Objective: To compare the fitness of soldered four-unit porcelain-fused-to-metal (PFM) fixed partial dentures with o ne-piece castings or single crowns on their abutments under the same conditi ons.

• 目的：比较相同条件下的整铸法与分段铸造炉内后焊法制作四单位前牙非贵金属烤瓷桥的适合性差别。