2. INTRODUCTION
• The Posterior PalatalSeal area is the posterior most limiting structure
in the maxillarydenture.
• Horizontal forces and lateraltorquing forces of the maxillarydenture
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, make the placement of the
placement of posterior palatal seal a quick and easy procedure with
predictable result.
3. DEFINITIONS
• POSTERIOR PALATAL SEAL :- The seal area at the posterior border of
maxillaryremovable dental prosthesis.
• POSTERIOR PALATAL SEAL AREA :- The soft tissues along the junction
of the hard and soft palate on which pressure within the physiologic
limits of the tissue can be applied by the denture to aid in the retention
of the denture – GPT 8
3
4. ANATOMYAND PHYSIOLOGY:-
Soft palate :-
• Musculo-membranous curtain.
• Functions asflap 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 nasalspace.
4
dimensions anddisplacement patterns ofposterior palatalseal, Silverman, j
prosthet dent, may1971
5. • 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 andanteroposteriorly.
• 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.
5
dimensions and displacement patterns of posterior palatal seal, Silverman, j prosthet
dent, may 1971
7. 4. Palatoglossus
• Origin – Palatineaponeurosis
• Insertion - Side of tongue
• Action - Draws palate down, raisestongue
5.Palatopharyngeus:-
• Origin – Arises as 2 fasciculi– Posterior fasciculiarisesfrom palatine
aponeurosis and anterior fasciculefrom 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.
7
8. Clinical Significance
• TensorVeli Palatini - When taut, can influence the denture contour in
the hamular notch area.
• LevatorPalati -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.
8
9. STRUCTURES RELATED TO POSTERIOR PALATAL SEAL
(winkler)
• Hamular process
• Pterygomaxillary notch or Hamular notch
• Median palatalraphe
• Fovea palatini
9
10. 1. Hamularprocess
• 2-4mm postero-medial to the distallimit of the maxillaryresidual
ridge.
• Affects the length and direction of the pterygomaxillary seal.
• Covered by mucous membrane and should not be covered by denture.
10
11. 2. Pterygomaxillarynotch
• Band of loose connective tissue lying between the pterygoid hamulus
of the sphenoid bone and the distal portion of the maxillarytuberosity.
• Lateral boundaries for the PPS.
11
12. 3. Median palatal raphe :-
• Thisoverlies the medial palatalsuture, containslittle or no submucosa
and will tolerate little compression.
• According to heartwell andrahn, thisband of tissuesis not meant to be
compressed, rather should be relieved id prominent
12
13. 5. Fovea palatini
• Two glandular openings within the tissues of posterior portion of hard
palate, usuallylying 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 hardand soft palate and shouldbe
used only as a guideline to placement of posterior palatal seal.
13
15. PTERYGOMAXILLARY SEAL:-
• Extends through pterygomaxillary notch continuing 3-4 mm
anterolaterally approximating the mucogingival junction.
• Occupies the entire width of hamular notch.
15
16. VIBRATINGLINE-
• The imaginary line across the posterior part of the palate marking the
division between the movable andimmovable tissues of the soft palate
which can be identified when the movable tissuesare moving.
• POST PALATAL SEAL:- Area between the anterior and posterior
vibrating linefound medially from one tuberosity to another.
16
17. ANTERIOR VIBRATINGLINE
• 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 nasalspine.
• Always on soft palataltissues.
• 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 areawhile instructing the patient to say
‘ah’ with short vigorous bursts(sharry)
17
18.
19. POSTERIOR VIBRATING LINE
• Imaginary line at the junction of aponeurosis of Tensor veli palatine
muscle andthe 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 functionalmovements.
• Visualized by instructing the patient to say “ah” in short bursts in a
normal unexaggerated fashion.
• Marksthe most distal extensionof the denture base.
19
20. CLASSIFICATION OF SOFT PALATE
(WINKLER)
• Basedupon 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 canbe covered by the denture base.
• Determined when the patient is in upright position with the head held
erect.
20
21. CLASS I
• A soft palate that israther horizontal as it extends posteriorly with
minimal muscular activity.
• Wide posterior palatal seal
• Most favorable configuration asmore tissue surface can be covered.
