Impression techniques in Removable partial denture.pptx
- 1. Impression techniques in Removable partial denture Presented by- Dr Vaishali Shrivastava 1st year post graduate student Department of prosthodontics, crown & bridge and implantology 1
- 2. CONTENTS 2 • Introduction • Impression materials • Impression tray selection , extension and techniques • Anatomic form and functional form • Concept of functional impression • Factors Influencing Support of the Distal Extension Base • Methods of functional impression • Alternate techniques • Recent advancements • Conclusion • References
- 3. What is an impression? 3 : a negative likeness or copy in reverse of the surface of an object; an imprint of the teeth and adjacent structures for use in dentistry -GPT 9 An impression of partially edentulous arch must record accurate the teeth in anatomic form and surrounding tissues in a functional form
- 4. IMPRESSION MATERIAL 4 Phillips science of dental materials edition 12
- 5. POSITION OF PATIENT AND OPERATOR Patient position Head and neck are in line with the trunk. Head is upright, occiput resting firmly on the headrest of the chair Operator position Right rear or rear position Height of the chair Patient’s mouth should be in level with the operator’s elbow Patient position Head and neck are in line with the trunk. Head is upright, occiput resting firmly on the headrest of the chair Operator position Right front position Height of the chair Patient’s mouth should be in level with the operator’s shoulder for maxillary impressions for mandibular impressions 5
- 6. IMPRESSION TRAY SELECTION AND EXTENSION TRAY a receptacle into which suitable impression material is placed to make a negative likeness; . a device that is used to carry, confine, and control impression material while making an impression GPT9 stock tray : a metal or plastic prefabricated impression tray typically available in various sizes and used principally for preliminary impressions GPT9 6
- 7. IMPRESSION TRAY SELECTION AND EXTENSION There should be 5 to 7 mm of space between the internal surfaces of the tray and the facial surfaces of the teeth and soft tissues This space is necessary so that in case of undercuts, the impression can spring over the undercuts. 7
- 8. Extending an impression tray Softened modeling plastic is carefully adapted to the impression tray 8
- 11. Anatomical and functional form of ridge 11
- 12. Indications for Functional impression Mandibular distal extension partial dentures •Mainly kennedy’s class I & II edentulous arches “recording the functional form of residual ridge to obtain uniformity of support when the functional load is applied Functional Impression SUPPORT OF DISTAL EXTENSION BASED PARTIAL DENTURE minor support abutment teeth major support elastic fibrous connective tissue pad 12
- 13. (1) record and relate the tissues under uniform loading, (2) distribute the load over as large an area as possible (3) accurately delineate the peripheral extent of the denture base Therefore, the impression of residual ridge must 13
- 14. Factors Influencing Support of the Distal Extension Base • Quality of soft tissue covering edentulous ridge • Type of bone in the denture-bearing area • Design of the prosthesis • Amount of tissue coverage of denture base • Anatomy of the denture-bearing area • Fit of denture base 14
- 15. ANATOMIC IMPRESSION • irreversible hydrocolloid • elastomeric impression materials • reversible hydrocolloid FUNCTIONAL IMPRESSIONS • fluid waxes • metallic pastes • elastomeric impression materials • soft liner Materials 15
- 16. Dual impression techniques Physiologic impressions Mclean-hindels method Functional reline method Selected pressure impression Fluid wax method Stewart’s clinical removable partial prosthodontics 4th edition Methods of functional impression 16
- 17. McLean physiologic impression 17 • The need for physiologic impressions was first proposed by McLean and others. • It is used to record the tissue of residual ridge that support a distal extension of denture base or its supporting form and as the second impression of arch remainder. • second impression pick up impression / over impression
- 18. Custom tray fabrication with occlusal rims Pickup impression Finger pressure needed during pickup impression PROCEDURE 18
- 19. Disadvantages 19 The bite force exerted by the patient cannot be controlled by the operator. The bite force need not be same as the masticatory force The pressure exerted while making the overimpression need not be the same as the bite force. Hence difference in displacement. Annals of Prosthodontics & Restorative Dentistry, April-June 2017:3(2):52-56
- 20. HINDEL’S MODIFICATION OF MCLEANS TECHNIQUE 20 1
- 21. Disadvantages 21 Dentures made using functional impressions will constantly pressurize the soft tissues Dentures made using functional impressions get occlusally displaced at rest due to tissue rebounce. This may lead to premature contacts
- 22. The functional relining method 22 • It consists of adding a new surface to the intaglio of the denture base. • The patient must keep the mouth partially open throughout the procedure to permit appropriate tissue control and the required visual assessment.
