This document discusses the posterior palatal seal (PPS), which is an important area for providing retention of maxillary dentures. It defines the PPS as the area of soft tissue on the soft palate that can withstand controlled pressure from a denture. The document covers the anatomy and muscles of the soft palate, classification of soft palate shapes, landmarks related to the PPS, and techniques for recording the PPS during the impression process such as the conventional technique.

1. A S W A T I S O M A N
P G R E S I D E N T
POSTERIOR PALATAL SEAL

2. CONTENTS
 Introdruction
 Muscles of Soft palate
 Classificationof soft palate
 Structures related to pps
 Pterygomaxillary seal
 Post palatal seal
 Vibrating line
 Technique to record PPS

3. INTRODUCTION
 The Posterior Palatal Seal area is the posterior most
limiting structure in the maxillary denture.
 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.
 The posterior border of maxillary denture has definite
anatomic and physiologic boundaries ,once understood,
the placement of the seal become a quick and easy
procedure with predictable result.

4.  POSTERIOR PALATAL SEAL AREA :
The soft tissue area limited posteriorly by the distal
demarcation of the movable and immovable tissues of the
soft palate and anteriorly by the junction of hard and soft
palate on which pressure within the physiologic limit can be
placed; this seal can be applied by a removable complete
denture aids in its retention.

5.  POSTERIOR PALATAL SEAL :
That portion of the intaglio surface of the maxillary
removable complete denture on its posterior border
which places pressure within the physiologic limit on the
posterior palatal seal area of the soft palate; this seal
ensures intimate contact of the denture base to the soft
palate

6. SOFT PALATE
 Musculo-membranous curtain.
 Functions as flap valve closes off nasopharynx during
swallowing.
 Part of a dual valve system which separates the
oropharynx from the oral space and the
nasopharynx from the nasal space.
Dimension and displacement pattern of posterior palatal seal, Silverman, j prosthet
dent, may 1971

7.  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 handle of
impression tray or dentist’s fingers, and should not protrude
beyond lips.

8. MUSCLES OF SOFT PALATE

9. Palatoglossus
 Origin – Palatine aponeurosis
 Insertion - Side of tongue
 Action - Draws palate down, raises tongue

10. Palatopharyngeus:-
 Origin – Arises as 2 fasciculi – Posterior fasciculi arises
from palatine aponeurosis and anterior fascicule from
posterior border of hard palate.
 Insertion – Lamina of thyroid cartilage, wall of pharynx
and its median raphe.
 Action – Helps in pulling up the wall of pharynx and
shortens it during swallowing.

11. Clinical significance
 Tensor Veli Palatini - When taut, can influence the
denture contour in the hamular notch area.
 Levator Palati - 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.

12. PTERYGOMAXILLARY SEAL
 Extends through pterygomaxillary notch continuing 3-4
mm anterolaterally approximating the mucogingival
junction.
 Occupies the entire width of hamular notch.

13. STRUCTURES RELATED TO PPS
 Hamular process
 Pterygomaxillary notch or Hamular notch
 Median palatal raphe
 Fovea palatini

14. PTERYGOMAXILLARY NOTCH
 Band of loose connective tissue lying between the
pterygoid hamulus of the sphenoid bone and the distal
portion of the maxillary tuberosity.
 Lateral boundaries for the PPS.

15. HAMULAR PROCESS
 2-4mm postero-medial to the distal limit of the maxillary
residual ridge.
 Affects the length and direction of the pterygomaxillary
seal.
 Covered by mucous membrane and should not be
covered by denture.

16. MID PALATINE RAPHAE
 This overlies the medial palatal suture, contains little or
no submucosa and will tolerate little compression.
 According to heartwell and rahn, this band of tissues is
not meant to be compressed, rather should be relieved if
prominent

17. FOVEA PALATINI
 Two glandular openings within the tissues of posterior
portion of hard palate, usually lying on either side of
midline.
 They are the ductal openings into which the ducts of
other palatal mucosal glands drain
 Doesnot represent the junction of hard and soft palate
and should be used only as a guideline to placement of
posterior palatal seal.

