impression procedures for removable partial dentures / academy of fixed orthodontics

1. www.indiandentalacademy.comwww.indiandentalacademy.com

2. INDIAN DENTAL ACADEMYINDIAN DENTAL ACADEMY Leader in continuing dental educationLeader in continuing dental education www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com

3.  INTRODUCTIONINTRODUCTION  IMPRESSIONIMPRESSION  IMPRESSION TRAYSIMPRESSION TRAYS  TRAYS USED IN RPD IMPRESSIONTRAYS USED IN RPD IMPRESSION PROCEDUREPROCEDURE  FACTORS INFLUENCING THE CHOICE OFFACTORS INFLUENCING THE CHOICE OF IMPRESSION MATERIALIMPRESSION MATERIAL  IMPRESSION MATERIALS USED-OVERVIEWIMPRESSION MATERIALS USED-OVERVIEW www.indiandentalacademy.comwww.indiandentalacademy.com

4.  RPD IMPRESSION Vs COMPLETE DENTURE IMPRESSION  PRIMARY IMPRESSION  OBJECTIVES  PROCEDURE  PATIENT MANAGEMENT  CONTROL OF SALIVA  PRECAUTIONS TO BE TAKEN FOR “ GAGGERS ”  EXAMINATION OF IMPRESSION  REASONS FOR REJECTING AN IMPRESSION www.indiandentalacademy.comwww.indiandentalacademy.com

5.  FINAL IMPRESSION METHODS  McLEAN’S TECHNIQUE  HINDEL’S TECHNIQUE  SELECTIVE PRESSURE TECHNIQUE  FUNCTIONAL RELINING TECHNIQUE  FLUID WAX TECHNIQUE  ALTERED CAST TECHNIQUE MODIFICATION  REVIEW OF LITERATURE  CONCLUSION  REFERENCES www.indiandentalacademy.comwww.indiandentalacademy.com

6. INTRODUCTIONINTRODUCTION Sensitive to technique and material procedures.Sensitive to technique and material procedures. Not a passive activity.Not a passive activity. Impression material accomplishes the taskImpression material accomplishes the task operator is merely an observer.operator is merely an observer. www.indiandentalacademy.comwww.indiandentalacademy.com

7. Combined effort event accomplished by:Combined effort event accomplished by: OperatorOperator basic fundamental knowledge of all aspects ofbasic fundamental knowledge of all aspects of the impression proceduresthe impression procedures Intra oral condition of the patient.Intra oral condition of the patient. The position of the patient.The position of the patient. The size and position of the tray.The size and position of the tray. The selection of the material and technique.The selection of the material and technique. Patient’s actions and facial muscle activity.Patient’s actions and facial muscle activity. www.indiandentalacademy.comwww.indiandentalacademy.com

8. Impression  A negative likeness or copy in reverse of the surface of an object ; imprint of teeth and adjacent structures for use in dentistry. GPT – 8 Partial denture impression  A negative likeness of a part or all of a partially edentulous arch - GPT – 8 www.indiandentalacademy.comwww.indiandentalacademy.com

9.  An impression of partially edentulous arch must record accurately the anatomic form of teeth and surrounding tissues. Unless the cast upon which the prosthesis is to be constructed is an exact replica of mouth, the prosthesis can’t be expected to fit. Properly made and accurate cast can be obtained only from an accurate impression. www.indiandentalacademy.comwww.indiandentalacademy.com

11. Impression trays A receptacle in to which suitable impression material is placed to make negative likeness OR A device that is used to carry, confine and control impression material while making an impression. www.indiandentalacademy.comwww.indiandentalacademy.com

13. Impression trays can be classified broadly in to stock trays and custom trays Stock trays for partially edentulous patients may be perforated to retain the impression material or they may be constructed with a rimlock for this purpose. Another type of stock tray designed for the reversible type of hydrocolloid is water cooled trays. It contains tubes through which water can be circulated for purpose of cooling the tray.www.indiandentalacademy.comwww.indiandentalacademy.com

14. Modified stock tray (individual tray) Robert R Renner’s technique The stock tray can be modified with modeling composition and with wax to create an accurately fitting tray. This technique can be employed in class I and class II cases. Technique: Softened modeling compound is placed in the stock impression tray in such a way that it may capture the edentulous areas of mouth and include one or two teeth adjacent to the space.www.indiandentalacademy.comwww.indiandentalacademy.com

15. The tray is positioned in the mouth and compound is allowed to cool but it not permitted to harden completely, so that it is prevented from becoming hard when in contact with the adjacent teeth. When it is hardened sufficiently to contour it is removed from the mouth and thoroughly chilled. www.indiandentalacademy.comwww.indiandentalacademy.com

16. The compound is trimmed so that it does not contact the adjacent teeth and surface of compound in the edentulous areas is scraped to a depth of 2 - 4 mm to provide space for a uniform layer of impression material. In maxillary impression the compound should cover the edentulous ridges and the palate and should accurately fit to post dam area. www.indiandentalacademy.comwww.indiandentalacademy.com

17. Modification of the tray to make it adhesive If Impression material to be used is either alginate or agar, we can heat surface of compound with a flame. An alternate method Is to paint the surface of compound with a solvent such an chloroform to make it tacky and then to embed cotton fibers in it, the impression material will become enmeshed in cotton fiber. And if rubber base material is to be employed rubber adhesive is painted on the compound www.indiandentalacademy.comwww.indiandentalacademy.com

18. Advantages over custom tray: 1. Impression can be accomplished in one appointment. 2. Can be used inpatient with tendency to gag. Advantages over conventional use of stock stray: Especially useful for mouth that is either exceptionally large or small or the one with anomalous contour which cannot be accurately fitted with conventional stock tray. www.indiandentalacademy.comwww.indiandentalacademy.com

19. Disadvantages: STOCK TRAY a. The peripheral borders cannot be accurately recorded. b. Considerably more bulkier than a custom tray. www.indiandentalacademy.comwww.indiandentalacademy.com

20. Custom impression trays: a. Peripheral borders can be precisely recorded in the impression b. Thickness of impression material can be controlled. This is important consideration when using rubber base type material, which should not exceed thickness of 2-4 mm because a section thicker than this is subject to distortion. www.indiandentalacademy.comwww.indiandentalacademy.com

21. C. Well fitted tray will better support the impression in the palate, then avoiding even present danger of material slumping in vital areas. Custom trays are sometimes needed for mouths that are abnormally or of unusual configuration. www.indiandentalacademy.comwww.indiandentalacademy.com