- 23. metal spacer may be placed on the dental cast to provide space for a functional reline. After the denture base has been processed, the metal spacer is removed. 23
- 24. The modeling plastic impression is completed Modeling plastic is removed 1mm from the intaglio surface before the final impression is made. Final impression with free-flowing zinc oxide–eugenol paste or a light-bodied polysulfide rubber base. 24
- 25. Disadvantages 25 • Failure to maintain the correct relationship between the framework and the abutment teeth during the impression procedure • failure to achieve accurate occlusal contact following the reline procedure. • It improves the fit of the denture after bone resorption. • The tissue surface of the metal framework can be relined after insertion Advantages
- 26. Corrected cast procedure for fluid wax technique 26 • Adding an impression tray • Correcting peripheral extensions • Border molding the impression tray • Relieving the tray and making the impression
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- 29. IMPRESSION PROCEDURE FOR FLUID WAX TECHNIQUE 29 OBJECTIVES (1) to obtain maximum extension of the peripheral borders while not interfering with the function of movable border tissues, (2) to record the stress-bearing areas of the ridge in their functional form (3) to record non-pressure-bearing areas in their anatomic form. The fluid wax impression is made using an open-mouth technique so that there is less danger of overdisplacement of the soft tissues by occlusal or vertical forces
- 30. MOST FREQUENTLY USED WAXES 30 Iowa wax Developed by Dr Earle S. Smith at the University of Iowa, Korrecta Wax No. 4, developed by Drs O. C. and S. G. Applegate at the Universities of Michigan and Detroit. Korrecta Wax No. 4 is slightly more fluid than Iowa wax
- 31. • water bath maintained at 51°C to 54°C (125°F to 130°F), into which a container of the wax is placed • Fluid wax is painted onto the intaglio surface of a tray or denture base. Subsequently, the framework will be seated in the oral cavity. completed impression The impression should be left in the mouth for 12 minutes to ensure that the wax has completely flowed and released any pressure that may be present 31
- 32. Disadvantages 32 • The wax fluid technique is time consuming. There is needed of accurately followed timing of procedures. • The excessive tissue displacement might be result to the impression if the timing period is not followed properly as mentioned.
- 33. Selected pressure impression 33 Advantages- The resorption rate of ridge will be lowered due to the nonstressed relieving areas • In some patients, the soft tissues covering the ridge will be easily displaced.To obtain more relief and prevent excessive tissue displacement, holes may be drilled through the impression tray • The selected pressure impression technique results in a denture base that is closely adapted to, and in firm contact with, the tissues covering the buccal shelf area. • In contrast, the crestal portion of the denture base is lightly adapted to the soft tissues, resulting in minimal force application.
- 34. The mandibular impression tray is selectively reduced at the ridge crest. This provides additional room for impression material and minimizes displacement of the soft tissue Holes may be placed in the tray to further minimize the pressures generated during impression procedures. 34
- 35. Preparing the original cast and pouring a corrected cast (Altered cast technique) 35 • This involves altering only the distal extension part of the master cast after a functional impression is made of the residual ridges. • For the functional reline, ridge correction and selective pressure impressions altered cast technique is used.
- 36. Fig1 fig 2 fig3 Fig 4 36 Fig 5 Fig 6
- 37. 37 • Single tray dual impression technique ALTERNATE TECHNIQUES Rapuano JA. Single-tray dual-impression technique for distal extension partial dentures. The Journal of Prosthetic Dentistry. 1970 Jul 1;24(1):41-6. Joseph A. Rapuano,
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- 41. • Impression technique for maxillary removable partial dentures Leach CD, Donovan TE. Impression technique for maxillary removable partial dentures. The Journal of Prosthetic Dentistry. 1983 Aug 1;50(2):283-6. 41 AUTHOR- Clyde D. Leach, D.D.S. T. E. Donovan, D.D.S. University of Southern California, Los Angeles, Calif.