18. VIBRATING LINE
 The imaginary line across the posterior part of the palate
marking the division between the movable and
immovable tissues of the soft palate which can be
identified when the movable tissues are moving.

19. 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 bow’ shaped due to the projection of posterior nasal
spine.
 Always on soft palatal tissues.
 To locate anterior vibrating line patient is asked to perform
valsalva maneuver(both nostrils are held firmly while patient
blows gently through the nose)
 Also located by visualizing the area while instructing the
patient to say ‘ah’ with short vigorous bursts(sharry)

20. POSTERIOR VIBRATING LINE
 Imaginary line at the junction of aponeurosis of Tensor veli
palatine muscle and the muscles of 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.
 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.

22. 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.

23. 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.

24. CLASS II
 Palatal contours between a class I and class II

25. CLASS III
 Most acute contour in relation to the hard palate
 Marked elevation of the musculature to effect
velopharyngeal closure
 Seen along with a high V-shaped vault usually.
 Smaller in width but deeper posterior palatal seal
area

26. PALATAL THROAT FORM
 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.

28. FUNCTIONS OF PPS
 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.

29.  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.

30. REVIEW OF LITERATURE
 1958, Hardy and Kapur stated - Retention and stability derived
from the forces of adhesion cohesion and interfacial surface
tension resist only the dislodging forces acting perpendicular
to the denture and fail to resist the dislodgement of the
dentures by horizontal forces and lateral torques.
 This dislodgement can be resisted by the retention provided
by the partial vacuum created by the denture border seal.

31.  In the posterior region sealing is done by developing a
posterior palatal seal.
 Such a seal will create a partial vacuum that will not
operate continuously, but one that will come into play
only when horizontal or tipping thrusts tend to
dislodge the denture and then only long enough to
overcome the emergency.
 This partial vacuum is unlikely to operate long enough
to do any damage to the supporting or border tissues.

32.  Sidney Silverman (1971) conducted a study and
concluded complete maxillary dentures can be extended
for an average of 8.2mm dorsally to the vibrating line or
flexion line, where the soft palate joins the hard palate.
 This extension varies from 4-12mm dorsally to a
transverse region.

33.  Antolino Colon, Keki Kotwal and David Mangessdorff (1982)
found that the form of the palate has direct influence on the
retention of complete dentures and will aid in the selection of
the type of posterior palatal seal needed.
 Rajeev M. Narvekar and Marc B. Appelbaum in 1989 used
ultrasound instrumentation as an non-invasive procedure to
locate the anatomic structures in the PPS region.
 In 1997, Izharul Haque Ansari described a method to
establish posterior palatal seal during the final impression
stage.

34. PARAMETRESOF PPS
 SIZE
 SHAPE
 LOCATION
Winland and Young, maxillary complete denture posterior palatal seal: variation in shape
size and location, j prosthet dent , march,1973

35. 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)
 The mean width was found to be different for right (8.2mm) and
left side (8. 1mm).
 The interhamular notch distance was found to be 35.8 mm (25-
48mm range)
 The interhamular notch distance was found to be different for
males (37.1 mm) and females (35.6 mm)

36. SHAPE

37. •BEAD
•DOUBLE BEAD
•BUTTERFLY
•BUTTERFLY WITH BEAD

38. CLASS I- MODIFIED BUTTERFLY
APPR 3-4 MM WIDE
CLASS II- MODIFIED BUTTERFLY
APPR 2-3 MM WIDE
CLASS III- A BEAD

39. TECHNIQUE TO RECORD PPS
 Prior to the corrective wash impression procedure, the
posterior denture border must be fully extended, which
means that all of the soft palate that is to be covered by
the denture has been captured in the border molded
custom tray.
 Intact tissue that is 1 to 2 mm distal to the expected
denture border should also be present in the impression
tray to protect against any overtrimming of the processed
denture base.

40. 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 downs the pharynx.
 To serve as a guide for positioning the impression tray
 To create slight displacement of the soft palate
 To determine if adequate retention and seal of the potential
denture border is present.

