The soft tissues along the junction of hard and soft palate on which pressure within the physiological limits of tissues can be applied by the denture to aid in retention of the denture.

1. Dr. Ibadat Jamil
Assistant professor
Dep. Of Prothodontics
POSTERIOR PALATAL SEAL

3. AIM
 According to Hardy and kapur retention and stability
that is achieved from adhesion, cohesion and
interfacial surface tension are able to resist only those
dislodging forces that act perpendicular to denture
base.
 Horizontal and lateral torquing of maxillary denture
can be resisted only by adequate border seal.
 Terminating the dentures on soft resilient tissues will
allow mucosa to move with denture base during
function and thereby maintain border seal.

4.  Thus proper placement of PPS demands a definite
procedural protocol if one needs to create optimally
retentive maxillary prosthesis.

5. DEFINITION
According to GPT:
“The soft tissues along the
junction of hard and soft
palate on which pressure
within the physiological
limits of tissues can be
applied by the denture to
aid in retention of the
denture.”

6. FUNCTIONS OF PPS
 Maintain contact with anterior part of soft palate
during functional movement of stomatognathic
system, thus primary function is retention of denture.
 When correctly diagnosed and incorporated in denture
reduces patients awareness of this area with a
subsequent reduction in gag reflex.
 Reduce food accumulation beneath posterior aspect of
denture.

7.  Reduce patient discomfort when dorsum of tongue
touches posterior denture base.
 Compensates for volumetric shrinkage of denture base
during polymerization of PMMA.
 Correctly placed PPS will not impinge upon the non-
displaceable tissues of hard palate nor it will limit the
muscular movement of soft palate.
 It creates partial vacuum beneath the maxillary denture.

8. HISTORICAL REVIEW
 1883: Ames and the Greene brothers introduced
atmospheric pressure as a means of denture retention
and recommended the use of functional denture
borders as opposed to passive borders in the
fabrication of complete dentures.
 1886: Wilson described adhesion as the primary
determinant in denture retention.
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9.  1920: Hall revived interest in the use of atmospheric
pressure as a retentive factor by interpreting and
demonstrating the functional denture borders.
 1948: Stanitz used a lab model to suggest that
atmospheric pressure is in equilibrium with fluid
pressure exerted on molecules within a capillary tube
with a liquid level in a container as well as the
attraction of two glass slabs. These models explained
how fluid film contributed to denture retention.
 1951: Craddock described the gripping action of the
buccinator muscle on the buccal flange of the
mandibular denture and also coined the term "pear
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10.  1962: Stamoulis believed that atmospheric pressure
combined with intimate tissue contact and peripheral
seal comprise the most critical retentive forces.
 1964: Fish discussed determinants of retention and
differentiated between tissue, polished, and occlusal
surfaces and how each permits the dentist to
incorporate mechanical, biologic, and physical factors
of the denture retention.
JIADS VOL -1Issue 1 Jan-March,2010

11. ANATOMICALAND PHYSIOLOGICAL
CONSIDERATIONS
Based on anatomic boundaries PPS is divided into two
separate areas:
Posterior palatal seal
Pterygomaxillary seal
 PPS- extends medially from one tuberosity to other.
 Pterygomaxillary seal-extends laterally pterygomaxillary
notch

12. PTRYGOMAXILLARY NOTCH
 The pterygomaxillary seal occupies the
entire width of pterugomaxillary notch.
 Ptrygomaxillary notch is a band of loose
connective tissue lying between pterygoid
hamulous of sphenoid bone and distal
portion of maxillary tuberosity.
 The notch is covered by the pterygomaxillary
fold which extends from posterior aspect of
tuberosity postero inferiorly to insert into
retromolar pad.

13.  This can influence border seal if mouth is opened in
wide position during final impression procedure.
 Hamular process position is important to note since it
affects length and direction of pterygomaxillary seal.
 Hamular process are covered by thin layer of mucous
memberane hence it should not be covered by denture.

