Objectives: Using two-dimensional finite element analysis, this study assessed tension distribution on RPD support structures associated with a 10.0 x 3.75 mm osseointegrated implant (Branemark System), located in the posterior edentulous alveolar edge area to support the RPD base. Methods: Three plane strain casts (sagital cut) were made: A (MA) – hemiarch containing natural tooth 33 and edentulous alveolar edge; B (MB) - similar to MA, with conventional RPD replacing absent teeth; C (MC) - similar to MB, with implant in posterior edge area under RPD base. Using finite element program ANSYS 5.4, casts were loaded with 50 N vertical and 45º oblique forces on each peak point of mesial and distal sides. Results: On applying vertical force, the general tension map shows most tension is concentrated between the upper and middle thirds of implant on mesial side (113.971 MPa) and least tension on implant upper part on mesial face (0,556 x 10-5 MPa). With mesial to distal force load at 45º, most tension on implant is noted between upper and middle third on distal side (153,447 MPa) and least in fixing screw region on mesial side (0.612 x 10-5 MPa). With distal to mesial 45º oblique force, most tension is noted on dentin (85,459 MPa) and least on implant fixing screw (0,146 x 10-5 MPa). Conclusion: Displacement tendency in cast with RPD supported by implant is smaller than in cast with prosthesis only. The 45º oblique force promotes displacement tendency and larger tension values than vertical force. Mesial to distal 45º oblique force generates lower tension values than the distal to mesial one, and the osseointegrated implant under the RPD base relieves the support tooth.

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