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POSTERIOR PALATAL SEAL
JANNU HARSHAVARDHAN
I MDS
2

CONTENTS
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• DEFNITION
• INTRODUCTION
• IMPORTANCE OF POSTERIOR PALATAL SEAL
• PARTS OF POSTERIOR PALATAL SEAL
• FUNCTIONS OF POSTERIOR PALATAL SEAL
• ANATOMIC AND PHYSIOLOGIC CONSIDERATIONS OF PPS
• ANTERIOR AND POSTERIOR VIBRATING LINES
• CLASSIFICATION OF SOFT PALATE
• TYPES OF PPS
• TECHNIQUES OF RECORDING PPS
• TROUBLE SHOOTING
• RECENT ADVANCEMENTS
• CONCLUSION
• REFERENCES

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DEFINITION
Posterior palatal seal: It is defined as “ the soft tissues along the junction of the hard and
soft palates on which pressure within the physiologic limits of the tissues can be applied
by a denture to aid in the retention of the denture.” – GPT 9.
E S S E N T I A L S O F C O M P L E T E D E N T U R E BY S H E L D O N W I N K L E R

INTRODUCTION
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• The proper placement of the posterior palatal seal begins with the initial oral
examination. The morphologic contours of the hard and soft palate, hamular
notch regions, as well as the integrity and displaceability of the mucosa and
underlying glandular tissues, should be evaluated and noted.
• Hardy and Kapur stated that the 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 the denture base.
• The dislodgement of denture by lateral torque and horizontal forces could be
resisted by retention provided by posterior palatal seal.
E S S E N T IA LS O F C O M P LE T E D E N T U R E B Y S H E LD O N W IN K LE R

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 The peripheral seal of the maxillary denture is the area of contact the mucosa and
the peripheral polished surfaces of the denture base; the seal prevents the passage
of air between the denture and the tissues. This seal depends upon the proper
extension of the denture borders, both in width and height, so that they fill the
mucobuccal space and contact the cheek tissues laterally.
 At the posterior aspect of the denture, in the area of the soft palate, there are no
cheek tissues to seal the denture border. Therefore; the proper placement of the
posterior palatal seal commands a definite clinical procedural protocol if one is to
create an optimally retentive complete maxillary prosthesis.

IMPORTANCE OF POSTERIOR PALATAL SEAL
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 The addition of a proper border seal transforms into a very stable base that
resists tipping thrust forces from all directions.
 Skinner has demonstrated the importance of the posterior palatal seal
experimentally and stated that the most effective addition to increasing
retention was the post dam.
 The posterior palatal seal will create a partial vacuum that will not operate
continuously, it comes into play when horizontal or tipping thrusts tend to
dislodge the denture then only to overcome the emergency.
 Posterior palatal seal complements the buccal and labial border seal
converts the denture to a sealed compartment resisting torquing forces.

FUNCTIONS OF THE POSTERIOR PALATAL SEAL AREA
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1.It provides a close contact of the denture base with the mucous membrane which prevents
food from getting under the denture.
2. It provides firm contact of the denture base with the tissue, and this diminishes or eliminates
gagging.
3. It supplies sunken distal borders which are less conspicuous to the tongue.
4. It supplies a thick border to counteract denture warpage.
5. It adds confidence and comfort to patient by enhancing retention.

PARTS OF POSTERIOR PALATAL SEAL
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The pterygomaxillary seal occupies
the entire width of the
pterygomaxillary notch, which is
defined as that band of loose
connective tissue lying between the
pterygoid hamulus of the sphenoid
bone and the distal portion of the
maxillary tuberosity.
The post palatal seal extends
medially from one tuberosity to
the other. Laterally, the
pterygomaxillary seal extends
through the Pterygomaxillary
(hamular notch) continuing for
3 to 4 mm anterolaterally
approximating the
mucogingival junction.

PTERYGOMAXILLARY NOTCH:
• The pterygomaxillary notch is covered by the pterygo mandibular fold, which
extends from the posterior aspect of the tuberosity posterior-inferiorly to insert
into the retromolar pad . This fold of tissue can influence the posterior border
seal if the mouth is in a wide open position during the final impression
procedure.
• It is important to note the exact position of the hamular process (located 2 to 4
mm posteromedial to the distal limit of residual ridge), since this will affect the
length and direction of the pterygomaxillary seal.
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ANATOMIC AND PHYSIOLOGIC CONSIDERATIONS OF PPS

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HAMULAR NOTCH
• The hamular process is covered by a thin layer of connective tissue One has
to palpate the process in the course of outlining the posterior palatal seal area
to realize the painful episode that the patient would experience if the denture
base was extended to this area.
• Therefore hamular process should be never covered under denture.