14. FOVEA PALATINI
 Fovea palatini are two glandular
openings within the tissues of
posterior portion of hard palate
lying on either side of midline.
 Position of fovea palatine does not
represent junction of hard and soft
palate.
 Fovea palatini should be used only
as guidelines to the placement of
PPS

15. MEDIAN PALATINE RAPHAE
 The median palatal raphae, which overlies
the median palatal suture contains little or no
submucosa will tolerate little compression.
 Judicious placement of PPS across
midpalatine suture in the region of
posterior nasal spine demands careful
attention.
 When prominent midpalatine fissure is
present on hard palate, it often extends into
soft palate.

16.  Thus when present it should be carefully reproduced
on the master cast.
 PPS should be extended in this fissure to ensure
proper border seal.

17. PALATINE TORUS
 Palatine torus if extends to bony limit
of the palate leaving no room for
placement of PPS then its removal is
indicated.

18. THICK ROPY SALIVA
 Presence of thick ropy saliva can
create a hydrostatic pressure in the
area anterior to posterior palatal
seal resulting in downward
dislodging force exerted on denture
base.
 Thus a fine line or cupids bow is
scribed on the cast, anterior to the
cluster of palatal mucous glands.

19. CLASSIFICATION OF SOFT
PALATE(HOUSE)
 Based on angle the soft palate make with hard palate.
 More acute the angle, more muscle activity necessary
to establish velopharyngeal closure.
 More the soft palate displaced in function- less that
covered by denture base.
More the resorption of ridges – difficult to determine
the soft palate configuration.

20. CLASS I
 30 degree angulation with hard
palate
 Soft palate that is horizontal as it
extends posteriorly with
minimal muscular activity.
 Considerable amount of
separation between anterior and
posterior vibrating lines

21.  Wide posterior palatal seal which is not deep.
 Most favorable- more tissue surface covered hence
greater retention.
 Gives flat modified butterfly shaped seal with
maximum antero posterior width: 3-4 mm. 3-4 mm
 Associated with “U” shaped palate.
osterior palatal seal which is not deep

22. CLASS II
 Less palatal coverage than
class I
 “High modified butterfly”
palatal seal
 45 degree angulation .
 Antero posterior width of
palatal seal is 2-3 mm

23. CLASS III
 Most acute contour – 70 degrees
 Musculature makes most
elevation for effective
velopharyngeal closure
 Area available for seal is
minimal.
 Gives a “Bead” type palatal
seal.

24.  Least favorable.
 Associated with “V” shaped palate.

26. ANTERIOR VIBRATING LINE
 An imaginary line located at the
junction of the attached tissue
overlying the hard palate and the
movable tissue of an immediately
adjacent soft palate.
 Shape – cupid Bow shaped
anteriorly.
 Such shape is due to the projection
of the posterior nasal spine.

27.  Located by –
Valsalva Maneuver – Both the nostril are held firmly
while patient blow gently through the nose. This
positions the soft palate downward at its junction with
the hard palate.
 Patient is asked to say ‘ah’ with short vigorous bursts.

28. POSTERIOR VIBERATING LINE
An imaginary line at the junction
of the aponeurosis of tensor
veli palatini and the muscular
portion of the soft palate.
 It represents demarcation
between that part of soft palate
that has a shallow movement
during function and the
reminder that is markedly
displaced.

29.  Located by: It can be verified when the patient says
‘ah’ in normal unexaggerated fashion.

31.  According to Shape
 According to Area covered
 According to relationship with Fovea Palatini

32. ACCORDING TO SHAPE
1. BEAD ON CAST
 Single bead at distal margin of the
denture
 May result in loss of seal in lateral
palatal area where functional
depth & width are variable
 If bead sharp-irritates palatal
mucosa

33. 2. DOUBLE BEADED
 One bead-distal margin of denture
 2nd bead – anterior aspect of
posterior palatal area
 May result in loss of seal in lateral
palatal area

34. 3. BUTTERFLY SHAPED
 Cross section- deepest at most compressible area
of the posterior palatal seal area.
 Merges gradually with anterior & posterior borders.
 Depth maximum at centre & tapers to zero towards
anterior and posterior borders.

