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Post-Dam Function — NDEB AFK MCQ

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ModerateProsthodonticsPost-Dam FunctionNDEB AFK

Which of the following correctly describes the purpose of the post-dam (posterior palatal seal) in a maxillary complete denture?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: CTo create a seal at the posterior border of the denture preventing air ingress, thereby enhancing retention

The post-dam (posterior palatal seal) is a raised area at the posterior border of the maxillary complete denture that creates intimate contact with the soft palate at the vibrating line. This seal prevents air from entering beneath the denture posteriorly, maintaining the negative pressure (suction) that contributes to denture retention. The post-dam also compensates for minor polymerisation shrinkage of the acrylic base. It is customised by scraping a groove in the master cast before processing.

Reference: Zarb – Prosthodontic Treatment for Edentulous Patients, 13th ed., 2013