Posterior Palatal Seal Area

Posterior Palatal Seal is an most important limiting structure
for maxillary denture as it affects the retention of maxillary denture

1. POSTERIOR PALATAL SEAL GUIDED BY – DR. S.R. GODBOLE DR. TRUPTI M. DAHANE DR. MITHILESH DHAMANDE PRESENTED BY – PRIYANKA N. KHUNGAR

2. SPECIFIC LEARNING OBJECTIVES SR. NO. CORE AREA DOMAIN SIGNIFICANE 1. DEFINITION OF POSTERIOR PALATAL SEAL COGNITIVE MUST KNOW 2. FUNCTIONS OF POSTERIOR PALATAL SEAL COGNITIVE MUST KNOW 3. TECHNIQUES TO RECORD THE POSTERIOR PALATAL SEAL COGNITIVE/PSYCHOMOTOR MUST KNOW 4. ERRORS THAT CAN OCCUR IN RECORDING PPS COGNITIVE/PSYCHOMOTOR MUST KNOW

3. CONTENTS INTRODUCTION DEFINITION OF POSTERIOR PALATAL SEAL FUNCTIONS OF PPS ANATOMIC AND PHYSIOLOGIC CONSIDERATION- PTERYGOMAXILLARY SEAL POSTPALATAL SEAL BOUNDARIES OF PPS ANTERIOR VIBRATING LINE POSTERIOR VIBRATING LINE

4. INTRODUCTION POSTERIOR PALATAL SEAL AREA is the posterior most limiting structure of the maxillary denture. The horizontal and lateral torqueing forces that act on the maxillary denture can be resisted only by achieving an adequate border seal. The soft tissue seal in the posterior border of the maxillary denture requires a special consideration during denture extension because the range and extent of the soft tissue activity along this border is profound.

5. Also, a well recorded postpalatal seal complements the labial and buccal border seal and converts the denture as a sealed compartment resisting the torqueing forces. So, definite evaluation and proper placement of the posterior palatal seal is important. For this, knowledge about the anatomy and physiology of the posterior palatal seal area makes its placement a quick and easy procedure.

6. DEFINITION: POSTERIOR PALATAL SEAL is that portion of the intaglio surface of a maxillary removable complete denture, located at its posterior border, which places pressure, within physiologic limits, on the posterior palatal seal area of the soft palate; this seal ensures intimate contact of the denture base to the soft palate and improves retention of the denture. (GPT 9)

7. POSTERIOR PALATAL SEAL AREA: The soft tissue area limited posteriorly by the distal demarcation of the movable and non-movable 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 the removable complete denture, to aid in its retention. (GPT 9)

8. FUNCTIONS OF POSTERIOR PALATAL SEAL DECREASES FOOD ACCUMULATION BENEATH THE DENTURE REDUCES PATIENT DISCOMFORT COMPENSATES FOR THE VOLUMETRIC SHRINKAGE DURING POLYMERISATION OF PMMA. REDUCTION IN GAG REFLEX RETENTION OF MAXILLARY COMPLETE DENTURE

9. ANATOMIC AND PHYSIOLOGIC CONSIDERATIONS

10. 1. PTERYGOMAXILLARY SEAL Laterally, PPS extends through the pterygomaxillary notch (hamular notch) continuing for 3-4mm anterolaterally approximating the mucogingival junction. It occupies the entire width of the hamular notch. HAMULAR NOTCH- it is band of loose connective tissue lying between the pterygoid hamulus and the distal portion of the maxillary tuberosity .

11. The hamular notch is covered by the pterygomandibular fold. Significance: When the mouth is opened wide, this fold is pulled forward and if the denture border extends beyond the hamular notch, it results in dislodgement of the denture. Also, overextension in this area may cause trauma to the mucosa overlying the pterygomandibular fold.

12. LOCATING THE HAMULAR NOTCH Located 2-4mm posteromedial to the distal limit of the maxillary residual alveolar ridge. Located using T-burnisher or Mouth mirror. Hamular process present distal to the hamular notch, is covered by a thin mucous membrane. Care should be taken that the denture base should not cover the hamular process as this may result into immense pain.