41. CLASSIFICATION TECHNIQUE OF RECORD 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.
Hardy and Kapur, posterior palatal seal- its rationale and importance, j prosthet
dent may 1958

42. The techniques used to mark posterior palatal seal are:
 Conventional technique
 Fluid wax technique
 Arbitrary scraping of the master cast
 Extended palate technique
 Adding PPS to an existing denture
 Determination of PPS by ultrasound

43. CONVENTIONAL TECHNIQUE
 Final impression is made, boxed, and poured.
 A well-adapted resin/shellac tray is fabricated on the
stone cast.
 The posterior palatal area is then dried with gauge; a “T”
burnisher /a mouth mirror is used to palpate for the
hamular process and marked with an indelible pencil

46.  The instrument (“T” burnisher/mouth mirror) is then placed
along the posterior angle of the tuberosity until it drops
into the pterygomaxillary notch.
 A line is placed with an indelible pencil, through the notch
and extended 3-4mm anterolateral to the tuberosity,
approximating the mucogingival junction.
 The same procedure is then performed on the opposite
side. This will complete the outlining of the
pterygomaxillary seal.

47.  The patient is asked to say “ah” in short bursts in an
unexaggerated fashion.
 While observing the movement of the soft palate the
posterior vibrating line is marked with an indelible pencil.
 By connecting the line through the pterygomaxillary seal
with the line just drawn demarcating the “postpalatal”seal
(posterior vibrating line), the posterior denture extension is
delineated.

48.  The resin /shellac tray is then inserted into the mouth and
the indelible pencil lines are transferred to the tray, which
is returned to the master cast to complete the transfer of
posterior border and tray is trimmed.
 The palatal tissues anterior to the posterior border are
palpated with the “T”burnisher /mouth mirror to
determine their compressibility in width and depth.

49.  The use of Valsalva maneuver / visualizing the area when
the patient says “ah” with
 short vigorous bursts may also be used.
 This line is marked with the indelible pencil and
transferred to the master cast

50.  A Kingsley scraper is used to scrape the cast.
 The deepest area of the seal are located on the either side of
the midline, one third the distance anteriorly from the post
vibrating line.
 It is scraped to the depth of the approximately 1-1.5mm.
 The tissue covering the median palatal raphe has little
submucosa and cannot withstand the same compressive
force on the tissues lateral to it. It is scraped to the depth of
approximately 0.5-1.0mm.

51.  Just posterior to the deepest portion of the seal, it is also
tapered to the posterior vibrating line. Failure to taper
the seal posteriorly may lead to tissue irritation.
 Shellac can be readapted to conform to the scored palatal
seal area and tried in the mouth to evaluate the retentive
qualities of the trial base.

52. ADVANTAGES
 More retentive trial base , which can produce more accurate
maxillomandibular records.
 Patients are able to experience the retentive qualities of the
trial base giving them the psychological security of knowing
that retention will not be a problem.
 The dentist is able to understand the retentive qualities of the
finished denture.
 The posterior extension of the denture can be understood by
the patient.

53. DISADVANTAGE
 Not a physiological technique and so depends upon the
accurate transfer of vibrating lines and careful scraping of
the cast.
 More potential for overcompression of the tissue.

54. FLUID WAX TECHNIQUE
 Similar to the conventional technique except that in this
technique the indelible transfer markings are recorded on
the final wash impression.
 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.

57.  Zinc oxide and eugenol /plaster are preferred over the
elastic impression material, as they set rigid.
4 types of wax –
 Iowa Wax (White) – Dr. Earl S. Smith
 Korecta Wax no.4 (Orange) – Dr. O.C. Applegate
 H-L physiologic paste (Yellow-White) – Dr. C.S. Howkins
 Adaptol (Green) – Dr. Nathan G. Kyne

58.  Designed to flow at mouth temperature.
 The melted wax is painted onto the impression surface with
the outline of the seal area and allowed to cool to below
mouth temperature to increase its consistency and make it
more resistant to flow.
 The impression is carried to the mouth and held in the place
under gentle pressure for 4-6 minutes to allow time for the
material to flow.