22. Impression MaterialsImpression Materials www.indiandentalacademy.com

23. Factors that influence the selection of impression materials are:  Convenience of use  Time of manipulation and set  Cost  Need for special trays  Operator training and preference www.indiandentalacademy.comwww.indiandentalacademy.com

24. Impression Materials • Non-elastic • Elastic – Aqueous hydrocolloids • Agar • Alginate – Non-aqueous elastomers • Polysulfide • Silicones – Condensation – Addition • Polyether www.indiandentalacademy.com

25. Impression Materials Non-elastic Elastic Aqueous Hydrocolloids Non-aqueous Elastomers Polysulfide Silicones Polyether Condensation Addition Agar (reversible) Alginate (irreversible) Plaster Compound ZnO - Eugenol Waxes O’Brien Dental Materials & their Selection 1997 www.indiandentalacademy.com

26. Reversible Hydrocolloid (Agar) • Indications – crown and bridge • high accuracy • Example – Slate Hydrocolloid (Van R) www.indiandentalacademy.com

27. Composition • Agar – complex polysaccharide • seaweed – gelling agent • Borax – strength • Potassium sulfate – improves gypsum surface • Water (85%) agar hydrocolloid (hot) agar hydrocolloid (cold) (sol) (gel) cool to 43 C heat to 100 C O’Brien Dental Materials & their Selection 1997 www.indiandentalacademy.com

28. Manipulation • Gel in tubes – syringe and tray material www.indiandentalacademy.com

29. Manipulation • 3 chamber conditioning unit – (1) liquefy at 100°C for 10 minutes • converts gel to sol – (2) store at 65°C – place in tray – (3) temper at 46°C for 3 minutes – seat tray – cool with water at 13°C for 3 minutes • converts sol to gel O’Brien Dental Materials & their Selection 1997 www.indiandentalacademy.com

30. Advantages • Dimensionally accurate • Hydrophilic – displace moisture, blood, fluids • Inexpensive – after initial equipment • No custom tray or adhesives • Pleasant • No mixing required Phillip’s Science of Dental Materials 1996 www.indiandentalacademy.com

31. Disadvantages • Initial expense – special equipment • Material prepared in advance • Tears easily • Dimensionally unstable – immediate pour – single cast • Difficult to disinfect Phillip’s Science of Dental Materials 1996 www.indiandentalacademy.com

32. Irreversible Hydrocolloid (Alginate) • Most widely used impression material • Indications – study models – removable fixed partial dentures • framework • Examples – Jeltrate (Dentsply/Caulk) – Coe Alginate (GC America) Phillip’s Science of Dental Materials 1996 www.indiandentalacademy.com

33. Composition • Sodium alginate – salt of alginic acid • mucous extraction of seaweed (algae) • Calcium sulfate – reactor • Sodium phosphate – retarder • Filler • Potassium fluoride – improves gypsum surface 2 Na3PO4 + 3 CaSO4 Ca3(PO4)2 + 3 Na2SO4 Na alginate + CaSO4 Ca alginate + Na2SO4 (powder) (gel) H2O O’Brien Dental Materials & their Selection 1997 www.indiandentalacademy.com

34. Manipulation • Weigh powder • Powder added to water – rubber bowl – vacuum mixer • Mixed for 45 sec to 1 min • Place tray • Remove 2 to 3 minutes – after gelation (loss of tackiness) Caswell JADA 1986 www.indiandentalacademy.com

35. Advantages • Inexpensive • Easy to use • Hydrophilic – displace moisture, blood, fluids • Stock trays Phillip’s Science of Dental Materials 1996 www.indiandentalacademy.com

36. Disadvantages • Tears easily • Dimensionally unstable – immediate pour – single cast • Lower detail reproduction – unacceptable for fixed prosthodontics • High permanent deformation • Difficult to disinfect Phillip’s Science of Dental Materials 1996 www.indiandentalacademy.com

37. RPD IMPRESSION Vs COMPLETE DENTURE The complete denture impression records the edentulous mucosa with underlying bone only, whereas partial denture impression records not only relative soft yielding tissues (the oral mucosa) as well as a hard unyielding substance (the remaining teeth). www.indiandentalacademy.comwww.indiandentalacademy.com

38. Removable partial denture impression need to record the teeth that are irregular in contour as well as varying in their vertical relations to occlusal plane. The chosen impression material must be capable of recording the tissue contours as accurately as possible without distortion, which occurs as impression is withdrawn. www.indiandentalacademy.comwww.indiandentalacademy.com

39. PRIMARY IMPRESSION Objectives: To obtain an impression of all the standing teeth and denture - supporting tissues of each jaw from which study casts may be prepared. The purpose of the study casts are: www.indiandentalacademy.comwww.indiandentalacademy.com

40. To enable special trays and occlusion rims to be constructed if necessary. To examine the occlusion in detail on an articulator. By use of a surveyor, to plan the path of insertion of the proposed denture, arrive at a tentative design and plan any mouth preparation. www.indiandentalacademy.comwww.indiandentalacademy.com

41. Checking Maxillary Tray For Correct Size Checking Mandibular Tray for Correct Size www.indiandentalacademy.comwww.indiandentalacademy.com

42. Control of Gagging It is usually a mistake to make too big an issue over the making of impressions. The dentist definitely should not bring up the subject of gagging. The dentist should ask whether the patient has had impression made previously. If this is to be the patient‘s first experience a brief description of the procedure should be given. www.indiandentalacademy.comwww.indiandentalacademy.com

43. That the material to be used has the consistency of thick whipped cream and that is sets up to a rubber consistency in several minutes, is usually all the explanation that is necessary. The dentist should proceed in confident, efficient manner. Dentist usually encounter more problems with gagging when they are in initial stages of dental practice and approach the making the impressions with unsure and nervous demeanor. www.indiandentalacademy.comwww.indiandentalacademy.com

44. Procedures that will help prevent Gagging Seating the patient in an upright position with the occlusal plane with the floor correcting the maxillary tray with modeling plastic and leaving sufficient unrelieved modeling plastic at the posterior borders that positive contact can be maintained against the posterior palate during the setting of the alginate. Not overfilling the tray with alginate. www.indiandentalacademy.comwww.indiandentalacademy.com

45. Seating the posterior part of the tray first and then rotating the tray into position thereby forcing excess alginate in an anterior direction rather than out of the posterior border of the tray. Asking the patient to keep the eyes open during the impression procedure This usually reduces the patient tension. Asking the patient to breath through the nose. Asking the patient to keep eyes focused on some small object. Giving all instructions to the patient in a firm controlled manner. www.indiandentalacademy.comwww.indiandentalacademy.com