35. 4. BUTTERFLY SHAPED WITH “BEAD” ON DISTAL
EDGE OF DENTURE
 Deepest portion lies at distal most part of posterior
palatal seal area in form of a bead
 Gradually merges with anterior border
 Irritation to tissues may be seen

36. 4. BUTTERFLY SHAPED WITH WIDENED PPS IN
EACH HAMULAR NOTCH REGION
 Similar to butterfly shaped with more width in each of
hamular notches.
 May result in instability of denture due to presence of
hamular process.

37. Modified by House and classified as-
 CLASS I – Butterfly shaped / 3-4 mm
 CLASS II – High Modified Butterfly/2-4 mm
 Class III – Bead /minimum width at posterior nasal
spine

38. Relationshipwith Fovea Palatini
 According to “Lye”-located 1.3 mm anterior to vibrating
line
 Not always bilaterally symmetrical

40. CONVENTIONAL TECHNIQUE
Stage of Recording – At the start of jaw relation.
Method – Locate the hamular notch using a T-burnisher or
mouth mirror marked with an indelible pencil.

43.  The posterior vibrating line is located and marked by
indelible pencil.
 The shellac or resin temporary dental base is pressed
into place in the ‘Mouth’ then on the cast to transfer
the marking.
 The base is then shorten accordingly.

44.  Next the tissue anterior to posterior vibrating line are
palpated with a ball burnisher to determine its
compressibility.
 This usually correspond to the anterior vibrating line.
It is then marked and transferred to cast

45.  A kingsley scraper is used to score the cast or follow.
 The deepest areas are on either side of midline ;one third
the distance in front of the posterior viberating line.
 Median raphe region is scrapped less (0.5-1mm).
 The scrapping taper to a feather edge as it approaches the
anterior vibrating line.

46.  If a shellac tray is used it is reheated and readapted
thus improving retention of the trial denture base itself
more accurate jaw relation can be recorded if the trial
base is stable and retentive.
 The seal is checked in the mouth with a mouth mirror.
 If a gap is seen the cast can be scraped some more.

47. FLUID WAX TECHNIQUE
In this technique zinc oxide eugenol or plaster are
preferred over the elastic impression materials:-
 Impressions made are slightly resilient.
 When reseated in mouth under pressure may
distort the relationship between wax added to the
posterior border & the rest of the denture bearing
surface.
 Wax will not adhere to elastic material

48. TYPE OF WAX TO BE USED
1. Iowa Wax, White, Dr Earl S. Smith
2. Korecta Wax, Orange, Dr OC Applegate
3. H-L Physiologic paste, Yellow White, Dr Harkin
4. Adaptol, Green, Dr Nathan G. Kaye.
All these waxes are designed to flow at mouth
temperature.

49. TECHNIQUE
 The melted wax is painted onto the impression surface
within the outline of the seal area.
 The wax is applied slightly in excess of the estimated
depth & allowed to cool to below mouth temperature to
increase its consistency & make it more resilient to flow.
 The impression is carried to the mouth & held in place
under gentle pressure for 4-6 minutes to allow time for the
material to flow.

52. According to Nelson:
 The soft palate should be impressioned in its most
functionally depressed position ( i.e. downward &
forward position).
 This can be recorded when Frankfort horizontal
plane (porion-orbitale) is 300 below the horizontal.
 Tongue is firmly positioned against the mandibular
anterior teeth.

54.  Flexion of the head also contributes to moving the
excess impression material & saliva out of the mouth,
rather than progressing down the pharynx.
 While maintaining the 300 flexion of the head &
anterior tongue position, the patient is asked to
periodically rotate the head so that all functional
positions of the soft palate are recorded.

