Abstract
The prerequisite to enhance the function of the free-end saddle R. P. D. is to diminish the denture dynamics in mastication. The authors have already reported the evaluating methods of the denture dynamics in the free-end R. P. D.'s with various retainers.
In the previous reports, the denture dynamics were mainly affected by the retainers used; the more rigidity the retainers were connected to the abutment teeth, the less the denture dynamics were obtained. What is the key to diminish the denture dynamics? and what is the main characteristics of the cone-crown-telescope, which was revealed to have the least dynamics among the various retainers?
So, we have conducted a study on the connecting rigidity which may seem to be the main characteristics of the cone-crown-telescope on the bench model assembly.
Following results were obtained:
1. The greatest value of the connecting rigidity was obtained in the cone-crown-telescope, then followed the R. P. P. I., the R. P. I. by Kratochvil, the R. P. I. by Krol, to the R.P.I. and the Aker's clasp without the guiding function in sequence.
2. It was clearly indicated that the guiding surface/guiding plate parallelism between the abutment teeth and the retainers played the most important role in obtaining the connecting rigidity in the clasp designed R. P. D.'s.
3. An ordinary refractory model method for obtaining the guiding/surface guiding plate function revealed to fail the genuine connecting rigidity matching for the one in the conecrown-telescope.
