Posterior palatal seal

Posterior palatal seal

1. POSTERIOR PALATAL SEAL Presented by, Dr. Chaithra Prabhu B 1st year PG Department Of Prosthodontics VSDC 65

2. CONTENTS I ntroduction Definition F unctions of posterior palatal seal A natomical and physiological considerations Anterior & Posterior vibrating lines C lassification of soft palate Parameters of posterior palatal seal R ationale behind recording posterior palatal seal. The techniques used to mark posterior palatal seal F ailure in recording posterior palatal seal Adding posterior palatal seal to the existing denture C onclusion 65

3. INTRODUCTION Horizontal forces and lateral torquing forces of the maxillary denture can be resisted only by adequate border seal. So, diagnostic evaluation and placement of the posterior palatal seal is of great importance. 65

4. DEFINITION “The soft tissues along the junction of the hard and soft palates on which pressure within the physiologic limits of the tissues can be applied by a denture to aid in the retention of the denture” Winkler The soft tissue area limited posteriorly by the distal demarcation of the movable and nonmovable tissues of the soft palate and anteriorly by the junction of the hard and soft palates on which pressure, within physiologic limits, can be placed; this seal can be applied by a removable complete denture to aid in its retention GPT 9 65

5. FUNCTIONS OF POSTERIOR PALATAL SEAL Retention of the maxillary denture base by resisting the horizontal forces and lateral torquing of the maxillary denture. Maintains contact of the denture with the anterior portion of soft palate during functional movements . Reduces patient’s awareness of the denture and reduction in the gag reflex as there is no separation of denture base and soft palate during normal functional movements. Reduces food accumulation beneath the posterior aspect of the denture due to proper utilization of tissue compressibility. Reduces patient discomfort when contact occurs between the tongue and the posterior end of the denture base as the posterior denture will closely approximate the soft palatal tissues. Compensate for the volumetric shrinkage that occurs during the polymerization of methylmethacrylate resin. 65

6. ANATOMIC AND PHYSIOLOGICAL CONSIDERATION POSTERIOR PALATAL SEAL POST PALATALSEAL PTERYGOMAXILLARY SEAL Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

7. Extends medially from one tuberosity to the other. Extends through the Pterygomaxillary notch ( hamular notch ) continuing for 3 to 4 mm anterolaterally approximating the mucogingival juntion POST PALATALSEAL PTERYGOMAXILLARY SEAL Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

8. Pterygomaxillary notch/ HAMULAR NOTCH The palpable notch formed by the junction of the maxilla and the pterygoid hamulus of the sphenoid bone GPT 9 Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

9. The notch is covered by the pterygomandibular fold , which extends from the posterior aspect of the tuberosity posterior-inferiorly to insert into the retromolar pad. This fold of tissue can influence the posterior border seal if the mouth is in a wide open position during the final impression procedure . Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

10. HAMULAR PROCESS Located 2-4mm postero -medial to the distal limit of the maxillary residual ridge. Affects the length and direction of the pterygomaxillary seal. Covered by thin layer of mucous membrane and should n ever be covered by denture. Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

11. F OVIA PALATINI Two glandular openings within the tissues of posterior portion of hard palate, usually lying on either side of midline. Not constant in all individuals. They are the ductal openings into which the ducts of other palatal mucosal glands drain. Does not represent the junction of hard and soft palate and should be used only as a guideline to placement of posterior palatal seal. Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

12. Disagreements regarding position- Swenson (1970) :- Vibrating line 2mm in front of fovea palatini . Lye (1975) :- 1.31mm anterior to the anterior vibrating line. Chen (1981) :- Located either on or behind the anterior vibrating line. Boucher stated that the vibrating line is usually located 2mm anterior to the fovea palatinae 65

13. MID PALATAL RAPHAE This overlies the medial palatal suture, contains little or no submucosa and will tolerate little compression. According to H eartwell and R ahn , this band of tissues is not meant to be compressed, rather should be relieved if prominent Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

14. TORI If the torus extends to the bony limit of the palate, leaving little or no room to place the posterior border seal, then its removal is indicated. Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

