastic, so cannot be used in undercut. Elastic material susceptible to being stretched compressed or distorted and then tending to resume the original shape. Submitted as partial fulfillment for a postdoctoral masters thesis, loyola university medical center, maywood, ill. The use of elastomeric impression material must comply to. Since then, many elastomeric impression materials have become available, as indicated on the time line. They reproduce an imprint faithfully, providing details of a high definition despite the presence of undercuts.
Along with this they have excellent dimensional stability due to 99% of elastic recovery. Comparative evaluation of elastic recovery of three different. Elastic and plastic properties of elastic dental impression. Nontoxic or irritant suitable setting time long shelf life. Many impression materials have an elastic recovery of more than 99%. The determination of elastic recovery of impression materials at the setting time k. The purpose of this investigation is to characterize the viscoelastic properties of silicone, polysulfide, and polyether impression materials. Jan 01, 2015 hence impression materials are classified as being elastic or non elastic. It has been accepted for inclusion in masters theses by an authorized administrator of loyola ecommons. Due to their soft inner structure, one can take silicone imprints that are true to detail and delicate impressions.
The accuracy of elastic impression materials loyola ecommons. Comparison of elastomeric impression materials used in. They are nontoxic and absolutely neutral in both color and taste. Comparison of elastomeric impression materials used in fixed. Elastic impression materials abhishek kavlekar slideshare. The ada recommends elastic recovery greater than 96. Elastic and plastic properties of elastic dental impression materials. The elastic recovery of the tree alginates tested was in the range of the minimum 95% called for in ansiada specification no.
Storage stability there is usually a significant delay between the taking of an impression and its arrival in the dental laboratory where the model is poured. The term elastic as applied to impression materials is fairly unequivocal since the materials which form this group all possess the ability to be stretched or compressed and give a. After the preparation, they are placed inside impression trays. A comparison of elastic impression materials sciencedirect. Accuracy of stone casts obtained by different impression materials. Comparative elasticity tests for elastomeric non putty. Product company viscosity elastic recovery, % strainin. The first elastic dental impression material was the hydrocolloid, which was introduced to dentistry in 1925.
Effect of viscosity on the accuracy and stability of elastic. Elastic impression materials fixed orthodontic courses by. After conducting the associated activity, students are introduced to the material behavior of elastic solids. Only a proper dental checkup by a professional in person can help diagnose the problem you are suffering from and help give you the required treatment. The performance and detail reproduction of 3m espe impression materials help you. The implant treatment plan can only be as accurate as your impression.
Elastic impression materials include reversible agaragar, irreversible alginate hydrocolloids and synthetic elastomers polysulfides, polyethers, silicones. Theamounts of instantaneous elastic response, retarded elastic response. The silicone impression materials are classified according to the type of chemical reaction by which they set. Reversible hydrocolloidorganic hydrophillic colloid extracted from seaweed. Impression material an overview sciencedirect topics. Tylman award, sponsored by the american academy of crown and bridge prosthodontics. Mechanical properties of elastomeric impression materials.
To separate cast from the impression, use warm water. Impression materials used in the various phases of denture construction may be classified as being rigid, thermoplastic, or elastic substances. Elastic impression materials and denture adhesives elastic impression materials and denture adhesives powerpoint ppt presentation free to view how materials work how materials work compression tension bending torsion if the orbit of the single electron of hydrogen were the diameter of the superdome, then the nucleus would be. Alginates guideline for taking perfect situation impressions. Request pdf evaluation of the elastic recovery of polyether impression materials to evaluate and compare the effects of induced strain, time of straining, and loading time on the elastic. As the material is reversible, it can be reused, but after sterilization. Sep 18, 2011 elastic material susceptible to being stretched compressed or distorted and then tending to resume the original shape. 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. Viscosity had no effect on accuracy or stability of the impression materials within the viscosity ranges studied. Mechanics of elastic solids lesson teachengineering. Tear energy, elastic recovery and deformation impression materials must have sufficient strength to allow removal from a gingival. This study was conducted to evaluate the methods used for measuring the elastic recovery of various elastomeric impression materials.
For compression tests, the polysulphide and silicone specimens made in metal moulds gave significantly less set than those made in acrylic. How engineers measure, calculate and interpret properties of elastic materials is addressed. An impression should return to its original dimensions after removal from undercut areas in the mouth. Jul 03, 2019 in this video, we talk about various impression materials including agar, alginate, polysulfide, condensation silicone, polyether, and pvs. Elastomeric impression materials offer high elastic recovery and acceptable flexibility on removal of the impression from the mouth. A ram and cylinder penetrometer was designed to measure the viscosity of impression materials at their time of placement. They are easy to handle and their accuracy is pretty good. The creep compliance test allows a separation and evaluation of the timedependent and time independent responses of elastic impression materials under load and provides a. Creep compliance measurements were shown to be effective in characterizing the elastic, retarded elastic, and viscous properties of polysulphide, silicone, and polyether impression materials. The invention relates to a method for preparing a dental impression which comprises applying a dental impression material to a tooth of which an impression is to be taken, curing the material and thereafter removing the resulting impression from the tooth, said dental impression material being a mixture of a. Pdf dental impression materials and techniques researchgate. Alginate materials and dental impression technique.
Recent advances in elastomeric impression materials. The accuracy of these final restorations is highly dependent on the impression materials and techniques utilized. Elastic properties of rubber base impression materials. So, silicone materials are the best materials that we use in the impression. Major advances in impression materials and their application have occurred during the last decade, with greater emphasis being placed on rubber impression materials than on dental compound, zinc oxideeugenol, and agar and alginate. This classification is based on the capability of the material to withdraw over the undercuts it has set. Dec 29, 2018 elastic impression materials include reversible agaragar, irreversible alginate hydrocolloids and synthetic elastomers polysulfides, polyethers, silicones. Elastic materials have a soft consistency but after setting, they become elastic. Mechanical properties of hydrocolloid and rubber impression.
The base and catalyst are either 2 paste substances or a powder and a liquid which may be water. Permlastic elastic impression material, standard packages. Impression materials should have high elastic recovery in order to record undercuts of teeth or residual ridges. Elastomeric impression materials addition silicones and polyethers offer high elastic recovery and.