46. Having the patient use astringent mouth rinse and cold water rinses before the impression is made. The use of an anesthetic spray is usually contraindicated because it will cause numbness of the tongue and palate and may contribute to the urge to gag. Most gagging problems are psychologic rather than physical, and confidence in the dentist will help eliminate many of them. www.indiandentalacademy.comwww.indiandentalacademy.com

47. Control of Saliva Alginate has a tendency to stick to teeth that are too dry. Therefore the teeth should not be air dried before making an impression. However, excessive amounts of saliva, particularly of the thick mucous type, will displace the alginate impression material and will contribute to an inaccurate impression. www.indiandentalacademy.comwww.indiandentalacademy.com

48. The saliva can be controlled for most patients by having the patient rinse cold water and then packing the mouth with 2x2 inch gauze that has been unfolded to form a strip of 2-inch gauze. In the maxillary arch one gauze strip is placed in the right buccal vestibule and another in the left vestibule. www.indiandentalacademy.comwww.indiandentalacademy.com

49. The patient can be asked to lightly hold a third piece of gauze in the palate. Because too much force by the patient may displace the tissue to be recorded in the impression, the dentist may prefer to wipe the palatal area just before making the impression. www.indiandentalacademy.comwww.indiandentalacademy.com

50. In the mandibular arch one gauze strip is placed in each of the buccal vestibules and another is placed in the linguoalveolar sulcus by having the patient raise the tongue, placing the gauze in the sulcus, and then having the patient relax the tongue to hold the gauze in position. The gauze is removed immediately before the impression is made. www.indiandentalacademy.comwww.indiandentalacademy.com

51. A few patients secrete an excessive amount of thick mucinous saliva from the palatal salivary glands. This heavy saliva displaces the alginate and results in an inaccurate and rough surface to the impression. These patients should be instructed to rinse with an astringent mouth rinse. The 2x2 inch sponges dampened in warm water should be used to place pressure over the posterior palate in an attempt to milk the glands. www.indiandentalacademy.comwww.indiandentalacademy.com

52. This is followed by an ice water rinse immediately before the impression is made. In rare instances the patient will secrete such copious amounts of saliva that impression making becomes extremely difficult if not impossible. www.indiandentalacademy.comwww.indiandentalacademy.com

53. The use of an antisialagogues in combination with mouth rinse and gauze packs effectively controls this salivation. A 15 mg propantheline bromide (pro- banthine) tablet taken 30 minutes before the impression appointment will also help control the excessive salivation. www.indiandentalacademy.comwww.indiandentalacademy.com

54. These drugs should never be prescribed in the presence of medical contraindications such as glaucoma, cardiac conditions in which any increase in the heart rate is to be avoided. www.indiandentalacademy.comwww.indiandentalacademy.com

55. Mixing Impression Material Alginate may be mixed by hand spatulation, mechanical spatulation, or mechanical spatulation under vacuum. The objective is to obtain a smooth, bubble- free mix of alginate. In hand spatulation a measured amount of distilled water at approximately 22 °C is placed in a rubber mixing bowl The pre-weighed alginate powder is sifted from its container into the water. www.indiandentalacademy.comwww.indiandentalacademy.com

56. The mixing should begin slowly using a stiff, broad - bladed spatula.When the powder is thoroughly wet, the speed of the spatulation should be increased The spatula should crush the material against the sides of the bowl to ensure that the material is completely mixed. The spatulation should continue for a minimum of 45 seconds. www.indiandentalacademy.comwww.indiandentalacademy.com

57. The strength of the gel can be reduced to 50 % if the mixing is not complete. Insufficient spatulation can result in failure of the ingredients to dissolve sufficiently. Then the chemical reaction of changing from sol to gel will not proceed uniformly throughout the mass of alginate. An incompletely spatulated mix will appear lumpy and granular and will have numerous areas of trapped air. www.indiandentalacademy.comwww.indiandentalacademy.com

58. Complete spatulation will result in a smooth, creamy mixture. The mixing should be completed by wiping the alginate against the side of the bowl with the spatula to remove any trapped air. The most consistent method of making a smooth, bubble- free mix is mechanical spatulation under vacuum. www.indiandentalacademy.comwww.indiandentalacademy.com

59. The pre-weighed powder is added to the pre-measured water in the mechanical mixing bowl .The powder is thoroughly incorporated into water by hand spatulation. The mix is then mechanically spatulated under 20 pounds of vacuum for 15 seconds. www.indiandentalacademy.comwww.indiandentalacademy.com

60. Longer spatulation will result in a greatly reduced setting time of the alginate and could affect the strength of the gel. www.indiandentalacademy.comwww.indiandentalacademy.com

61. Loading the Impression Tray Small increments of the impression material should be placed in the tray and forced under the rim lock. Placing too large a portion of alginate at one time increases the possibility of trapping air The tray should be filled to the level with the flanges of the tray. Overfilling should be avoided. www.indiandentalacademy.comwww.indiandentalacademy.com

62. Making the Impression The mandibular impression is made first because it usually entails less patient discomfort Patient confidence is increased when an impression has been successfully completed while holding the tray with the left hand the dentist uses the right hand to remove the gauze pads from the patient’s mouth. www.indiandentalacademy.comwww.indiandentalacademy.com

63. The syringe is used to inject the impression material over the occlusal surface of the teeth and into the vestibular and alveolingual sulcus areas. The impression material will remain in place if the tissues are fairly dry. A tendency for the alginate to form a ball and not remain where placed indicates that the tissues are too moist and that voids are likely to be present in the impression. www.indiandentalacademy.comwww.indiandentalacademy.com

64. There is not enough time to repack the mouth before gelation begins, so the impression procedure should be completed. The impression should be carefully inspected and if voids are present in critical areas, the impression procedure should be repeated. Packing the mouth with more or larger gauze pads and avoiding removal of the gauze until ready to apply the alginate will usually prevent this problem. www.indiandentalacademy.comwww.indiandentalacademy.com

65. The layer of alginate applied with the syringe should be 3 to 4 mm thick; If it is too thin, the heat of the tissues of the oral cavity may cause the material to set before the tray is seated, resulting in a layered impression. www.indiandentalacademy.comwww.indiandentalacademy.com

66. The fingers of the left hand that are retracting the right cheeks should depress the lower lip to provide good visibility. When the tray is correctly lined up over the teeth, the patient is asked to protrude the tongue. The tray is carefully seated so that its flanges are below the gingival margins of the teeth. www.indiandentalacademy.comwww.indiandentalacademy.com