FOVEA PALATINI
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• There are two glandular openings within the tissues of the posterior portion
of the hard palate, usually lying on either side of the midline.
• The fovea palatini, as they are known, are not constant findings in every
individual; however, they are unique to humans.
• Therefore, the position of the fovea does not represent the junction of the
hard and soft palates. The fovea palatini should be used only as guidelines
to the placement of the posterior palatal seal

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• The median palatal raphe, which overlies the medial palatal suture, contains
little or no submucosa and will tolerate little compression.
• The judicious placement of the posterior palatal seal across the mid palatal
suture in the region of the posterior nasal spine demands careful attention.
• When a prominent mid-palatal fissure is present on the hard palate, it often
extends onto the soft palate. When the fissure is present, it should be
carefully reproduced in the master cast. The posterior seal should be
extended into this fissure to ensure proper peripheral seal.

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• The presence of thick, ropy saliva may create a problem for maxillary
complete denture retention. Thick saliva can create hydrostatic pressure
in the area anterior to the posterior palatal seal, resulting in a downward
dislodging force exerted upon the denture base.
• A fine line or Cupid’s bow can be scribed on the master cast, anterior to
the cluster of palatal mucous glands to alleviate this problem.

ANTERIOR VIBRATING LINE
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The anterior vibrating line is an imaginary line located at junction of the
attached tissues overlying the hard palate and the movable tissues of the
immediately adjacent soft palate.
One way to locate the anterior vibrating is to have the patient perform the
Valsalva
maneuver, which requires that both nostrils be held firmly while the patient
blows gently through the nose.
This will position the soft palate inferiorly at its junction of hard palate.
It can also be approximated by visualizing the area while instructing the
patient to say “ ah " with short vigorous bursts.

POSTERIOR VIBRATING LINE
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The posterior vibrating line is An imaginary line at the junction of the
aponeurosis of the tensor veli palatini muscle and the muscular portion of the
soft palate.
It represents the demarcation between that part of the soft palate that has
limited or shallow movement during function (quivers) and the remainder of
the soft palate that is markedly displaced during' functional movements.
The posterior vibrating line is visualized by instructing the patient to say “ ah ”
in short bursts in a normal, unexaggerated fashion. It denotes the distal limit of
denture.

CLASSIFICATION OF SOFT PALATE
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CLASS I: indicates a soft palate that is rather horizontal as it extends
posteriorly, with minimal muscular activity. Class I palates are considered the
most favorable configuration, since more retentive denture.

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CLASS II: It indicates soft palate Class II designates those palatal contours
that lie somewhere between class I and class III.

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CLASS III: Class III indicates the most acute contour in relation to the hard
palate, necessitating marked elevation of the musculature to create
velopharyngeal closure. It is usually seen in conjunction with a high V -shaped
palatal vault.

DIFFERENT TYPES OF PPS
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1) Bead type.
2) Double bead type.
3) Butterfly-type.
4) Butterfly type with bead on posterior limit.
5) Butterfly with widened with No. 9 round bur.
6) Posterior palatal seal constructed with reference to
House classification,
POSTERIOR PALATAL SEAL VARIATIONS BY ROGER AND JOHN YOUNG

TECHNIQUES OF RECORDING PPS
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According to Hardy Kapur, there are 3 different types of recording PPS.
• FUNCTIONAL: In this method the final impression is moulded by the
functional movement performed by the patient.
• SEMI FUNCTIONAL: Border moulding done by dentist.
• EMPIRICAL: Developed on cast by grooving the cast to desire depth.

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The patient should be instructed to rinse with an astringent mouthwash to remove stringy saliva
that might prevent clear transfer markings.
CONVENTIONAL METHOD (Winkler method )
The posterior palatal area is then dried with gauze; a “T ” burnisher or a mouth Mirror is
used to palpate for the hamular processes. Once located, they should be marked with an
indelible pencil or noted visually to ensure that they are not covered by denture.

