Three-dimensional Finite Element Analysis Of Separate Removable Partial Denture And Conical Telescope

Separate Removable Partial Denture is a kind of special design Removable Partial Denture, which is composed of double bases. All kinds of clasps are designed on the upper base, which contact with each abutment directly for the function of retention and clasping and stabilize the denture. The lower base to which the artificial teeth are attached contacts with the alveolar ridges and oral mucosa intimately, acting the function of supporting. The kind of design is able to protect the abutments effectively and prolong the life-span of abutments. Separate Removable Partial Denture is capable of not only performing the function of Traditional Removable Partial Denture effectively, but also better protecting the abutments, especially for the patients who have I～II mobile abutments and/or whose oral conditions are not well. An effective type of retainer, possessing retention, support and a splinting action between multiple abutment teeth, is a double crown known as the telescope retainer. There are several advantages of telescopic retainer: These retainers provide adequate retention and proper stress distribution by eliminating standard metal clasp. The abutments are be protected well. But the telescope is always made of expensive material. And crown of abutment should be cut too much . When the telescope are moved from mouth, the patients would lose the fuction of chewing and pronouncing. Then that woluld have an harmful effect on the beautiful outlook of patients. So telescope is hard to be popularized in China.A patient was chosed in the study who had losed the second premolar and the first molar on the upper jaw, and had I～II mobile abutments. The study have constructed two precise three dimensional finite element models by using SCT image reconstruction technique and Materialise Mimics, Pro/Engineer, ANSYS Workbench software . Three different forces were loaded on the two models .The aim of the study is to compare the von Mises stress distribution of the edentulous mucose and the periodontal membranes of abutments between the separate removable partial denture and conical telescope. We get the following results. First, the von Mises stress values of the edentulous mucose of the separate removable partial denture are larger than that of the conical telescope. Second, the von Mises stress values of the periodontal membranes of the second premolar of the separate removable partial denture are similar with that of the conical telescope. Third, the von Mises stress values of the periodontal membranes of the first molar of the separate removable partial denture are smaller than that of the conical telescope. From the results we can conclud that the separate removable partial denture can protect the abutments as conical telescope.Based on these results , the separate removable partial denture have several advantages :cheaper materials, cutting little teeth tission, have less effect on the outlook and chewing when the prosthes are moved from mouth . So the separate removable partial denture have an goodperspectation.