59.  After 4-6 minutes, the impression tray is removed from the
mouth and the wax examined for uniform contact through
out the posterior palatal seal area.
 If tissue contact has not been established, the wax will appear
dull. If the tissue has been contacted, the wax will have a
glossy appearance.
 Where the wax appears dull, more wax should be applied and
the procedure repeated.
 The secondary impression is reinserted and held for 3-5
minutes of firm pressure applied to the midpalatal area of the
impression tray.

60. PRECAUTION
 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.
 The borders of the wax should terminate in feather edge
towards the vibrating line .If a butt joint is formed, proper
flow may have not taken place.

61. ADVANTAGE
 Physiologic technique displacing tissues within their
physiologically acceptable limits.
 Overcompression of the tissues is avoided
 Posterior palatal seal is obtained increasing retention at
an early stage.
 Mechanical scraping of the cast is avoided.

62. DISADVANTAGE
 More time is needed
 Difficulty in handling the material

63. EXTENDED PALATAL TECHIQUE
 (Silverman 1971)
 Denture border is extended 8mm approximately beyond the
anterior vibrating line.
 Not widely used currently.
 Method -
 After border molding tray is extended by adding compound.
 Green stick compound is added to the seal area and record is
made with head flexed 30 degree downward.

64. ADDING PPS TO 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.

66. 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.

67.  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.
 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.

68. Rajeev M. Narvekar, and Marc B. Appelbaum
 Investigated the anatomic position of posterior palatal seal
by ultrasound.
 Ultrasound refers to sound with frequencies higher than the
audible range (20 to 20,000 Hz).
 Basic elements of an ultrasound scanning system include –
 1. Transducer 2.Couplant

69. ULTRA SOUND TRANSDUCER
 The active element that has piezoelectric properties
which transform mechanical energy into electric energy
and vice versa

70. COUPLANT
 Necessary between the ultrasonic transducer and the skin
because air is a poor conductor of sound energy.
B mode (Brightness modulation)
 The brightness or shade of gray in the display represents
the amplitude of the echoes received from the anatomic
cross section of the patient.

71. RESULT OF THE STUDY
 The distance from the junction of the hard and soft palates
varied from a maximum of 4.3mm to a minimum of 2 mm,
with a patient average of 2.5 mm.
 The average distance from the posterior vibrating line to
the junction of the hard and soft palates was 2.9 mm.
 The average width of the posterior palatal seal is considered
to be approximately 4 to 6 mm. Therefore, part of the seal
would lie on the glandular posterior third of the hard
palate.

72. ARBITRARY SCRAPPING OF THE CAST
 Anterior and the posterior vibrating lines are visualized by
examining the patient’ mouth and approximately marked
on the mastercast.
 Least accurate and leaves a chance at insertion
appointment since it relies on dentist’s recollection of
palatal configuration and tissue compressibility.
 Inaccurate and not physiological.

73. BOUCHERS TECHNIQUE
 Stage of recording- during jaw relations
 Method the posterior vibrating line is located and transferred
on to the master cast.
 The temporary denture base is reduced to this line.
 This will create a raised narrow and sharp bead along the
posterior portion of the denture which sinks into the tissues
and forms a seal.
 Advantage: According to Boucher a narrow bead like seal is
more effective.

75. Bernard Levin’s Technique
For class III soft palate forms: He described a, “double bead”
technique for class III soft palate.
 In this technique, a depth of about 1mm and width of 1.5mm is
scraped in posterior vibrating line.
 A distance 3 to 4 mm from posterior border, anterior vibrating
line is beaded. This is known as rescue bead.

76. For class I and class II soft palate
 Using no. 8 round bur of 2mm diameter, 2 holes of 2mm
are drilled at thethe deptho the bur in the area between
the midline and hamular notch
 One hole of 1mm depth is drilled to half the diameter of
the bur in the center
 A cone shaped acrylic resin bur is used to rough out the
seal

78.  The hamular notch region is not reduced more than
0.25mm in width and 0.5mm in depth andnot extended
onto the tuberosity vetibule
 The soft tissue part of the seal is scraped to 6mm in width
where , the median raphae region is scraped to 4mm in
width

79. Swenson’s Technique
 A groove is cut along the posterior line to a depth of 1 to
1.5 mm that will cause the posterior border stand straight
out from the hard palate, turning neither up nor down.
 Posterior line is tapered towards the anterior line by
scraping the cast.