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The instrument (“T ” burnisher or mouth mirror) is then placed along the posterior angle
of the tuberosity until it drops into the pterygo maxillary notch. Through the notch and
extended 3 to 4 mm anterolateral to the tuberosity, approximating the mucogingival
junction. The same procedure is then performed on the opposite side.
The patient is asked to say “ ah ” in short bursts in an unexaggerated fashion. 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 posterior
vibrating line, the posterior denture extension is delineated.

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The resin or shellac tray is then inserted into the mouth and seated firmly to place. Upon
removal from the mouth, the indelible lines should have been transferred to the tray, which
in turn transfer to cast to complete the transfer of the posterior border is trimmed.
“T ” burnisher or mouth mirror determines their compressibility in width and depth. The
termination of the glandular usually coincides with the anterior vibrating line. The use of the
Valsalva maneuver .’ or the area while the patient says’ ah" vigorous bursts may also be
marked with an indelible pencil and transferred to the master cast.

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A Kingsley scraper is then used to score the cast. The deepest areas of the seal are
located on either side of the midline, one-third the distance anteriorly from the posterior
vibrating line. It is usually scraped to a depth of approximately 1 to 1.5 mm
As the seal approaches the anterior vibrating line there is just a slight scraping of the cast.
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.

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Shellac base can be re-adapted to reconfirm the scored cast is
verified in the patient’s mouth for the retentive property.

ADVANTAGES
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1. The trial base will be more retentive; this can produce more accurate maxilla
mandibular records.
2. Patients will be able to experience the retentive qualities of the trial base,
giving them the psychological security of knowing that retention will not be a
problem in the completed prosthesis.
3. The practitioner will be able to determine the retentive qualities of the
finished denture, leaving nothing to chance at the insertion appointment.

DISADVANTAGES
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1. It is not a physiologic technique and therefore depends upon accurate transfer
of the vibrating lines and careful scraping of the cast.
2. The potential for over-compression of the tissues is great.

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FLUID WAX TECHNIQUE
1. In this method the indelible transfer markings are recorded on the final wash
impression. Zinc oxide and eugenol or plaster are preferred over the elastic
impression materials, as they are set rigid.
2. Impressions made with elastic materials are slightly resilient, and when
reseated in the mouth under pressure may distort the relationship between wax
added to the posterior border and the rest of the denture-bearing surface.
3. All procedures of location and transferring the anterior and posterior
vibrating line are same as conventional approach.

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Materials used in fluid wax technique
Zinc oxide eugenol impression is preferred over elastic impression material.
The different types of waxes used are
1. Iowa Wax (White) - Dr. Earl S.Smith.
2. Korecta Wax no 4 (Orange) - Dr.O.C.Applegate.
3. H L physiological paste (Yellow – White) - Dr. C.S Howkins.
4. Adaptol (Green) - Dr.Nathan.

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1. Any of four mouth temperature waxes is used to paint on the
impression surface of the posterior seal area and allowed to cool below
room temperature to increase it’s consistency and make it more
resistant to flow.
2. While maintaining the 30° flexion of the head and the anterior tongue
position, the patient is asked to periodically rotate the head so that all
functional positions of the soft palate are recorded.
3. After 4-6 minutes, the impression tray is removed from the mouth and
wax examined for through contact.
4. Where tissue contact doesn’t contact it appears as dull and if tissue has
been contacted it appears as glossy surface.
FLUID WAX TECHNIQUE

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5. The secondary impression is reinserted and held for three to five
minutes under gentle pressure, followed by two to three minutes of firm
pressure applied to the mid-palatal area of the impression tray.

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ADVANTAGES
1. Physiological displacing of tissues occurs within physiologically acceptable
limits.
2. Over compression of tissues is avoided.
3. Mechanically scraping of cast is not required.
DISADVANTAGES
1. More time-consuming method.
2. Difficulty in handling material.

SEMI FUNCTIONAL METHOD
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• In this method, the dentist performs the border moulding.
• Border moulding determines the extension by functional and manual
manipulation of tissues.

ARBITRARY SCRAPING OF MASTER CAST
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1. Anterior and posterior vibrating line are visualized by examining the
patient’s mouth and are approximately marked on the master cast.
2. The least accurate leaves the chance of tissue compressibility.
3. Inaccurate and not physiological.

