Final answer:
Stops in a custom dental tray are essential for securing the tray in a consistent and stable position during impression making, leading to accurate dental impressions with minimal distortion.
Step-by-step explanation:
When constructing the custom tray, it is important to place stops to ensure that the tray fits securely. The purpose of the stops is not to prevent the impression material from running out of the tray, nor is it to make the tray aesthetically pleasing or to ensure that the patient is comfortable, although the latter can be a secondary benefit. The stops are critical to provide a consistent and stable position for the custom tray during impression making, which helps to accurately capture the dental structures and minimize distortion in the final impression.