The use of ribbon sprue in the fabrication of a nickel-chromium coping: A laboratory case report

This study aimed to evaluate the casting quality of nickel-chromium copings fabricated using ribbon sprue designs. Ribbon sprues were fabricated from heat-resistant materials and attached to wax patterns. A centrifugal casting technique was employed to deliver molten metal into the mold. After casting, the copings were assessed from mesial-distal, buccal-lingual, and occlusal-cervical views. Parameters examined included marginal fit, surface porosity, shrinkage, and the presence of fractures. Nickel-chromium copings produced using the ribbon sprue demonstrated excellent metal flow and complete mold filling. The castings showed minimal defects, and margins exhibited accurate adaptation to the abutment structures, with no visible fractures or porosity under visual and microscopic inspection. The ribbon sprue configuration enhances the quality of nickel-chromium casting by promoting even distribution of molten metal and reducing the likelihood of common casting defects. This technique provides reliable outcomes in fixed prosthodontic restorations.