15. CONSISTENCY OF THE SALIVA. Thick saliva can create hydrostatic pressure in the area anterior to the posterior palatal seal, resulting in a downward dislodging force exerted upon the denture base. According to Watt and MacGregor , A fine line or Cupid’s bow can be scribed on the master cast, anterior to the cluster of palatal mucous glands (and distal to any torus that is present). This extension of the posterior palatal seal line will contain the thick mucus in the posterior part of the denture to provide a seal even if the posterior portion of the denture base is slightly out of contact with the palatal tissues. Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

16. ANTERIOR & POSTERIOR VIBRATING LINES The posterior palatal seal area lies between anterior & posterior vibrating lines. Careful observation and palpation of the tissues is necessary to accurately locate these lines. Their location varies with the contour of the soft palate Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

17. ANTERIOR VIBRATING LINE An imaginary line located at the junction of the attached tissues overlying the hard palate and the movable tissues of the immediately adjacent soft palate. Cupid's bow shaped due to the projection of posterior nasal spine. Always on soft palatal tissues. S hould not be confused with junction between hard and soft palate . Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

18. To locate Patient is asked to perform Valsalva Maneuver (both nostrils are held firmly while patient blows gently through the nose) This positions the soft palate inferiorly at its junction with the hard palate Also located by visualizing the area while instructing the patient to say ‘ah’ with short vigorous bursts Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

19. POSTERIOR VIBRATING LINE Imaginary line at the junction of aponeurosis of Tensor veli palatini muscle and the muscular portion of the soft palate. Represents the demarcation between the part of soft palate that has limited movement during function and the remainder of soft palate that is markedly displaced during functional movements. Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

20. Visualized by instructing the patient to say “ah” in short bursts in a normal unexaggerated fashion. Marks the most distal extension of the denture base. A clinical study was conducted on edentulous patients to investigate the relative location of the foveae palatinae and vibrating line. The anterior vibrating line was located approximately 2.58 ±1.19 mm anterior to the foveae palatinae , and the posterior vibrating line was located 0.71 ±0.68 mm posterior.   Kyung K, Kim K, Jung B. The study of anatomic structures in establishing the posterior seal area for maxillary complete dentures. The Journal of Prosthetic Dentistry. 2014;112(3):494-500. 65

21. SOFT PALATE Part of a dual valve system which separates the oropharynx from the oral space and the nasopharynx from the nasal space. The function of the soft palate in these dual valving actions requires freedom of movement in three dimensions or planes of space, i.e., superoinferiorly , mediolaterally and anteroposteriorly . An impression should be made when the soft palate is placed at a desired denture border position. The functional position is achieved when patient is seated in upright position, with head flexed 30 degrees forward and placing the tongue under tension against either on the handle of impression tray or dentist’s fingers , and should not protrude beyond lips. dimensions and displacement patterns of posterior palatal seal, Silverman, j prosthet dent, may 1971 65

22. 65

23. Clinical Significance Tensor Veli Palatini - When taut, can influence the denture contour in the hamular notch area. Levator Veli Palatini - Closing of the oropharynx from the nasopharynx during swallowing and determining the position of the vibrating line. Palatoglossus – On contraction, draw the tongue and soft palate towards each other and causes lateral pressure to the lingual extension of the mandibular denture. Arthur O. Rahn & Charles M. Heartwell , Elsevier, Syllabus of complete dentures,4 th edition 65

24. CLASSIFICATION OF SOFT PALATE Based upon the angle the soft palate makes with the hard palate. The more acute the angle of the soft palate in relation to the hard palate, more muscular activity will be necessary to effect velopharyngeal closure (closing of the nasopharynx ). So the more the soft palate is markedly displaced in function, the less that can be covered by the denture base. Determined when the patient is in upright position with the head held erect. Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

25. CLASS I A soft palate that is rather horizontal as it extends posteriorly with minimal muscular activity. Wide posterior palatal seal Most favorable configuration as more tissue surface can be covered ,yielding potentilaly more retentive denture base Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

