An in vitro study on the effect of the temperature of cylinders and liner on the dimensions of casting posts in base metals

Sabooni, MohammadReza and Ghanbarzadeh, Jalil and Goharian, Reza and Esmaeili, Habibollah (2005) An in vitro study on the effect of the temperature of cylinders and liner on the dimensions of casting posts in base metals. Journal of Mashhad Dental School, 29 (Issue). pp. 215-222.

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Abstract

Introduction: Casting posts are recommended for endodontically treated teeth, specially in cases with extensive damaged crowns. Because the length and diameter of the post are effective in generating stress on the roots, and can be influenced according to the casting conditions, the purpose of this research was to study the effect of using liners and the temperature of burn out on the dimensions of the casting posts in base metals. Materials & Methods: In this experimental study, 80 acrylic posts with the length of 12.095 mm and the diameter of 2.096mm were made. On top of each post a reference point was contrived and the posts were grouped into 4 groups of 20. In the first group, humidified liner and casting temperature of 900ºc were used, the second group were without liner and the temperature was 900ºc , the third group were with humidified liner and temperature of 600ºc and the fourth group were without liner and were casted in 600ºc temperature. The lengths of the posts were measured from top to the bottom in the center (diameter in the upper most part in the reference point) with a metallurgy microscope and the results were statistically compared using student-t, Mann-Whitney and Kruskal-wallis tests. Results: Mean and standard deviation of the acrylic post lengths were obtained. The difference (0.127mm) was significant (P<0.001). Also, mean and standard deviation of the diameter of the acrylic posts (2.87mm±0.118) was significantly less than that of metal post (2.97mm±0.166), (P<0.001). Differences in length was significant among studied groups so that in the group with 600ºc temperature and without liner, the least measures occurred compared to the other groups (P=0.001). Difference in the diameter of the acrylic and metal posts in the four groups showed that the use of 600ºc temperature without humidified liner produced the least differences compared with the other groups (P=0.001). Conclusion: It can be concluded that the best condition for investing and casting the casting posts is 600ºc temperature without using the liner. Key words: Metal cylinder, base metal, liner, casting post.

Item Type: Article
Subjects: WU Dentistry. Oral surgery
Divisions: Journals > Journal of Mashhad Dental School
Depositing User: jmds jmds
Date Deposited: 25 Sep 2017 13:54
Last Modified: 25 Sep 2017 13:54
URI: http://eprints.mums.ac.ir/id/eprint/3813

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