Which instrument is used to SCORE the master cast when creating the posterior palatal seal?

Correct answer: A. Kingsley scraper

• A. CORRECT. The KINGSLEY SCRAPER is the laboratory instrument designed for carving the posterior palatal seal into the master cast. The seal is scored to a depth that reflects the DISPLACEABILITY of the soft tissue at each point along the line — typically 1-1.5 mm at the pterygomaxillary (hamular) notches where tissue is most compressible, tapering to a minimal depth over the midpalatal raphe where thin mucosa lies directly on bone and cannot be compressed.
• B. The Ash No. 5 carver is a general wax carving instrument for contouring the denture base and festooning; it is not the designated instrument for scoring the seal.
• C. A Willis gauge measures facial vertical dimension between the base of the nose and the base of the chin. It is used to establish OVD and has nothing to do with the posterior palatal seal.
• D. The T-burnisher is used INTRAORALLY to identify the vibrating line and assess tissue displaceability. It is the clinical, not the laboratory, instrument.

Note: Over-carving produces tissue soreness, inflammation and eventually papillary hyperplasia. Under-carving loses the peripheral seal so the denture drops. Always provide RELIEF over a torus palatinus or a prominent midpalatal raphe.