posterior palatal seal

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2. The posterior palatal seal
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3. Posterior palatal
seal
Defnition
Purpose
Functions
Anatomic
considerations
Physiologic
consideration
Anterior and
posterior vibrating
lines
Soft palate
Techniques
Trouble
shooting
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4. introduction
• The diagnostic evaluation and
placement of posterior palatal seal
often given minor attention in cd
construction.
• The posterior border of the maxillary
denture has definite anatomic and
physiologic boundaries
• Once understood make PPS a quick
and easy procedure.
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5. • Proper placement of PPS begins with
intraoral examination such as –
1. Morphologic contours of hard and
soft palate
2. Hamular notch regions
3. Integrity and displaceability of the
mucosa and underlying glandular
tissues .
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6. • Hardy and Kapur stated that adhesion
cohesion and interfacial surface tension
act only on perpendicular dislodging
forces .
• Horizontal forces and lateral torquing
resisted only by adequate border seal.
• Therefore primary purpose-retention of
maxillary denture .
• If properly placed reduce gag reflex.
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7. Definitions: GPT 8
• Posterior palatal seal area/
Postpalatal seal area/
Postdam area:
 The soft tissue area at or beyond
the junction of the hard and soft
palates on which pressure within
physiologic limits, can be applied by
a denture to aid in its retention.
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8. Signs of correctly placed PPS
1. Will not impinge non displaceable
tissues of hard palate.
2. Will not limit muscular movements
of the soft palate .
3. Create a partial vacuum beneath the
maxillary denture .
4. Activated only when horizontal or
tipping forces are directed .
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9. functions
• Complete denture
Retention of maxillary denture.
Reduces gag reflex.
Prevents food accumulation.
Reduces patients discomfort.
Compensates for volumetric
shrinkage.
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10. Functions
• Impression tray
Establishes positive contact posteriorly
and prevents impression wash material
from sliding down the pharynx.
Guides the positioning of impression
tray.
Creates slight displacement of soft
tissues .
Help verify retention and seal of
potential denture border.
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11. Anatomic and physiologic
consideration
• Divided into 2 based on anatomic
boundaries-
1. Extends medially from one
tuberosity to the other .
2. Laterally extends through the
hamular notch continuing for 3 to 4
mm anterolaterally approximating
the mucogingival junction.
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13. • Hamular notch covered by the
pterygomandibular fold .
• This fold can influence posterior
border seal.
• Hamular process should never be
covered by the denture-
location-: 2 -4 mm posteromedially
to the distal limit of the maxillary
residual ridge.
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15. • Fovea palatini, when present ,lie on
either side of the midline .
• Location
 According to Lye-1.31mm anterior
to the anterior vibrating line .
According to Chen-located either on
or behind the anterior vibrating line.
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17. • Placement of PPS in the region of
posterior nasal spine demands extra
attention.
• The PPS should be extended to
prominent midpalatal fissure if it
extends into soft palate.
• Narrow cordlike band of tissue-
posterior nasal spine & aponeurosis
of the tensor veli palatini muscle.
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18. • A/C Heartwell and Rahn-this band of
tissue if prominent should given
relief.
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19. • Torus palatinus if extends to the
bony limit of the palate leaving little
or no room to place PPS should be
removed .
• Evaluation at initial diagnostic
session.
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21. • Thick ,ropy saliva can create problem
in maxillary complete denture
retention.
• Treatment –a fine line or cupid’s bow
can be scribed on the master cast
anterior to the cluster of palatal
mucous glands .
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22. Anterior and posterior
vibrating lines
• Anterior vibrating lines –imaginary
line located at the junction of the
attached tissues overlying the hard
palate and the movable tissues of
the immediately adjacent soft palate
.
• Note-should not be confused about
location
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24. • Two ways of locating AVL
1. Valsava maneuver
2. Visualizing while saying “ah” with
short vigorous bursts.
• Always on soft palate .
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25. • Posterior vibrating lines –imaginary
line at the junction of the
aponeurosis of the tensor veli
palatini muscle and the muscular
portion of the soft palate .
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27. • Visualized by instructing the patient
to say “ah” in short bursts in a
normal, unexaggerted fashion.
• Marks most distal extension of
denture base.
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28. Classification of soft palate
• Based on the degree of flexure that
the soft palate makes with the hard
palate and the width of the palatal
seal area, the soft palate
configuration may be classified as -
1. Class 1
2. Class 2
3. Class 3
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30. • Class 1
1. Almost horizontal with little
movement making <10degree with
hard palate .
2. Most favourable as it allows best
tissue coverage >5mm .
3. Development of wide posterior seal .
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31. • Class 2
1. makes a 45 degree angle with the
hard palate.
2. Tissue coverage 3-5mm.
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32. • Class 3
1. makes a 70 degree angle with the
hard palate.
2. Least favourable
3. Tissue coverage <3mm
4. Usually associated with v shaped
palate .
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33. Muscles of the soft palate
• Tensor veli palatini
• Levator veli palatini
• Musculus uvulae
• Palatoglossus
• Palatopharyngeus
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35. Treatment of soft palate
defects
• Palatal lift prosthesis
 Addresses velopharyngeal incompetence
 By physically displacing the disfunctional
soft palate.