67. The tray should not be over seated because this could result in the cusps of the teeth contacting the tray, causing an inaccurate impression. Great care must be exercised in seating the tray if the patient has mandibular tori or other exostoses, or the making of this impression can be a very painful experience for the patient. www.indiandentalacademy.comwww.indiandentalacademy.com

68. As the tray is being seated, the cheeks are pulled out to prevent the trapping of buccal tissues under the tray. The patient is asked to keep the tip of the tongue in contact with the upper surface of the tray during the gelation of the impression material. www.indiandentalacademy.comwww.indiandentalacademy.com

69. The dentist must maintain the position of the tray during the entire gelation period. This can be accomplished most conveniently and effectively by placing the forefinger of each hand on the top of the tray in the premolar area and by placing the thumbs under the patient ‘s chin. www.indiandentalacademy.comwww.indiandentalacademy.com

70. The dentist through tactile sense can maintain an even amount of pressure on the tray even if the patient swallows or opens or closes the mouth. Any movement of the tray during the gelation period will result in an inaccurate impression. Allowing the patient or the assistant to hold the tray or leaving the patient unattended must be avoided. Within 3 to 4 minutes the alginate should be set. www.indiandentalacademy.comwww.indiandentalacademy.com

71. For maxillary impression, the patients is prepared by using the rinses and placing the gauzes pads described for making the mandibular impression. While holding the loaded tray with the left hand the dentist uses the right hand to remove the gauze pads. www.indiandentalacademy.comwww.indiandentalacademy.com

72. Alginate is injected onto the occlusal surfaces and in all vestibular areas as for the mandibular arch. In addition, a fairly large amount should be wiped onto the palate. Failure to accomplish this step will usually result in an impression with a large void in the palatal area. www.indiandentalacademy.comwww.indiandentalacademy.com

73. The loaded maxillary tray is grasped by the thumb and forefinger of the right hand. As the right posterior flange of the impression tray stretches the right corner of the mouth, the dentist ‘s left arm should be behind the patient’s head and headrest so that the thumb and index finger may grasp the left corner of the mouth and distend it slightly to allow the impression tray to enter the mouth in a straight line. www.indiandentalacademy.comwww.indiandentalacademy.com

74. No attempt should be made to seat the tray until the tray is in its correct anteroposterior position. Once the tray is in the mouth, the thumb and forefinger of the left hand should raise the upper lip to allow the dentist to see the relationship between the labial flange of the tray and the anterior teeth or the residual ridge. www.indiandentalacademy.comwww.indiandentalacademy.com

75. The tray must be centered and properly aligned. This position can best be verified by looking at the patient ‘s face from above and observing the position of the handle of the tray. www.indiandentalacademy.comwww.indiandentalacademy.com

76. It should protrude straight from the center of the mouth. After the proper position has been verified the tray is seated by using the fingers of both hands over the premolar areas. As the tray is being seated the cheeks must be lifted outward and upward to prevent the buccal tissues from being trapped under the flanges of the tray. www.indiandentalacademy.comwww.indiandentalacademy.com

77. The lip must also be lifted up and out to allow good visibility and to avoid trapping the lip between the flanges of the tray and the anterior teeth. Care must be taken not to over seat the tray to avoid. contact between the tray and cusp tips of incisal edge of the teeth. www.indiandentalacademy.comwww.indiandentalacademy.com

78. The tray should be stabilized throughout the set of the impression material by keeping light pressure over the premolar areas on both sides of the arch The alginate should set in 3 to 4 minutes. www.indiandentalacademy.comwww.indiandentalacademy.com

79. Effect of movement of tray: Gelation of alginate occurs by a chemical reaction. When mixed with water, the sodium alginate and calcium sulfate in the powder react to form a lattice work of fibrils of insoluble calcium alginate. The heat of the oral tissues accelerates the chemical reaction, causing the alginate next to the tissues to gel first . www.indiandentalacademy.comwww.indiandentalacademy.com

80. If the dentist exerts pressure or allows the tray to move during gelation of the remainder of the alginate, internal stresses are created that can distort the impression as it is removed from the mouth. www.indiandentalacademy.comwww.indiandentalacademy.com

81. Removal of Impression from Mouth: Clinically, the initial set of alginates is determined by a loss of surface tackiness. The impression should be left in the mouth for an additional 2 to 3 minutes to allow the development of additional strength. Early removal of the weak alginate may lead to unnecessary tearing of the impression. www.indiandentalacademy.comwww.indiandentalacademy.com

82. The gel strength doubles during the first 4- minutes after initial gelation. No further strengthening is found after that time. In fact, Impression is left in the mouth for 5 minutes rather than the recommended 2 to 3 minutes after initial gelation exhibits definite distortion. www.indiandentalacademy.comwww.indiandentalacademy.com

83. Most alginates improve their elasticity with time, providing a better opportunity for accurate reproduction of undercuts. Impressions removed too early after initial gelation produce a rough surface of the poured cast. These data indicate the alginate impressions should not be removed from the mouth for at least 2 to 3 minutes after initial gelation. www.indiandentalacademy.comwww.indiandentalacademy.com

84. There are two reliable methods of determining the correct time for removal of the impression 1. A timer can be used to measure the 2 to 3 minute period after initial gelation or 2. A small mound of the original mix of alginate can be placed on a glass or metal surface; when this alginate will fracture cleanly with finger pressure, the impression is ready to be removed from the mouth. www.indiandentalacademy.comwww.indiandentalacademy.com

85. Reasons for Rejecting Impression The following are specific reasons for rejecting and repeating an impression: 1. Bubbles or voids in and around rest preparations. 2. Contact of cusp with the tray, especially when the teeth are involved in the frame work design. 3. Show through between teeth and modeling plastic or modeling plastic and hard palate (if the tray has been modified for an alginate impression) www.indiandentalacademy.comwww.indiandentalacademy.com

86. 4. Voids or bubbles in palatal vault when palatal major4. Voids or bubbles in palatal vault when palatal major connectors are to be constructed.connectors are to be constructed. 5. Peripheral underextension when a denture base has5. Peripheral underextension when a denture base has been designed and a corrected cast impression isbeen designed and a corrected cast impression is not planned.not planned. 6. Interproximal tearing of the impression material6. Interproximal tearing of the impression material when coverage of those teeth has been designed.when coverage of those teeth has been designed. 7. Lack of detail on the impression surface.7. Lack of detail on the impression surface. 8. Any doubt as to the accuracy of the impression.8. Any doubt as to the accuracy of the impression.www.indiandentalacademy.comwww.indiandentalacademy.com

