Finite element analysis of the relationship between clasp dimensions and flexibility

A parameter study with use of the finite element method was conducted for examination of the relationships between the shape parameters of a clasp (width and thickness at the base and tip of the clasp) and its displacement or stress. By synthesis of these relationships, a simple formula defining the clasp tip displacement in terms of clasp dimensions ("displacement formula") was obtained. A stiffness parameter "Fd" (the load producing a 1-mm displacement of the clasp tip) was proposed, and a formula defining Fd in terms of shape parameters was derived from the displacement formula. Fd would be a practical parameter for the definition of clasp retention, and the present formulae appear to be useful tools for investigation of the retention of removable partial dentures.