The placement of rest seats in dentistry, particularly for removable partial dentures (RPDs), is crucial to avoid occlusal interferences and ensure the stability of the prosthesis. Here are the essential guidelines for the optimal placement of rest seats:

1. Location Relative to Marginal Ridges: Rest seats should be positioned on the tooth structure in such a way that they are apical (below) the marginal ridges and occlusal surfaces of the teeth. This positioning helps to ensure that the forces acting on the denture are directed downwards, reducing the risk of dislodgment during functional activities like chewing.

2. Concave Shape: Ideally, the floor of the occlusal rest seat should be concave or spoon-shaped. This shape helps to stabilize the denture and prevents movement of the framework, contributing to the overall retention of the prosthesis. Source.

3. Angles with Minor Connectors: The rest should form an angle of less than 90 degrees with the minor connector. This ensures that the forces exerted during mastication do not create horizontal stress that could compromise the integrity of the rest seat. Source.

4. Consideration of Rotational Path of Insertion: When dealing with inclined or tilted molars, especially in the case of rotational path dentures, it is suggested to place mesial long occlusal rest seats on those tilted teeth. This helps ameliorate potential interferences during insertion or removal of the denture. Source.

5. Sufficient Space: It's imperative to ensure that ample space is present around the rest seats to avoid any detrimental contact with opposing occlusion. Over-reduction or elimination of contact points must be avoided, as this could lead to a poor fit and increased risk of prosthetic failure. Source.

In summary, the best places for rest seats to avoid interferences include locations apical to the marginal ridges, adopting a concave shape, forming appropriate angles with minor connectors, and considering the rotational paths for tilted teeth. Proper planning and consideration of these factors are essential to ensure the success of removable partial dentures.

Sources

6: Rests and Rest Seats | Pocket Dentistry[PDF] Removable Partial Denture ManualHow come some dentists don't prep rest seats for RPDs ... - RedditInterference factors regarding the path of insertion of rotational-path ...Rest Options for RPD Frameworks - Streamline Dental LabRest and rest seats | PPT - SlideShareTooth preparation | British Dental Journal - Nature

Related Questions

Where should rest seats be placed?

What is the most common reason for failure of rest seat in RPD?

What are the disadvantages of incisal rest?

What are the advantages of mesial rests for removable partial dentures?