The Posterior Palatal Seal

By Dr.Swathi Pai on Tuesday, January 6, 2009 with 0 comments

The posterior palatal seal area is described and its anatomical borders are defined. The methods used to achieve a seal are (1) scraping the cast, (2) a selective loading impression technique, and (3) a physiological impression technique. Each method is described and its problems are discussed. The authors believe that the physiological impression technique using wax requires the least amount of skill and experience to master competently.

Posterior palatal seal defined- an area of soft tissue along the junction of the hard and soft palate on which pressure, within the physiologic limits of the tissues, can be applied by a denture to aid in its retention.

Functions of the Posterior palatal seal- (1) to provide retention, (2) to prevent food from getting under the denture base, (3) to diminish gagging, (4) to make the sunken distal border less conspicuous to the tongue, and (5) to supply a thick border to counteract denture warpage due to dimensional changes during the curing process.

Techniques (1) Scraping cast technique- done chairside, it is an educated guess by the clinician (2) selective loading technique- depends on making an impression of the edentulous maxilla under constant load and taking into account the varying tissue densities of the mucosa, effective but requires skill and experience. (3) Physiologic technique- uses a mouth temperature impression wax to create the posterior palatal seal, advantages are that it can be developed in steps and that it can be corrected.

Conclusions- the most common problem associated with lack of retention of the maxillary complete denture is a faulty posterior palatal seal. Many dentures do not cover the tuberosities, nor do they extend into the pterygomaxillary notches, while others are extended too far posteriorly past the vibrating line.

A careful examination of the patient’s tissues helps to delineate the anatomical boundaries of the posterior palatal seal area so that an adequate seal can be established.

Category: Prosthodontics Notes



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