26. CLASS II Palatal contours between a class I and class II. CLASS III Most acute contour in relation to the hard palate Marked elevation of the musculature to create velopharyngeal closure Seen along with a high V-shaped palatal vault usually. Smaller in width but deeper posterior palatal seal area Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

27. PALATAL THROAT FORM CLASSIFICATION ACCORDING TO M.M. HOUSE Class I :- Large and normal in form with a relatively immovable band of resilient tissue 5-12 mm distal to a line drawn across distal edge of the tuberosities . Class II :- Medium size and normal in form with relatively immovable resilient band of tissue 3-5 mm distal to a line drawn across distal edge of the tuberosities . Class III :- Usually accompanies a small maxilla. The curtain of soft tissues turns down abruptly 3-5 mm anterior to a line drawn across distal edge of the tuberosities . House MM. The relationship of oral examination to dental diagnosis . J Prosthet Dent 1958;8:208-19 . 68

28. PARAMETERS OF POSTERIOR PALATAL SEAL Posterior palatal seal has specific characteristics with different parameters, Its variable in its size, shape location Depends on anatomical configuration of soft and hard palatal, their relationship, muscle coordination, and amount of tissue displaceability. Goyal S, Goyal MK, Balkrishanan D, Hegde V, Narayana AI. The posterior palatal seal: Its rationale and importance: An overview. European Journal of Prosthodontics. 2014 May 1;2(2):41-7. 65

29. SIZE: According to Hardy and Kapur (1958) , the dimension of PPS was 2 mm at the midpalatal region and hamular notch and 4mm at the greatest curvature region of PPS. Silverman performed a study on 92 patients & found the following – The greatest mean anteroposterior width of PPS is 8.0 mm (with 5-12 mm of range) Goyal S, Goyal MK, Balkrishanan D, Hegde V, Narayana AI. The posterior palatal seal: Its rationale and importance: An overview. European Journal of Prosthodontics. 2014 May 1;2(2):41-7. 65

30. SHAPE Single bead scribed on the posterior vibrating line Double line scribed in the anterior and posterior vibrating line Butterfly shaped posterior palatal seal Butterfly shaped posterior palatal seal with notching of posterior vibrating line Butterfly shaped posterior palatal seal with notching of hamular notch Goyal S, Goyal MK, Balkrishanan D, Hegde V, Narayana AI. The posterior palatal seal: Its rationale and importance: An overview. European Journal of Prosthodontics. 2014 May 1;2(2):41-7. 65

31. Variations used with different shaped soft palate based on the classification . Class 1: A butterfly shaped posterior palatal seal with 3-4 mm width Class 2: Posterior palatal seal is narrow with 2-3 mm of width Class 3: A single beading made on the posterior vibrating line. Goyal S, Goyal MK, Balkrishanan D, Hegde V, Narayana AI. The posterior palatal seal: Its rationale and importance: An overview. European Journal of Prosthodontics. 2014 May 1;2(2):41-7. 65

32. LOCATION Location of posterior palatal seal is not consistent and show lot of variation but on an average anterior vibrating line is 1.31 mm distal to fovea palatine. Goyal S, Goyal MK, Balkrishanan D, Hegde V, Narayana AI. The posterior palatal seal: Its rationale and importance: An overview. European Journal of Prosthodontics. 2014 May 1;2(2):41-7. 65

33. THE RATIONALE FOR THE PLACEMENT OF A SEAL IN THE IMPRESSION TRAY To establish positive contact posteriorly to prevent the final impression material from sliding down the pharynx. To serve as a guide for positioning the impression tray, especially if a shim has been used within the tray to establish the borders. To create slight displacement of the soft palate. To determine if adequate retention and seal of the potential denture border is present. Essentials of Complete Denture Prosthodontics Winkler 2nd Ed 65

34. POINTS TO BE NOTED D etermine the type of soft palate during initial examination . T ransfer the posterior extent onto the custom tray. 1-2 mm distal to the expected denture border should be present in the impression tray to protect against any overtrimming of the processed denture base. 65

