Fiction Coefficient between Abutment Materials and Clasp Materials and Estimation of Retention Force of Circumferential Clasp

지대치의 재료와 Clasp 재료 사이의 마찰계수와 원형 clasp의 유지력 추정

  • Lim, Dong-Chun (Dept. of Dental Laboratory Technology, Kwangju Health College)
  • 임동천 (광주보건대학 치기공과)
  • Published : 1999.07.01

Abstract

The purpose of this study is to evaluate the friction coefficients between abutment materials and clasp materials, and to an estimation formula for retention force. The coefficients of friction between three clasp materials and four abutment materials were measured under various conditions, polished and sandblasted and wet and dry. The measurement was repeated for each combination up to a total measurement of 1200 times. Estimation formula for retention force is measured as sum of two terms, which the one time is proportional to the product of friction coefficient ${\mu}$ and undercut u and the other term is proportional to u-squared. Two proportional coefficient were obtained by least square method. The results are as follows: 1. Friction coefficients were ranged from 0.08 to 0.53 under various conditions. 2. Friction coefficients of non-metal abutment materials are greater in wet conditions than dry conditions. 3. Friction coefficients of sandblasted clasp against abutment are greater than that of polished clasp. 4. Clasp retention force can be estimated with the model as F=$F_d(3.0{\mu}u+1.5u^2/h)$ with minor error.

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