POSTERIOR PALATAL SEAL

CONTENTS Introduction Definition Purpose Parts of PPS Vibrating Lines Classification of PPS Techniques of recording PPS Failures in recording PPS Bibliography

POSTERIOR PALATAL SEAL Defined as an area of soft tissue along the junction of the hard and soft palate on which pressure, within physiologic limits of tissues, can be applied by a denture prosthesis to aid in its retention. The posterior border and the posterior palatal seal are the two, of the most critical areas for maxillary denture prosthesis retention. OTHER NAMES- POSTERIOR PALATAL SEAL” “POSTERIOR VALVULAR SEAL” “POST DAM” “POSTERIOR BORDER SEAL” “POSTERIOR PERIPHERAL SEAL” “POSTERIOR PALATAL SEAL AREA

PURPOSE OF THE POSTERIOR PALATAL SEAL Prevents food from getting under the denture base Firm contact with the tissue of the soft palate reduces the tendency to gag To provide retention Aids in compensating for dimensional changes during curing

POSTERIOR PALATAL SEAL IS DIVIDED INTO TWO SEPARATE BUT CONFLUENT AREAS BASED UPON ANATOMIC BOUNDARIES. POST PALATAL SEAL which extends medially from one maxillary tuberosity to the other. Laterally, PTERYGOMAXILLARY SEAL which extends through the pterygomaxillary notch continuing for 3-4 mm anterolaterally approximating the mucogingival junction. A- Clinical junction of hard and soft palates B- Ah- line (ANTERIOR VIBRATING LINE) C- Anatomical junction of hard and soft palate. (POSTERIOR VIBRATING LINE )

VIBRATING LINES imaginary lines, marking the division between movable and relatively immovable tissues of the soft palate, not just a line but an area , form the posterior valvular seal. 1.ANTERIOR VIBRATING LINE located at junction of the attached tissues overlying the hard palate and the moveable tissues of soft palate. Can be located by say “Ah” with short vigorous bursts & 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 with the hard palate). 2.POSTERIOR VIBRATING LINElocated at junction of soft palate that has limited or shallow movement and the freely movable soft palate. This is most distal extension of the denture base. Is visualize by say “Ah” in short bursts in unexaggerated fashion.

( HOUSE’S CLASSIFICATION ) DIFFERENT SOFT PALATE FORMS ( HOUSE’S CLASSIFICATION ) Class I Class II Class III Posterior Peripheral Extension(Variations)

CLASSIFICATION OF SOFT PALATE (ANGLE) Class I : indicates a soft palate that is rather horizontal as it extends posteriorly, with minimal muscular activity. Favorable & Ideal for retention, 5 mm movable tissue. Class II: Between Class I & Class III, 1-5mm of movable tissue available; Good retention Class III;Acute contour in relation to the hard palate, with a high V-shaped palatal vault. less than 1mm of movable tissue available; Poor retention. These classifications are determined when the patient is in an upright position with the head held erect. The positional changes of the head and physiologic functioning of the tongue can influence soft palatal placement.

TECHNIQUES Classified into Conventional or Functional Fluidwax Arbitrary scraping

Conventional or Functional Technique Fabricate a well-adapted resin tray on the master cast. The patient is seated upright & PPS area is dried with a gauze. Palpate for hamular notch with a “T” burnisher or a mouth mirror & mark with an indelible pencil. The patient is asked to do Valsalva maneuver’ & say ‘Ah’ in short bursts & in an unexaggerated fashion. Vibrating lines are drawn & resin tray is inserted into the mouth and the lines are transferred to the tray & then tray is returned to the cast to complete the transfer of the lines. A Kingsley Scraper is used to score the cast. The tray is modified according to the ‘scored’ master cast and checked for any gap between the tray and soft palate.

FLUID WAX TECHNIQUE All the conventional procedures are followed. The indelible transfer markings are recorded on the final wash impression. Mouth temperature wax (e.g. Iowa wax, Korecta No.4 wax, Adaptol) is used. The melted wax is painted onto the impression surface within the outline of the seal area. Once cooled below mouth temperature the impression is carried to the mouth and held in mouth under gentle pressure for 4-6 minutes to allow time for the material to flow.

The patient’s head is positioned forward and downward and the tongue is firmly positioned against the mandibular anterior teeth during the procedure. (A properly positioned maxillary tray handle can serve as a substitute for the missing incisors). The impression tray should be removed from the mouth and the wax should be examined for uniform contact throughout the posterior palatal seal area. The wax should terminate in a feather edge near the anterior vibrating line.

ARBITRARY SCRAPING OF MASTER CAST Least accurate. Depend on “Guesstimation”

FAILURES IN RECORDING POSTERIOR VALVULAR SEAL Under extension. Under post damming. Over post damming. Over extension.

BIBLIOGRAFY Zarb-Bolender ; Prosthodontic treatment for edentulous patients; 12th edition.