CONTENTS INTRODUCTION CLASSIFICATION POLYSULFIDE CONDENSATION SILICONE ADDITION SILICONE POLYETHER MANIPULATION IMPRESSION TECHNIQUES DISINFECTION FAILURES CONCLUSION ID: 1034322
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1. ELASTOMERIC IMPRESSION MATERIALS
2. CONTENTSINTRODUCTIONCLASSIFICATION POLYSULFIDE CONDENSATION SILICONE ADDITION SILICONE POLYETHERMANIPULATIONIMPRESSION TECHNIQUESDISINFECTIONFAILURESCONCLUSIONREFERENCES
3. INTRODUCTIONDEFINITION:ELASTOMER:A lightly cross linked impression material that exhibits elastic behaviour after setting.They are chemically or physically cross linked.They can be easily stretched and rapidly recover their original dimension when the applied stress is released.ADA specification no:19
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5. POLYSULFIDEFirst synthetic elastomeric impression material.Also known as Mercaptan or Thiokol.Supplied in dispensing tubes. Base paste and catalyst pasteConsistencies: Light bodyMedium body Heavy body
6. COMPOSITIONBASE PASTE: Polysulfide polymer. Filler-Lithopone or Titanium dioxide. Plasticizer- Dibutyl phthalate. 0.5% SulfurCATALYST PASTE: Lead dioxide Retarder- Oleic acid or stearic acid .PHILIPS SCIENCE OF DENTAL MATERIALS 11 TH EDITION
7. SETTING REACTONPOLYSULFIDE PREPOLYMER + LEAD DIOXIDE POLYSULFIDE+H2OPHILIPS SCIENCE OF DENTAL MATERIALS 11TH EDITION
8. PROPERTIESHydrophilic.Working time- 4-7 mins.Setting time- 7-10 mins.Low viscosity.Excellent reproduction of details.Percentage contraction at 1 hr -0.40-0.45Tear strength- 2500-7000.PHILIPS SCIENCE OF DENTAL MATERIALS 11TH EDITION
9. In vitro investigation have shown that the impression material can penetrate and remain entrapped inside the dentinal tubules during the impression procedures(FPD). This aspect might have a negative influence on the adhesion, and thus this study strongly supports the use of an immediate dentine sealing procedure for adhesive restorations. Penetration of Different Impression Materials into Exposed Dentinal Tubules during the Impression Procedure Bruna Sinjari , Gianmaria D’Addazio , Edit Xhajanka , Sergio Caputi , Giuseppe Varvara and Tonino Traini
10. Sinjari et al demonstrated how an adequate surface cleaning protocol can reset the interactions with the impression material. In their study, they proposed that following the adhesion protocol, the surface should be cleaned with prophy paste and a surfactant agent (e.g., Marseille soap). Sinjari, B.; D’Addazio, G.; Murmura, G.; Di Vincenzo, G.; Semenza, M.; Caputi, S.; Traini, T. Avoidance of interaction between impression materials and tooth surface treated for immediate dentin sealing: An in-vitro study. Materials (Basel) 2019, 12, 3454.
11. MODIFICATIONSLead dioxide is replaced by cumene hydroperoxide or t- butyl hydroperoxide.A recently developed polysulfide replaces the lead dioxide by a zinc carbonate / organic accelerator system.E.C .COOMBE NOTES OF DENTAL MATERIALS 6TH EDITION
12. CONDENSATION SILICONEFirst type of silicone impression material .Otherwise known as conventional silicone.If the setting occurs in room temperature then it known as RTV.MODE OF SUPPLY:Collapsible tubes.Base pasteAccelerator low viscosity liquidPutty supplied in jars.
13. COMPOSITIONBASE PASTE: Alpha omega hydroxyl terminated polydimethyl siloxane. Inert filler – silica.CATALYST: Tetra ethyl orthosilicate. Activator-Dibutyl tin dilaurate/stannous octoate.PHILIPS SCIENCE OF DENTAL MATERIALS 11 TH EDITION
14. SETTING REACTIONDIMETHYL SILOXANE + TETRA ETHYL ORTHO SILICATESTANNOUS OCTOATESILICONE RUBBER + ETHYL ALCOHOLPHILIPS SCIENCE OF DENTAL MATERIALS 11 TH EDITION
15. PROPERTIESHydrophobic.Working time-2.5-4 mins.Setting time-6-8 mins.Percentage contraction at 1 hr- 0.38-0.60 .Tear strength-2300-2600.It can be copper plated or silver platedMore stiffer than polysulfide.
