Which material provides the best retention for pin restorations?

Amalgam is known for its excellent retention properties in pin restorations. This is primarily due to its unique physical properties, including its ability to bond tightly to the walls of the cavity preparation. When amalgam is placed, it adapts well to the surface of the tooth, creating a strong mechanical lock that enhances retention. The setting reaction of amalgam also contributes to this strong bond as it allows the material to fill the voids and contours of the tooth structure.

Additionally, amalgam does not shrink significantly upon setting, which helps maintain the integrity and retention of the restoration over time. This makes it particularly effective in areas requiring strength and durability, such as posterior teeth where mastication forces are more significant.

While other materials like gold inlay, composite, and glass ionomer each have their own advantages, they do not typically match amalgam’s overall retention capabilities in pin restorations. Gold inlay is also strong but often requires more precise fitting and preparation, while composite materials may not provide the same level of mechanical retention due to their adhesive bonding mechanism, and glass ionomer, although useful for certain indications, has different retention characteristics that make it less ideal for high-stress areas.