 In the hope of closing the velophryngeal
port
 Enough to mitigate hypernasal speech
and/or prevents nasopharngeal
regurgitation of liquids or solids
 During pharngeal phase of swallowing
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36. Consists of an oral components that
stabilizes and secures the prosthesis
and
An oropharngeal extension that
superiorly and and posteriorly
displaces the impaired soft palate .
Classified as interim and defintive
prosthesis .
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38. Recording the PPS
• This can be achieved by the following
methods-
1. Scrapping of cast-functional
&arbitrary
2. Impression technique-using fluid
wax and using low fusing compund
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39. Functional scrapping of cast
• Done on the trial denture base
• Pts sits in an upright position
• PVL marked with T burnisher
• The AVL marked by valsava
menoeuvre and transferred to the
cast.
• Scrapping the master cast
functionally .
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42. • After scrapping the master cast ,the
post dam should be checked .
• Scrapped area should be readapted
by shellac denture base or cold cure
resin material added .
• Modified record base checked with
mouth mirror as the pts say “ah”in
an unexaggerated manner.
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43. • Presence of space indicates under
postdamming
• Then the depth of the scrapping
should be increased .
• The procedure repeated until no
space exists .
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44. advantage
• The trial denture base has increased
retention due to this technique ,thereby
increasing the accuracy of the jaw relation
procedure .
• The pts can experience and is aware of the
retentive qualities expected from the final
denture
• the dentist is also aware of the amount of
retention denture will process .
• Adjustment for posterior extension is less
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45. Disadvantage
• Not a physiological technique hence,
it is technique sensitive .
• Excessive scrapping of the cast can
lead to over postdamming .
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46. Arbitrary scrapping of the
master cast
• This is mostly done by the technician
prior to processing the denture when
the dentist fails to establish the seal
clinically .
• It is an arbitrary notched line formed
in the imaginary posterior vibrating
line area extending to the hamular
notches .
• It should be discouraged .
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48. Fluid wax technique
• Any wax that is designed to flow at
mouth temperature
• Seal established after making final
impression but before pouring master
cast
• ZOE & impression plaster are suitable
impression materials
• The AVL &PVL marked by conventional
technique and transferred to the final in
the mouth.
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51. • Final impression painted with fluid wax.
• Pts head should be in frankfort’s
horizontal plane at 30 degree.
• Pts tongue should be positioned against
the mandibular anterior teeth .
• Pts is asked to periodically rotate the
head .
• Glossy areas which represent tissue
contact should be checked after 4 -
6minutes.
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53. • Wax is added to areas that appear
dull &the procedure repeated .
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55. Advantage
• Physiological technique
• Over compression of tissue avoided .
• Increased retention of the record
base and convenience in jaw relation
.
• There is no need of scrapping the
master cast mechanical.
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56. Disadvantage
• Increased chairside time .
• Handling of material difficult.
• Care needed while pouring the
master cast.
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57. Low fusing compound
• Green stick compound can also be
used to make an impression of the
seal area using a similar procedure
as described for fluid wax.
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58. Errors in establishing the PPS
1. Underextension
2. Overextension
3. Underpostdamming
4. overpostdamming
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59. underextension
• Using fovea palatine as the limit for
posterior denture extension results in
loss of several mm of denture extension
• Gag reflex prompting the dentist to
intestinally leave the posterior border
short .
• Incorrect delineation of the AVL &PVL.
• Asking the technician to establish the
seal on the cast arbitrarily.
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60. Overextension
• Can lead to ulceration and painful
deglutition.
• Covering of the hamular process can
also lead to sharp pain in the region .
• These ares should be indentified,
trimmed and examined .
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61. underdamming
• Occur when the pts mouth wide open
while making final impression .
• Seal areas becomes taut in this position
and space is created in other position .
• Verified by inserting wet denture
• If air bubbles escapes indicates
underdamming .
• Corrected by adding a new seal to the
existing denture .
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62. Overdamming
• Occurs due to excessive scrapping of
the master cast in the hamular notch
region.
• Mild cases causes irritation and
excessive displaces the denture .
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63. Summary
• The placement of the correct PPS area is
not a difficult procedure once the anatomy
and physiology of the areas are understood
.
• Careful examination during the diagnostic
phase of the treatment can alleviate many
potential problems .
• Following established techniques for the
placement of the border seal area will
ensure a more retentive prosthesis for the
pts whose satisfaction is the practitioner’s
main concern.
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64. • Winkler; Essentials of complete denture prosthodontics
• Bernard Levin, impressions for complete dentures
• Chen MS: Reliability of the fovea palatini for determining the
posterior border of the maxillary denture.J Prosthet Dent
1980;43:133-137
• Silverman SI: Dimensions and displacement patterns of the
posterior palatal seal.J Prosthet Dent 1971;25:470-488
References
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65. • Winland RD, Young JM: Maxillary complete denture
posterior palatal seal: Variations in size, shape, and
location. J Prosthet Dent 1973;29:256-261
• Hardy IR, Kapur KK: Posterior border seal: Its
rationale and importance.J Prosthet Dent 1958;8:386-
397
• Boucher CO, Hickey JC, Zarb GA: Prosthodontic
Treatment for Edentulous Patients
• Heartwell CM Jr, Rahn AO: Syllabus of Complete
Dentures
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