PATIENT VISIT 3– Posterior Palatal Seal
Clinical Procedures

Procedure

1. Gently dry the tissues in the posterior palatal seal and pterygomaxillary notch with a gauze sponge.

2. Locate the pterygomaxillary (hamular) notches with a T burnisher by passing it posteriorly along the crest of the ridge until it drops into the notch. Mark the notches with the indelible marker.

3. Locate the vibrating line by having the patient say a series of short "ahs" and mark it in the mouth with the indelible marker. Mark the area of the soft palate where movement just begins.

4. Insert the dried maxillary record base in the patient's mouth and seat it fully. Visually observe the relationship of the record base to the line marked in the patient's mouth. Ask the patient to tilt his head down and swallow and/or say a series of short "ahs."

5. Remove the maxillary record base. The indelible marking may have transferred to the record base. If the line has not transferred to the record base, reinsert the base and instruct the patient to blow through his or her nose while you gently pinch it shut. Look in the patient's mouth. You may be able to see the indelible marker line through the translucent record base.

6. Trim the posterior border of the record base to the transferred marking using a bur designed for trimming acrylic. Reinsert the record base in the patient's mouth and evaluate the relationship of the posterior border to the vibrating line. Adjust until the correct length is obtained. The fovea palatine are not reliable indicators of the location of the vibrating line.

7. Place the maxillary record base on the cast. Scrape a line into the cast, marking the posterior border of the record base using a sharp instrument. Extend this line approximately 3 mm beyond the crest of the pterygomaxillary notch continuous with the disto-buccal border. This marks the posterior limit of the denture.

8. Palpate the tissue anterior to the vibrating line with the ball end of the T-burnisher. Examine the thickness and displaceability of the tissue. Using a pencil, outline the posterior palatal seal on the cast. The generally accepted outline is a butterfly or mustache pattern. The average dimensions are 2-3 mm in the midline and distal to the tuberosities. A width of 4-6 mm is appropriate for the intervening areas between the midline and pterygomaxillary notches. The seal should be deeper posteriorly becoming more shallow as it extends anteriorly. It should be rounded and smooth in contour.

9. Scrape the master cast using a discoid/cleoid to the proper depth. This is usually one-half the depth the ball of the T-burnisher displaces the tissues. The deepest part of the posterior palatal seal usually is placed on either side of the midline where the seal approaches the hamular notches. This is generally in the range of 1.0 - 1.5 mm in depth.

10. Formerly compound was placed on the record base to make an impression of the posterior palatal seal area. This step should be omitted.

Heat initiated polymerization results in the resin pulling away from the cast up to 0.8 mm in the central areas between each hamulus. This area should be scraped on the cast to a depth of 1.0 - 1.5 mm to the assure that the post-palatal seal still displaces adequate tissue for denture retention. The lateral areas which run through the pterygomaxillary notches should be scraped to a depth of 0.5 - 1.0 mm. These area will not have the resin pull away from the cast to any great extent. The seal should be scraped such that the deepest portion of the seal is at the posterior....exactly at the vibrating line. It should be a distinct line that the technician can clearly read. It is better to error in favor of a deeper post palatal seal than one which is too shallow because a moderately excessive seal can be easily adjusted with a pressure indicating paste at the insertion appointment.

4. Posterior Palatal Seal on Master Cast

Grade A - Outline of posterior palatal seal neatly carved to correct position and size. Extends about 3 mm lateral to pterygomaxillary notches. Narrows in midline area. On average 2-3 mm in width in midline, 2 mm in width at pterygomaxillary notches and 4-6 mm wide in between. Depth of seal is in the range of 1.0-1.5 mm deep except in the pterygomaxillary notch area where depth is slightly less.

Grade B - Minor discrepancies from above which do not compromise the quality of the clinical treatment. Outline of posterior palatal seal neatly carved, and correctly positioned. Size and/or shape slightly out of norm. Slightly rough or irregular.

Grade C - Posterior palatal seal carved in master cast is adequate to make a clinically acceptable complete denture, but marginally so. Indelible marker ink spread out making markings somewhat indistinct. Standard shape of "ideal" posterior palatal seal present. Depth deviates significantly from above.

Grade E - Posterior palatal seal prevents clinically acceptable complete denture treatment. Posterior palatal seal absent or is grossly indistinct, ill-shaped or sized. Excessive or inadequate depth into master cast. Does not extend into buccal vestibule. Located much too far posteriorly or anteriorly relative to the structures used for reference.