3. INTRODUCTION
The 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, make the placement of the
posterior palatal seal a quick and easy
procedure with predictable result
4. DEFINITION
Acc. to GLOSSARY OF PROSTHODONTICTERMS-9
POSTERIOR PALATAL SEAL :That portion of the intaglio
surface of maxillary removable complete denture ,
located at its posterior border, which places pressure,
within physiologic limits, on the pps area of the soft
palate ;this seal insures intimate contact of the denture
base to the soft palate and improves retention of the
denture
POSTERIOR PALATAL SEAL AREA:The soft tissue area
limited posteriorly by the distal demarcation of the
movable and nonmovable tissues of the soft palate and
anteriorly by the junctionof 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.
5. BOUNDARIES OF THE POSTERIOR
PALATAL SEAL AREA
ANTERIORLY-Anterior vibrating line
POSTERIORLY-Posterior vibrating line
LATERALLY-Pterygomaxillary notch
Anterolaterally extented ahead of hamular notch
Superoinferiorly – soft palatal tissues
6. BOUNDARIES OF THE POSTERIOR
PALATAL SEAL AREA
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”
7. ANTERIOR VIBRATING LINE
It is 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.
This line can be located by having the patient
perform the “valsalva maneuver”.
8. ANTRIOR VIBRATING LINE
The anterior vibrating line can also be
approximated by visualizing the area while
the patient says “ah” in short vigorous bursts.
The anterior vibrating line is ‘cupid bow’
shaped.
9. POSTERIOR VIBRATING LINE
It is an imaginary line
located at the junction
of soft palate that shows
limited movement and the
soft palate that shows
marked movement.
It also represents the junction of aponeurosis of
Tensor veli palatine muscle and the muscular
portion of soft palate.
10. POSTERIOR VIBRATING LINE
The posterior vibrating line can be visualized
by instructing the patient to say “ah” in short
bursts in a normal unexaggerated fashion.
This line marks the most distal extension of
the denture base.
11. FUNCTIONS OF POSTERIOR PALATAL
SEAL
The primary purpose of the posterior palatal
seal is the retention of the maxillary dentures.
A properly developed PPS will help reduce
the gag reflex.
Reduce food accumulation beneath the
posterior aspect of the denture due to proper
utilization of tissue compressibility.
12. FUNCTIONS OF POSTERIOR PALATAL
SEAL
Reduce patient discomfort when contact
occurs between the tongue and the posterior
end of the denture base .
Will compensate for the volumetric shrinkage
that occurs during the polymerization of
methylmethacrylate resin.
13. ANATOMIC AND PHYSIOLOGIC
CONSIDERATIONS
The posterior palatal seal is divided into two
separate but confluent areas based upon
anatomic boundaries.
The postpalatal seal
The pterygomaxillary seal
14. ANATOMIC AND PHYSILOGIC
CONSIDERATION
POSTPALATAL SEAL-This is a part of the
posterior palatal seal that extends between
the two maxillary tuberosities while,
PTERYGOMAXILLARY SEAL-This is the part
of posterior palatal seal that extends across
the hamular notch and it extends 3 to 4 mm
anterolaterally to end in the mucogingival
junction on the posterior part of maxillary
ridge.
16. PHYSIOLOGICAL CONSIDERATION OF
POSTERIOR PALATALSEALAREA
Pterygomaxillary notch
Pterygomandibular fold
The hamular process
The fovea palatine
The median palatal raphe
Midpalatal fissure
17. PHYSIOLOGICAL CONSIDERATION OF
POSTERIOR PALATALSEALAREA
Pterygomaxillary notch-is a depression
situated between maxillary tuberosity and
hamulus of medial pterygoid plate
The tissues in this region can be safely
displaced to achieve posterior palatal seal
18. PHYSIOLOGICAL CONSIDERATION OF
POSTERIOR PALATALSEALAREA
PTERYGOMANDIBULAR FOLD extends from
the posterior aspect of tuberosity postero-
inferiorly to insert into the retromolar pad.
