Impressions / implant dentistry course

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Indian Dental Academy: will be one of the most relevant and exciting training

center with best faculty and flexible training programs for dental

professionals who wish to advance in their dental practice,Offers certified

courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry,

Prosthetic Dentistry, Periodontics and General Dentistry.

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Impressions / implant dentistry course

  1. 1. 11 IMPRESSIONS INIMPRESSIONS IN COMPLETE DENTURESCOMPLETE DENTURES INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com
  2. 2. 22 INTRODUCTIONINTRODUCTION An impression is defined as, "an imprint or nega­ tive likeness of the teeth and/or edentulous areas where the teeth have been removed, made in a plastic material which becomes relatively hard or set while in contact with these tissues. Impressions may be made of full complements of teeth, of areas where some teeth have been removed, or in mouth from which all teeth have been removed" ­ GPT. www.indiandentalacademy.comwww.indiandentalacademy.com
  3. 3. 33 Complete denture impression is a negative registration of the entire denture bearing, stabilizing and border seal areas present in the edentulous mouth. - GPT. www.indiandentalacademy.comwww.indiandentalacademy.com
  4. 4. 44 Impressions are made to produce a negative replica of the patient's mouth into which plaster or stone can be poured to form the positive replica­ the cast. The cast acts as a template over which the CD is fabricated. www.indiandentalacademy.comwww.indiandentalacademy.com
  5. 5. 55 CLASSIFICATIONCLASSIFICATION 1) Depending on the theories of impression making. 2) Depending on the technique 3) Depending on the tray type 4) Depending on the purpose of the impression 5) Depending on the material used www.indiandentalacademy.comwww.indiandentalacademy.com
  6. 6. 66 Depending on theories of impression making  Mucostatic.Mucostatic.  Mucocompressive.Mucocompressive.  Selective pressure.Selective pressure. www.indiandentalacademy.comwww.indiandentalacademy.com
  7. 7. 77 Mucostatic or Passive ImpressionMucostatic or Passive Impression First proposed byFirst proposed by RichardsonRichardson and later popularised byand later popularised by Harry PageHarry Page.. The impression is made with the oral mucous membraneThe impression is made with the oral mucous membrane and the jaws in a normal, relaxed condition. Borderand the jaws in a normal, relaxed condition. Border moulding is not done here.moulding is not done here. The impression is made with an oversized traThe impression is made with an oversized tra Impression material of choice is impression plaster.Impression material of choice is impression plaster. Retention is mainly due to interfacial surface tension.Retention is mainly due to interfacial surface tension. The mucostatic technique results in a denture, which isThe mucostatic technique results in a denture, which is closely adapted to the mucosa of the denture­bearingclosely adapted to the mucosa of the denture­bearing area but has poor peripheral seal.area but has poor peripheral seal. www.indiandentalacademy.comwww.indiandentalacademy.com
  8. 8. 88 Mucocompressive ImpressionMucocompressive Impression (Carole Jones)(Carole Jones) Records the oral tissues in a functional and displacedRecords the oral tissues in a functional and displaced form. The materials used for this technique includeform. The materials used for this technique include impression compound, waxes and soft liners.impression compound, waxes and soft liners. The oral soft tissues are resilient and thus tend to returnThe oral soft tissues are resilient and thus tend to return to their anatomical position once the forces are relieved.to their anatomical position once the forces are relieved. Dentures made by this technique tend to get displacedDentures made by this technique tend to get displaced due to the tissue rebound at rest. During function, thedue to the tissue rebound at rest. During function, the constant pressure exerted onto the soft tissues limit theconstant pressure exerted onto the soft tissues limit the blood circulation leading to residual ridge resorption.blood circulation leading to residual ridge resorption. www.indiandentalacademy.comwww.indiandentalacademy.com
