posterior palatal seal

1. Posterior Palatal Seal
Guided by:-
DrAkshey Sharma
Dr Rajesh Bhanot
DrPardeep Bansal
DrGagan Chahal
Submitted by:-
DrAditi Ghai
PG 2nd year
DIRDS, Faridkot

2. INTRODUCTION
• The Posterior PalatalSeal areais 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

6. MUSCLES OF SOFT PALATE
6

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 hamularnotch 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 shouldnot 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:-
• This overlies the medial palatalsuture, containslittle or no submucosa
and will tolerate little compression.
• According to heartwell and rahn, thisband of tissues is 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 hard and soft palate and should be
used only as a guideline to placement of posterior palatalseal.
13

14. Disagreementsregarding position-
• Sicher(1952):- Posteriortothelocationofhard andsoftpalate.
• NagleandSears (1958):-Posteriorlimitofhard palate.
• Fennandassociates(1961):- Glandularregionofsoftpalate.
• Swenson(1970):- Vibratingline2mminfrontoffovea palatini.
• Lye(1975):- 1.31mmanterior totheanterior vibratingline.
• Chen(1981):- Locatedeither onorbehindtheanteriorvibratingline.
14

15. PTERYGOMAXILLARY SEAL:-
• Extends through pterygomaxillary notchcontinuing 3-4 mm
anterolaterally approximating themucogingival 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 and immovable tissues of the soft palate
which can be identified when the movable tissuesare moving.
• POST PALATAL SEAL:- Area between the anterior and posterior
vibrating line found medially from one tuberosity to another.
16

17. ANTERIOR VIBRATINGLINE
• Animaginarylinelocatedat thejunctionoftheattachedtissuesoverlying
thehardpalateandthemovabletissuesoftheimmediatelyadjacentsoft
palate.
• Cupidbow’shapedduetotheprojectionofposteriornasal spine.
• Alwaysonsoftpalataltissues.
• To locateanteriorvibratinglinepatientisaskedtoperformvalsalva
maneuver(bothnostrilsare heldfirmlywhilepatientblowsgentlythrough
thenose)
• Alsolocatedbyvisualizing thearea whileinstructingthepatienttosay‘ah’
withshortvigorousbursts(sharry)
17

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 extension of the denture base.
19

20. CLASSIFICATION OF SOFT PALATE
(WINKLER)
• Basedupon the angle the soft palate makes with the hardpalate.
• 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 is rather horizontal as it extends posteriorly with
minimal muscular activity.
• Wide posterior palatalseal
• 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 :-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 thetuberosities.
• Class III:- Usually accompaniesa small maxilla. Thecurtain of soft tissues turns
down abruptly 3-5 mm anterior to a line drawn across distal edge of the
tuberosities.
23

24. FUNCTIONSOF POSTERIOR PALATAL SEAL-
(winkler)
1. Retention of the maxillary denture base by resisting the horizontal
forces andlateral torquing of the maxillarydenture.
2. Maintains contact of the denture with the anterior portion of soft
palate during functionalmovements.
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 studyand 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 palatal seal needed.
• Rajeev M. Narvekar and Marc B. Appelbaum in 1989 used
ultrasound instrumentation as an non-invasive procedure to locate the
anatomicstructures in the PPS region.
• In 1997, Izharul Haque Ansari described a method to establish
posterior palatal seal 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, march1973

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 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).
 Theinterhamular notch was found to be 35.8mm(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, march1973

34. III. Dimension
ClassI – modified butterfly
approx. 3-4mm wide
Class II – modified butterfly
approx. 2-3mm wide
Class III – a bead

35. TECHNIQUESFORRECORDINGPOSTERIOR 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 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.
35

36. The rationaleforthe placementofa sealintheimpressiontray :
• To establishpositivecontactposteriorlytopreventthe final
impressionmaterialfrom slidingdowns the pharynx.
• To serve asa guideforpositioningthe impression tray
• To create slightdisplacementofthesoftpalate
• To determineif adequateretentionand sealofthe potential
denture border is present.
36

37. Classificationof techniquesof recording 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.
37
hardyand kapur,posterior palatal seal- its rationale and importance, j prosthet dent, may
1958

38. The techniques used to mark posterior palatalsealare:
1. Conventional technique
2. Fluid wax technique
3. Arbitrary scraping of the master cast
4. Extended palate technique
5. Adding PPS to an existing denture
6. Determination of PPS by ultrasound
38

39. CONVENTIONAL TECHNIQUE
(winkler)
• Final impression is made,boxed, andpoured.
• A well-adapted resin/shellac tray is fabricated onthe stone cast.
• Theposterior palatal area is then dried withgauge; a “T”burnisher/a mouth mirror
is used to palpate for the hamular process andmarkedwith anindelible pencil
39