Hamular notch is covered by pterygomandibular
fold
19. PHYSIOLOGICAL CONSIDERATION OF
POSTERIOR PALATALSEALAREA
HAMULAR POCESS is located 2 -4 mm
posteromedial to the distal limit of the maxillary
residual ridge
Covered by a thin layer of mucous membrane
The hamular processes should never be covered
by the denture
20. PHYSIOLOGICAL CONSIDERATION OF
POSTERIOR PALATALSEALAREA
FOVEA PALATINA is formed by collection of
ducts of several mucous glands
They are not constant findings in every
individual,however,they are unique to humans
It act as an arbitrary guide to locate the posterior
border of the denture
21. RATIONALE FOR PLACEMENT OF SEAL
IN 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.
22. CLASSIFICATION OF SOFT
PALATE
Based upon the angle that soft palate makes with the
hard palate
Class I – Soft palate is rather horizontal as it extends
posteriorly with minimal muscular activity
Class III –Most acute contour in relation to the hard
palate,marked elevation of musculature to create
velopharyngeal closure.
Class II – palatal contour lie between Class I and
ClassIII
23. Types Of
Posterior Palatal Seal Area
According To Shape:
BEAD ON CAST:
Single bead at the distal margin of the denture.
DOUBLE BEADED:
One bead at the distal margin and other at anterior aspect
of the palpated posterior palatal seal area.
24. BUTTERFLY SHAPED:
Deepest at the most
compressible area of the
posterior palatal seal area. It
merges gradually with its
anterior and posterior
borders.
BUTTERFLY SHAPED
25. BUTTERFLY SHAPEDWITH
BEAD ON DISTAL EDGE OF
DENTURE:
Deepest part lies at the distal
most part of posterior seal
area,in the form of bead.
26. BUTTERFLY SHAPED WITH WIDENED POSTERIOR
PALATAL SEAL IN EACH HAMULAR NOTCH
REGION:
More wide in each of the hamular notches.
Studies done by the workers shown that
altering the type of posterior palatal seal
affects the retention.None of the type is
tested proved to be superior.
27. ACCORDING TO THE AREA
COVERED
Posterior palatal seal can generally be
extended to about 4 mm from the
distal border of the denture. In
hamular notch areas it may be narrow
down to 2 mm.
Silverman advocates that denture
can be extended to an average of 8.2
mm dorsally to the “flexion line”.
28. House modification
class I: flat modified butterfly with the
maximum antero-posterior width 3-4 mm
class II: high modified butterfly,2-3 mm
with the maximum antero-posterior width 2-
3 mm.
class III: intermediate a bead type-
minimum width at posterior palatal spine.
29. PLACEMENT TECHNIQUE
The techniques used to mark posterior palatal
seal are:
1. Conventional technique
2. Fluid wax technique
3. Arbitrary scrapping of the master cast
4. Extended palate technique
5. PPS on master cast ( other methods)
6. Adding PPS to an existing denture
30. CONVENTIONAL TECHNIQUE
After an accurate and fully extended final
impression has been made and poured, a well
adapted resin tray is fabricated on the stone
cast.
The posterior palatal seal area is first dried
with a gauge and then aT-burnisher is used
to palpate the hamular process
31.
32. CONVENTIONAL TECHNIQUE
The anterior and posterior vibrating lines are
then marked using an indelible pencil.
• The resin or shellac tray is then inserted in the
mouth and seated firmly to place.
• Upon removal from the mouth, the indelible
lines should have been transefered to the
tray.The tray is then returned to the master
cast to transfer the line.
33.
34. CONVENTIONAL TECHNIQUE
A kinsley scraper is then used to scrap the
cast.
The deepest areas of the seal are located on
eitherside of midline, one-third the distance
anteriorly from the posterior vibrating line.
It is scraped to a depth of approximately 1 to
1.5mm.
35.
36. CONVENTIONAL TECHNIQUE
In the area of the median palatal raphe; the
cast is scraped to a depth of 0.5-1mm
• If the shellac tray is used, it is then replaced
on the moistened master cast, reheated and
readapted to conform to the scored palatal
seal area.
• After the tray has cooled, it is placed back in
the patient’s mouth and its retentive qualities
are evaluated.
37. ADVANTAGES
The trial base will be more retentive, which
can produce more accurate
maxillomandibular records.
Patients will be able to experience the
retentive qualities of the trial base giving
them the psychological security.
The dentist will be able to understand the
retentive qualities of the finished denture
The posterior extension of the denture can
be understood by the patient.