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- 44. • A new procedure for separating the edentulous distal extension portion from the master cast when an altered cast is made Ansari IH. A new procedure for separating the edentulous distal extension portion from the master cast when an altered cast is made. The Journal of Prosthetic Dentistry. 1994 Dec 1;72(6):666-9. 44 AUTHOR- Izharul Haque Ansari, BDS, MDS’ Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan
- 45. Ansari IH. A new procedure for separating the edentulous distal extension portion from the master cast when an altered cast is made. The Journal of Prosthetic Dentistry. 1994 Dec 1;72(6):666-9. . Boxed elastomeric final impression in which edentulous ridges have been separated with contoured baseplate wax (A arrows) and sealed to anatomic contour of impression at base. Triangular wax bars (arrows) are attached to make dovetails (three separate compartments of impression). 45
- 46. Ansari IH. A new procedure for separating the edentulous distal extension portion from the master cast when an altered cast is made. The Journal of Prosthetic Dentistry. 1994 Dec 1;72(6):666-9. 46
- 47. (1) the edentulous portion can be separated easily, (2) there is no need to saw the cast or make dovetails for retention of stone (3) the edentulous portion can be separated even if cast is wet, because it is difficult to saw a wet cast Advantages The disadvantage of this procedure is that the cast cannot he used with hydrocolloid impression materials because they require quick pouring of the impression, and the impression cannot be boxed because it will distort as a result of pressure. Ansari IH. A new procedure for separating the edentulous distal extension portion from the master cast when an altered cast is made. The Journal of Prosthetic Dentistry. 1994 Dec 1;72(6):666-9. 47
- 48. • A simple technique for boxing impressions for fabrication of altered casts Jahangiri, Leila & Mascarenhas, Patrick & Kitzis, Donald. (2001). A simple technique for boxing impressions for fabrication of altered casts. The Journal of prosthetic dentistry. 85. 519-20. 10.1067/mpr.2001.114264. 48 AUTHOR- Leila Jahangiri, BDS, DMD, MMSc, Patrick Mascarenhas, DDS, MDS, Donald Kitzis, DDS, MSDc College of Dentistry, New York University, New York, N.Y
- 49. Jahangiri, Leila & Mascarenhas, Patrick & Kitzis, Donald. (2001). A simple technique for boxing impressions for fabrication of altered casts. The Journal of prosthetic dentistry. 85. 519-20. 10.1067/mpr.2001.114264. 49 Replacement of impression and framework on master cast after removal of edentulous distal extension areas of cast Protection of teeth in master cast with irreversible hydrocolloid.
- 50. 50 Immersion of master cast and frame assembly within supporting base Completed altered cast.
- 51. Plummer KD. Technique for boxing an altered cast impression. The Journal of prosthetic dentistry. 1982 May 1;47(5):573-5. • Technique for boxing an altered cast impression 51 AUTHOR- Kevin D. Plummer, D.D.S. United States Army, APO N.Y.
- 52. Plummer KD. Technique for boxing an altered cast impression. The Journal of prosthetic dentistry. 1982 May 1;47(5):573-5. 52
- 53. Plummer KD. Technique for boxing an altered cast impression. The Journal of prosthetic dentistry. 1982 May 1;47(5):573-5. 53
- 54. Dumbrigue HB, Esquivel JF. Selective-pressure single impression procedure for tooth- mucosa–supported removable partial dentures. The Journal of prosthetic dentistry. 1998 Aug 1;80(2):259-61. • Alternative to Altered cast Technique 54 AUTHOR - Herman B. Dumbrigue, DDM, Josephine F. Esquivel, DDM, MS University of Florida College of Dentistry. Gainesville, Fla.
- 55. Dumbrigue HB, Esquivel JF. Selective-pressure single impression procedure for tooth-mucosa–supported removable partial dentures. The Journal of prosthetic dentistry. 1998 Aug 1;80(2):259-61. 55
- 56. Dumbrigue HB, Esquivel JF. Selective-pressure single impression procedure for tooth-mucosa–supported removable partial dentures. The Journal of prosthetic dentistry. 1998 Aug 1;80(2):259-61. 56
- 57. Bauman R, DeBoer J. A modification of the altered cast technique. The Journal of Prosthetic Dentistry. 1982 Feb 1;47(2):212-3. • A modification of the altered cast technique 57 AUTHOR- Richard Bauman, D.D.S., James DeBoer, D. D.S. U. S. Army DENTAC, Ft. Carson, Cola.
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- 59. Advantages- Correct extension of the denture base, control the relationship of tooth and tissue-bearing areas of the prosthesis, make centric jaw relation records in a single clinical visit. 59
- 60. 60 Recent Advancements Digital impression Digital technology and its application to the design and fabrication of a single tooth to a complete-arch prosthesis is advancing rapidly
- 61. 61 . For residual teeth, scanning was performed in a zig-zag fashion, in the order of the occlusal surface, the buccal surface, and the lingual surface. Additionally, for edentulous ridge mucosa, zig-zag scanning was performed while maintaining continuity of images.
