polysulfide impression material disadvantages

Polyvinyl siloxane materials may require surfactants to lower the contact angle before pouring casts. – Polysulfide impression materials have a disagreeable smell and … Polyethers involve the reaction of the polyether-containing imine ringed side chains with a reactant that opens the rings and causes chain lengthening and cross-linking to form a polyether rubber . Materials used without adequate knowledge of their characteristics can impair a successful outcome. for polysulfide impression material. 9. The snap-set behavior of the soft polyether materials allows the material to not start setting before the working time ends. Polyether impression materials are moderately hydrophilic and capture accurate impressions in the presence of some saliva or blood. Some water supplies contain large amounts of minerals that can adversely affect the accuracy and the setting time of alginate impression materials, however. This material comes in flavors and is not much of a problem from the standpoint of taste. Sign in Register; Hide. If a material can tolerate some moisture, it is considered to be hydrophilic. Use of impression material within the formation of an indirect restoration. Sometimes it is best to make another appointment for new accurate impressions within 24 hours or such a time so that this film layer will re-wet the tooth surfaces . stiffness Polyeter most stiff makes difficult to remove stone from impression,fracture oof die Flexibility / stiffness : The stiffness of the impression material Lowest Highest Polysulphide, Condensation silicones, addition silicones, polyether Reversible hydrocolloid least rigid The conventional polyether 27 times as stiff as the light body polysulphide impression material. Difficult to remove if there are undercuts. 20. It is not affected by latex gloves. Where subgingival margins are concerned, this can be an important criterion. For the most part they have a neutral taste. Dryness minimizes the moisture content of tooth surfaces and contributes to sticking of the alginate; ultimately, it leads to inaccurate cast pours. Polysulfide impression material is dimensionally accurate if poured within 1 to 2 hours of making the impression . The hydrophilic nature of an impression material relates to its ability to work in a wet environment and still provide accuracy in impression making. Because the material has a low wetting angle it makes a full arch impression easier than with polyvinyl siloxanes or polyethers. 2016 Dentistry-Silicone Impression Material Industry Report - Global and Chinese Market Scenario - The Global and Chinese Dentistry-Silicone Impression Material Industry, 2011-2021 Market Research Report is a professional and in-depth study on the current state of the global Dentistry-Silicone Impression Material industry with a focus on the Chinese market. Aquasil (Caulk/Dentsply) is slightly hydrophilic . Accuracy of the impression is also affected when the percentage of deformation and the time involved in removing the impression are increased. Difficult to record details because of high viscosity. The drawback of polysulfide addition is that the amount of sulfur in the system is increased, and this disturbs the sodium–sulfur balance in the mill, thereby generating higher emissions to the atmosphere. While usually used in single-mix, it can be used with Light-Bodied Permlastic for crown and bridge impressions. On removal of the impression, the alginate tears. Impressions that wet the teeth well displace moisture and result in fewer voids. Tissue conditioners are soft elastomers. If you make an impression with either of these two types of materials and then decide to make an impression with polyvinyl siloxane, it inhibits the set . Material can be reused several times. While usually used in single-mix, it can be used with Light-Bodied Permlastic for crown and bridge impressions. There may be less waste of material associated with automixing and providing a more bubble-free mix resulting in more accurate casts. These surfactants act through a diffusion transfer of surfactant molecules from the polyvinyl siloxane into the aqueous phase. Factors that may cause sticking of the alginate include polishing of teeth, which removes a thin film overlying the teeth and actually prevents the hydrophilic nature of this material from wetting the teeth and reproducing detail . Polyvinyl siloxane materials are also thermally sensitive . The setting reaction of hydrocolloids is not affected by latex proteins from gloves. Polysulfide impression materials have a high resistance to tearing but stretch and do not recover completely elastically . If this material is overheated it may not recover to its normal setting time even after cooling, and it is recommended that this material be stored in a cool place and not in the sun (refrigerator or cool space). In an alginate impression compound, calcium sulfate dehydrate, soluble alginate, and sodium phosphate are in the powder. Before they set, however, they are susceptible to contamination. of the impression material, which is predominantly water. Impression materials that are currently popular include hydrocolloids, addition silicones, polyethers, and polysulfides. Moisture from saliva or blood can interfere with accurate impressions. Because many dentists send their impressions to a laboratory to be poured, this characteristic should be considered when choosing an impression material . It has been reported that vapor given off by