38. DISADVANTAGES
It is not a physiological technique and so
depends upon the accurate transfer of
vibrating lines and careful scraping of the
cast.
The potential for overcompression of the
tissue is great.
39. FLUID WAX TECHIQUE
The fluid wax technique is similar to the
conventional technique except that in this
technique the indelible transfer markings are
recorded on the final wash impression.
Corrective wax is used in this technique.
40. PROCEDURE
The wax is melted and painted on to the
impression surface within the outline of the seal
area.
The wax is then allowed to cool slightly below
the mouth temperature to increase its
consistency and to make it more resistant to
flow.
The impression is carried to the mouth and held
under gentle pressure for 4-6 minutes to allow
time for material to flow.
41. The melted wax is painted onto the final impression
within the outline of the posterior palatal seal area
42. • After 4-6 mins the impression is removed
from the mouth and the wax is examined for
uniform contact.
• The secondary impression is reinserted and
held for 3-5 mins under gentle pressure
followed by 2-3 minutes of firm pressure
applied to the midpalatal area of the
impression tray.
• Final impression is then boxed and poured
43. Upon removal from the mouth wax that extended
beyond the posterior palatal seal area has
been trimmed
44. ADVANTAGES
It is a physiologic technique displacing
tissues within their physiologically acceptable
limits.
Overcompression of the tissues is avoided
Posterior palatal seal is obtained increasing
retention
Mechanical scraping of the cast is avoided.
45. DISADVANTAGES
More time is needed.It is a time consuming
process
Difficulty in handling the material
46. ARBITRARY SCRAPING OF THE
MASTER CAST
In this technique the anterior and the
posterior vibrating lines are visualized by
examining the patient’ mouth and
approximately marked on the master cast.
0.5-1mm of stone is scraped in the posterior
palatal seal area of the master cast and the
denture is fabricated
This technique is inaccurate and not
physiological and should be avoided.
47. EXTENDED PALATAL TECHNIQUE
Described by Silverman in 1971.
In this technique, the denture border is
extended 8.2 mm beyond the anterior
vibrating line.
This method is not widely used currently.
48. Determining PPS on Master
Cast
The second commonly reported technique is
locating and transferring the PPS area on the
master cast followed by subsequent scrapping.
The scraping of the PPS on the cast allows the
seal area to have a convex surface on the denture
that slightly displaces the soft palate thereby
achieving peripheral seal.
Some of the techniques of scrapping and designs
of PPS are explained here.All of these scoring
techniques are done after correctly transferring
the PPS area on the master cast.
49. Boucher’s Technique
Stage of recording: before
Jaw relation record:
Posterior vibrating line is located and
transferred on the master cast
Temporary denture base is reduced to this
line
‘V’ shaped groove is scraped 2mm anterior to
the line
According to Boucher narrow bead like seal
is more effective
50. Bernard Levin’s Technique
For class III soft palate forms: He describes a
‘double bead’ technique for class III soft palate .
Here, the posterior vibrating line is scrapped 1 mm
deep and 1.5 mm wide. An anterior bead line is
created about 3 to 4 mm from the posterior border.
This is considered as the ‘rescue bead’. Bernard
stated that even though the anterior bead is
located on the hard palate,
the keratinization of the mucosa can tolerate small
amount of tissue displacement and pressure.
51. Bernard Levin’s Technique
For class I and class II soft palate forms: Using
No. 8 round bur of 2 mm diameter, two holes
of 2 mm depth are drilled at the depth of the
bur in the area between the midline and
hamular notches .
One hole of 1 mm depth is drilled to half the
diameter of the bur in the center. A cone-
shaped acrylic resin g bur is used to rough out
the seal.
52. The hamular notch region is not reduced
more than 0.25 mm in width and 0.5 mm in
depth and not extended onto the tuberosity
vestibules.
The softest part of the seal is scraped to 6
mm in width, whereas the median raphe
region is scraped to 4 mm in width. A medium
grid sand paper is used to smooth the
surface.
53. : PPS designs with the cross-sectional views depicted
in wax: (A) Single bead (Boucher’s technique) and
(B) double bead (Bernard Levin class III technique)
54. 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 .