87. Impression Methods: There are basically two dual impression techniques. The physiologic, or functional, impression technique records the ridge portion by placing an occlusal load on the impression tray as the impression is being made. www.indiandentalacademy.comwww.indiandentalacademy.com

88. The underlying s tissues will be displaced because displacement will normally occur under function. The physiologic impression techniques that discussed are as follows: Mc Lean’s and Hindel’s methods, the functional relining method, and the fluid wax method. www.indiandentalacademy.comwww.indiandentalacademy.com

89. The selected pressure impression technique not only equalizes the support between the abutment teeth and the soft tissue, but has the added advantage of directing the force to the portions of the ridge that are most capable of withstanding the force. This is accomplished by providing relief in the impression tray in selected areas and permitting the impression to be recorded. www.indiandentalacademy.comwww.indiandentalacademy.com

92. In those areas of the tray where relief was not provided (the buccal shelf of the mandibular ridge and the buccal slope and crest of the maxillary ridge), greater displacement of the underlying mucosa will occur. www.indiandentalacademy.comwww.indiandentalacademy.com

93. In both the fluid wax functional impression technique and the selected pressure technique an impression of the displaced edentulous ridge is made by using an impression tray attached to the frame work, and the master cast is altered to accommodate the new ridge impression. www.indiandentalacademy.comwww.indiandentalacademy.com

94. For this reason the technique is often referred to as the “Altered cast impression technique” or the “corrected cast impression technique”. www.indiandentalacademy.comwww.indiandentalacademy.com

95. The advantage of the difference inThe advantage of the difference in terminology is doubtful, and theterminology is doubtful, and the descriptive terms minimally displaced referdescriptive terms minimally displaced refer to the situation that has respondedto the situation that has responded favorably and excessively “displaced” tofavorably and excessively “displaced” to that which responds unfavorably are used.that which responds unfavorably are used. www.indiandentalacademy.comwww.indiandentalacademy.com

97. The need for physiologic impressions was first recognized by McLean and others They realized the need of recording the tissues of the residual ridge that would eventually support a distal extension denture base in the functional or supporting form and then relating this functional impression to the remainder of the arch by means of a second impression. www.indiandentalacademy.comwww.indiandentalacademy.com

98. For this dual impression a custom impression tray was constructed over a preliminary cast of the arch, a function impression of the distal extension ridge was made, and then hydrocolloid impression was made with the first impression held in its functional position with finger pressure. www.indiandentalacademy.comwww.indiandentalacademy.com

100. The greatest weakness of the technique was that finger pressure could not produce the same functional displacement of the tissue that biting force produced. The apparent advantage of the technique was lost with this weakness. Many variations of this technique have been developed and advocated, but all require some form of finger loading pressure as the second impression is made. www.indiandentalacademy.comwww.indiandentalacademy.com

102. Hindels and other developed irreversibleHindels and other developed irreversible hydrocolloid trays for the second impression thathydrocolloid trays for the second impression that were provided with holes so that finger pressurewere provided with holes so that finger pressure could be applied through the tray as thecould be applied through the tray as the hydrocolloid impression was made.hydrocolloid impression was made. www.indiandentalacademy.comwww.indiandentalacademy.com

104. The main change that Hindels introducedThe main change that Hindels introduced to McLean ‘s original technique was thatto McLean ‘s original technique was that the impression of the edentulous ridgethe impression of the edentulous ridge was not made under pressure but was anwas not made under pressure but was an anatomic impression of the ridge at restanatomic impression of the ridge at rest made with a free flowing zinc oxidemade with a free flowing zinc oxide eugenol paste.eugenol paste. www.indiandentalacademy.comwww.indiandentalacademy.com

105. As the hydrocolloid second impressionAs the hydrocolloid second impression was being made, however, finger pressurewas being made, however, finger pressure was applied through the holes in the traywas applied through the holes in the tray to the anatomic impression. The pressureto the anatomic impression. The pressure had to be maintained until the alginatehad to be maintained until the alginate was completely set. The two were relatedwas completely set. The two were related to each other, however, as if masticatingto each other, however, as if masticating forces were taking place on the dentureforces were taking place on the denture base.base. www.indiandentalacademy.comwww.indiandentalacademy.com

106. The main purpose of these techniques was to relate an impression of the edentulous ridge to the teeth under a form of functional loading. www.indiandentalacademy.comwww.indiandentalacademy.com

107. A disadvantage of these techniques was that if the action of the retentive clasps of the partial denture is sufficient to maintain the denture base in relation to the soft tissues in the displaced or functional form, interruption of blood circulation would ensue, with possible adverse soft tissue reaction and resorption of the underlying bone. www.indiandentalacademy.comwww.indiandentalacademy.com

108. If the action of the retentive clasps was not sufficient to maintain that functional relationship of the denture base to the soft tissue, when the partial denture was in the mouth at rest, the partial denture would be slightly occlusal to the position it would assume when occlusal force was applied. www.indiandentalacademy.comwww.indiandentalacademy.com

110. This means that each time the patient ‘s teeth came together, the remaining natural teeth should contact only after the mucosa had been displaced to the position at which the impression was made. This early or premature contact of the artificial teeth is objectionable to many patients. www.indiandentalacademy.comwww.indiandentalacademy.com

112. Most methods of obtaining a physiologicMost methods of obtaining a physiologic impression for support of a distal extensionimpression for support of a distal extension denture base accomplish the impressiondenture base accomplish the impression procedure before completion of the denture,procedure before completion of the denture, usually following the construction of theusually following the construction of the framework.framework. It is possible, however, to obtain the sameIt is possible, however, to obtain the same results after the partial denture has beenresults after the partial denture has been completed.completed. The technique is referred to as a functionalThe technique is referred to as a functional reline. It consists of adding a new surface to thereline. It consists of adding a new surface to the inner, or tissue, side of the denture base.inner, or tissue, side of the denture base. www.indiandentalacademy.comwww.indiandentalacademy.com

113. The procedure may be accomplishedThe procedure may be accomplished before the insertion of the partial denture,before the insertion of the partial denture, or it may be done at a later date f becauseor it may be done at a later date f because of bone resorption, the denture base noof bone resorption, the denture base no longer fits the ridge adequately.longer fits the ridge adequately. Although the functional reline has manyAlthough the functional reline has many advantages, and fir correcting the fit ofadvantages, and fir correcting the fit of denture base that has been worn for adenture base that has been worn for a period of time is essential, it does presentperiod of time is essential, it does present many difficulties.many difficulties. www.indiandentalacademy.comwww.indiandentalacademy.com