40. • 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 tothe tuberosity, approximating the mucogingival junction.
• The same procedure is then performed on the opposite side. This will complete the
outlining of thepterygomaxillary seal.
40

41. • Thepatient 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
markedwith 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.
41

42. • 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
posterior borderand 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.
• The use of Valsalva maneuver / visualizing the area when the patient says “ah” with
short vigorous bursts may also beused.
• This line is markedwith the indelible pencil and transferred to the master cast
42

43. • A Kingsleyscraper 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.
43

44. • 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 canbe readapted to conform to the scored palatalsealarea and
tried in the mouth to evaluate the retentive qualities of the trial base.
44

45. ADVANTAGES
• More retentive trial base , which can produce more accurate
maxillomandibular records.
• Patients are able to experience the retentive qualities of the trialbase
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.
45

46. DISADVANTAGES
• 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.
46

47. FLUID WAX TECHNIQUE
• Similar to the conventional technique except 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 finalwash impression.
47

48. • Zinc oxide and eugenol /plaster are preferred over the elastic
impression material, asthey 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-L physiologic paste (Yellow-White) – Dr. C.S. Howkins
4. Adaptol (Green) – Dr. NathanG. Kyne
48

49. • 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.
49

50. • After 4-6 minutes, the impression tray is removed from the mouth and
the wax examined for uniform contact through out the posterior
palatalsealarea.
• If tissue contact has not been established, the wax will appear dull. If
the tissue hasbeen contacted, the wax willhave 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.
50

51. PRECAUTIONS:
• The patient should not protrude histongue beyond the approximated
position of the incisaledge as this may shorten the posterior border of
the finalimpression.
• The patient should be cautionedagainstrinsing with cold water as this
may contract the tissues and reduce the flow properties of wax.
• The borders of the waxshould terminate in feather edge towards the
vibrating line .If a butt joint is formed, proper flow may have not taken
place.
51

52. ADVANTAGES
1. Physiologic technique displacing tissues within their physiologically
acceptable limits.
2. Overcompression of the tissues is avoided
3. Posterior palatalseal isobtained increasing retention at anearly
stage.
4. Mechanicalscraping of the cast is avoided.
52

53. DISADVANTAGES
• More time is needed
• Difficulty in handling the material
53

54. EXTENDED PALATAL TECHNIQUE:
(Silverman1971)
• Denture border is extended 8mm approximately beyond the anterior
vibratingline.
• Notwidelyused currently.
Method -
1. Afterbordermolding trayis extended byadding compound.
2. Greenstick compound is addedto the seal area and recordis madewith
head flexed 30degreedownward.

55. 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 sinksinto the tissues and forms a seal.
• Advantage: According to Boucher a narrow bead likeseal ismore
effective.

56. ARBITRARY SCRAPING OFTHE MASTER 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 palatalconfiguration and tissue
compressibility.
• Inaccurate and not physiological.
56

57. ADDING POSTERIORPALATAL SEAL TOTHE EXISTING
DENTURE
• Markthe vibratinglinein themouthwithan
indelible marker.
• Form thedesired thicknessandextensionofthe PPS
onthe denturein thepatient’smouthwithsoftened
green modeling compound
• Transferthelocationsofthe vibratingline tothe
denture
• Make acastofthe intagliosurfaceofthe denture
withputtymaterial;the castmustincludeall ofPPS
additionandextend5 to6 mm posteriorly
• Afterputtymaterialhasset, useascalpel tocut
channelswhich will allow excessautopolymerizing
acrylicresin toescape.
• Removethegreen stickcompoundandreplacewith
autopolymerizingresin in a pressurepot.
57Izharul Haque Ansari, JProsthet Dent 1994;72;449

58. Arthur Nimmo-Suggestedcorrection of posterior palatalsealby
using a visiblelightcured resin.
• Identify and mark the vibrating line in the mouth with an indelible
marking stick
• Roughen the denture surface in the posterior palatalseal areawith 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.
58

59. • 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
1. Noexothermic reaction to irritate the oral tissues.
2. Minimal volumetric shrinkageduring curing.
3. More closely approximates a physiologic technique.
4. Can be performed with relatively little chair time.
59

60. Rajeev M. Narvekar, and Marc B. Appelbaum
• Investigated the anatomicposition of posterior palatalseal by
ultrasound.
• Ultrasound refers to sound with frequencies higher thanthe audible
range (20 to 20,000 Hz).
• Basicelements of an ultrasound scanningsystem include –
1. Transducer
2.Couplant
60