From the depth of this posterior cut, the cast is
scraped in a tapering manner, so that it tapers up
to the anterior line.
55. Calomeni, Feldman, Kuebker’s
Technique
A posterior bead line is scraped on the cast to a depth
of 1 to 1.5 mm extending bilaterally through the
hamular notches .
The anterior line is placed 5 or 6 mm anterior to the
posterior line.The area between the anterior and
posterior lines is scraped with Kingsley Scraper No 1.
The depth of the cast scraped should vary from zero at
the anterior line to the depth of 1 to 1.5 mm along the
posterior border. In the midline, the distance between
the anterior and posterior lines should be
about 2 to 3 mm.
56. : PPS designs with the cross-sectional views depicted in wax
: (A) Butterfly (Swenson technique) and
(B) butterfly with bead (Calomeni technique)
57. Pound’s Technique
Pound advocates a single bead posterior palatal seal with
anterior extensions for additional air seal . A ‘V’-
shaped groove is carved across the palate from the hamular
notch to hamular notch 1 to 1.5 mm wide and 1 to 1.5 mm
deep.
This is placed 2 mm anterior to vibrating line. A loop is
carved on either side of the midline to provide air seal.The
depth and width of the anterior loop are determined by
palpating the area with a blunt end of the instrument.
58. Apple Baum-Winkler’s
Technique
A Kingsley scraper is used to score the cast .The deepest parts
of the seal are located on either side of the midline,
one-third distance anteriorly from the posterior vibrating line.
It is scraped to a depth of 1 to 1.5 mm.
Close to mid-palatine region, the area is scraped to a depth of
0.5 to 1.0 mm as it has little submucosa and cannot withstand
the same compressive forces as tissues lateral to it.
The scraping is gradually feathered out as it approaches the
anterior vibrating line and is tapered toward the posterior
vibrating line.The posterior palatal seal resembles, like Cupid’s
bow.
59. (A)Pound’s technique and (B)Winkler’s
technique of PPS designs with the cross-
sectional views depicted in wax
60. Silverman’s Technique
A pencil line is inscribed from hamulus to hamulus
midway between the anterior and posterior flexion
lines . A shallow scratch mark is placed on the
anterior flexion line and the posterior flexion line is
scored to a depth of one half of that of the midscore
line.
The cast is scraped over the entire seal area.The
depth of the cast scraping diminishes from the
midline to the anterior and posterior vibrating lines.
He also suggested that complete maxillary dentures
can be extended on an average distance of 8.2 mm
dorsally to the vibrating line
61. Hardy and Kapur Technique1
The depth of the posterior palatal seal area is
identified by pressing the ball portion of theT
burnisher .The posterior palatal seal is
extended 4 mm from the distal border of the
denture and narrowed down to 2 mm in width
through the hamular notch region.
The scraping of the cast is done in such a
fashion that the depth of the posterior palatal
seal is maximum at the center and tapers to
zero toward its anterior and posterior border.
62. Winland andYoung surveyed the commonly employed
posterior palatal seal designs and summarized them as follows:
1. A bead posterior palatal seal
2. A double bead posterior palatal seal
3. A butterfly posterior palatal seal
4. A butterfly posterior palatal seal with a bead on the posterior
limit
5. A butterfly posterior palatal seal with the hamular notch
area cut to half the depth of a no. 9 bur
6. A posterior palatal seal constructed in reference to House’s
classification of palatal forms.
On comparison of these designs with the scrapping
techniques discussed above; a beaded PPS design results
from
Boucher’s technique of scrapping, a double-beaded
technique
63. results from Bernard scrapping design for class III soft
palate, butterfly PPS design using Swenson’s method,
a butterfly design with a bead on the posterior limit results
from Calomeni’s technique.
A) Silverman’s technique (B) Hardy and Kapur’s technique of PPS
designs with the cross-sectional views depicted in wax
64. ADVANTAGES OF PLACING THE PALATAL
SEAL ON THE TEMPORARY RECORD BASE
• The trial base will be more retentive which can
produce a more accurate jaw relation
• The patient will get a psychologic security of
knowing that retention will not be a problem with
the final denture
• The dentist can assess the retentive qualities of the
denture at an early stage
65. ADDING POSTERIOR PALATAL SEAL
TO THE EXISTING DENTURE
This technique is similar to fluid wax
technique except that in this technique wax is
added to an already existing denture.
