Stress distribution around titanium-zirconium narrow-diameter implants retaining mandibular over dentures with Novaloc versus locator attachment systems. A three-dimensional finite element analysis

Statement of the problem: The use of narrow diameter implant to retain an implant overdenture could be the treatment of choice to restore resorbed mandibular ridge, however its success or failure depends on the amount of stresses transferred to the surrounding bone via the selected attachment system. The goal of this study was to evaluate the stress distribution around two narrow- diameter titanium-zirconium implants retaining mandibular overdenture with novel Novaloc attachment system in comparison with traditional locator attachment using 3 D finite element analysis
Materials and methods: Two 3D finite element models were prepared simulating completely edentulous mandibular ridge with complete overdentures supported by two narrow diameter implants in the canine region. Model 1,represented implants with locator attachment while Model 2, represented implants with Novaloc attachment. The models’ components were created on a commercial CAD/CAM package then imported to finite element software. Load of 100 N was applied on molar area of the mandible vertically and oblique Load of 50 N at 30º and 45º angle.
Results: Within the limitations of this research, similar deformations and stresses distributions were reported in the bone and implant complex with a little more stresses in the Novaloc system. All values found were within acceptable physiological limits of the studied parts. Stress received by the PEEK matrix of the Novaloc attachment was significantly less than that of the locator nylon cap.
Conclusion: Within the limitations of this in-vitro study it may be concluded that locator attachments may provide little less stress on the bone and implant complex in implant retained overdenture than did the Novaloc attachment. However, the lifetime of the flexible caps may be longer for Novaloc system in comparison to locator ones.