Accurate location of postpalatal seal area on the maxillary complete denture cast

Evaluation of the conventional method for establishing the posterior palatal seal

“…By using the methods described by [23,3,27] anterior and posterior vibrating lines were positioned. A precise location of the PPS area on the upper cast was determined according to the technique illustrated by [6]. The patient was seated in an upright position and instructed to rinse with an astringent mouthwash to eliminate the stringy saliva that might preclude obvious transfer marking [5].…”

“…The base was returned to the master cast and the posterior border was determined. As stated by [6] the acrylic base was cut with a carbide bur to the posterior markings. [3,6] explained that ''the anterior vibrating line represents the anterior border of the PPS area.''…”

“…As stated by [6] the acrylic base was cut with a carbide bur to the posterior markings. [3,6] explained that ''the anterior vibrating line represents the anterior border of the PPS area.'' For locating this line the acrylic base was returned once more to the mouth, the palatal tissues anterior to the posterior border were palpated by using the ''T'' burnisher to determine their compressibility and the anterior outline of the PPS area (anterior vibrating line) [23].…”

“…This line was marked in the mouth with an indelible pencil and transferred to the acrylic base. The base was trimmed to the markings, and it was put again on the master cast for transferring the anterior border of the PPS area [6]. A scraper was used to carve the cast.…”

“…The functions of the PPS of the maxillary complete denture include improving retention, performing sealing of the denture base with the underlying tissue and decreasing the gagging reflex [14,3,27] The PPS is performed by positioning the anterior and posterior vibrating lines [8]. [20,6] Stated that ''the one vibrating line concept for establishing the PPS is taught by 75-80% of schools.'' The palatal seal of the upper complete denture can be obtained by scraping the cast before denture processing, or by using physiologic impression technique or selective pressure impression technique [14].…”