PROCEDURE
After the wax has been placed in the PPS
area, the denture is removed from the
mouth. An indelible pencil is used to outline
the anterior extent of the seal of the denture.
66. ADDING POSTERIOR PALATAL SEAL
TO THE EXISTING DENTURE
Utility wax is placed vertically across the palate
separating the posterior two-thirds from the
anterior region and extended across the
posterior portion of the denture.
Stone is vibrated into the denture wax surface
outlined by the utility wax. After the stone has
set, wax is eliminated and the denture is cleaned.
The denture is then trimmed distal to the
anterior vibrating line.
67. ADDING POSTERIOR PALATAL SEAL
TO THE EXISTING DENTURE
Lubricant is then applied to the unground
areas including the polished surface of the
denture and separating medium is applied to
the cast
Autopolymerising resin powder is then added
into the area created by the elimination of
the wax, and the cast is held firmly to the
denture by rubber bands.
68. ADDING POSTERIOR PALATAL SEAL
TO THE EXISTING DENTURE
After the initial set has taken place,they are
placed in a pressure pot with water (140⁰ F)
for 20 minutes under 30 psi pressure.
After the cast and denture are separated, the
excess acrylic is trimmed off and the denture
is polished.
69. UNDER EXTENSION
The most common cause of failure of the seal
in the posterior palatal area is the under
extended distal denture border.
Commonly, this is a result of the practitioner’s
use of the fovea palatine as the landmark for
terminating the denture base. By so doing, he
may be depriving the patient of as much as 4
to 12 mm of tissue coverage.
70. UNDEREXTENSION
The dentist may intentionally leave the
posterior borders underextended in order to
reduce the patient’s anxiety to gagging
Underextended posterior borders frequently
result when the Laboratory Technician is
asked to trim and polish the processed denture
borders.
71. UNDERPOSTDAMMING
It may be the result of recording the tissue
when the mouth was wide open during the
final impression.
The correction can easily be made by further
scraping the cast and readapting the trial base
if the conventional approach is used, or by
adding more wax and reminding the patient to
refrain from opening the mouth so wide if the
fluid wax technique is employed .
72. OVERPOSTDAMMING
It is not uncommon that the master cast was
scraped too aggressively and the posterior
palatal seal displaces too much tissue.
Selective reduction of the denture border with
a carbide bur, followed by lightly pumicing
the area while maintaining its convexity will
resolve the problem
73. CONCLUSION
Although the posterior palatal seal has
been discussed separately, it must be
remembered that it is a part of overall
peripheral seal.
The main difference between this and
rest of the peripheral seal is that it does
not have tissues surrounding it and
draping over it to provide a seal.
Thus the manner in which seal is
obtained in the posterior palatal
region is different.
74. CONCLUSION
The posterior palatal seal is obtained
through intimate contact and the
application of pressure within the
physiologic limit by the denture in this
region.
This would require an intimate knowledge
of the anatomy, functions and movements
of the tissues of the region.
75. REFERENCES:
1.Sheldon Winkler, Essential of complete denture prosthodontics,
A.I.T.B.S. Publishers and Distributors,Ed:2nd
2. LyeTL.The significance of the fovea palatine in Complete
Denture Prosthodontics. J Prosthet Dent 1975;33(5):504-10.
3.Zarb G.A., Bolender C.L. Prosthodontic treatment for
edentulous patients. Mosby, Ed:12th.
4. Heartwell C.M., Rahn A.O. Syllabus of complete dentures.
Varghese Publishing house, Ed:5th.
5 Moghadam BK, Scandrett FR. A technique for adding the
posterior palatal seal. J Prosthet Dent 1974;32(4):443-7.
6. Kolb HR.Variable denture limiting structures of the edentulous
mouth. J Prosthet Dent 1966;16(2):194-201.
7. Chen MS. Reliability of the fovea palatine for determining the
posterior border of the maxillary denture. J Prosthet Dent 1980;
43(2):133-37.
Kim Y, Michalakis KX, Hirayama H.-Effect of relining
method on dimensional accuracy of posterior palatal seal.
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Epub 2007 Jan 11
