الفهرس | Only 14 pages are availabe for public view |
Abstract In this study we investigated the effect of: 1. Finish line design 2. Different types of waxes 3. Time of investing On the accuracy of the vertical marginal gap and the internal surface adaptation of full coverage metallic crown. We used two metal dies made by milling machine having two different finish line, one of the metal die have bevel finish line and the other chamfer finish line. 100 wax patterns were made on the two metallic dies using different types of waxes of different physical properties; we use hard, medium and soft type. The used waxes were different in the melting temperature, softening temperature, hardness and casting shrinkage. The wax pattern were invested using two different time, were 50 of them invested immediately and the other 50 invested after 24 hours. After casting was done the metal crowns were examined using the stereomicroscope to measure the vertical marginal gap distance then crowns were sectioned longitudinally and again were examined under stereomicroscope to detect how these factors control the accuracy of the full coverage metallic crown at the marginResults showed that bevel finish line with the medium type of wax when invested immediately gave less vertical marginal gap, while the use of soft-hard wax gave better internal surface adaptation however the type of finish line design. . and there internal surface adaptation. |