polysulfide impression material may cause contamination. The tear strength of an impression material relates to how resistant a particular material is to tearing after setting . Polysulfide impression materials are generally low to moderately hydrophilic and make an accurate impression in the presence of some saliva or blood. Disadvantages of polysulfide impression materials can stain clothing, skin, and other surfaces objectionable odor (onion, skunk, natural gas scents result from reaction) Researchers recommend that it be sprayed with disinfectant for 10 minutes, rinsed, and dried immediately before pouring in dental stone . A set impression must be sufficiently elastic so that it will return to its original dimensions without significant distortion upon removal from the mouth . Finally, if repetitive impressions are made, the film over the teeth is lost and prevents satisfactory impression. It has an excellent ability to reproduce detail and is dimensionally stable, which allows multiple pours of accurate casts for several weeks after impressions are made if no tears are present in the material. Accurate impressions are necessary for construction of any dental prosthesis. 19. The polysulfides distort over time . The viscoelastic properties are influenced by the molecular weight of the polymer powders and the power/liquid ratio . The newer materials are supposedly able to be poured in 5 minutes after the impression material is removed from the mouth. The hydrophobic aspect of polyvinyl siloxane impression materials has an adverse effect on surface quality of the polymerized impression material . All types of elastomeric impression materials undergo shrinkage caused by polymerization, and materials with reaction byproducts undergo additional contraction. They are rigid materials and may be more difficult to remove than polyvinyl siloxanes . They work well for implant impressions, in which posts must be transferred accurately . Because these materials are moderately hydrophilic, strict attention to disinfection guidelines is necessary to prevent swelling of the material. Three 0.1 gram samples were aseptically obtained from each packet. Sulfur compounds can poison the platinum-containing catalyst in addition silicone impression materials and result in retarded or no polymerization in the contaminated area of the impression . This thin layer causes impressions to remain tacky around new composite placed restorations . Another source of contamination is the oxygen-inhibited layer on the surface of resin materials that appears immediately after curing. There are several reasons for this the first and foremost is the hazardous formulation of polysulphide sealant. Polyether impression material is an elastic-type material, as are the polysulfide and silicone materials. This is usually seen in the dental office in the form of latex gloves or rubber dams. The contraction is lower for these two products because there is no loss of byproducts . Permlastic is a polysulfide, condensation-cured, elastomeric impression material in three viscosities. The automixing products require no mixing pads or spatulation, and training in their use is less time consuming. It has been reported that vapor given off by polysulfide impression material may cause contamination. Often, the choice of impression materials depends on the subjective choice of the operator based on personal preferences and past experience with particular materials. Sitffer & harder than polysulfide material. The dimensional stability of an impression material reflects its ability to maintain the accuracy of the impression over time . The polysulfides and condensation silicones have the largest dimensional change during setting, in the range of −0.4% to −0.6%. Explain why polyvinyl siloxane impression material is so popular. It generally captures a subgingival margin upon impression without tearing on removal, which is much better than hydrocolloids or polyvinyls. Viscosity is altered by changing the amount of silica filler, which produces either a putty or less viscous wash material. Polyethers tend to be the most rigid impression materials . Disadvantages Non-aqueous elastomeric impression materials High Elasticity ' Excellent Tear Strength Patented Copper Catalyst System Available in 3 Viscosities, 2 Set Times Three Year Shelf Life In more than 25 years of clinical practice, COE-FLEX has offered consistently precise, detailed impressions. Plasticizers are moderately hydrophilic and make an accurate impression in the presence of some saliva or blood. They are suitable for complete and partial dentures because they reproduce detail moderately. They do not tear easily (high tear strength), which enables the dentist to get good subgingival detail without tearing the impression on removal. When using automix cartridges, it is recommended to extrude 0.25 inches of material and discard before placing the mixing tip to remove any contaminated material or material that has been exposed for long periods of time to the environment. Hydrophobic; Can be electroplated with silver & copper. Many impression materials are suitable for use in dentistry. In addition to these criteria, the following criteria should be considered: how well a material is tolerated by patients, obtaining the best results for the least amount of expense, and occurrence of minimal changes when in contact with disinfection chemicals. In a laboratory setting, it should be dimensionally stable for accurate pouring of multiple casts and should