114. The main problems that arise are caused byThe main problems that arise are caused by failure to maintain the correct relationshipfailure to maintain the correct relationship between the framework and the abutment teethbetween the framework and the abutment teeth during the impression procedure and failure toduring the impression procedure and failure to maintain accurate occlusal contact following themaintain accurate occlusal contact following the reline.reline. The procedures for relining and rebasing anThe procedures for relining and rebasing an existing removable partial denture are discussedexisting removable partial denture are discussed in detail.in detail. www.indiandentalacademy.comwww.indiandentalacademy.com

115. The functional reline discussed here is that doneThe functional reline discussed here is that done to a completed partial denture before initialto a completed partial denture before initial insertion for the purpose of perfecting the fit ofinsertion for the purpose of perfecting the fit of the denture base to the residual ridge.the denture base to the residual ridge. The partial denture is constructed on the castThe partial denture is constructed on the cast made from a single impression, usually withmade from a single impression, usually with irreversible hydrocolloid. This is an anatomicirreversible hydrocolloid. This is an anatomic impression, and no attempt is made to alter it orimpression, and no attempt is made to alter it or produce a functional impression of theproduce a functional impression of the edentulous ridge.edentulous ridge. www.indiandentalacademy.comwww.indiandentalacademy.com

116. To allow room for the impression material between the denture base and the ridge, space must be provided. One of the most accurate methods of ensuring uniform space for the impression is to adapt a soft metal spacer over the ridge on the cast before processing the denture base. After processing, the metal is removed leaving an even space between the base and the edentulous ridge. www.indiandentalacademy.comwww.indiandentalacademy.com

118. The portion of the technique that introduces theThe portion of the technique that introduces the greatest hazard is the making of the relinegreatest hazard is the making of the reline impression. The patient must maintain the mouth inimpression. The patient must maintain the mouth in a partially open position while the border moldinga partially open position while the border molding and impression are being accomplished because:and impression are being accomplished because: 1.The border tissues, cheek, and tongue are thus1.The border tissues, cheek, and tongue are thus best controlled andbest controlled and 2.The relationship between the partial denture frame2.The relationship between the partial denture frame work and the teeth must be observed.work and the teeth must be observed. www.indiandentalacademy.comwww.indiandentalacademy.com

121. The functional reline method of improvingThe functional reline method of improving the fit of the denture base to the residualthe fit of the denture base to the residual ridge, although fraught with potentialridge, although fraught with potential danger, has the advantage that thedanger, has the advantage that the amount of soft tissue displacement can beamount of soft tissue displacement can be controlled by the amount of relief given tocontrolled by the amount of relief given to the modeling plastic before the finalthe modeling plastic before the final impression is made. The greater the reliefimpression is made. The greater the relief the less will be the tissue displacement.the less will be the tissue displacement. www.indiandentalacademy.comwww.indiandentalacademy.com

123. The fluid wax impression may be used toThe fluid wax impression may be used to make a reline impression for an existingmake a reline impression for an existing partial denture or to correct the distalpartial denture or to correct the distal extension edentulous ridge portion of theextension edentulous ridge portion of the original master cast.original master cast. www.indiandentalacademy.comwww.indiandentalacademy.com

124. OBJECTIVES To obtain maximum extension of the peripheral borders of the denture base while not interfering with the function of movable border tissues. To record the stress bearing areas of the ridges in their functional form. To record non pressure bearing areas in their anatomic form. www.indiandentalacademy.comwww.indiandentalacademy.com

125. The fluid wax impression is made with theThe fluid wax impression is made with the open mouth technique so that there is lessopen mouth technique so that there is less danger of over displacement of ridgedanger of over displacement of ridge tissue by occlusal or vertical forces.tissue by occlusal or vertical forces. www.indiandentalacademy.comwww.indiandentalacademy.com

126. The term fluid wax is used to denoteThe term fluid wax is used to denote waxes that are firm at room temperaturewaxes that are firm at room temperature and have the ability to flow at mouthand have the ability to flow at mouth temperature.temperature. www.indiandentalacademy.comwww.indiandentalacademy.com

127. The most frequently used fluid waxes are Iowa wax, developed by Dr.Smith at the University of Iowa, and Korrecta Wax no 4, developed by Dr. 0. C. and S. G Applegate at the Universities of Michigan and Detroit, respectively. Korrecta wax no. 4 is slightly more fluid than Iowa wax. www.indiandentalacademy.comwww.indiandentalacademy.com

128. The key to the use of fluid wax lies in two areas: space and time. Space refers to the amount of relief provided between the impression tray and the edentulous ridge. :1 to 2 mm is desired. Each time the tray is introduced into the mouth, it must remain in place 5 to 7 minutes to allow the wax to flow and to prevent buildup of pressure under the tray with resulting distortion or displacement of the tissue. www.indiandentalacademy.comwww.indiandentalacademy.com

129. The clinical technique for the use of the fluidThe clinical technique for the use of the fluid wax calls for the water bath maintained atwax calls for the water bath maintained at 51° to 54° C into which a container of the51° to 54° C into which a container of the wax is placed. At this temperature the waxwax is placed. At this temperature the wax becomes fluid. The wax is painted on thebecomes fluid. The wax is painted on the tissue side of the impression tray with atissue side of the impression tray with a brush.brush. www.indiandentalacademy.comwww.indiandentalacademy.com

131. The peripheral extension of theThe peripheral extension of the impression tray is critical. The bordersimpression tray is critical. The borders must be short of all movable tissue, but notmust be short of all movable tissue, but not more than 2 mm short because the fluidmore than 2 mm short because the fluid wax does not have sufficient strength towax does not have sufficient strength to support itself beyond that distance.support itself beyond that distance. www.indiandentalacademy.comwww.indiandentalacademy.com

132. Inaccuracies will develop if the wax isInaccuracies will develop if the wax is extended beyond that length. Originally aextended beyond that length. Originally a harder wax, Korrecta Wax no:1 was usedharder wax, Korrecta Wax no:1 was used to support the softer No.4 wax ifto support the softer No.4 wax if extension beyond that length wasextension beyond that length was needed. The no.1 wax however, is noneeded. The no.1 wax however, is no longer available.longer available. www.indiandentalacademy.comwww.indiandentalacademy.com

133. The wax is painted on the surface of the tray to aThe wax is painted on the surface of the tray to a depth slightly greater than the amount of reliefdepth slightly greater than the amount of relief provided. The tray is seated in the mouth. Theprovided. The tray is seated in the mouth. The patients must remain with the mouthpatients must remain with the mouth approximately half open for about 5 minutes. Theapproximately half open for about 5 minutes. The tray is removed, and the wax examined fortray is removed, and the wax examined for evidence of tissue contact. Where tissue contactevidence of tissue contact. Where tissue contact is present the wax surface will be dull.is present the wax surface will be dull. www.indiandentalacademy.comwww.indiandentalacademy.com

