The posterior palatal seal (PPS) area plays a critical role in the retention of maxillary complete dentures and is often missed by the clinician.
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The PPS area is defined by the Glossary of Prosthodontic Terms3
as “the soft tissue area limited posteriorly by the distal demarcation of the movable and nonmovable tissues of the soft palate and anteriorly by the junction of the hard and soft palates on which pressure, within physiologic limits, can be placed; this seal can be applied by a removable complete denture to aid in its retention.” Various techniques have been proposed to record the PPS area.4
However, the success of these techniques depends on the accurate location and transfer of the anatomic boundaries of the posterior palatal seal area to either the primary or definitive cast, which may be identified with a T-burnisher and indelible marking pencil. In 2006, Chang and Wright described a technique for the location of the PPS intraorally and accurate transfer to the maxillary complete denture cast.5
However, a drawback of this technique is the replication of the intraoral markings on the record base. This article describes a straightforward and modified technique for the transfer of the PPS area on the maxillary cast by using a thermoplastic sheet.Procedure
- 1.Make an irreversible hydrocolloid impression (Jeltrate; Dentsply Sirona) of the maxillary arch with a perforated stock tray and pour the impression with Type III gypsum (Kaldent; Kalabhai Karson).
- 2.Adapt a resilient polyvinyl thermoplastic sheet (Easy-Vac Gasket; 3A Medes) by using a vacuum forming machine (Easy-Vac; 3A Medes) on the primary cast.
- 3.Locate and delineate the anterior and posterior vibrating line on the soft palate by using an indelible pencil (Staedtler; Nozomi) (Fig. 1A).
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Figure 1A, Intraoral delineation of anterior and posterior vibrating line with indelible pencil. B, Transfer of anterior and posterior vibrating line to thermoplastic sheet. C, Thermoplastic sheet trimmed to posterior vibrating line. - 4.Place the thermoplastic sheet template intraorally and transfer the markings of the anterior and posterior vibrating line to it by using a black permanent marker (Permanent marker; Camlin) (Fig. 1B).
- 5.Trim the thermoplastic sheet template to the marked posterior vibrating line of the PPS area (Fig. 1C).
- 6.Place the thermoplastic sheet template on the definitive cast and draw the posterior vibrating line of the PPS area on the cast by using the indelible pencil (Fig. 2A).
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Figure 2A, Transfer of posterior vibrating line to definitive cast. B, Thermoplastic sheet trimmed to anterior vibrating line. C, Transfer of anterior vibrating line to definitive cast. - 7.Trim the thermoplastic sheet template to the marked anterior vibrating line of the marked PPS area (Fig. 2B).
- 8.Place the thermoplastic sheet template on the definitive cast and draw the anterior vibrating line of the PPS area on the cast with the indelible pencil (Fig. 2C).
Acknowledgments
The authors thank Dr Sabita M. Ram, Director Research, MGM Institute of Health Sciences, Navi Mumbai, and Dr Naisargi Shah, HOD, Department of Prosthodontic, Terna Dental College and Hospital, Navi Mumbai, for the guidance and their encouragement for innovations.
References
- Defining the posterior palatal seal on a definitive impression for a maxillary complete denture by using a non fluid wax addition technique.J Prosthet Dent. 2014; 112: 1597-1600
- A method of correcting the posterior palatal seal area of a maxillary complete denture.J Prosthet Dent. 1979; 42: 690-692
- The glossary of prosthodontic terms. Ninth edition.J Prosthet Dent. 2017; 117: e1-e105
- The study of anatomic structures in establishing the posterior seal area for maxillary complete dentures.J Prosthet Dent. 2014; 112: 494-500
- Accurate location of postpalatal seal area on the maxillary complete denture cast.J Prosthet Dent. 2006; 96: 454-455
Article info
Publication history
Published online: January 13, 2020
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© 2019 by the Editorial Council for The Journal of Prosthetic Dentistry.
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