21
22. • CLASS II :- Palatal contours between a classI and classII
• 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 vaultusually.
• Smaller in width but deeper posterior palatalsealarea
22
23. HOUSE CLASSIFICATION OF 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 edgeofthe tuberosities.
• Class II :-Mediumsize and normal in form with relatively immovable resilient
band of tissue 3-5 mm distal to a line drawn across distal edgeof the tuberosities.
• Class III:- Usually accompaniesa small maxilla. Thecurtain of soft tissues turns
downabruptly 3-5 mm anterior to a line drawn across distal edgeofthe
tuberosities.
23
24. FUNCTIONSOF POSTERIOR PALATAL SEAL-
(winkler)
1. Retention of the maxillary denture base by resisting the horizontal
forces andlateraltorquing of the maxillarydenture.
2. Maintains contact of the denture with the anterior portion of soft
palate during functional movements.
3. 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.
24
25. 4. Reduces food accumulation beneath the posterior aspect of the
denture due to proper utilization of tissue compressibility.
5. Reduces patient discomfort when contact occurs between the tongue
and the posterior end of the denture base as the posterior denture
willclosely approximate the soft palataltissues.
6. Compensate for the volumetric shrinkage that occurs during the
polymerization of methylmethacrylate resin.
25
26. 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
lateraltorques.
• This dislodgement can be resisted by the retention provided by the
partial vacuum created by the denture border seal.
26
27. • 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.
27
28. • Sidney Silverman (1971) conducted a study and concluded complete
maxillarydentures can be extended for anaverage 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.
28
29. • 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 palatalseal 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 palatalseal during the finalimpression stage.
29
30. PARAMETERS OF PPS :-
• Size
• Shape
• Location
30
winland and young,maxillary complete dentureposterior palatal seal: variation in
shape, size and location, j prosthet dent, march 1973
31. I. 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 92patients &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).
Theinterhamular notch 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)
31
32. II. SHAPE-
• John M. Young and RogerD. Winland
32
Bead posterior palatal seal extending through
hamularnotch
Double Bead posterior palatal seal. Posterior bead
located on posterior limit of denture
Butterfly posterior palatal seal with width and depth
depending onamount of displacement of tissues
Butterfly posterior palatal seal with a bead on posterior
limit of denture
33. CROSS-SECTIONAL VIEWS OF VARIOUS POSTERIOR PALATAL
SEALS-
• Bead
• Double Bead
• Butterfly
• Butterfly With Bead
33
winland and young,maxillary complete dentureposterior palatal seal: variation inshape, size
and location, j prosthet dent, march 1973
34. III. Dimension
Class I – modified butterfly
approx. 3-4mm wide
Class II – modified butterfly
approx. 2-3mm wide
ClassIII – a bead
35. PART 2
POSTERIOR PALATAL SEAL
1. Journal of Scientific and Innovative Research 2014; 3(6): 602-605,
Posterior Palatal Seal (PPS): A brief review
2. Sheldon Winkler ,A.I.T.B.S. Publishers,Essentials of complete denture
Prosthodontics,2nd edition
3. European Journal of Prosthodontics | May-Aug 2014 | Vol 2 | Issue 2
The posterior palatal seal: Its rationale and importance: An overview
37. TECHNIQUESFOR RECORDINGPOSTERIOR PALATAL SEAL
(winkler)
• 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
denturehas been captured in theborder molded customtray.
• 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.
37
38. The rationale for theplacementof a seal in theimpression tray :
• To establish positive contactposteriorly to prevent the final
impression materialfrom sliding downs thepharynx.
• To serve as a guide for positioning theimpression tray
• To create slightdisplacementof thesoft palate
• To determineif adequate retentionand seal of the potential
dentureborder is present.
38
39. Classificationof techniques of recording PPS-
Hardy and Kapur(1958) –
• Functional :- Final impression is border molded in PPS area
with soft stick modeling compound / wax by sucking
movementsperformed by thepatient.
• Semi functional:- Border moldingis done by thedentist.
• Empirical :- Developed on the cast by grooving the cast to the
desired depth.