134. If needed additional wax is painted on those areasIf needed additional wax is painted on those areas not in contact with the tissue. The tray must remainnot in contact with the tissue. The tray must remain in the mouth a minimum of 5 minutes after eachin the mouth a minimum of 5 minutes after each addition of wax. The peripheral extensions areaddition of wax. The peripheral extensions are developed by tissue movements by the patient. Fordeveloped by tissue movements by the patient. For the buccal and distobuccal extension in athe buccal and distobuccal extension in a mandibular impression the patient must move to amandibular impression the patient must move to a wide- open-mouth position. This will activate thewide- open-mouth position. This will activate the buccinator muscle and pterygomandibular raphebuccinator muscle and pterygomandibular raphe and produce the desired border anatomy.and produce the desired border anatomy. www.indiandentalacademy.comwww.indiandentalacademy.com

135. For the proper lingual extension for a mandibularFor the proper lingual extension for a mandibular impression the patient must thrust the tongueimpression the patient must thrust the tongue into the cheek opposite the side of the archinto the cheek opposite the side of the arch being border molded. The distolingual extensionbeing border molded. The distolingual extension is obtained by having the patient press theis obtained by having the patient press the tongue forward against the lingual surface of thetongue forward against the lingual surface of the anterior teeth.anterior teeth. www.indiandentalacademy.comwww.indiandentalacademy.com

136. These movements must be repeated aThese movements must be repeated a number of times after the impression hasnumber of times after the impression has been in the mouth long enough for thebeen in the mouth long enough for the wax to have softened sufficiently to flow.wax to have softened sufficiently to flow. www.indiandentalacademy.comwww.indiandentalacademy.com

137. When the impression evidences complete tissueWhen the impression evidences complete tissue contact and when the anatomy of the limitingcontact and when the anatomy of the limiting border structure is evident, the impression shouldborder structure is evident, the impression should be replaced in the mouth for 12 minutes. This finalbe replaced in the mouth for 12 minutes. This final time to be certain that the wax has completelytime to be certain that the wax has completely flowed and released any pressure that may beflowed and released any pressure that may be present.present. www.indiandentalacademy.comwww.indiandentalacademy.com

139. The finished impression must be handledThe finished impression must be handled carefully and the new cast poured as sooncarefully and the new cast poured as soon as possible because the wax is fragile andas possible because the wax is fragile and subject to distortion.subject to distortion. www.indiandentalacademy.comwww.indiandentalacademy.com

140. The fluid wax impression technique can produce an accurate impression if the technique is properly executed The procedure is time consuming, but if the time periods are not followed accurately, an impression with excessive tissue displacement will result. www.indiandentalacademy.comwww.indiandentalacademy.com

142. Corrected castCorrected cast www.indiandentalacademy.comwww.indiandentalacademy.com

143. Technique 1. Fashioning custom acrylic resin impression tray1. Fashioning custom acrylic resin impression tray to retention lattice work of removable partialto retention lattice work of removable partial denture.denture. 2. Developing denture base impression on these2. Developing denture base impression on these trays.trays. 3. Removing edentulous ridge from master cast.3. Removing edentulous ridge from master cast. 4. Securing framework with developed bases to4. Securing framework with developed bases to master cast.master cast. 5. Pouring the impression with dental stone.5. Pouring the impression with dental stone. www.indiandentalacademy.comwww.indiandentalacademy.com

145. Modifications: Variation of altered cast technique by Robert. P Renner After the fit of framework has been refined intra orally, the border of residual ridge are outlined on master cast. A small residual ridge are outlined on master cast. A small segment of bone plate wax is warmed over Bunsen burner and adapted to penciled outline. The wax will act as shim / space between residual ridge and custom tray. www.indiandentalacademy.comwww.indiandentalacademy.com

146. Retention latticework of removable partial denture framework is warmed over a frame and framework is seated back on master cast. It should be freed in one or two areas so that the auto polymerizing acrylic resin tray will be adapted to it. www.indiandentalacademy.comwww.indiandentalacademy.com

147. Apply separating medium, allow it to dry and autodry and auto polymerizing acrylic resin material is mixed andpolymerizing acrylic resin material is mixed and adapted to edentulous area of master cast, anyadapted to edentulous area of master cast, any excess material is trimmed.excess material is trimmed. When acrylic material is polymerized, assembly isWhen acrylic material is polymerized, assembly is placed in warm slurry water to soften and removeplaced in warm slurry water to soften and remove wax spacer. Border molding is done. Vent holeswax spacer. Border molding is done. Vent holes are placed in order to reduce hydrostatic pressureare placed in order to reduce hydrostatic pressure developed between tray and tissues. Finaldeveloped between tray and tissues. Final impression is accomplished using metallic oxideimpression is accomplished using metallic oxide paste or rubber base impression material.paste or rubber base impression material. www.indiandentalacademy.comwww.indiandentalacademy.com

149. Procedure 11. A metallic paste impression is received in the laboratory. Remove impression material from the framework in areas that contact the teeth. www.indiandentalacademy.comwww.indiandentalacademy.com

150. 2. Trim the master cast so that the functional impression can be poured in correct relationship to the remaining teeth. www.indiandentalacademy.comwww.indiandentalacademy.com

151. 3. Seat the framework on the cast, and inspect it for contact between the functional impression and the cast. If contact is present, the cast must be trimmed until clearance is present. www.indiandentalacademy.comwww.indiandentalacademy.com

152. 4. Cut retention grooves into the areas of the cast that will be corrected when the functional impression is poured www.indiandentalacademy.comwww.indiandentalacademy.com

153. 5. Adapt and seal beading wax 2 to 3 mm above the borders of the functional impression www.indiandentalacademy.comwww.indiandentalacademy.com

154. 6. Seat the framework on the cast, and secure it in position with sticky wax www.indiandentalacademy.comwww.indiandentalacademy.com

155. 7.7. Seal the leading edge of the impression to the cast to prevent dental stone from flowing onto the teeth when the cast is poured. www.indiandentalacademy.comwww.indiandentalacademy.com

156. 8. Use strips of base plate wax to compete the boxing of the impression on the buccal and lingual aspects www.indiandentalacademy.comwww.indiandentalacademy.com