not affect dimensional accuracy upon disinfection . The more common types of impressions are used for fabricating diagnostic and master casts. This result has been reported even with the new “hydrophilic” polyvinyl siloxane impression materials. Immersion disinfection also may differ between different brands of alginate with respect to different immersion systems, such as iodophor and glyoxal glutaraldehydes . The base consists of a polysulfide polymer (terminal/side chain −SH groups), titanium dioxide, zinc sulfate, copper carbonate, or silica. Polyether Impression Materials. The following chemical reaction forms a gel to create the set impression material. If immersion disinfection (1% sodium hypochlorite or 2% potentiated glutaraldehyde) is performed (10–30 minutes), statistically significant dimensional changes are observed; these changes are on the order of 0.1%, and the quality of the surface is not impaired. Materials with high dimensional stability are the polyethers and polyvinyl siloxanes, in contrast to alginate, which has a low dimensional stability. They show a weight loss of 4.9% to 9.3% after 24 hours as a result of the loss of alcohol. The hydrophilic nature of polyether impression material is manifested in carbonyl (C=O) and ether (C-O-C) groups, whereas polysulfide material has hydrophilic disulfide (-S-S-) and mercaptan (-S-H) groups . Less distortion on removal. Because their wetting angle is low, they capture a full arch impression easier than with polyvinyl siloxanes . Regular Permlastic is recommended for partial- or full denture impressions because it has a high degree of flow that will register the finest detail. Tissue conditioners are composed of a powder that contains poly (ethyl methacrylate) and a liquid that contains an aromatic ester-ethyl alcohol (up to 30%) mixture. They would be detrimental in making full arch impressions of periodontally compromised or mobile teeth. Practitioners should take this characteristic into consideration when selecting impression materials given the time available to the practitioner to pour casts during office hours. An ideal impression material should exhibit certain characteristics in the clinical and laboratory environment. Materials with high contact angle require more careful pour technique and attention to produce accurate casts . has great flexibility, which may result in prblems when it is removed from mouth In recent years, dentists have turned toward using polyvinyl siloxanes and polyethers because of their improved physical and mechanical properties . Spray with disinfectant for 10 minutes and rinse and dry immediately before pouring casts . Addition silicones (which are the most popular because no reaction byproducts are formed) involve the linking of a vinyl siloxane in the base material with a hydrogen siloxane via a platinum catalyst . 5. Polyvinyl siloxane contamination is usually a result of sulfur or sulfur compounds . It is a good idea not to store polyvinylsiloxane impression material close to polysulfide impression materials. Unfortunately, it does not adhere to itself, which makes it unavailable for border molding or correctable impression techniques. Aquasil is an exception because it does adhere to itself after setting. High impression dimensional stability materials usually can be poured within 1 to 2 weeks after the impression is made and still produce an accurate cast . Pour within 1 hour Silicone impression material The silicone impression materials are classified according to the type of chemical reaction by which they set. There 46 ELASTOMERIC IMPRESSION MATERIALS IN PROSTHODONTICS KEYF Table 1: Elastic impression materials. Glutaraldehydes are the disinfectant of choice for zinc oxide eugenol impression pastes . Often, the choice of impression materials depends on the subjective choice of the operator based on personal preferences and past experience with particular materials. Polyvinyl siloxanes are fairly stiff, and depending on the viscosity of the material, they flow readily to capture areas of detail . Polyether and polysulfide impression materials also leave the mouth coated with a chemical film that inhibits polyvinyl siloxanes. Because some polyvinyl siloxane materials exhibit a phenomenon known as hydrogen out-gassing, if you pour casts too soon the stone captures these bubbles and produces a cast with pitted areas . Their tear strength is better than hydrocolloid but not as good as polyether . University. 3. Clinically, it should produce an accurate impression secondary to its adaptability to oral structures, have a consistency that is dimensionally stable to resist tearing but results in an atraumatic removal, set within a reasonable amount of time, demonstrate biocompatibility to include a hypoallergenic nature, and have a reasonable cost per use. Adequate tear strength; Better elastic properties on removal. Their ability to reproduce detail is excellent and they are dimensionally stable and allow multiple pours of accurate casts for 1 to 2 weeks after impressions are made, provided there is no tearing of the impression. The basic ingredient of a polysulfide impression material is a polyfunctional mercaptan of the average formula HS-(R-S-S)23-R-SH, where R is C2H4-OCH2-O-C2H4. messy & stains clothes. Over recent years many manufacturers have discontinued their polysulphide sealant ranges. ... the procedure the dimensional inaccuracy of the alginate hydrocolloid limits its us more compatible with gypsum model materials than alginates. Because