- 63. 63 Four major systems
- 64. 64 Advantages • Less patient discomfort • Simplified clinical procedure • Less time consuming • No more plaster cast
- 65. 65 The Use of Digital Impressions to Fabricate Tooth- Supported Partial Removable Dental Prostheses: A Clinical Report Mansour M, Sanchez E, Machado C. The use of digital impressions to fabricate tooth‐supported partial removable dental prostheses: A clinical report. Journal of Prosthodontics. 2016 Aug;25(6):495-7.
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- 67. 67 CAD/CAM Constructed Poly(etheretherketone) (PEEK) Framework of Kennedy Class I Removable Partial Denture: A Clinical Report Harb IE, Abdel‐Khalek EA, Hegazy SA. CAD/CAM constructed poly (etheretherketone)(PEEK) framework of Kennedy class I removable partial denture: a clinical report. Journal of Prosthodontics. 2019 Feb;28(2):e595-8.
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- 71. 71 A novel digital altered cast impression technique for fabricating a removable partial denture with a distal extension Wu J, Cheng Y, Gao B, Yu H. A novel digital altered cast impression technique for fabricating a removable partial denture with a distal extension. The Journal of the American Dental Association. 2020 Apr 1;151(4):297-302.
- 72. 72 . Unrestored, partially edentulous condition of the patient. A. Frontal view of the central occlusion. B. Partially edentulous mandibular arch with distal extension
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- 75. 75 The final removable partial denture (RPD) fit to the patient
- 76. 76 Use of intraoral scanning and 3-dimensional printing in the fabrication of a removable partial denture for a patient with limited mouth opening Wu J, Li Y, Zhang Y. Use of intraoral scanning and 3-dimensional printing in the fabrication of a removable partial denture for a patient with limited mouth opening. The Journal of the American Dental Association. 2017 May 1;148(5):338-41.
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- 79. conclusion 79 An accurate impression is vital for the success of a removable partial dentures . so proper selection of material ,impression technique and the skill of the dentist plays a key role in the success of the overall treatment
- 80. References • Stewart’s Clinical REMOVABLE PARTIAL PROSTHODONTICS Fourth Edition • Annals of Prosthodontics & Restorative Dentistry, April-June 2017:3(2):52-56 • Phillips science of dental materials edition 12 • Ansari IH. A new procedure for separating the edentulous distal extension portion from the master cast when an altered cast is made. The Journal of Prosthetic Dentistry. 1994 Dec 1;72(6):666-9 • Jahangiri, Leila & Mascarenhas, Patrick & Kitzis, Donald. (2001). A simple technique for boxing impressions for fabrication of altered casts. The Journal of prosthetic dentistry. 85. 519-20. 10.1067/mpr.2001.114264 • Plummer KD. Technique for boxing an altered cast impression. The Journal of prosthetic dentistry. 1982 May 1;47(5):573-5 • Dumbrigue HB, Esquivel JF. Selective-pressure single impression procedure for tooth-mucosa–supported removable partial dentures. The Journal of prosthetic dentistry. 1998 Aug 1;80(2):259-61 • Bauman R, DeBoer J. A modification of the altered cast technique. The Journal of Prosthetic Dentistry. 1982 Feb 1;47(2):212-3. • Leach CD, Donovan TE. Impression technique for maxillary removable partial dentures. The Journal of Prosthetic Dentistry. 1983 Aug 1;50(2):283-6. • Wu J, Cheng Y, Gao B, Yu H. A novel digital altered cast impression technique for fabricating a removable partial denture with a distal extension. The Journal of the American Dental Association. 2020 Apr 1;151(4):297-302. 80
- 81. 81 • Mansour M, Sanchez E, Machado C. The use of digital impressions to fabricate tooth‐supported partial removable dental prostheses: A clinical report. Journal of Prosthodontics. 2016 Aug;25(6):495-7. • Wu J, Cheng Y, Gao B, Yu H. A novel digital altered cast impression technique for fabricating a removable partial denture with a distal extension. The Journal of the American Dental Association. 2020 Apr 1;151(4):297-302. • Harb IE, Abdel‐Khalek EA, Hegazy SA. CAD/CAM constructed poly (etheretherketone)(PEEK) framework of Kennedy class I removable partial denture: a clinical report. Journal of Prosthodontics. 2019 Feb;28(2):e595- 8.
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