39
hardyand kapur,posterior palatal seal- its rationale and importance, j prosthet dent, may
1958
40. The techniquesused to markposterior palatal seal
are:
1. Conventionaltechnique
2. Fluidwax technique
3. Arbitrary scraping of the master cast
4. Extendedpalate technique
5. AddingPPS to an existing denture
6. Determination of PPS by ultrasound
40
41. CONVENTIONAL TECHNIQUE
(winkler)
• Finalimpressionis made, boxed, andpoured.
• 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 anindeliblepencil
41
42. • The instrument(“T” burnisher/mouthmirror) is thenplaced
along theposterior angle of the tuberosity untilit drops into the
pterygomaxillary notch.
• A line is placed with an indelible pencil, throughthe notchand
extended3-4mm anterolateralto thetuberosity, approximating
themucogingivaljunction.
• The same procedure is thenperformed on theopposite side. This
will complete theoutliningof the pterygomaxillary seal.
42
43. • The patient is asked to say “ah” in short bursts in an
unexaggeratedfashion.
• While observing the movement of the soft palate the
posterior vibrating lineis markedwith anindeliblepencil.
• 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.
43
44. • 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 mastercast to complete the transfer of
posteriorborder andtray istrimmed.
• The palatal tissues anterior to the posterior border are
palpated with the “T”burnisher /mouth mirror to
determine their compressibilityinwidthanddepth.
44
45. • The use of Valsalva maneuver / visualizing the area
when the patient says “ah” with short vigorous bursts
may alsobe used.
• This line is marked with the indelible pencil and
transferred tothe master cast
46. • A Kingsleyscraper is used toscrape thecast.
• 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 tothe depthof theapproximately 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
approximately0.5-1.0mm.
46
47. • Just posteriorto the deepest portion of the seal, it is
also tapered tothe posterior vibrating line.Failureto
taper the sealposteriorlymay lead totissueirritation.
• Shellaccan be readapted toconform to the scored
palatal seal areaand tried in the mouth to evaluatethe
retentive qualitiesof the trialbase.
47
48. ADVANTAGES
• More retentivetrial base , which can produce more accurate
maxillomandibularrecords.
• Patientsare able to experience the retentive qualitiesof the
trial base giving themthe psychological security of knowing
thatretentionwillnot be a problem.
• The dentist is able to understand theretentive qualitiesof the
finished denture.
• The posterior extensionof thedenture can be understood by
thepatient.
48
49. DISADVANTAGES
• Not a physiological techniqueand so depends upon the
accurate transfer of vibrating lines and careful scraping of the
cast.
• More potentialfor overcompression of the tissue.
49
50. FLUID WAX TECHNIQUE
( Functional technique or
Physiological technique )
• Similar to theconventional techniqueexcept that in thistechnique
the indelible transfer markings are recorded on the finalwash
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.
50
51. • Zinc oxide and eugenol /plaster are preferred over the elastic
impression material,as they set rigid.
• 4 types of wax –
1. Iowa Wax (White) – Dr. Earl S. Smith
2. Korecta Wax no.4 (Orange) – Dr. O.C. Applegate
3. H-Lphysiologic paste (Yellow-White) – Dr. C.S. Howkins
4. Adaptol(Green) – Dr. NathanG. Kyne
51
52. • Designedtoflowat mouthtemperature.
• 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 resistantto 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
materialtoflow.
52
53. • After 4-6 minutes, the impression tray is removed from the
mouth and the wax examined for uniform contact through
out theposterior palatalseal 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
theprocedure repeated.
• The secondary impression is reinserted and held for 3-5
minutesof firm pressure applied to themidpalatalarea of the
impression tray.
53
54. PRECAUTIONS:
• The patientshould notprotrude his tonguebeyond the
approximated position of theincisaledge as thismay shorten
theposterior border of thefinalimpression.
• The patientshould becautioned againstrinsing with cold
water as this may contract thetissues and reduce theflow
properties of wax.
• The borders of thewax should terminatein featheredge
towards the vibrating line .If a butt jointis formed, proper
flow may have nottaken place.
54
55. ADVANTAGES
1. Physiologictechniquedisplacing tissues withintheir
physiologically acceptable limits.
