R Zakaria, Maan, and Haidar H Jassim. 2003. “Evaluation of the Effects of Porcelain Firing Cycles on the Marginal Fit Changes of porcelain– fused–to–metal Crowns Constructed Utilizing Two Different Marginal Designs and Alloys”. Al-Rafidain Dental Journal 3 (1):13-20. https://doi.org/10.33899/rden.2020.165736.