The effects of buccolingual width and position of occlusal rest seats on load transmission to the abutments for tooth-supported removable partial dentures.
OBJECTIVE
The suitable buccolingual width and the location of occlusal rest seats for removable partial dentures have not been scientifically established. The aim of the present study was to use three-dimensional geometric analysis to evaluate the effects of buccolingual width and the location of occlusal rest seats on load transmission to the abutments for tooth-supported removable partial dentures.


METHODS
A tooth-supported portion of a maxillary removable partial denture with two conventional circumferential cast clasps and an indirect retainer was analyzed. Occlusal loading of 100 N was applied to the buccal mesial cuspal incline 2.0 mm from the central fossa of the first molar or to the lingual mesial cuspal tip. Four combinations of position and width (wide, buccal shift, middle, and lingual shift) were simulated.


RESULTS
For buccal loading, the wide rests and buccal-shift rests produced lower tensile forces at the indirect retainer. For lingual loading, the buccal-shift rests produced the lowest compressive force to the anterior abutment.


CONCLUSIONS
Based on the tooth-supported removable partial dentures that were analyzed, buccal shifting of the rest seats seems to be advantageous for load transmission to the abutments.
Sato
Y
Y
Department of Removable Prosthodontics, Faculty of Dentistry, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan. sato@hiroshima-u.ac.jp
Hosokawa
R
R
Tsuga
K
K
Kubo
T
T
D001641:Bicuspid / Q000502:physiology; D019245:Compressive Strength; D000044:Dental Abutments; D003799:Dental Stress Analysis; D003832:Denture, Partial, Removable; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008437:Maxilla; D008963:Molar / Q000502:physiology; D013718:Tensile Strength; D019231:Tooth Preparation, Prosthodontic