Posterior palatal s /certified fixed orthodontic courses by Indian dental academy


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Posterior palatal s /certified fixed orthodontic courses by Indian dental academy

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. Posterior palatal seal Posterior palatal seal is the seal at the posterior border of maxillary prosthesis. (GPT 7). Posterior palatal seal area: the soft tissues area at or beyond the junction of the hard and the soft palate on which pressure , within physiological limits , can be applied to aid in retention.(GPT7)
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  4. 4. Anterior and posterior vibrating lines: PPSA lies between anterior and posterior vibrating lines. Anterior vibrating line: is an imaginary line located at the junction of attached tissues overlying the hard palate and movable tissues of the immediately adjacent soft palate.
  5. 5. One way to locate is to have patient perform Valsalvamaneuver . Second way is by asking the patient to say “ah”in short vigorous bursts.
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  7. 7. • Posterior vibrating line: It is an imaginary line at junction of the tensorveli palatine muscle and muscular portion of the soft palate. It is visualized by asking the patient say “ah” in short bursts in a normal and unexaggerated fashion. It marks most distal extension of the denture base.
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  9. 9. The rationale for the placement of the PPS in the impression tray is as follows: 1.To establish positive contact posteriorly. 2.To serve as a guide for positioning the tray. 3.To create slight displacement of the soft palate. 4.To determine adequate retention and seal.
  10. 10. • Technique: Method to mark PPSA: “T” burnisher is used . It is placed along the posterior angle of the tuberosity until it drops into pterygomandibular notch. A line is placed through the notch and extended 3-4mm anterolateral to the tuberosity approximating the mucogingival junction.
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  12. 12. This completes outlining the pterygomaxillary seal. The posterior vibrating line is recorded by asking the patient to say “ah” in unexaggerated and the line is marked by connecting the pterygomaxillary seal.
  13. 13. Anterior vibrating line: the palatal tissues anterior to the posterior border are palpated with “T” burnisher to determine their compressibility in width and depth. The termination of glandular tissues usually coincide with the anterior vibrating line.
  14. 14. • The visual outline is of cupids bow.
  15. 15. Border molding of the mandibular tray: Armamentarium:
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  17. 17. Mandible: Border molding the labial and buccal flanges:
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  20. 20. Buccal flange: molded when cheek is moved outward, upward and inward. Posteriorly the effect of masseter muscle is recorded by asking the patient to exert closing force while the dentist exerts downward pressure on the tray.
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  23. 23. Lingual flanges: In the anterior region the compound is added and placed in the patient’s mouth and the patient is instructed to protrude the tongue and push the tongue against the front part of the palate.
  24. 24. Protruding movement creates the functional movement of the floor of the mouth including the lingual frenum and determines the length of the lingual flange.
  25. 25. Pushing the tongue develop thickness of the anterior part of the flange. The distal end of the lingual flange is molded by asking the patient to protrude the tongue and this develops the slope for the lingual flange in the molar region to allow action for the mylohyoid muscle.
  26. 26. • Compound on the distal end of the flange is heated, and the tray is placed in the mouth .patient is asked to protrude the tongue to activate superior constrictor then he is asked to close opposing the pressure. • This results contraction of medial pterygoid acting on retromyloid curtain, can limit border extension in the retromylohyoid fossa.
  27. 27. The length and form of the lingual flange is formed by asking the patient to wipe the tip of his tongue across the vermillion border of the lip.
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  29. 29. Border molding with elastomeric impression material. Smith etal.,the effective simultaneous border molding material is polyether impression material called impregum.
  30. 30.
  31. 31. They are easy to use when there are undercuts because they are elastic. Disadvantages: They are difficult to trim once it is set. Final impression materials crack or craze because the borders are not rigid. They are hard to use, easy to abuse and costly. The tray should not be under extended 6mm or more.
  32. 32. Border molding with waxes: Waxes were oldest material used. Waxes were abonded as pressure created by most of the waxes causes tissue distortion. Large undercuts distort the wax. Chilled wax is brittle and subjected to flaking and breaking.
  33. 33. Border molding with self-cure resins and tissue conditioners. Remiseal was the first one specifically developed for border molding. The monomer was irritating, so it was further modified . Flexacryl is the material which is nonexothermic, non irritant.
  34. 34. Resin called Peripheal seal was recommended by smith. Denturlyne and Reprodent are premixed soft resins.
