Blockout and relief Blockout: elimination of undesirable undercuts on the master cast.
Types of Blockout 1. Parallel blockout 2. Shaped blockout 3. Arbitrary blockout… Sites of Parallel Blockout 1.proximal tooth surfaces to be used as guiding plane surfaces. 2.beneath all minor connectors. 3.tissue undercuts to be crossed by rigid connectors. 4.tissue undercuts to be crossed by origin of bar clasp. 5.deep interproximal spaces to be covered by minor connector or linguoplate. 6.beneath bar clasp arms to gingival crevice
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Shaped Blockout Involves ledges or shelves for locating clasp pattern Sites Buccal and lingual surfaces to locate wax pattern for clasp arm.
Block out and relief to the cast
Block outRelief
Relief : is the reduction or elimination of undesirable pressure or forces from a specific region under a denture base. Advantages of Relief 1.To avoid tissue impingement by cast framework during function 2.To provide space for attachment of acrylic denture base to mesh frameworkRelief