80. Calomeni, Feldman, Kuebker’s Technique
 In this technique a depth of 1 to 1.5 mm scraped as
posterior bead in which extends through hamular notches
and distance of 5 to 6 mm from posterior line, anterior
line is beaded.
 Using a Kingsley scraper No.1 a depth 0 at anterior line to
a depth of 1 to 1.5 mm along posterior border is
scrapped.
 A distance of 2 to 3 mm should be present in between the
anterior and posterior lines from the midline.

82. Pound’s Technique
 Pound recommends a single bead posterior palatal seal
with anterior extensions for additional air seal.
 In the palate from the hamular notch to hamular notch a
‘V’ shaped groove is carved measuring a width of 1 to 1.5
mm and depth of 1 to 1.5 mm and is placed 2 mm
anterior to vibrating line.
 In order to provide adequate air seal a loop is carved on
either side of the midline.
 Palpate the area with a blunt of the instrument to
determine the width of anterior loop.

84. Hardy and Kapur Technique
 Using the ball portion of the T burnisher depth of
positerior palatal seal is examined.
 The posterior palatal seal is extended 4 mm from distal
border of denture .
 Then the hamular notch region is narrowed to 2 mm in
width through the hamular notch.
 Posterior palatal seal is at its maximum depth in center
and minimizes to zero at its anterior and posterior border
by scraping the cast.

86. TROUBLE SHOOTING
 Under extension
 Over extension
 Under post damming
 Over post damming

87. UNDER EXTENSION
 Most common cause for failure of the seal in the posterior
palatal area
Causes
 Practitioner’s use of the fovea palatine as the landmark for
terminating the denture base. By doing, so he may be
depriving the patient of as much as 4 to 12 mm of tissue
coverage.
 Failure of the dentist to carefully examine the hard and soft
palates, making note of the palatal configuration
 Over trimming of posterior border by laboratory technician
 Due to fear of gagging

88. UNDER POSTDAMMING
 May be the result of recording the tissue when the mouth was
wide open during the final impression.
 When the mouth is in the wide open position, the
pterygomandibular fold becomes taut.
 When the patient assumes any position other than a wide
open position, a space will be present between the denture
base and the tissue since the fold is no longer activated.

89.  Diagnosis :- place the wet denture base into the mouth
and slowly press in the midpalatal region until it is firmly
seated while observing the distal denture border.
 If air bubbles are seen escaping from beneath the distal
border, then at that point the denture base is
underpostdammed.

90. CORRECTION
 Further scrap the cast and readapting the trial base if the
conventional approach is used
 Add more wax and remind the patient to refrain from
opening the mouth so wide if the fluid wax technique
employed.

91. OVER POSTDAMMIMG
 Over scrapping of master cast and the posterior palatal seal
displaces too much tissue.
 Significant over post damming especially in the
pterygomaxillary seal area - posterior border will be displaced
inferiorly.
 Moderately over postdammed - tissue irritation across the
posterior palatal region
 Selective reduction of the denture border with carbide bur,
followed by lightly pumicing the area while maintaining its
convexity.

92. OVER EXTENSION
 The most frequent complaint from the patient will be
that swallowing is painful and difficult. Small ulcerated
areas in the region of the soft palate will be evident.
 If the hamuli are covered by the denture base, the patient
will experience sharp pain, especially during function.
 By marking the lesion with an indelible pencil and
transferring it to the denture base, the precise position
of the overextension can be removed with a bur and then
carefully repolished.

93. REFERENCE
 Zarb Bolender, Mosby,Prosthodontic treatment for
edentulous patients,12th edition
 Sheldon Winkler ,A.I.T.B.S. Publishers,Essentials of
complete denture Prosthodontics,2nd edition
 B.D. Chaurasia , Human Anatomy- Vol.3 Head and Neck
 Hardy I R, Posterior border seal –its rationale and
importance, J Prosthet Dent 1958:8;386-97

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