13. 2. POSTPALATAL SEAL The post palatal seal extends medially from one hamular notch to the other. MEDIO-LATERAL EXTENSION OF PPS ANTERO-INFERIOR EXTENSION OF PPS

14. BOUNDARIES OF POSTERIOR PALATAL SEAL AREA: Posterior palatal seal area is the area between the anterior and posterior vibrating line found medially from one hamular notch to other. . POSTERIOR PALATAL SEAL AREA ANTERIOR VIBRATING LINE POSTERIOR VIBRATING LINE

15. ANTERIOR VIBRATING LINE DEFINITION- It is an imaginary line located at the junction of attached tissues overlying hard palate and the movable tissues of immediately adjacent soft palate . METHODS FOR LOCATING: Valsalva Maneuver Saying ‘Ah’ (in short vigorous bursts) It is not a straight line, but of cupid’s bow shape.

16. POSTERIOR VIBRATING LINE DEFINITION- It is an imaginary line that represents the demarcation between that part of soft palate that shows limited or shallow movement during function and remainder of the soft palate that is markedly displaced during function. Marks the most distal extension of the denture base. LOCATED BY- saying ‘Ah’ (short bursts but in normal unexaggerated way)

17. PARAMETERS OF POSTERIOR PALATAL SEAL: Size Shape Location Displaceability/Compressibility

18. 1. SIZE HARDY AND KAPUR (1958) The dimension of PPS was 2mm at the midpalatal region and hamular notch and 4mm at the greatest curvature region of PPS. SILVERMAN (1971) Silverman performed a study and he found that the greatest mean anteroposterior width of posterior palatal seal is 8.0 mm (with 5-12 mm of range)

19. PALATAL THROAT FORM - HOUSE CLASSIFICATION It is based on the angle formed between the soft and the hard palate and the soft palate muscle activity that will be necessary to establish the velopharyngeal closure. CLASS I The soft palate is horizontal requiring minimal muscular activity for velopharyngeal closure allowing more than 5 mm of seal area. CLASS II The type of soft palatal contour lies somewhere between class I and class III allowing 1 to 5 mm of seal area depending on the muscular activity of the soft palate  CLASS III The soft palate is more acute in relation to the hard palate necessitating marked elevation of the musculature for velopharyngeal closure permitting a narrow seal of less than 1 mm .

20. 2. SHAPE - WINLAND AND YOUNG Single bead scribed on the posterior vibrating line– PPS extending through hamular notch Double line scribed in the anterior and posterior vibrating line Butterfly shaped posterior palatal seal. Width and depth depending on the displaceability of the tissues. Butterfly shaped posterior palatal seal with notching of posterior vibrating line

21. Variations used with different shaped soft palate based on the classification: Class 1: A butterfly shaped posterior palatal seal with 3-4 mm wide. Class 2: Posterior palatal seal is narrow with 2-3 mm of width. Class 3: A single beading made on the posterior vibrating line.

22. There is lot of difference of opinion on the location of fovea palatini and anterior vibrating line. According to Sicher , fovea palatine is located just posterior to location of hard and soft palates. According to Swenson, vibrating line is 2 mm in front of fovea palatine

23. 3. LOCATION SICHER- Fovea palatine is located just posterior to location of hard and soft palates. SWENSON- Vibrating line is 2 mm in front of fovea palatine. SILVERMAN- Posterior palatal seal can be extended 8.2 mm distal to vibrating line for retention and stability. LYE- In the study, found that the mean position of vibrating line is 1.31 mm behind fovea. CHEN- found that in majority of patients’ fovea was located at or behind the anterior vibrating line.

24. 4. DISPLACEABILITY/COMPRESSIBILITY Variation in displaceability depends on the form of palatal vault: - Class I palate – Shallow PPS. Class II palate – Medium PPS Class III palate – Deep PPS. Low compressibility – In Midpalatal raphe and Hamular notch region. High compressibility – In Lateral part of cupid’s bow.

25. TECHNIQUES TO RECORD THE PPS:

26. 1. Conventional technique (WINKLER) Palpate for hamular process using T-burnisher/mouth mirror. Mark them with indelible pencil make sure denture does not cover them. Pass the T-burnisher along posterior angle of maxillary tuberosity until it drops into pterygomaxillary notch. Extend the mark from pterygomaxillary notch 3-4 mm antero-lateral to maxillary tuberosity approximating mucogingival junction. Ask patient to say “ah” in short bursts, in unexaggerated fashion. Observe movement of soft palate and mark posterior vibrating line, and then connect it to pterygomaxillary seal.