  9. 9. 99 Selective Pressure ImpressionSelective Pressure Impression (Boucher)(Boucher) In this technique, the impression is made to extend overIn this technique, the impression is made to extend over as much denture-bearing area as possible withoutas much denture-bearing area as possible without interfering with the limiting structures at function andinterfering with the limiting structures at function and rest.rest. The selective pressure technique makes it possible toThe selective pressure technique makes it possible to confine the forces acting on the denture to the stress-confine the forces acting on the denture to the stress- bearing areas. This is achieved through the design of thebearing areas. This is achieved through the design of the special tray in which the non stress-bearing areas arespecial tray in which the non stress-bearing areas are relieved and the stress-bearing areas are allowed to comerelieved and the stress-bearing areas are allowed to come in contact with the tray.in contact with the tray.www.indiandentalacademy.comwww.indiandentalacademy.com
  10. 10. 1010 Depending on the technique Open-mouthOpen-mouth Closed-mouthClosed-mouth www.indiandentalacademy.comwww.indiandentalacademy.com
  11. 11. 1111 Depending on the tray type  Stock trayStock tray  Custom trayCustom tray www.indiandentalacademy.comwww.indiandentalacademy.com
  12. 12. 1212 Depending on the purpose of the impression DiagnosticDiagnostic PrimaryPrimary SecondarySecondary www.indiandentalacademy.comwww.indiandentalacademy.com
  13. 13. 1313 DIAGNOSTIC IMPRESSIONDIAGNOSTIC IMPRESSION The negative replica of the oral tissues used toThe negative replica of the oral tissues used to prepare a diagnostic cast.prepare a diagnostic cast. Used for study purposes like measuring theUsed for study purposes like measuring the undercuts, locating the path of insertion.undercuts, locating the path of insertion. Is made as a part of treatment plan and toIs made as a part of treatment plan and to estimate the amount of pre-prosthetic surgery.estimate the amount of pre-prosthetic surgery. Articulate the casts on tentative jaw relation andArticulate the casts on tentative jaw relation and evaluate the inter-arch spaceevaluate the inter-arch spacewww.indiandentalacademy.comwww.indiandentalacademy.com
  14. 14. 1414 PRIMARY IMPRESSIONPRIMARY IMPRESSION (PRELIMINARY IMPRESSION)(PRELIMINARY IMPRESSION) An impression made for the purpose ofAn impression made for the purpose of diagnosis or for the construction of a tray.diagnosis or for the construction of a tray. There should be at least 5mm clearanceThere should be at least 5mm clearance between the stock tray and the ridge.between the stock tray and the ridge. The tray should extend over hamular notch andThe tray should extend over hamular notch and maxillary tuberosity. Mandibular tray shouldmaxillary tuberosity. Mandibular tray should cover retromolar pad.cover retromolar pad. Tray can be extended using modelling wax.Tray can be extended using modelling wax. Impression compound, Alginate, Impression plasterwww.indiandentalacademy.comwww.indiandentalacademy.com
  15. 15. 1515 SECONDARY IMPRESSIONSECONDARY IMPRESSION (WASH IMPRESSION)(WASH IMPRESSION) Involve:Involve: Fabriction of custom tray.Fabriction of custom tray. Border molding.Border molding. Developing the posterior palatal seal.Developing the posterior palatal seal. Making the wash impressionMaking the wash impression.. www.indiandentalacademy.comwww.indiandentalacademy.com
  16. 16. 1616 Depending on the material usedDepending on the material used  Reversible hydrocolloid impression.Reversible hydrocolloid impression.  Irreversible hydrocolloid impression.Irreversible hydrocolloid impression.  Modeling plastic impression.Modeling plastic impression.  Plaster impression.Plaster impression.  Wax impression.Wax impression.  Silicone impression.Silicone impression.  Thiokol rubber impression. (Polysulphide)Thiokol rubber impression. (Polysulphide) www.indiandentalacademy.comwww.indiandentalacademy.com
  17. 17. 1717 OBJECTIVES OF IMPRESSIONOBJECTIVES OF IMPRESSION MAKINGMAKING 1)1) RetentionRetention 2)2) StabilityStability 3)3) SupportSupport 4)4) AestheticsAesthetics 5)5) Preservation of remaining structuresPreservation of remaining structures www.indiandentalacademy.comwww.indiandentalacademy.com
  18. 18. 1818 RETENTIONRETENTION That quality inherent in the prosthesisThat quality inherent in the prosthesis which resists the force of gravity,which resists the force of gravity, adhesiveness of foods, and the forcesadhesiveness of foods, and the forces associated with the opening of the jaws.associated with the opening of the jaws. (GPT)(GPT) www.indiandentalacademy.comwww.indiandentalacademy.com
  19. 19. 1919 Factors affecting RetentionFactors affecting Retention  Anatomical factorsAnatomical factors  Physiological factorsPhysiological factors  Physical factorsPhysical factors  Mechanical factorsMechanical factors  Muscular factorsMuscular factors www.indiandentalacademy.comwww.indiandentalacademy.com
  20. 20. 2020 Anatomical factorsAnatomical factors  Size of the denture bearing areaSize of the denture bearing area  Quality of the denture bearing area.Quality of the denture bearing area. Factors affecting RetentionFactors affecting Retention www.indiandentalacademy.comwww.indiandentalacademy.com