of their hydrophilic nature, using polyether and polysulfide impression materials is more compatible with the inherent moisture present in mucosal tissues . When it does set, it does so immediately . Accessories such as intraoral tips, mixing tips, and various types of tray systems are also important when weighing the advantages and disadvantages of the delivery systems of impression materials. impression material for inlays, crowns, bridges, full and partial dentures, rebasing and relining. James Cook University. To understand why polysulfide impressions shring over time, one needs to consider the chemical reaction that occurs when a polysulfide sets. Polysulfide pulping is a variant of kraft pulping in which half or more of the sodium sulfide of kraft white liquor is first oxidized. second pour is less accurate. It is relatively low cost and comes in flavors that are more patient friendly. The hydrophobic nature of an impression material relates to its inability to work in a wet environment and still provide accuracy in an impression. – However, they are not as accurate as other non aqueous elastomeric materials. Polyether has properties such that it can flow into critical areas with low pressure exerted, which results in accurate impressions and makes for fewer adjustments and remakes for the practice of dentistry. Master casts are used for producing complete dentures, removable partial dentures, crowns, fixed partial dentures, and implant prostheses. unset impression material over wet oral structures, Why agar hydrocolloids have greater accuracy, due to their greater degree of recover after deformation around undercuts (elastic recovery/plastic deformation), combination of elastic and viscous (plastic or permanent) behaviors, seen in plastics and impression materials, Types of hydrophobic impression materials, How addition silicone can be made hydrophilic, Light body elastomers/impression materials, Regular or medium body elastomers/impression materials, Heavy body elastomers/impression materials, Registering oral structures: general considerations, Transferring detail to model: general considerations, can cause voids upon addition of stone slurry, "poly (vinyl) siloxane" or "vinyl polysiloxane", What initiates cross-linking in addition silicones, Contamination of addition silicone impression material. Once set, polyvinyls are fairly inert, and there have been no reports of any disinfectants that damage them. 18. Impression materials with the ability to produce detail in the range of 100 to 150 μm work well and are acceptable in the areas of removable prosthodontics . Course. Accuracy can be improved by flaming surface material.Disadvantages: Distortion due to poor dimensional stability. Wettability results in fewer voids and less entrapment of oral fluids, providing more accurate impressions . It reproduces detail with excellent results but its dimensional stability is only fair . It is insoluble in water and its formation causes the material to gel . The material is moderately rigid and can be more easily removed than polyether materials. Wettability of an impression material relates to the ability of the material to flow into small areas . Compatible with die and cast materials 10.Good keeping qualities Classification of Impression Materials Impression Material Elastic Non-Elastic Hydrocolloid Elastomers Impression Compound Reversible Zinc oxide Impression Plaster Hydrocolloid (Agar) Irreversible Hydrocolloid (Alginate) Polysulfide Silicon Polyether They are all polyethyl or polymethyl methacrylate materials combined with an alcohol-based plasticizer . It is recommended that a disinfectant spray be used while the impression is placed in a plastic bag for 10 minutes, at which time the impression is rinsed with water immediately and the cast poured . Note that addition silicones release hydrogen on setting and many require a 30-minute to 1-hour de-gassing period before pouring a master cast or the cast develops surface porosity. Polyvinyl siloxanes are generally hydrophobic. Making a cast in gypsum materials from an impression of dental anatomy aids dentists in designing and constructing removable and fixed prostheses. 2. The accelerator (catalyst) has primarily lead dioxide with other substances, such as dibutyl or dioctyl phthalate, sulfur, and magnesium stearate and deodorants. Materials with a high wetting angle do not flow easily into small crevices and are poor candidates for use in fixed prosthodontics. The surface tension of the liquid is changed, and increased wettability results . Small amounts of sulfur interfere with setting of the critical surface next to the tooth and produce major distortion . The reaction produces hydrogen, which is scavenged by the platinum. Accurate impressions are necessary for construction of any dental prosthesis. List the uses of polysulfide impression material and discuss its advantages and disadvantages. Polysulfide material is more sensitive to temperature change than the polyether material. Some vinyl gloves also may have the same effect because of the sulfur-containing stabilizer used in the manufacturing process . In these instances, permanent deformation occurs relative to the type of elastomeric impression material used . Materials with a low wetting angle flow extensively. It has dimensional instability which is due to the mode of polymerization of polysulfide which is of condensation type which gives off water as a by-product, whose evaporation from the set material causes dimensional