2. Overcompression of the tissuesis avoided
3. Posterior palatal seal is obtained increasing retentionat an
early stage.
4. Mechanical scraping of thecast is avoided.
55
57. EXTENDED PALATAL TECHNIQUE:
(Silverman1971)
• Dentureborder is extended8mmapproximately beyond
the anterior vibrating line.
• Not widely used currently.
Method -
1. After border moldingtray is extended by adding
compound.
2. Green stick compound is added to the sealarea and record
is made with head flexed30 degree downward.
58. BOUCHERS TECHNIQUE
• Stage of recording- during jaw relations
• Method the posterior vibrating lineis located and transferred
on to the master cast.
• The temporary denturebase is reduced to this line.
• This willcreate a raised narrow and sharp bead alongthe
posterior portion of the denturewhich sinks into thetissues
and forms a seal.
Advantage: According to Boucher a narrow bead like seal is more
effective.
59. ARBITRARY SCRAPING OFTHE MASTER CAST
• Anterior and theposterior vibrating lines are visualized by
examiningthepatient’ mouthand approximately marked on
themastercast.
• Least accurate and leaves a chanceat insertion appointment
since it relies on dentist’srecollection of palatal configuration
and tissue compressibility.
• Inaccurate and not physiological.
59
60. ADDING POSTERIORPALATAL SEAL TOTHE EXISTING
DENTURE
• Mark thevibrating line in the
mouthwith an indeliblemarker.
• Form thedesired thickness and
extensionof thePPSon the
denturein the patient’smouth
with softened green modeling
compound
• Transfer thelocations of the
vibrating line to the denture
60
Izharul Haque Ansari, J Prosthet Dent
1994;72;449
61. • Make a cast of theintagliosurface of thedenturewith putty
material;the cast mustinclude all of PPSaddition and extend
5 to 6 mm posteriorly
• After putty materialhas set, use a scalpel to cut channels
which willallow excess autopolymerizing acrylic resin to
escape.
• Remove thegreen stick compound and replace with
autopolymerizingresin in a pressure pot.
62. Arthur Nimmo - Suggested correctionof posterior palatal
seal by using a visiblelight cured resin.
• Identify and markthe vibrating linein themouth withan
indeliblemarking stick
• Roughenthe denturesurface in the posterior palatal sealarea
witha carbide bur.
• Adapt the VLC resin
• Place thedenturein the mouthand allow it to remain in place
for approximately 3 minutes.During thistime thematerial
will flow.
62
63. • Positiona hand-heldvisible lightsource near theborder of the
dentureand apply light directly to theregion for several minutes.
• Remove any excess resin with a carbide bur and smooththe
junctionbetween theseal and thepolished surface of the
denture.
ADVANTAGES
1. No exothermicreaction to irritate the oral tissues.
2. Minimalvolumetric shrinkage duringcuring.
3. More closely approximates a physiologic technique.
4. Can be performed withrelatively littlechair time. 63
64. Rajeev M. Narvekar, andMarc B.Appelbaum
• Investigatedthe anatomicposition of posterior palatal seal by
ultrasound.
• Ultrasound refers to sound with frequencieshigher thanthe
audiblerange (20 to 20,000 Hz).
• Basic elements of an ultrasound scanningsystem include–
1. Transducer
2.Couplant
64
65. Ultrasonictransducer
• The active elementthathas
piezoelectric properties
which transform
mechanicalenergy into
electric energy and vice
versa
65
66. Couplant
• Necessary between the ultrasonic transducer and the skinbecause 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.
66
67. RESULTS 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,
witha patientaverage of 2.5 mm.
• The average distance from the posterior vibrating line to the
junctionof thehard 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 lieon theglandularposterior third of thehard palate.
67
69. UNDEREXTENSION
• Most common cause for failure of theseal in the posterior palatal
area
Causes
• Practitioner’s useof the fovea palatine as thelandmark for
terminatingthe denturebase. By doing, so he may be depriving the
patientof as muchas 4 to 12 mm of tissue coverage.