55.  After 4-6 minutes the impression tray is removed from the
mouth & the wax examined for uniform contact
throughout the posterior palatal seal area.

56. TISSUE CONTACT
IF ESTABLISHED
IF NOT BEEN
ESTABLISHED
WAX WILL APPEAR
DULL
WAX WILL APPEAR
GLOSSY

58.  Upon removal of the tray from the mouth, it is
carefully examined to see if the wax terminates in a
feather edge near the anterior vibrating line.
 The final impression with the physiologic posterior
border seal is carefully boxed & poured in stone as
soon after completion as possible.

59. ADVANTAGES
 It is physiologic technique displacing tissues within
their physiologically acceptable limits.
 Over compression of tissues is avoided.
 Posterior palatal seal is incorporated into the trial
denture base for added retention.
 Mechanical scraping of the cast is avoided.

60. DISADVANTAGES
 More time is necessary during the impression
appointment.
 Difficulty in handling the materials and added care
during the boxing procedure.

61. STICK COMPOUND
TECHNIQUE
 STAGE OF RECORDING:
During border moulding of the special tray, before the
final impression is made.
TECHNIQUE:-
 The stick compound is softened & applied on the tray
between the anterior & posterior vibrating lines.
 It is pressed gently into place in mouth.

62.  After material hardens, excess material beyond the
anterior vibrating line is trimmed off and tapered.
 The region is flamed and the process is repeated.

63. TISSUE CONTACT
POSITIVE CONTACT
NEGATIVE
CONTACT
GLOSSY
APPEARANCE
DULL
APPEARANCE

65. UNDEREXTENSION
1. Underextended distal border.
commonest cause:-
- Practitioner’s use of fovea palatini as the land mark
for terminating the denture base.
- Thus depriving the patient 4-12mm of tissue
coverage which could have significantly improved the
retentive qualities of the denture.

66. 2.There are patients who inform the dentist on the very
first visit for complete denture therapy that they are
gaggers.

67. MANAGEMENT:-
 Ask the patient to concentrate upon a point on the wall
while taking even & equal breaths through the nose.
 For individuals who require more conditioning, it may
be necessary to construct highly polished
autopolymerized resin tray on the master cast that is
extended to the posterior vibrating line.
 The patient is instructed to wear this appliance in the
comfort of his home.

68. 3. Failure of dentist to carefully examine the hard & soft
palates, making note of the palatal configuration.
-Without careful visualization, palpation & marking the
vibrating lines, it is easy to misinterpret the proper
posterior border extension.
4. When the technician is asked to trim & polish the
processed denture borders.

69. OVEREXTENSION
 Causes:
- In an attempt to maximize the retentive qualities of
the denture
- We may in advertently violate the physiology of the
soft palatal musculature and place the posterior
border too far distally.
- When this occurs, the active portion of the soft palate
drapes against the hard, unyielding denture base.

70. PATIENT’S COMPLAIN:-
 Swallowing is painful & difficult.
 Small ulcerations in soft palate will be evident.
 If hamuli is covered by denture base, the patient will
experience sharp pain.

71. MANAGEMENT:
By marking the lesion with an indelible pencil &
transferring it to the denture base, the precise portion
of the over extension can be moved with a bur & then
carefully repolish.

72. UNDERPOSTDAMMING
 It may be the result of recording the tissues when the
position of head & mouth is improper.
 As in case when mouth was wide open during the final
impression.
 When mouth is wide open, then the pterygomandibular
fold becomes taut.
 Thus creating a space between denture base & tissues.

73. HOW TO DIAGNOSE
UNDERPOSTDAMMING ?
 Place the wet denture base into the mouth and slowly
pressing in the mid-palate region until it is firmly
seated.
 If air bubbles can be seen escaping from beneath the
distal border, then at that point the denture base is
underpostdammed.