35. Classification of techniques of recording PPS- Hardy and Kapur (1958) – Functional :- Final impression is border molded in PPS area with soft stick modeling compound / wax by sucking movements performed by the patient. Semi functional :- Border molding is done by the dentist. Empirical :- Developed on the cast by grooving the cast to the desired depth.   Natarajan R, Ramesh P, Selvaraj S, Mohan J. Evolution of Techniques in Recording Posterior Palatal Seal–A Review. Journal of Academy of Dental Education.;13:17. 65

36. The techniques used to mark posterior palatal seal 1. Conventional technique 2. Fluid wax technique 3. Arbitrary scraping of the master cast 65 Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed

37. CONVENTIONAL TECHNIQUE ( winkler ) After accurate & fully extended final impression has been made,boxed and poured, master cast is obtained Adaption of trial denture base Autopolymerising resin Shellac Patient in upright position Astringent mouth wash------remove stringy saliva drying with gauze piece 65

38. Transfer the marking onto the denture base and then onto the cast Trimming of the trial base Returning to the patient's mouth,palatal tissue anterior to the posterior vibrating line is palpated to check for compressibility in terms of width & depth Locating anterior vibrating line and transfer of the same short vigorous burst of “ah” valsalva maneuver Anterior vibrating line-----cupid's bow shape 65

39. Feather edge taper to the anterior and the posterior vibrating line . Failure to taper the seal anteriorly or posteriorly may lead to tissue irritation . Scoring of the master cast 65 Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed 1-1.5mm. 0.5-1.0mm Kingsley scraper Re-adaptation of trial denture base Shellac ---- reheated -----readapted-----checked again in patients mouth R esin ----- small increments

40. E valuation of the seal while patient says “ah” in short unexaggerated manner . N o space  adequate seal P resence of space  further increase the depth. CONVENTIONAL TECHNIQUE ( winkler ) 65 Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed

41. CONVENTIAL TECHNIQUE ADVANTAGE Rententive Record base---> Accurate maxillomandibular relation Pyschological security to patient The dentist is able to understand the retentive qualities of the finished denture. Ease adjustment period DISADVANTAGE Not a physiologic method depends on accurate transfer of the vibrating lines. Tissue overcompression Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed 65

42. FLUID WAX TECHNIQUE (functional technique or physiological technique) All the procedures for location and transfer marking of the anterior and posterior vibrating lines are same as for the conventional approach. Indelible transfer markings are recorded on the final wash impression. Zinc oxide eugenol /plaster are preferred over the elastic impression material, as they set rigid. Chances of distortion of relation between added wax on the posterior border and rest of the denture bearing surface Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed 65

43. 4 types of wax – 1 . Iowa Wax (White) – Dr. Earl S. Smith 2. Korecta Wax no.4 (Orange) – Dr. O.C. Applegate 3. H-L physiologic paste (Yellow-White) – Dr. C.S. Harkins 4. Adaptol (Green) – Dr. Nathan G. Kyne Designed to flow at mouth temperature. Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed 65

44. PROCEDURE Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed 65

45. PROCEDURE Melted wax in excess of the estimated depth is painted onto the outlined seal area on impression allowed to cool and carried to the mouth Impression held under gentle pressure for 4- 6 mintues Position of head and tongue IMPORTANT Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed 65

46. POSITION OF HEAD AND TONGUE Soft palate Functionally depressed possition Prevents progression of material down the pharynx Patient should not protrude tongue beyond the approximated position of incisors --------- tray handle The patient is asked to periodically rotate the head so that all functional positions of the soft palate are recorded. 30 degrees Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed 65

47. Evaluation of the impression After 4- 6 min the impression is removed from the mouth and evaluated Glossy apprearance feather edge near the anterior vibrating line Dull appearence But joint near the anterior vibrating line--( no proper flow) Any excess is removed carefully with sharpe scalple Any deficient -----wax is added & procedure is repeated Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed 65