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BOUCHER TECHNIQUE
The width of the posterior palatal seal is limited to bead on denture
with 1.5 mm depth and 1.5 mm height.
YA B IN D H O O E T A L P O S T E R IO R PA LATA L S E A L A LIT E R AT U R E R E V IE W

BERNARD LEVIN METHOD IN CLASS III
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BERNARD LEVINS METHOD IN CLASS I AND II PALATE
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SWENSON’S METHOD
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SWENSON’S TECHNIQUE
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YA BINDHOO ET AL POSTERIOR PALATAL SEAL A LITERATURE REVIEW

ADDING PPS TO EXISTING DENTURE
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There are numerous techniques to improve the posterior palatal seal on an existing
denture. Moghadam and Scandrett suggest a procedure that utilizes the fluid wax
technique. All of the steps outlined for locating, marking, and placing the wax in the
seal area are followed, except that this time the wax is placed on the processed
denture base.
After the wax has had an adequate chance to flow, the denture is re moved from the
mouth. An indelible pencil is used to outline the anterior extent of the seal on the
denture. Utility wax is placed vertically across the palate, separating the posterior
two-thirds from the anterior region, and extended around the posterior portion of the
denture.

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After PPS is recorded, the denture is removed from the mouth. The stone is
vibrated on the denture wax surface After the stone is set wax is eliminated.
The auto-polymerizing acrylic powder is sprinkled between the denture base
and cast while holding on vibrator.
The monomer is added drop wise the denture is relaced on stone cast and held
with rubber bands.
Then they are placed in the pressure pot with water 140 F for 20 minutes
under 30 psi pressure.
After the denture and cast are separated ,the excess acrylic is trimmed and
border is polished lightly .

TROUBLESHOOTING OF PPS
43
Overextension:
The most common complaint of patient where swallowing is painful and difficult.
Small ulcers are seen in the region of the soft palate.
If the hamuli are covered in denture the patient feel pain during the function and
experience pain.

OVER POST DAMMING
44
Over-scrapping of the master cast produces the posterior palatal seal displaces
to much tissue compressibility is seen.
Significant over-post damming causes the posterior border displaces inferiorly.
Moderately over post-damming causes tissue irritation across the posterior
palatal region.

UNDER EXTENSION
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Commonly, this is a result of the practitioner’s use of the fovea palatini 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, which can significantly improve
the retentive qualities of the denture.
Over-trimming of the denture by the lab technician.
Due to fear over gaging the dentist tries to over-trim the denture.

UNDER POST DAMMING
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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.
The diagnosis of this condition consists of placing the wet denture base into the
mouth and slowly pressing in the midpalate region until it is firmly seated, all the
while observing the distal denture border. If air bubbles can be seen escaping from
beneath the distal border.

47

RECENT ADVANCEMENTS
48
The use of an intraoral scanner may help in recording completely edentulous jaws,
particularly in patients with flabby ridges or with undercuts, where conventional
impression-making may be challenging.
Digital intraoral scans are also useful when fabricating immediate complete
dentures, in particular, when teeth are mobile or in a position making conventional
impressions difficult.
Nevertheless, digital scans have drawbacks, as they can produce a mucostatic
recording of the tissues but fail to capture the appropriate extension of the movable
tissues.

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The molding of a peripheral border in function is still not possible with a digital
intraoral scan and the standard impression for CD fabrication consists of molding
the peripheral border with a plastic material and subsequently loading the custom
tray with a zinc oxide/ eugenol-based paste or an elastomer.
A combination of conventional border molding and an intraoral scan has been
described to compensate for the shortcomings of the scan. A definitive cast was
made by combining the digital files from the scan and those issued from a border-
molded custom tray. However, this interesting technique requires an additional
software program operation to combine the information from the 2 recording
Najila et al Fit and retention of complete denture bases: Part II e conventional
impressions versus digital scans: A clinical controlled crossover study .JPD

CONCLUSION
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1. Placement of the correct posterior palatal seal is given importance in
complete denture fabrication.
2. Following established techniques for placement of border seal will
ensure the retentive prosthesis
3. Careful examination during the diagnostic phase of the treatment can
alleviate many potential problems .

REFERENCES
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1. Essentials of the complete denture by Sheldon Winkler.
2. Prosthodontic treatment for edentulous patients by Zarb Bolender.
3. Hardy IR, posterior border it’s Rationale and Importance J Prostheth Dent.
4. Winland, Young Maxillary complete denture posterior palatal seal, variations in size, shape,
and location.
5. YA Bindhoo et al Posterior palatal seal a Literature review .

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