Thompson W D, Kratochvil F J, Caputo A A
J Prosthet Dent. 1977 Sep;38(3):261-73. doi: 10.1016/0022-3913(77)90303-1.
The results of this study showed that: 1. The design of a retainer with a mesial rest in conjunction with a buccal I-bar or a wrought-wire and cast lingual arm exhibited the most favorable distribution of vertically applied forces. 2. Retainer designs with a distal rest tend to move the clinical crown distally and the root mesially at the apex, resulting in horizontal forces in the bone. 3. Placing rests of distal-extension removable partial dentures more anteriorly provides an axis of rotation that directs applied forces in a more vertical direction. 4. The distal rest in conjunction with circumferential retainers developed greater horizontal forces within the supporting structures.
