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
POSTERIOR PALATAL
SEAL AREA
PTERYGOMAXILLARY
SEAL
POSTPALATAL SEAL

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:
1. Size
2. Shape
3. Location
4. 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:
1. CONVENTIONAL
TECHNIQUE
2. FLUID WAX
TECHNIQUE
3. ARBITRARY
SCRAPING

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- 1/3rd distance anteriorly from
posterior vibrating line.
Red line- midline
Yellow line- 1/3rd 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
1. UNDEREXTENSION
2. OVEREXTENSION
3. UNDERPOSTDAMMING
4. 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:
1. Seat dentures in mouth ask patient to say ‘‘ah’’ and with mouth mirror view of any gap during
speech.
2. 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,2nd 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