48. PRECAUTIONS: The patient should not protrude his tongue beyond the approximated position of the incisal edge as this may shorten the posterior border of the final impression. The patient should be cautioned against rinsing with cold water as this may contract the tissues and reduce the flow properties of wax. Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed 65

49. FLUID WAX TECHNIQUE ADVANTAGES Physiological technique overcompression is avoided Added Retention Mechanical scraping is avoided DISADVANTAGES Time consuming Difficulty in handling material and extra care during boxing procedure Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed 65

50. Half base plate wax and half stickicy wax

51. MODIFIED BORDER MOULDING TECHNIQUE In an Indian set-up, we usually follow this modified version of the fluid wax technique. Here before making the definitive impression, PPS Area is recorded in the Low-fusing impression compound . Followed by Definitive Impression. Posterior Palatal Seal (PPS): A brief review Journal of Scientific and Innovative Research 2014; 3(6): 602-605 65

52. ARBITRARY SCRAPING OF THE MASTER CAST Anterior and the posterior vibrating lines are visualized by examining the patient’s mouth and approximately marked and scraped on the master cast. Least accurate and leaves the most to chance at insertion appointment since it relies on dentist’s recollection of palatal configuration and tissue compressibility. Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed 65

53. Other techniques Boucher’s Technique Bernard Levin’s Technique Swenson’s Technique Pound’s Technique Silverman’s Technique Hardy and KapurTechnique Natarajan R, Ramesh P, Selvaraj S, Mohan J. Evolution of Techniques in Recording Posterior Palatal Seal–A Review. Journal of Academy of Dental Education.;13:17. 65 Emperical methods

54. TROUBLESHOOTING Under extension Over extension Under post damming Over post damming 65 Essentials Of Complete Denture Prosthodontics Winkler 2nd Ed

55. Source : Natarajan R, Ramesh P, Selvaraj S, Mohan J. Evolution of Techniques in Recording Posterior Palatal Seal–A Review. Journal of Academy of Dental Education.;13:17. 65

56. Moghadam and Scandrett suggest a procedure that utilizes the fluid wax technique. After the wax has had an adequate chance to flow, the denture is removed from the mouth and the anterior extent of the seal on the denture is outlined. ADDING POSTERIOR PALATAL SEAL TO THE EXISTING DENTURE Moghadam BScandrett F. A technique for adding the posterior palatal seal. The Journal of Prosthetic Dentistry. 1974;32(4):443-447. 65

57. Utility wax is placed vertically across the palate, separating the posterior two thirds from the anterior region, and extended around the posterior portion of the denture . Stone is vibrated into the denture-wax surface outlined by the utility wax. After the stone has set, the wax is eliminated and the denture cleaned. The denture base is ground distal to the anterior vibrating line that has been delineated by the indelible pencil. Moghadam BScandrett F. A technique for adding the posterior palatal seal. The Journal of Prosthetic Dentistry. 1974;32(4):443-447. 65

58. A separating medium is applied to the stone cast and the denture is then replaced on the stone cast and held firmly with rubber bands . Autopolymerizing acrylic powder is sprinkled between the denture base and the cast while held on a vibrator and monomer is then added dropwise. The cast and denture are placed in an upright position until the initial set has taken place. They are then placed in a pressure pot with water (140°F) for 20 minutes under 30 psi pressure. After the cast and denture are separated, the excess acrylic is trimmed and the border polished lightly. Denture should be stored in water for 24 to 36 hours to avoid tissue irritation due to excess monomer. Moghadam BScandrett F. A technique for adding the posterior palatal seal. The Journal of Prosthetic Dentistry. 1974;32(4):443-447. 65

59. ADDING POSTERIOR PALATAL SEAL TO THE EXISTING DENTURE Mark the vibrating line in the mouth with an indelible marker. Form the desired thickness and extension of the PPS on the denture in the patient’s mouth with softened green modeling compound Transfer the locations of the vibrating line to the denture Make a cast of the intaglio surface of the denture with putty material; the cast must include all of PPS addition and extend 5 to 6 mm posteriorly After putty material has set, use a scalpel to cut channels which will allow excess autopolymerizing acrylic resin to escape. Remove the green stick compound and replace with autopolymerizing resin in a pressure pot. Ansari IH. A procedure for adding posterior palatal seal to an existing denture in dental office. J Prosthet Dent 1994;72:449. 65