  35. 35. The tissue conditioning material were suitable for treating abused soft tissues as well as for developing functional borders or dynamic impressions. Hydrocast
  36. 36. Final impressions: Final impression materials: Plaster of Paris: the setting time of the plaster should be modified so that the molding time will be increased. It absorbs some of the mucous secretions. Difficult to record undercuts. It has enough body to support itself 1.5mm beyond the tray.
  37. 37. Zinc oxide eugenol paste: It accurately records surface details. It does not absorb the mucous secretions and can cause defects in palatal part of the mucosa. Since the material is fluid the tray should be accurately formed.
  38. 38. • Tissue conditioning materials: They are resilient and can flow under stresses up to 24hrs. They are useful in making functional impressions.
  39. 39. Silicone ,polysulfide rubber, polyether ; They can record the shape of the soft tissues accurately if they are adequately supported by the tray. The polysulfide material should be closely confined to the soft tissues. They are useful in making impressions of thin high mandibular ridges with soft tissue undercuts.
  40. 40. Poly ether: They have sufficient body to make up discrepancy up to 4-5mm. Can be shaped by fingers. They are accurate in reproducing details.
  41. 41. Technique. Preparing the tray to secure final impression. The spacer wax is removed from inside the tray along with the border molding material that has flown over it. 2-3mm of thickness should be reduced from one buccal frenum to other.
  42. 42. Approximately 0.5mm is removed from the inner outer and top surface of the border. Finally the holes are placed in the tray with medium sized round bur to provide escape holes for the material.
  43. 43. • Richard P. Frank(1969): He stated that reduced pressure would most likely be achieved by the use of zinc-oxide eugenol paste in a tray with relief space and escape holes. (JPD 1969;22(4);400-12)
  44. 44. • Osamu Komiyama etal.,(2004) • In there study they concluded that a tray with 1mm dia or large or spacer with 1.4mm wax produced pressures in the mid palatal point significantly lower than ridge crest. • JPD 2004;91:570-6.
  45. 45. According to Heart well:2 holes in the region of the rugae and 2 holes in the posterior area are made to allow escape of the air.
  46. 46.
  47. 47. According to Sharry: A small hole should be drilled through the tray in the incisive papilla region to prevent hydraulic in the vault region.
  48. 48. • According to Boucher: • Holes should be placed in the palatal region because the mucous membrane over the mid palatal region and the anterolateral and posterolateral regions in the hard palate are not excessively displaced.
  49. 49. • Holes can also be placed over the RR where the soft tissues are mobile and displaceable. • The objective is to record denture bearing area in undisplaced position.
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  51. 51. • In the mandible holes are placed 10mm apart in center of the alveolar ridge and retromolar pads.
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  53. 53. • According to Bernard levin: in maxilla 8-10 holes are drilled over the crest of the ridge. • In mandible 8-10 holes are drilled over the crest of the ridge.
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  55. 55. Impressions: Maxillary: First the placement of the tray should be practiced. The tray is centered as it carried to the upper ridge. When the frenums are positioned within the notch the index fingers are sifted to the
  56. 56. First molar region and with alternating pressure the tray is carried upward until the posterior seal of the tray fits properly in the hamular notches across the palate. The tray is held in position with the finger placed in the palate anterior to PPS.
  57. 57. The final impression of choice is mixed and loaded in the tray uniformly. When the material is set it is removed and inspected.
  58. 58. • Establishing posterior palatal seal: Fluid wax technique: Four types of waxes can be used Iowa wax. Korecta wax no4, orange. H-L physiologic paste. Adaptol.
  59. 59. The waxes are designed to flow at mouth temperature.
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  64. 64. • The advantages of this technique: It is a physiologic technique displacing tissues within their physiologic limits. PPS is incorporated into the trial base for added retention. Mechanical scrapping of the cast is avoided.
  65. 65. • Establishing posterior seal during final impression stage. (JPD 1997;78:324-25).
  66. 66.
  67. 67.
  68. 68. Mandidular: the tray is rotated into the mouth until the anterior handle is on the ridge. At this time the patient is asked to raise the tongue and the tray is moved downwards towards it final position.
  69. 69. • The dentists fingers are placed over the posterior handles and with alternating pressure the tray is seated until the buccal flanges come in contact with the buccal self.
  70. 70. The material is uniformly loaded and the tray is seated and the movements are performed .after material sets the impression is removed and inspected.
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  73. 73. Closed mouth techniques: Mac Millan in 1947 stated that only these impressions are capable of adequately trimming the lingual borders of the impressions as the tongue movements are more forceful when teeth are together.