27. Yellow line- 1/3 rd distance anteriorly from posterior vibrating line . Red line- midline Yellow line- 1/3 rd distance anteriorly from posterior vibrating line . Red line- midline

28. ADVANTAGES Highly retentive trial bases give good jaw relation. Gives psychological confidence to patient that retention will not be a problem in final denture. Dentist is able to determine the retention of final denture Patient will be able to realize the posterior extent of denture, which may ease the adjustment period. DISADVANTAGES Not A physiological technique and therefore depends upon accurate transfer of vibrating line and careful scrapping It has potential for over compression.

29. 2. Fluid wax technique The melted wax is painted into the impression surface. The impression is carried to the mouth and held in place under gentle pressure for 4-6 min and allow time for the material to flow. Take care for head position (30° to FH plane). After 4 min remove impression tray and trim excess (or) if no tissue contact is established then add and redo the procedure.

30. ADVANTAGES Physiologic technique displacing tissues No over compression of tissues Posterior palatal seal incorporated into trial denture base for added retention No mechanical scrapping of cast is required. DISADVANTAGES Time consuming, Cumbersome Difficulty in handling material Additional care to be taken during boxing procedure

31. 3. ARBITRARY SCRAPING OF THE CAST Anterior & posterior Vibrating lines are visualized by examining the patient’s mouth and approximately marked on master cast. Scrapping 0.5 to 1mm in posterior palatal seal area of the master cast is done followed by denture fabrication. This tech is least accurate and not physiological and should be avoided.

32. ERRORS IN RECORDING PPS AREA UNDEREXTENSION OVEREXTENSION UNDERPOSTDAMMING OVERPOSTDAMMING

33. 1. UNDEREXTENTION It is the most common cause of seal failure . It mainly occurs due to use of fovea palatine as a guideline for marking anterior and posterior vibrating line. By doing so, 4-12 mm of tissue coverage loss occur leading to decreased retention. The dentist may intentionally leave the posterior borders under extended in order to reduces the patient’s anxiety to gagging. Improper delineation of anterior & posterior vibrating lines. Excessive trimming of the posterior border of the cast by technician.

34. 2. OVEREXTENTION It mainly occurs due to overzealous extension of denture. Base for increased retention by dentist cause physiological violation of soft palate musculature. It mainly shows with symptoms of mucosal ulcerations, painful swallowing, physiological violation of soft palate muscle, sharp pain if pterygoid hamulus is covered. It can be managed by selectively relieving the pressure areas and decrease the distal length.

35. 3. UNDERPOSTDAMMING It mainly occurs due to- improper depth of postdamming . use of improper technique. recording posterior palatal seal in a wide open position which causes toughening of pterygomandibular ligament and shorten the pterygomaxillary seal. It can be diagnosed using two tests: Seat dentures in mouth ask patient to say ‘‘ah’’ and with mouth mirror view of any gap during speech. Place wet denture base and press slowly in midpalatal region and bubbles escaping at any point on distal denture border indicates area of underpostdamming .

36. 4. OVERPOSTDAMMING Commonly occur due to aggressive scraping of cast. If it occurs in pterygomaxillary seal, the denture will be displaced downward. If moderate over postdamming is present, then mild irritation is found. It can be overcome by selectively relieving denture border. Gagging is commonly encountered and should be managed carefully before altering any prosthesis.

37. SUMMARY The posterior border of the Maxillary denture has a definite anatomic and physiologic boundaries that, once understood, make the placement of the posterior palatal seal a quick and easy procedure with predictable results. Placing the posterior palatal seal in the denture is dentist’s responsibility and not the technician’s obligation. Hence, thorough knowledge of the anatomy, function and movements of the tissues of this region is required and should be applied to enhance the retention and thereby stability of the maxillary complete denture.

38. REFERENCES Winkler ; essentals of complete denture prosthodontics,2 nd edn . Shelly Goyal :The posterior palatal seal: Its rationale and importance: An overview ; European Journal of Prosthodontics, May-Aug 2014, Vol 2, Issue 2 The Glossary of Prosthodontic Terms. 9th ed. J Prosthet Dent 2005;94:10‑92. YA Bindhoo : Posterior palatal seal – A Literature Review; International journal of prosthodontics and restorative dentistry; Jul-sept 2011. Rajeev MN, Applelboum BM. An investigation of the anatomic position of the posterior seal by ultrasound. J Prosthet Dent 1989;61:331-6.

39. THANK YOU The determination of the posterior limit and palatal seal of the maxillary denture is not the technicians obligation but the responsibility of the dentist..! R.B.Porter