The Impact of Recasting on the Bond Strength of Metal Ceramic Restorations

Abstract

Objective: The objective of this study is to evaluate the effect of recasting of Nickel Chromium (Ni-Cr) alloy on the bond strength of metal-ceramic restoration. Materials and Methods: Forty-five samples fabricated from one Ni-Cr alloy were divided into three groups. Group 1 consisted of 100% fresh alloy; Group 2 consisted of 50% fresh alloy mixed with 50% alloy taken from sprue and button remnants of group 1 and group 3 consisted of 50% new alloy mixed with 50% alloy taken from sprue and button remnants of group 2. All samples were then bonded to a ceramic material. The bond strength of the Metal-Ceramic was then assessed using a 3-point bending test. The failure mode was investigated under a stereomicroscope and confirmed under scanning electron microscopy (SEM). Results: Group 1 (100% fresh alloy) showed the highest bond strength amongst the other groups, while the lowest was recorded for group 3 (50% fresh alloy with 50% cast twice alloy). According to the International Organization for Standardization (ISO), the bond strength of fresh alloy and the group casted once attained the required level. Conclusion: The outcome of this study indicates that the use of 100% fresh Ni-Cr base metal alloy yields the highest bond strength of metal ceramic restoration.