Comparison of stress distribution between complete denture and implant-retained overdenture

Objectives: Compare stress distribution induced by functional loads on conventional complete dentures and implant-retained overdentures with different attachment systems using Finite Element Analysis (FEA-2D). Methods: Four representative models of edentulous mandible were constructed on a software; Group A (control), a model of edentulous mandible supporting a complete denture; Group B, a model of edentulous mandible supporting an overdenture retained by two splinted implants connected with bar-clip system; Group C, a model of edentulous mandible supporting an overdenture retained by two unsplinted implants with o'ring system; Group D, a model of edentulous mandible supporting an overdenture retained by two splinted implants connected with bar-clip system associated with two distally o'ring system. Evaluation was performed on Ansys software, with 100N vertical load applied on lower central incisive teeth. The principal stress was used as analysis criteria. Results: Group A (64.305 MPa) showed the lowest maximum stress values followed by groups C (119.006 MPa), D (258.65 MPa) and B (349.873 MPa). The same trend a little slight was observed regarding supporting tissues. Cortical bone showed the highest stress values. Conclusion: The use of an attachment system increased stress values. Furthermore, the use of unsplinted implants associated with the o'ring attachment system showed the lowest maximum stress values in comparison to the others overdenture groups. In addition o'ring system also improved stress distribution when associated with bar-clip system.

Financial Support: FAPESP (grant numbers: 06/52230-6 and 06/59770-6)