California Registered Dental Assistant (RDA) Written Practice Exam

What is the first step in processing a preliminary impression before it is sent to the lab?

1. Rinsed and disinfected

2. Scanned for quality

3. Directly poured up

4. Photographed

The correct answer is: Rinsed and disinfected

Before sending a preliminary impression to the lab, it is important to first rinse and disinfect the impression. This step helps ensure that any excess debris or bacteria from the patient's mouth is removed, providing a more accurate representation of the patient's teeth and gums. Option B, scanning for quality, may seem like a viable first step but it can potentially compromise the accuracy of the impression if there is debris or bacteria present. Directly pouring up the impression (option C) might seem like a more efficient step, but it is important to first rinse and disinfect to ensure the mold used for pouring is not contaminated. Lastly, while photographing the impression (option D) may be useful for documentation purposes, it does not address the necessary step of cleaning and disinfecting the impression before sending it to the lab.