The Undercut
by Dana Shboul
1. Localized
2. Generalized
3. Undercut Definition
3.1. The portion of the surface of an object that is below the height of contour in relationship to the path of placement .
3.2. The contour of a cross-sectional portion of a residual ridge or dental arch thet prevent the insertion of a dental prosthesis .
3.3. Any irregularity in the wall of a prepared tooth that prevent the withdrawal or seating of a wax pattern or casting .
4. Undercut Management -Tx.-
4.1. Leave it
4.1.1. outside denture area .
4.1.2. reduced distolingual length .
4.2. Utilize it
4.2.1. if less than 180 degree .
4.2.2. Unilateral.
4.2.3. Surgical correction
4.2.3.1. soft tissue correction.
4.2.3.2. Bone shaping .
4.2.4. Rotation path of insertion .
4.3. Relief it
4.3.1. For one of the bilateral undercut .
4.4. The use of implant retained fixed dentures
4.4.1. Without flanges.
5. undercut shapes
6. Dalia Zaitoun 20110050031 #228
7. Dana Al-Shboul 20110050092 #275
8. Causes of Undercut
8.1. Normal variations
8.1.1. Maxillary areas
8.1.1.1. Pemaxilla .
8.1.1.2. Canine eminence .
8.1.1.3. Tuberosity.
8.1.2. Mandibular areas
8.1.2.1. Distolingual slop of the ridge.
8.2. Developmental causes
8.2.1. Mandibular tori
8.3. Soft tissue diseases
8.3.1. Fibromatosis.
8.3.2. Soft tissue tumors
8.4. Bone diseases
8.4.1. Bone exostosis
8.4.2. Bone tumors
8.5. Post-extraction problems
8.5.1. Uncompressed socket
8.6. Aging Changes
8.6.1. Interior oblique ridge prominence
8.6.2. Genial tubercle prominence
8.6.3. Tubersosity with pneumenization of Maxillary sinus air cells