61. Ultrasonictransducer
• The active element that has
piezoelectric properties which
transform mechanicalenergy
into electric energy and vice
versa
61

62. Couplant
• Necessary between the ultrasonictransducer 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.
62

63. 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, with a patient average
of 2.5 mm.
• The average distance from the posterior vibrating line to the junction
of the hard andsoft 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.
63

64. TROUBLESHOOTING
• Under extension
• Over extension
• Under post damming
• Over post damming
64

65. UNDEREXTENSION
• Most common cause for failure of the sealin the posterior palatalarea
Causes
• Practitioner’s use of the fovea palatineas the landmark for terminating
the denture base. By doing, so he may be depriving the patient of as
much as4 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
65

66. UNDERPOSTDAMMING
• May be the result of recording the tissue when the mouth was wide
open during the finalimpression.
• 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 willbe present between the denture base and the
tissue since the foldis no longer activated.
66

67. Diagnosis:- place the wet denture base into the mouth and slowlypress
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.
67

68. Correction–
• Further scrap the cast and readapting the trial base if the conventional
approach is used
• Add more waxand remind the patient to refrain from opening the
mouth so wide if the fluid waxtechnique employed.
68

69. OVERPOSTDAMMING
• Over scrappingofmaster castandtheposteriorpalatalsealdisplacestoo
muchtissue.
• Significantoverpostdammingespeciallyinthepterygomaxillarysealarea -
posteriorborderwillbedisplacedinferiorly.
• Moderatelyoverpostdammed- tissueirritationacrosstheposteriorpalatal
region
• Selectivereductionofthedentureborder withcarbidebur,followedby
lightlypumicingthearea whilemaintainingitsconvexity.
69

70. OVEREXTENSION
• 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
willbe evident.
• If the hamuli are covered by the denture base, the patient will experience
sharppain, 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.
70

71. CONCLUSION
• The recording of PPS is of great significancebecause it is vitalfactor in
establishing the peripheral seal which enhancesretention by utilizing the
atmospheric pressure.
• The PPS of a maxillarycomplete denture can be established during the
making of the preliminary impression, during the making of final
impression, by scoring the finalcast or by incorporating the sealin the
finaldenture.
• The posterior palatalseal is obtained through intimate contact and the
application of pressure withinthe 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.
71

72. REFERENCES
• ZarbBolender,Mosby,Prosthodontictreatmentfor edentulous
patients,12th edition
• Sheldon Winkler,A.I.T.B.S.Publishers,Essentialsofcomplete
denture Prosthodontics,2nd edition
• Arthur O.Rahn & CharlesM.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
72

73. • SilvermanS.L. “Dimensions and displacement patternsofthe posteriorpalatal
seal”. J ProsthetDent 1971:25;470-88
• WinlandRD, Young JM,Maxillarycomplete denture posteriorpalatal seal:
Variationsin size, shape & location, J ProsthetDent 1973:29;256-61
• LyeTL,The significance of the fovea palatinein complete denture prosthodontics. J
Prosthet Dent1975:33;504-10
• NikoukariH,A studyof posteriorpalatalseals withvaryingpalatal forms,J Prosthet
Dent1975:34;605-13
• ChenMS,Reliabilityofthe fovea palatini fordetermining the posteriorborder of
the maxillary denture. J Prosthet Dent1980:43;13-37
• AntolinoColon et al, Analysisofthe posterior palatalseal andthe palatalforms as
relatedtothe retentionofcomplete dentures. J Prosthet Dent1982:47;23-27.
• Ming-Sheh Chenetal, Methods taughtin dental schools fordetermining thePPS
region.J ProsthetDent 1985:53; 380-83
73

74. • NimmoA.,Correctionoftheposterior palatalseal by using a visible-lightcure
resin: Aclinical reportJ Prosthet Dent 1988:59;529-30
• NarvekarRM,Appelbaum MB,An investigationof the anatomic positionof the
posteriorpalatal seal by ultrasound, J ProsthetDent1989:61;331-36
• IzharulHaque Ansari ,A procedure foradding posteriorpalatal seal toanexisting
denture indental office, JProsthet Dent1994:72;449
• IzharulHaque Ansari “Establishing the posterior palatalseal during the final
impressionstage”. J ProsthetDent1997:78;324-26
• Yuuji Sato, Immediatemaxillarydenture base extension ,J Prosthet Dent
2000:83;371-73
• AaronYJ,TerryE D.Engaging the posteriorpalatal seal withthe frameworkof
maxillarycomplete overdenture.J ProsthetDent2009;101:3:214-5.
74