157. 9. A tight seal of beading and boxing wax is critical in this pouring method and is difficult to attain. Test the completeness of the seal by pouring clear slurry water into the boxed impression. A difficult area to seal is the relief area under the major connector. www.indiandentalacademy.comwww.indiandentalacademy.com

158. 10. Place the cast and impression in clear slurry water to soak for 4 to 5 minutes in preparation for pouring the corrected cast. www.indiandentalacademy.comwww.indiandentalacademy.com

159. 11. Measure and mix the improved dental stone. Pour the boxed impression by adding small increments of stone and using light vibration. Sufficient stone must be used to support the heel of the cast. www.indiandentalacademy.comwww.indiandentalacademy.com

160. 12. Remove the boxing and luting materials from the corrected cast. Shape the cast on a model trimmer. www.indiandentalacademy.comwww.indiandentalacademy.com

161. 13.13. Soften the impressionSoften the impression material in warm water, andmaterial in warm water, and remove the framework and impression tray from theremove the framework and impression tray from the corrected cast.corrected cast. www.indiandentalacademy.comwww.indiandentalacademy.com

162. 14. Burn the impression tray off the framework and place it on the cast. Smooth the land area of the cast, and the corrected cast procedures is complete. www.indiandentalacademy.comwww.indiandentalacademy.com

163. AN ALTERED CAST PROCEDURE TO IMPROVE TISSUE SUPPORT FOR REMOVABLE PARTIAL DENTURES - R J. LEUPOLD, F J. KRATOCHVIL : JPD 1965(15), 4, 672- 678 www.indiandentalacademy.comwww.indiandentalacademy.com

166. SINGLE- TRAY DUAL- IMPRESSION TECHNIQUE FOR DISTAL EXTENSION PARTIAL DENTURES JOSEPH A. R- JPD 1970(24,1,41-46) www.indiandentalacademy.comwww.indiandentalacademy.com

170. IMPRESSION TECHNIQUE FOR MAXILLARY REMOVABLE PARTIAL DENTURES - C D. LEACH & T E. DONOVAN JPD 1983 (50)2,283-285 www.indiandentalacademy.comwww.indiandentalacademy.com

172. AN ALTERED CAST IMPRESSION TECHNIQUE THAT ELIMINATES CONVENTIONAL CAST DISSECTING & IMPRESSSION BOXING -M S. CHEN AND et al - JPD 1987 (57) 4, 471-474 www.indiandentalacademy.comwww.indiandentalacademy.com

178. A MODIFICATION OF THE ALTERED CAST TECHNIQUE -RICHARD BAUMAN & JAMES .D B – JPD 1982(47) 2, 212-213 www.indiandentalacademy.comwww.indiandentalacademy.com

180. AN IMPRESSION TECHNIQUE TO MAKE NEW MASTER CAST FOR AN EXISTING REMOVABLE PARTIAL DENTURE -PHILIP J. R - JPD 1992 (67) 4, 488-490 www.indiandentalacademy.comwww.indiandentalacademy.com

186. For the production of accurate master cast the impression technique far out weights the selection of the impression material. No available knowledge of the person making the impression material will produce results greater than the skill and knowledge of the person making the impression. www.indiandentalacademy.comwww.indiandentalacademy.com

187. ““ Good technique pays off ” is not merely a motto to hang on a wall but these are words of wisdom. Good technique will indeed result in better treatment and improved patient care. www.indiandentalacademy.comwww.indiandentalacademy.com

188. 1. Glossary of Prosthodontic Terms -8 th Edn, 2005.1. Glossary of Prosthodontic Terms -8 th Edn, 2005. 2.2. Stewart, Rudd, KuebkerStewart, Rudd, Kuebker : Clinical Removable Partial: Clinical Removable Partial Prosthodontics.Prosthodontics. 3.3. McGivney GP, Alan B Carr David T BrownMcGivney GP, Alan B Carr David T Brown :: McCracken’s Removable Partial Dentures-11 th Edn.McCracken’s Removable Partial Dentures-11 th Edn. 4.4. Joseph E. Grasso, Ernest L. MillerJoseph E. Grasso, Ernest L. Miller : Removable Partial: Removable Partial Prosthodontics.Prosthodontics. 5.5. Alan A. Grant, Wesley JohnsonAlan A. Grant, Wesley Johnson : Removable Partial: Removable Partial Dentures.Dentures. www.indiandentalacademy.comwww.indiandentalacademy.com

189. 6.6. F. James KratochvilF. James Kratochvil : Partial Removable Prosthodontics.: Partial Removable Prosthodontics. 8.8. Robert P. Renner, Louis J. BoucherRobert P. Renner, Louis J. Boucher : Removable Partial: Removable Partial Dentures.Dentures. 9.9. Kenneth D Rudd, MorrowKenneth D Rudd, Morrow: Dental Lab, Procedure for: Dental Lab, Procedure for Removable Partial Dentures.Removable Partial Dentures. 10.10. DavenportDavenport: Color Atlas of Removable Partial Dentures.: Color Atlas of Removable Partial Dentures. 11.11. BatesBates: Removable Denture Construction.: Removable Denture Construction. 12.12. OsborneOsborne: Partial Dentures.: Partial Dentures. www.indiandentalacademy.comwww.indiandentalacademy.com

190. AN ALTERED CAST PROCEDURE TO IMPROVE TISSUE SUPPORT FOR REMOVABLE PARTIAL DENTURES - R J. LEUPOLD, F J. KRATOCHVIL : JPD 1965(15), 4, 672- 678 SINGLE- TRAY DUAL- IMPRESSION TECHNIQUE FOR DISTAL EXTENSION PARTIAL DENTURES JOSEPH A. R- JPD 1970(24,1,41-46) IMPRESSION TECHNIQUE FOR MAXILLARY REMOVABLE PARTIAL DENTURES - C D. LEACH & T E. DONOVAN JPD 1983 (50)2,283-285 AN ALTERED CAST IMPRESSION TECHNIQUE THAT ELIMINATES CONVENTIONAL CAST DISSECTING & IMPRESSSION BOXING -M S. CHEN AND et al - JPD 1987 (57) 4, 471-474 A MODIFICATION OF THE ALTERED CAST TECHNIQUE -RICHARD BAUMAN & JAMES .D B – JPD 1982(47) 2, 212-213 AN IMPRESSION TECHNIQUE TO MAKE NEW MASTER CAST FOR AN EXISTING REMOVABLE PARTIAL DENTURE -PHILIP J. R - JPD 1992 (67) 4, 488-490www.indiandentalacademy.comwww.indiandentalacademy.com

191. For more details please visitFor more details please visit www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com