  74. 74. The objective of this technique is to record the functional form of the denture bearing area. Rationale: the thought the natural movements by patients will confirm the impression material to anatomic limitations when the mouth is closed under pressure
  75. 75. Initially waxes were used . But now softliners are advocated. Technique: Impression trays with occlusal rims are used instead of handles. Impression material is loaded in the tray and placed in the patient’s mouth.
  76. 76. • Both upper and lower impressions are made simultaneously. • The patient is asked to apply pressure by closing against the occlusal rims. • He is asked to perform functional movements like swallowing, wetting the lips, grinning, sucking, etc.
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  78. 78. Disadvantages : Does not allow for the adequate muscle trimming of the periphery. The dentures are over extended. Because of continuous pressure there is resorption of the bone.
  79. 79. Modified Functional Impression Technique for complete dentures
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  85. 85. Specialised techniques. Impression technique in flat mandibular ridges: The technique uses the tissue conditioning materials. A preliminary impression is obtained to a generally overextended registration.
  86. 86. Using the cast the resin tray is fabricated with occlusal rim and tried in patients mouth The buccal and labial extensions of the tray are adjusted short of the reflections of the cheeks and the lips. The retromolar pad is covered but show no influence on the tray.
  87. 87. • The operator can use close mouth or open mouth technique. • The closed mouth technique requires the use of well fitting maxillary tray, well occluding rims and acceptable vertical dimensions.
  88. 88. Technique; 3 applications of tissue conditioning material are coe product. 2applications of viscous material i,e.,coe soft. Each application allowed to remain in mouth 8-10 min. then it is checked . Pressure areas are corrected.
  89. 89. Final wash is made with relatively light bodied material. The impression obtained has very thickened comforting buccal borders and a relatively thick lingual and subcreascent area. Overall denture is more bulkier with more surface contact area with minimal bony contact in the alveolar ridge area with improved retention.
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  91. 91. Impression techniques for flabby ridges: Mucocompression without displacement: This is a two stage technique design to compress the flabby tissue so that the compression throughout the whole denture bearing area is uniform as possible.
  92. 92. Preliminary impression is made with plaster. Pour impression and make cold cure acrylic tray. The tray is checked in the mouth.
  93. 93. A compound impression of the tray is made. The flabby area is marked with the pencil and the tray is inserted in the mouth and removed to outline the impression surface.
  94. 94. • With a pin point flame soften the area surrounding the flabby ridge. • The impression is tempered and inserted in the mouth. • Load should be applied in vertical direction to compress the flabby ridge without displacing it.
  95. 95. The procedure is repeated for two times. The impression is dried and completed with zinc oxide eugenol impression paste. If the impression is correctly made the compound should show through the ZOE in the flabby ridge area.
  96. 96.
  97. 97. • Mucostatic, open window technique: On the priliminary cast an custom tray is made with an opening surrounding the flabby ridge. The tray is border molded and the impression paste wash is made. Reinsert the tray and apply thin mix of plaster over the flabby ridge which lies through the window
  98. 98. When the plaster has set remove the whole.
  99. 99.
  100. 100. Impression technique in minimal mouth opening A sectional impression tray was designed with right and left sections that could be detached and then joined together in the correct original position. Maxillary and mandibular impression trays were then fabricated.
  101. 101. Putty silicon impression paste (Speedex, Coltene Whaledent Inc, Mahway, NJ) was placed intraorally with finger pressure, and maxillary and mandibular impressions were made. The impressions were cast in dental stone
  102. 102.
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  106. 106. Summary.
  107. 107. Conclusion.
  108. 108. References: Text book of complete denturesHeartwell 5 Edn. Essentials of complete dentures – Winkler Prosthodontic management of edentulous patients- Zarb- Bolender. Clinical dental prosthesis – A. Roy Mcgregor.
  109. 109. Impressions for complete dentures: Bernard Levin.
  110. 110. • physical considerations in impression making. JPD 1953:3(4);449-62) • complete denture impressions .JPD1965:15;603-14. • Posterior border seal – its rationale and importance.JPD1958:8;386-97 • complete denture impressions .JPD1965:15;603-14
  111. 111. • Impression border molding with a cold cure resin.JPD1973:30;914-17 • principles involved in complete dentures.JPD1973:29;594-9 • border molding of complete denture impressions using a polyether impression material.JPD1979:41;347-517
  112. 112. • the sublingual crescent extensions and its relation to the stability and retention of mandibular complete dentures.JPD1992:67;205-10 • Functional metallic handles for final impressions of complete dentures.JPD1998:79;607-8
  113. 113. Thank you For more details please visit