Final answer:
To prevent a custom tray from seating too far on the arch, stops are created. These stops are essential for ensuring consistent seating and preventing distortion of the impression material.
Step-by-step explanation:
To prevent a custom tray from seating too far on the arch, stops are created. In dentistry, when fabricating a custom impression tray, it is essential to include stops to ensure that the tray seats in the same position consistently. These stops are placed on the cast before forming the tray and serve as a physical limit to prevent over seating, which could lead to distortion of the impression material and hence an inaccurate representation of the dentition or arch. Usually, these stops are made from a small amount of wax or a similar material that hardens and are strategically positioned in areas where they will not affect the accuracy of the impression, such as on the occlusal surfaces of the teeth or on bony prominences in edentulous arches.