  21. 21. 2121 Physiological factorsPhysiological factors  Saliva and its qualitySaliva and its quality Factors affecting RetentionFactors affecting Retention www.indiandentalacademy.comwww.indiandentalacademy.com
  22. 22. 2222 Physical factorsPhysical factors  AdhesionAdhesion  CohesionCohesion  Interfacial surface tensionInterfacial surface tension  Capallarity and capillary attractionCapallarity and capillary attraction  Atmospheric pressure and peripheral sealAtmospheric pressure and peripheral seal Factors affecting RetentionFactors affecting Retention www.indiandentalacademy.comwww.indiandentalacademy.com
  23. 23. 2323 Mechanical factorsMechanical factors  UndercutsUndercuts  Retentive springsRetentive springs  Magnetic forcesMagnetic forces  Denture adhesiveDenture adhesive  Suction chambers and suction discsSuction chambers and suction discs Factors affecting RetentionFactors affecting Retention www.indiandentalacademy.comwww.indiandentalacademy.com
  24. 24. 2424 Muscular factorsMuscular factors  The muscles apply supplementary retentiveThe muscles apply supplementary retentive forces on the denture.forces on the denture.  It is most effective in the neutral zone.It is most effective in the neutral zone. Factors affecting RetentionFactors affecting Retention www.indiandentalacademy.comwww.indiandentalacademy.com
  25. 25. 2525 STABILITYSTABILITY The quality of a denture to be firm, steady,The quality of a denture to be firm, steady, or constant, to resist displacement byor constant, to resist displacement by functional stresses and not to be subject tofunctional stresses and not to be subject to change of position when force is applied.change of position when force is applied. It is the ability of the denture to withstandIt is the ability of the denture to withstand horizontal forces.horizontal forces. www.indiandentalacademy.comwww.indiandentalacademy.com
  26. 26. 2626  Vertical height of the residual ridge.Vertical height of the residual ridge.  Quality of soft tissue covering the ridge.Quality of soft tissue covering the ridge.  Occlusal planeOcclusal plane  Quality of the impression.Quality of the impression.  Teeth arrangement.Teeth arrangement.  Contour of the polished surfaces.Contour of the polished surfaces. FACTORS AFECTING STABILITYFACTORS AFECTING STABILITY www.indiandentalacademy.comwww.indiandentalacademy.com
  27. 27. 2727 SUPPORTSUPPORT The resistance to vertical forces ofThe resistance to vertical forces of mastication, occlusal forces and othermastication, occlusal forces and other forces applied in a direction towardsforces applied in a direction towards the denture-bearing area.the denture-bearing area. www.indiandentalacademy.comwww.indiandentalacademy.com
  28. 28. 2828  The denture base should cover asThe denture base should cover as much denture-bearing area as possiblemuch denture-bearing area as possible to provide good support.to provide good support.  Confining the occlusal forces to stress-Confining the occlusal forces to stress- bearing area and reliving the non-bearing area and reliving the non- stress-bearing areas will aid tostress-bearing areas will aid to improve supportimprove support SUPPORTSUPPORT www.indiandentalacademy.comwww.indiandentalacademy.com
  29. 29. 2929 AESTHETICSAESTHETICS  The thickness of the denture flanges is one ofThe thickness of the denture flanges is one of the important factors that govern esthetics.the important factors that govern esthetics.  Thicker denture flanges are preferred in long-Thicker denture flanges are preferred in long- term edentulous patients to give required labialterm edentulous patients to give required labial fullness.fullness.  Impression should perfectly reproduce the widthImpression should perfectly reproduce the width and height of the entire sulcus for the properand height of the entire sulcus for the proper fabrication of the flanges.fabrication of the flanges. www.indiandentalacademy.comwww.indiandentalacademy.com
  30. 30. 3030 PRESERVATION OF REMAININGPRESERVATION OF REMAINING STRUCTURESSTRUCTURES  De Van (1952) stated that, “the preservation ofDe Van (1952) stated that, “the preservation of that which remains is of utmost importancethat which remains is of utmost importance and not the meticulous replacement of thatand not the meticulous replacement of that which has been lost.which has been lost.  Impressions should record the details of theImpressions should record the details of the basal seat and peripheral structures in anbasal seat and peripheral structures in an appropriate form to prevent injury to the oralappropriate form to prevent injury to the oral tissues.tissues. www.indiandentalacademy.comwww.indiandentalacademy.com
  31. 31. 3131 THANK YOUTHANK YOU For more details please visit www.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com

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