60. Arthur Nimmo - Suggested correction of posterior palatal seal by using a visible light cured resin.   Identify and mark the vibrating line in the mouth with an indelible marking stick Roughen the denture surface in the posterior palatal seal area with a carbide bur. Adapt the VLC resin Place the denture in the mouth and allow it to remain in place for approximately 3 minutes. During this time the material will flow. Position a hand-held visible light source near the border of the denture and apply light directly to the region for several minutes. Remove any excess resin with a carbide bur and smooth the junction between the seal and the polished surface of the denture. Nimmo A. Correction of the posterior palatal seal by using a visible light-cured resin: A clinical report. The Journal of Prosthetic Dentistry. 1988;59(5):529-531. ADDING POSTERIOR PALATAL SEAL TO THE EXISTING DENTURE 65

61. ADVANTAGES No exothermic reaction to irritate the oral tissues. Minimal volumetric shrinkage during curing. More closely approximates a physiologic technique. Can be performed with relatively little chair time. DISADVANTAGE: Cost of the curing unit Nimmo A. Correction of the posterior palatal seal by using a visible light-cured resin: A clinical report. The Journal of Prosthetic Dentistry. 1988;59(5):529-531. ADDING POSTERIOR PALATAL SEAL TO THE EXISTING DENTURE 65

62. CONCLUSION The recording of PPS is of great significance because it is vital factor in establishing the peripheral seal which enhances retention by utilizing the atmospheric pressure. The PPS of a maxillary complete denture can be established during the making of the preliminary impression, during the making of final impression, by scoring the final cast or by incorporating the seal in the final denture. It is not a difficult procedure once you have an intimate knowledge of the anatomy and physiology of the tissues of the region. 65

63. REFERENCES & cross references Sheldon Winkler ,A.I.T.B.S. Publishers,Essentials of complete denture Prosthodontics, 2nd edition Zarb Bolender , Mosby,Prosthodontic treatment for edentulous patients,12 th edition Arthur O. Rahn & Charles M. Heartwell , Elsevier,Textbook of complete dentures,5 th edition Hardy I R, Posterior border seal –its rationale and importance, J Prosthet Dent 1958:8;386-97 Silverman S.L. “Dimensions and displacement patterns of the posterior palatal seal”. J Prosthet Dent 1971:25;470-88 Winland RD, Young JM, Maxillary complete denture posterior palatal seal: Variations in size, shape & location , J Prosthet Dent 1973:29;256-61 Lye TL, The significance of the fovea palatine in complete denture prosthodontics . J Prosthet Dent 1975:33;504-10 Wicks R, Ahuja S, Jain V. Defining the posterior palatal seal on a definitive impression for a maxillary complete denture by using a non fluid wax addition technique. J Prosthet Dent 2014;112:1597-600 65

64. E Abd AlAziz O, A Baraka O, Y Farahat M. An In-Vivo Comparative Study of Retention of Heat Cured and Thermoplastic Acrylic Resins in Maxillary Complete Denture Bases Made with Different Posterior Palatal Sealing Techniques. Al-Azhar Journal of Dental Science. 2018 Jul 1;21(3):237-43. Nikoukari H, A study of posterior palatal seals with varying palatal forms, J Prosthet Dent 1975:34;605-13 Nimmo A.,Correction of the posterior palatal seal by using a visible-light cure resin : A clinical report J Prosthet Dent 1988:59;529-30 Izharul Haque Ansari , A procedure for adding posterior palatal seal to an existing denture in dental office, J Prosthet Dent 1994:72;449 Izharul Haque Ansari “Establishing the posterior palatal seal during the final impression stage”. J Prosthet Dent 1997:78;324-26 65

65. THANK YOU