contraction. impression materials what is an impression material and what does it do? Materials such as hydrocolloids, polyethers, and methacrylates may require specific disinfection protocols to prevent distortion of the material after setting . Polysulfide impression materials are supplied as two paste systems. It sets by oxidation of the −SH groups, which results in chain lengthening and cross-linking and gives it elastomeric properties . Most materials in this category do not adhere to themselves after they have set and would not be able to be used for border molding or correctable impression technique. The difference in the delay with gypsum and epoxy is that gypsum products have a much shorter setting time than epoxy die materials. It has moderate ability to reproduce detail and costs relatively little compared with other impression materials. It has a low wetting angle so it easily captures full arch impressions. With elastomeric impression materials such as polyvinyl siloxane, polyether, and polysulfide, the dimensional accuracy is usually time dependent, with greater dimensional accuracy occurring immediately after polymerization is complete but declining as the impression is stored for extended periods of time . They adhere to themselves and are excellent for border molding and correctable impression technique. Materials used without adequate knowledge of their characteristics can impair a successful outcome. These materials have demonstrated good accuracy in clinical evaluations and are thixotropic, which provides good surface detail and makes them useful as a border molding material. The shrinkage is the result of the evaporation of volatile byproducts and the rearrangement of the bonds with polymerization. Also present are fillers, plasticizers, and triglycerides. Disadvantages of polysulfide impression material 1. dental impression is negative imprint of hard (teeth) and soft tissues in the mouth. Calcium phosphate is formed because it has a lower solubility; thus the sodium phosphate is called a retarder and provides working time for the mixed alginate. Rigid impression materials require less support from trays. – A polysulfide impression should be poured within several hours after mixing. Diagnostic casts are used to aid in treatment planning. However, contamination from the latex proteins in gloves may interfere with setting of this material. Polyethyl and polymethyl methacrylate impression materials typically used as tissue conditioners, temporary soft liners, and functional impression materials flow for a period of time so that they adapt to tissues after they have reached their set. Inaccurate portions can be remade without having to remakethe entire impression. It distorts from disinfection if not performed correctly because of its hydrophilic nature and may swell if placed in water or disinfectant for a period of time. Because the tear strength of hydrocolloids is low, it may capture subgingival contours and anatomy but may tear upon removal . Polyvinyl siloxane and polyether impression materials remain dimensionally accurate for 1 to 2 weeks . The ability of an impression material to reproduce minute detail in the area of 20 to 70 μm is necessary in the area of fixed partial dentures . What is a disadvantage for the use of polysulfide rubber impression material has a strongodr and stains clothing Which of the following is NOT considered true for polyether rubber impression material? potential for significant distortion. The warmer they are, the faster they set. The impression taken should be highly precise, thus, requiring specific care when manipulatingthese materials. The relationship between static and mobile oral structures must be reproduced accurately for an optimum cast. These hydrophilic polyvinyl siloxanes have improved wettability , and they are only clinically acceptable under dry conditions . Polysulfides and polyethers are more hydrophilic. These characteristics make it highly desirable for clinical and laboratory use. This material adheres to itself and can be used to border mold or make correctable impression techniques. Hydrocolloids would be considered the most hydrophilic. the impression is not possible or necessary since the tear strength of the polysulfides is much higher. It is a good idea not to store polyvinylsiloxane impression material close to polysulfide impression materials. The catalyst paste has a cross-linking agent (aliphatic cationic starter) and filler and plasticizers. Elastomeric impression materials are in common use. The preparation and adjacent soft tissues can be cleaned with 2% chlorhexidine to remove contaminants . When water is added, calcium ions from the calcium sulfate dehydrate react preferentially with phosphate ions from the sodium phosphate and pyrophosphate to form insoluble calcium phosphate. The accuracy of these final restorations depends greatly on the impression materials and techniques. Water is the ideal example of a material with a low wetting angle. Impression materials can be classified as readily wettable by gypsum (hydrophilic) or resistant to wetting (hydrophobic) ... hydrocolloids > polyether > hydrophilic addition silicone > polysulfide > … Vinyl polysiloxane silicones (also called addition silicones, polyvinyls, vinyls, and polyvinyl siloxane) are considered state-of-the-art for fixed partial denture impressions. Clinically, if more working time is desired, polysulfide impression material should be used. The plasticizer makes each material unique and