16. ADDITION SILICONEThe addition silicones are frequently called polyvinyl siloxane or vinyl polysiloxane impression material.Supplied in tubesBase pasteCatalyst pastePutty supplied in jars.
17. COMPOSITIONBASE PASTE:Polymethyl hydrogen siloxane .Other siloxane prepolymers.CATALYST PASTE: Divinyl polydimethyl siloxane. ACTIVATOR- platinum salt . Palladium. Retarders. Fillers.PHILIPS SCIENCE OF DENTAL MATERIALS 11 TH EDITION
18. SETTING REACTIONPOLYMETHYL HYDROSILOXANE+DIVINYLPOLYSILOXANE + CHLORPLATINIC ACID SILICONE RUBBERPHILIPS SCIENCE OF DENTAL MATERIALS 11 TH EDITION
19. PROPERTIESHydrophobic.Working time-2-4mins.Setting time- 4-6.5 mins.Percentage contraction at 1 hr- 0.14-0.17Tear strength-1500-4300.Pseudoplastic.Exhibits lowest permanent distortion.
20. Sulfur as a reactive element contained within latex gloves or rubber dam material may react with chloroplatinic acid catalyst in elastomeric impression material, even with concentrations as low as 0.05% may totally inhibit the polymerization reaction.The vinyl glove did not inhibit the polymerization of the addition silicone An Evaluation of the Effect of Various Gloves on Polymerization Inhibition of Elastomeric Impression Materials: An In vitro StudyVinuta Hiremath, G. Vinayakumar,Mallikarjuna Ragher,Sounyala Rayannavar, Mahantesh Bembalagi, and B. L. Ashwini Journal of pharm bioalligned sciences 2017,nov 9
21. siloxanes cured by the thiol-ene reaction displayed highly accurate detail reproduction and greater mechanical strength would be achieved through variable filler loading, would prove a superior impression material in clinical dentistryThiol-ene functionalized siloxanes for use as elastomeric dental impression materials Megan A. Cole a, Katherine C. Jankousky a, Christopher N. Bowmana,b. Dental materials 13 2014 (449-455)
22. POLYETHERFirst elastomer to be developed primarily to function as impression material.Supplied in tubes.Base paste.Accelerator paste.
23. COMPOSITIONBASE PASTE:Polyether polymer.Inert filler – silica.Plasticizer- Glycolether or phthalate.CATALYST PASTE:Alkyl aromatic sulfonate.Inert filler – silica.Plasticizer- Glycolether or phthalate.PHILIPS SCIENCE OF DENTAL MATERIALS 11 TH EDITION
24. SETTING REACTION POLYETHER + SULFONIC ESTER CROSS LINKED RUBBER
25. PROPERTIESHydrophilic.Working time-3mins.Setting time- 6mins.Percentage contraction at 1 hr- 0.19-0.24Tear strength-1800-4800.Pseudoplastic.Least amount of distortion.Hypersensitivity.Contact dermatitis
26. ELASTIC RECOVERYMECHANICAL PROPERTIES OF ELASTOMERIC IMPRESSION MATERIALS:CRAIGS RESTORATIVE DENTAL MATERIALS 12TH EDITION
27. STRAIN IN COMPRESSIONCRAIGS RESTORATIVE DENTAL MATERIALS 12TH EDITION
28. FLOWCRAIGS RESTORATIVE DENTAL MATERIALS 12TH EDITION
29. TEAR STRENGTHCRAIGS RESTORATIVE DENTAL MATERIALS 12TH EDITION
30. MANIPULATIONCRAIGS RESTORATIVE DENTAL MATERIALS 12TH EDITION
31. IMPRESSION TRAYSThe use of a custom tray is recommended to reduce the quantity of the materials used to make impressions with polysulfide. Disposable stock trays work satisfactorily for polyether and addition silicone when the putty-wash technique is used for making impressions.
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33. HAND MIXINGEqual length of catalyst and base paste are dispensed on a paper pad.The mixture is spread over the mixing pad. The mass is then scraped up with the spatula blade and spread uniformly back and forth on the mixing pad. Mixing time 45 secs.
34. STATIC AUTOMIXINGBase and catalyst are in separate cylinders.Catridge placed in mixing gun containing 2 plungersEqual amount of both pastes forced through static mixing tip.Mixed material can be extruded directly either into impression tray or onto the prepared tooth.
35. DYNAMIC MECHANICAL MIXINGCatridge is inserted into the top of mixing machine.A new plastic mixing tip is placed on the front.On pressing the button parallel plungers push against the plastic bags ,thus opening the bags.Material is forced into the dynamic mixing tip .mixing done by rotation +Forward motion through spiral.
