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. 2022 Apr 30;15(9):3248.
doi: 10.3390/ma15093248.

Stress Distribution on Various Implant-Retained Bar Overdentures

Övül Kümbüloğlu  1 , Beril Koyuncu  1 , Gözde Yerlioğlu  1   2 , Nadin Al-Haj Husain  3   4 , Mutlu Özcan  4
Affiliations

Stress Distribution on Various Implant-Retained Bar Overdentures

Övül Kümbüloğlu et al. Materials (Basel). .

Abstract

The purpose of this study was to evaluate the effects of various fabrication techniques and materials used in implant-supported mandibular overdentures with a Hader bar attachment over added stress distribution. Three-dimensional geometric solid models, consisting of two implants (3.3 mm × 12 mm) placed at the bone level on both mandibular canine regions and a Hader bar structure, were prepared. Model 1 simulated a bar retentive system made from Titanium Grade 5 material by Computer Numerical Control (CNC) milling technique without using any converting adapter/multi-unit element on the implants, while Model 2 simulated the same configuration, but with converting adapters on the implants. Model 3 simulated a bar retentive system made from Cobalt-Chromium material, made by using conventional casting technique with converting adapters on the implants. Static loads of 100 Newton were applied on test models from horizontal, vertical and oblique directions. ANSYS R15.0 Workbench Software was used to compare Von Mises stress distribution and minimum/maximum principal stress values, and the results were evaluated by using Finite Element Analysis method. As a result, the highest stress distribution values under static loading in three different directions were obtained in Model 1. Stress was observed intensely around the necks of the implants and the surrounding cortical bone areas in all models. In scope of the results obtained, using converting adapters on implants has been considered to decrease transmission of forces onto implants and surrounding bone structures, thus providing a better stress distribution. It has also been observed that the type of material used for bar fabrication has no significant influence on stress values in those models where converting adapters were used.

Keywords: CNC milling; finite element analysis; hader bar; implant-supported mandibular overdenture.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Model 2 after being meshed into elements.
Figure 2
Figure 2
Loads of 100 N in vertical direction, bucco-lingual direction and oblique direction, respectively.
Figure 3
Figure 3
Model 1, Model 2 and Model 3 implants, and the distribution of Von Mises stress after vertical loading, respectively.
Figure 4
Figure 4
The distribution of Von Mises stress after vertical loading on Model 1 bar attachment and screw.
Figure 5
Figure 5
The Von Mises stress distribution on Model 1, Model 2 and Model 3 implants after horizontal loading.
Figure 6
Figure 6
The Von Mises stress distribution on Model 2 and Model 3 multi-unit abutment after horizontal loading.
Figure 7
Figure 7
Model 1 implants and the Von Mises stress distribution after oblique loading.
Figure 8
Figure 8
Model 2 multi-unit abutment and the Von Mises stress distribution from occlusal view after oblique loading.
See this image and copyright information in PMC

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