What is the principal cause of failure in amalgam restoration?

The principal cause of failure in amalgam restoration is related to improperly prepared cavity preparation. A well-executed cavity preparation plays a crucial role in the success of an amalgam restoration. The cavity must be of appropriate shape and size to ensure that the amalgam can adequately bond to the tooth structure. An improperly prepared cavity can lead to inadequate retention, poor adaptation of the amalgam to the tooth, and increased likelihood of leakage at the margins.

In addition, poorly designed cavity preparations can also impact the strength and durability of the restoration. For instance, if the cavity walls are not appropriately angled or if there is insufficient bulk of amalgam material, the restoration can easily fracture or become dislodged under normal mastication forces.

While factors like improperly prepared amalgam and the presence of periodontal issues may contribute to restoration failures, these factors often stem from issues related to the cavity preparation itself. Effective cavity preparation establishes a solid foundation for the restoration, ensuring that the amalgam can be placed effectively and perform optimally over time.