36. IMPRESSION TECHNIQUESPHILIPS SCIENCE OF DENTAL MATERIALS 11 TH EDITION
37. DUAL VISCOSITY TECHNIQUELow consistency material is injected with a syringe into and around the critical areas.High consistency material is mixed and placed in the tray.
38. MONOPHASE TECHNIQUEOnly one mix is made part of it placed in a tray.Another portion placed in syringe for injection.Medium viscosity of addition and polyether can be used.
39. PUTTY WASH TECHNIQUEDeveloped for condensation silicone to minimize the effect of polymerization shrinkage on the dimensional changes. Two approaches can be used: a two-stage procedure and a single-stage procedure.TWO STAGE PROCEDURE:Thick putty material is placed in a stock tray and a preliminary impression is made.After preparation light body is syringed into the prepared tooth and the preliminary impression is reinserted and the impression is made.
40. SINGLE STAGE PROCEDURE: The wash material is syringed into place, and then the unset putty is scaled over the light-body material.Occlusal stops should be used in the tray to avoid pushing through the wash or syringe material.
41. REMOVAL OF IMPRESSION All elastomeric impression materials are viscoelastic, and it is necessary to use a quick snap to minimize plastic deformation of the impression during the final step of the removal process.
42. MATERIALMETHODRECOMMENDED DISINFECTANTCOMMENTSPOLYSULFIDEIMMERSIONGlutaraldehyde , chlorine compounds , iodophors , phenolicsNot > than 30 mins.CONDENSATION SILICONEIMMERSIONSame as polysulfideNot > than 30 mins.ADDITION SILICONEIMMERSIONSame as polysulfideNot > than 30 mins.POLYETHERChlorine compounds and iodophors.Short term exposure < 10 mins.DISINFECTION
43. The dimensional changes of polyether impression after disinfection and prolonged storage complied with ANSI/ADA standard. The tested polyether impression materials were dimensionally stable for clinical use after disinfection for 30 minutes in glutaraldehyde and storage for up to 2 weeks.The effect of prolonged storage and disinfection on the dimensional stability of 5 vinyl polyether silicone impression materials Usama Nassar*, Carlos Flores-Mir, Giseon Heo, Ysidora Torrealba J Adv Prosthodont 2017;9:182-7
44. PREPARATION OF STONE CASTS AND DIESAll non aqueous elastomeric impression materials are compatible with all types of gypsum products during the setting of the gypsum products.The time interval between impression pours should not be greater than 30 minutes.
45. FAILURES ROUGH OR UNEVEN SURFACEDISTORTIONROUGH OR CHALKY STONE CASTIRREGULARLY SHAPED VOIDSBUBBLES
46. CONCLUSIONThe understanding of basic knowledge of the impression materials and their behaviour during handling are important for their use in oral environment and clinical success.The selection of the material best suited for particular clinical situation and technique rests with the operator.
47. REFERENCESPHILIPS science of dental materials.CRAIGS restorative dental materials 12th edition.E.C.COOMBE Notes on dental materials 6th edition.Penetration of Different Impression Materials into Exposed Dentinal Tubules during the Impression Procedure Bruna Sinjari , Gianmaria D’Addazio , Edit Xhajanka , Sergio Caputi ,Giuseppe Varvara and Tonino Traini Sinjari, B.; D’Addazio, G.; Murmura, G.; Di Vincenzo, G.; Semenza, M.; Caputi, S.; Traini, T. Avoidance of interaction between impression materials and tooth surface treated for immediate dentin sealing: An in-vitro study. Materials (Basel) 2019, 12, 3454. An Evaluation of the Effect of Various Gloves on Polymerization Inhibition of Elastomeric Impression Materials: An In vitro StudyViBembalagi, and B. L. Ashwini nuta Hiremath, G. Vinayakumar,Mallikarjuna Ragher,Sounyala Rayannavar, Mahantesh Journal of pharm bioalligned sciences 2017,nov 9 .The effect of prolonged storage and disinfection on the dimensional stability of 5 vinyl polyether silicone impression materials Usama Nassar, sCarlos Flores-Mir, Giseon Heo, Ysidora Torrealba J Adv Prosthodont 2017;9:182-7. Thiol-ene functionalized siloxanes for use as elastomeric dental impression materials Megan A. Cole a, Katherine C. Jankousky a, Christopher N. Bowmana,b. Dental materials 13 2014 (449-455) .
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