Expanded Function Dental Assistant (EFDA) Board Practice Exam

The primary purpose of using a matrix band during amalgam restorations is to shape the restoration. A matrix band acts as a form or mold that helps in reproducing the original contour of the tooth, allowing for the proper anatomical shape and contact points to be achieved when placing the restorative material. This is particularly important in posterior teeth, where the proximal surfaces must be accurately shaped to ensure proper alignment with adjacent teeth.

The use of a matrix band also assists in creating a tight seal that helps maintain the integrity of the restoration during the setting process, which is crucial for long-term success. Properly shaped restorations enhance occlusion and function, helping to restore the tooth’s bite effectively.

While isolation of the tooth, prevention of contamination, and providing a rough surface may be considered during various restorative procedures, these factors are not the primary functions of the matrix band in the context of amalgam restorations. The matrix band specifically focuses on the shaping aspect, ensuring the restoration mimics the tooth's natural anatomy.