Which of the following tasks can not be delegated to EFDA's in Ohio?

Taking the final impression for a metal ceramic crown (MCC) is a task that cannot be delegated to an Expanded Function Dental Assistant (EFDA) in Ohio. This is primarily because the final impression is a critical step in the fabrication of restorations that requires a high level of clinical judgment and expertise that goes beyond the training and scope of practice for an EFDA. This task typically requires the skills of a licensed dentist, who is responsible for ensuring accuracy and precision during the impression process, which is essential for the fit and function of the final dental prosthesis.

In contrast, the other tasks mentioned, such as placing composite restorations, placing bases and liners, and finishing and polishing a large cusp build-up amalgam, fall within the delegated duties of an EFDA. These tasks have been included in the EFDA's scope of practice following appropriate training and education, allowing them to support dentists effectively while ensuring high-quality patient care.