European Journal of Prosthodontics and Restorative Dentistry

cover art

Cover Date:
March 2007
Print ISSN:
0965-7452
Vol:
15
Issue:
1

Mathematical Analysis of Occlusal Rest Design for Cast Removable Partial Dentures

Abstract - Aims: To establish the minimum dimensions for a non-precious cast metal occlusal rest by using mathematical analysis. An occlusal rest in a removable partial denture (RPD) provides vertical support and allows occlusal forces to be transmitted through the long axis of the abutment tooth. Methods: The stress status of an occlusal rest in a posterior tooth-bounded RPD resembles that of a cantilever beam under a uniformly distributed load. A mathematical model based on a short rectangular cantilever beam was derived by using the yield strengths of a cast cobalt-chromium alloy and a cast titanium alloy (Ti-6Al-4V), with an applied static occlusal force of 400 N. Results: For the cobalt-chromium alloy, the minimum rectangular dimensions for a 2.0 mm long occlusal rest are; when the width is 2.0 mm, the depth or thickness should be at least 1.03 mm. For the titanium alloy, the minimum dimensions are; when the width is 2.0 mm, the depth or thickness should be at least 0.85 mm. A decrease in the occlusal width will increase the bending stress, requiring a thicker rest for compensation, which may lead to dentin exposure during the rest seat preparation. Conclusion: The mathematical analysis found that the traditional spoon-shaped occlusal rest seat dimensions comply with the mechanical requirements for non-precious cast metal occlusal rests in RPDs.

KEY WORDS: Occlusal rest, removable partial denture, shear stress rest

Article Price
£15.00
Institution Article Price
£
Page Start
29
Page End
32
Authors
Nathan K. C. Luk, Victor H.F. Wu, Bernard M.H. Liang, Ya-Ming Chen, Kevin H.K.Yip, Roger J. Smales

Articles from this issue

  • Title
  • Pg. Start
  • Pg. End

  1. Long-term Survival of Direct and Indirect Restorations Placed for the Treatment of Advanced Tooth Wear
  2. 2
  3. 6

  1. Breakaway Forces of Flat and Domed Surfaced Magfittm Implant Magnet Attachments
  2. 7
  3. 12

  1. The Abrasion of Dental Composite by CobaltChromium Clasps
  2. 13
  3. 18

  1. Fracture Resistance of Roots with Thin Walls Restored Using an Intermediate Resin Composite Layer Placed Between the Dentine and a Cast Metal Post
  2. 19
  3. 22

  1. The Effect of a Range of Disinfectants on the Dimensional Accuracy and Stability of Some Impression Materials
  2. 23
  3. 28

  1. Mathematical Analysis of Occlusal Rest Design for Cast Removable Partial Dentures
  2. 29
  3. 32

  1. Analytical and Electrochemical Evaluation of the in vitro corrosion behavior of Nickel-chrome and Cobaltchrome casting alloys for metal-ceramic restorations.
  2. 33
  3. 40

  1. Apexification with Mineral Trioxide Aggregate: an overview of the material and technique
  2. 41
  3. 45