Research On The Influence Of Different Pattern Materials On The Marginal Adaptation And Distortion Of Crown

Pattern material is used to make rudiment of casting in fixed prosthesis. With the need for casting precision, people take more attention to the quality of pattern material. Contractility and rigidity of pattern material would make great influence on the Marginal adaptation and Distortion of crown.At present, there are few research report about the pattern Marginal adaptation, the pattern distortion and the pattern material found capability. In this study, we pay more attention to the influence of different pattern materials on the Marginal adaptation and Distortion of crown. There are many kinds of pattern materials used in this study. It be researched about the influence of different pattern materials on the Marginal adaptation and Distortion of crown. This research include four part of experiments:The first part of experiment is to evaluate the influence of different wax pattern materials on the Marginal adaptation of the wax pattern of metal crown. Standard cast specimens and round capsules simulated post tooth crowns were made. 4 groups wax patterns were prepared on the as-cast specimens. The first three groups wax patterns were made by three kinds of inlay wax. There are 10 wax patterns in every groups. The fourth group wax patterns were made by three kinds of inlay wax match with one kinds of Cervical Wax. There are 20 wax patterns in this group. The marginal opening of the wax pattern is measured under traveling microscope. Results: There hardly showed significant difference between the first group and the second group, (p > 0.05) However, They showed significant different with the other groups.(p < 0.05) There hardly showed significant difference between the third group andthe fourth group, (p > 0.05 )The second part of experiment is to evaluate the influence of the temperature variation on the Distortion of crown pattern which is made of different pattern materials. Standard cast specimens and round capsules simulated post tooth crowns were made. 3 group wax pattern were prepared on the as-cast specimens. There three kinds of pattern material are used in every groups. There are 10 wax pattern in every groups. The crown pattern was put in constant temperature case. The stain gauge is placed at the pattern body near occlusion and the pattern body near cervical. The temperature rise 5°C from 25°C.The parallel distortion of crown pattern was measured by stain gauge. Results: There showed significant distortion of crown pattern with the temperature variation in 3 groups. In 3 groups with the distortion of the pattern body near occlusion is different the distortion of the pattern body near cervical.The third part of experiment is to evaluate the influence of softening temperature of the pattern materials on the Marginal adaptation of the metal full-crown casting. Standard cast specimens and round capsules simulated post tooth crowns were made. 3 group patterns were prepared on the as-cast specimens. The Soften inlay wax with softening temperature of 41°C is used in the first group. The Harden inlay wax with softening temperature of 65 °C is used in the second group. The autopolymerizing acrylic resin with softening temperature of 75 °C is used in the third group. There are 10 patterns in every group. The investment material for the 3 groups is Dentaurum phosphate investment material which is made in Germany. The Dentaurum NiCrMo dental casting alloy is used for every group. The marginal opening of the metal full-crown was measured with SEM. Results: There hardly showed significant difference between the first group and the second group, (p >0.05) However, the third group showed significant different with the other groups, (p <0.05) The fourth part of experiment is to evaluate the influence of 3 kinds of dental...