75.  In conventional approach correction can be done by
scraping the cast and readapting the trial base.
 In fluid wax technique by adding more wax and
reminding the patient to refrain from opening the
mouth so wide.

76. OVERPOSTDAMMING
 It commonly occurs when the master cast is scraped
too aggressively & posterior palatal seal displaces too
much tissue.
 In significant overpostdamming, especially in
pterygomaxillary seal area, then upon insertion of the
denture the posterior border will be displaced
inferiorly.

77.  If it is moderately overpostdammed then on the first
or post insertion appointment, tissue irritation will be
discernible across the posterior palatal region.
CORRECTION
 Selective reduction of the denture border with a
carbide bur, followed by lightly pumicing the area
while maintaining its convexity will remedy the
problem.

78. ADDING A POSTERIOR PALATAL
SEAL TO AN EXISTING DENTURE
 The deficiency may be either in
1. Depth
2. Length of the denture base
3. Both.
 However prior to taking any corrective measure, the
dentist should evaluate the entire prosthesis.

79. TECHNIQUES TO IMPROVE
POSTERIOR PALATAL SEAL
Attached paraffin
wax sheet at
posterior palatal seal
area.
Denture and set silicone putty. Roughening posterior
border of denture with
grinding of 45-degree bevel
joint.
Finished denture.
Immediate maxillary denture base extension for posterior palatal
seal : Yuuji Sato,aRyuji Hosokawa,b Kazuhiro Tsuga, and Mitsuyoshi ,Yoshida,
J Prosthet Dent 2000;
83:371-3
Packing mixed direct
relining resin.

80. Repair Of Posterior Base Of A Maxillary Complete Denture By
Use Of A Cast Of Stone And Resilient Material
Shyh-yuan Lee, and Steven M. Morgano
•Remove acrylic resin in the
area of the deficient posterior
palatal seal and relieve any
undercuts in the tuberosity
•region.
•Roughen the tissue surface of
the denture with laboratory
burs from the fracture lines to
the posterior border. J PROSTHET DENT1995;74:546-8.)

81.  Place modeling compound wherever the borders are
short.
 Seat the denture in the patient's mouth and perform the
traditional border molding procedures.
 Apply rubber adhesive over the tissue surfaces of the area
to be repaired and slightly over the adjacent polished
surfaces.

82.  Mix an adequate amount of
light-bodied polysulfide
rubber impression material
and place the material in an
evencoat in the area of the
repair.
 Seat the denture in the
patient's mouth, and allow the
patient to close into centric
occlusion. Maintain the
denture in this position and
allow the impression material
to set.

83.  Mix and apply polyether
impression material in any
undercuts.
 Mix yellow stone with slurry
water and decrease the
water/powder ratio (0.27) to
shorten the setting time.

84.  After the stone sets, remove
the denture from the cast,
discard the small broken
pieces, and fit the denture
back on the stone cast with
resilient material to verify
stability.
 Transfer the record of the
posterior palatal seal from
the patient to the master cast
and paint the master cast
with Triad-model release
agent

85. Establishing The Posterior Palatal Seal During The
Final Impression Stage: Izharul Haque Ansari
Maxillary ZOE final impression.
Redefined transfer pencil marking shows
anterior and posterior vibrating lines.
Criss-cross grooves made with
hot instrument for anchorage of
modeling compound.
Heated impression compound in plastic
disposable syringe is expressed directly onto
outlined PPS. J Prosthet Dent 1997;78:324-6.
Boxed final impression, after
completing posterior palatal seal,
ready for pouring cast.

86. SUMMERY
 The PPS should be prepared with an understanding of patient
palatal throat form, anatomical boundaries, extent and depth of
displaceable tissues.
 A method of determining the PPS for the maxillary complete
denture has been outlined and illustrated.
 Different techniques has been discussed to record the PPS and
repair of the broken denture.

87. 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.
 Clinicians don't take into consideration the polymerization
shrinkage, which occurs during processing.
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.