Making a Posterior Palatal Seal

7/27/2019 Making a Posterior Palatal Seal

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Posterior Palatal Seal


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The posterior palatal seal is placed in themaxillary complete denture because theacrylic will distort slightly and pull awayfrom the posterior palatal area of themaxillary cast. The acrylic will shrink

toward the areas of greatest bulk, which arethe areas over the ridge where the teeth areplaced. The posterior palatal seal provides avacuum seal between the denture and the

soft palate that holds the maxillary completedenture securely in place.


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The amount of area in which the palatalseal can be placed varies with the shape of

the posterior palate. In Housesclassification of the posterior palate, a class1 palate will allow 5-10 mm of surface area toplace the seal, a class II posterior palate will

allow 3-5 mm and a Class III posterior palatewill allow only 1-3 mm.


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Houses Classifications

House classified the soft palate according to how it drapes.

5-10 mm

Vibrating line

Vibrating line Vibrating line

Class III

Class I

3-5mm 1-3 mm

Class I easiest to tolerate, broadest range, hardest to locate.

Class II

most common Class III

easiest to locate, hardest to tolerate.

Class II


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Posterior Palatal Seal

Posterior Nasal Spine

Velum

Glandular tissue


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Orally, the area of the vibrating line is

recorded by making marks with an indelibletransfer stick in the fovea palatina area andthe hamular notch areas on both sides of thepalate and then connecting them with a solidline.


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In the lab exercise, mark points on themaxillary cast in the fovea palatina area andthe hamular notch areas.


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Connect these points with a solid linewhich will appear as a gentle curve towardthe anterior. This line will extend into the

buccal vestibular areas of the hamular notch.


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Place points in the glandular area 5-8 mmforward of this first line and about two mmanterior to this line in the mid palatal area.


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Draw a second line anterior to the first linethat connects these dots and forms a butterflypattern. It looks like two mountains with avalley in between.


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Make a depth cut on the posterior line with a cleoid/disoid or thepoint of a green-handled knife. It should be .5 mm deep in themiddle of the posterior palate, 1 mm deep in the hamular notch area,and 1.5 mm deep in the glandular area between the hamular notchand the middle of the posterior palate.


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Use the back of the green-handled knife to form the palatalseal. It should feather out to zero at the anterior line. It shouldnot extend onto the maxillary tuberosities or onto a torus.


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It should feather out to zero at the anterior line. It shouldnot extend onto the tuberosities or onto a torus as these areasare not depressable and would prevent the denture from seatingentirely.


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Dimensions of Post-Palatal Seal


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Documents

Making a Posterior Palatal Seal