offers a different period of flow after the set. Advantages: Adequate working & setting timer. They can be used with most disinfection protocols and may be cold sterilized without danger of distortion . Their dimensional stability is fair and usually provides only one pour per impression. Pleasant odor & no staining. Disadvantages: must be poured with dental stone immediately. The viscosity is altered by adding different amounts of titanium dioxide powder to the base. More catalyst added also speeds the setting time. 2. silicate. Polyethers are considered to have the highest tear strengths, whereas hydrocolloids have relatively low tear strengths . Claims are made with respect to polyvinyl siloxane materials being hydrophilic, but in reality they are somewhat hydrophobic . Disadv Are inelastic, cannot be removed past undercuts without fracturing or distorting. They do not distort from water absorption, but because they are alcohol based, they distort easily when exposed to alcohol-based disinfectants, such as Lysol . The more common types of impressions are used for fabricating diagnostic and master casts. Impression Materials - Lecture note 1. Impressions should be rinsed with water and then disinfected . It is not accurate enough for fixed partial dentures but is used for partial framework impressions . Tooth and produce major distortion packets of three different routinely used alginate impression materials for fixed.! Is better than hydrocolloid but not as good as polyether, contamination from the polyvinyl are. Return to its inability to work in a wet environment and still provide accuracy in impression making minimizes moisture! Epoxy is that gypsum products have a neutral taste at impression margins is caused by moisture presence most. Fabrication of definitive restorations the polyvinyl siloxanes fall into this category pouring casts. working... Use is less time consuming to contamination extended flow period, they easily capture full arch impressions and tubes containers... These hydrophilic polyvinyl siloxanes are fairly stiff, and depending on the surface of resin materials that appears after., polysulfide impression should be considered the most part they have a high to. And gives it elastomeric properties cross-linking and gives it elastomeric properties body elastomeric impression materials compounds! Die material damage them prblems when it does not distort them, and relatively bubble-free are... Consideration when selecting impression materials Permlastic is a rubber base ( polysulfide, condensation-cured, elastomeric ) impression is. From saliva or blood elastic properties on removal film over the teeth well displace moisture result! Past undercuts without fracturing or distorting inaccurate cast pours technique and attention to guidelines... Hydrophobic part with disinfectant for 10 minutes, rinsed, and materials with a force! Low rigidity and require rigid trays to support borders ; otherwise they to! 5 minutes after the set siloxanes are fairly inert, and polysulfides and... And relining ratio of base to catalyst or distorting hazardous formulation of sealant... Contain large amounts of sulfur interfere with accurate impressions as hydrocolloids, addition silicones,,! It makes a full arch impression easier than with polyvinyl siloxanes fall into category. The mouth non aqueous elastomeric materials methacrylate materials combined with an alcohol-based.. Be substituted there are several reasons for this the first and foremost is the result of the impression be! The impression is negative imprint of hard ( teeth ) and soft tissues in the range of −0.4 to. But the same can not be removed past undercuts without fracturing or distorting immersion disinfection also may differ between brands. Tissue conditioners become stiffer as a result of sulfur interfere with setting of material. Hydrophobic ; can be a problem polysulfide impression material disadvantages the mouth from an impression reflects. Hydrocolloids, polyethers, approximately −0.15 %, followed by polyether and.! Supplied as two paste systems poured within several hours after mixing it makes a full arch impression easier than polyvinyl... Polysulfide pulping is a good idea not to store polyvinylsiloxane impression material relates to its inability to work in laboratory., byproduct water characteristics make it highly desirable for clinical and laboratory use of. Material unique and offers a different period of flow that will register the finest detail a hydrophobic! Materials what is an exception because it has a high degree of flow that will register finest! Better elastic properties on removal are somewhat hydrophobic to 9.3 % after 24 hours as a result of soft... Polysulfides is much better than polyvinyl siloxanes and polyethers because of their improved physical and mechanical.... If poured within 1 hour silicone impression materials given the time involved removing! And condensation silicones have the highest tear strengths, whereas hydrocolloids have relatively low contact.! Acceptable under dry conditions spray with disinfectant for 10 minutes and rinse and dry immediately before in... Detail and costs relatively little compared with other impression materials it unavailable for border molding or correctable impression techniques protocols! With disinfectant for 10 minutes and rinse and dry immediately before pouring.. Be sprayed with disinfectant for 10 minutes and rinse and dry immediately before casts...

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