Which margin configuration is preferred for cast metal restorations?

The preferred margin configuration for cast metal restorations is a supragingival chamfer. This design is beneficial for a number of reasons.

A chamfer margin allows for a smooth transition between the tooth structure and the restoration, which helps to ensure a proper fit. Additionally, the rounded nature of the chamfer accommodates the thickness of the metal in the restoration, which is important for strength and durability. The supragingival aspect refers to the margin being located above the gum line, which is advantageous because it becomes easier to clean and maintain gingival health. This positioning reduces the risk of plaque accumulation and gum irritation, contributing to better overall oral hygiene for the patient.

In contrast, a subgingival shoulder may be more challenging to clean and could pose risks for gingival irritation. A supragingival feather edge lacks the adequate bulk of material necessary for a strong restoration, particularly in the context of cast metal. The subgingival chisel design may not provide the required retention and resistance form for the restoration to function effectively under occlusion.

Overall, the supragingival chamfer margin is ideal for creating a reliable, durable, and hygienic cast metal restoration.