• Failure of the dentistto carefully examine thehard and soft palates,
makingnote of thepalatal configuration
• Over trimmingof posterior border by laboratory technician
• Dueto fear of gagging
69
70. UNDERPOSTDAMMING
• May be theresult of recording thetissue when the mouthwas
wide open during the final impression.
• When the mouthis in thewide open position, the
pterygomandibularfold becomes taut.
• When the patientassumes any position other thana wide
open position, a space willbe present betweenthe denture
base and thetissue since thefold is no longer activated.
70
71. Diagnosis:-place thewet denturebase into themouth and
slowly press in themidpalatalregion untilit is firmlyseated
while observing thedistal dentureborder.
• If air bubbles are seen escaping from beneaththedistal
border, then at thatpoint the denturebase is
underpostdammed.
71
72. Correction–
• Further scrap thecast and readapting thetrial base if the
conventional approach is used
• Add more wax and remind thepatientto refrain from opening
themouthso wide if thefluidwax techniqueemployed.
72
73. OVERPOSTDAMMING
• Over scrapping of master cast and the posterior palatal seal
displaces too muchtissue.
• Significantoverpostdamming especially inthe
pterygomaxillary seal area - posterior border will bedisplaced
inferiorly.
• Moderately overpostdammed - tissue irritation across the
posterior palatal region
• Selective reduction of thedenture border with carbide bur,
followed by lightlypumicingthe area whilemaintainingits
convexity.
73
74. OVEREXTENSION
• The most frequent complaint from the patient will be that
swallowing is painful and difficult. Small ulcerated areas in the
region of thesoft palate willbe evident.
• If the hamuli are covered by the denture base, the patient will
experiencesharp pain, especially duringfunction.
• By marking the lesion with an indelible pencil and transferring it
to the denture base, the precise position of the overextension
can be removed witha bur and thencarefullyrepolished.
74
75. CONCLUSION
• The recording of PPS is of great significancebecause it is vital factor
in establishingthe peripheral seal whichenhancesretentionby
utilizingtheatmospheric pressure.
• The PPSof a maxillary complete denturecan be established during
the makingof the preliminary impression, during themakingof
finalimpression, by scoring thefinalcast or by incorporating the
seal in the finaldenture.
• The posterior palatal sealis obtained throughintimatecontact and
theapplication of pressure withinthephysiologic limit by the
denturein this region.
• This would requirean intimateknowledgeof the anatomy,
functionsand movements of thetissues of the region. 75
76. REFERENCES
• Zarb Bolender,Mosby,Prosthodontic treatmentfor edentulous
patients,12th edition
• Sheldon Winkler ,A.I.T.B.S.Publishers,Essentialsofcomplete
denture Prosthodontics,2nd edition
• Arthur O.Rahn & Charles M.Heartwell,Elsevier,Textbookof
completedentures,5th edition
• B.D.Chaurasia , HumanAnatomy-Vol.3Head andNeck
• Grays Human Anatomy
• Hardy I R,Posterior border seal–its rationaleand importance,J
ProsthetDent1958:8;386-97
76
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prosthodontics. J Prosthet Dent 1975:33;504-10
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border of the maxillarydenture. J Prosthet Dent 1980:43;13-37
• Antolino Colon et al, Analysis of the posterior palatalseal and the palatal
forms as related to the retention of complete dentures. J Prosthet Dent
1982:47;23-27.
• Ming-Sheh Chen et al,Methods taught in dental schools for determining the
PPS region. J Prosthet Dent 1985:53; 380-83
77
78. • Nimmo A.,Correction of the posterior palatalseal by using a visible-light
cure resin : A clinicalreport J Prosthet Dent 1988:59;529-30
• Narvekar RM, Appelbaum MB, An investigation of the anatomic position of
the posterior palatalseal by ultrasound, J Prosthet Dent 1989:61;331-36
• Izharul Haque Ansari , A procedure for adding posterior palatalseal to an
existing denture in dental office, J Prosthet Dent 1994:72;449
• Izharul Haque Ansari “Establishing the posterior palatalseal during the
final impression stage”. J Prosthet Dent 1997:78;324-26
• Yuuji Sato , Immediate maxillarydenture base extension , J Prosthet Dent
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78