Effect of Abutment Height Difference on Stress Distribution in Mandibular Overdentures: A Three-Dimensional Finite Element Analysis

Implant-supported overdentures are a treatment option for edentulous patients. One of the important factors in determining the prognosis of overdenture treatment is to control the distribution of stress in the implant-bone and attachment complex. This study assessed the effect of implant abutment height difference on stress distribution in mandibular overdentures.

In this study, three models of mandibular overdentures were designed independently using finite element analysis (FEA). The implants were placed at different height levels relative to the adjacent implant (1 mm, 2 mm and 3 mm). A 100 N load was applied to the overdenture, and the software was programmed for stress analysis in the models. The load was applied bilaterally, unilaterally, vertically, and obliquely. Finally, the von Misses stresses were produced numerically, color-coded, and compared among the models.

The models in which the implants had up to 2 mm height difference with each other showed better stress distribution than the model with 3 mm height difference between the implants. In all conditions, the implant neck showed the high-est concentration of stress among all areas of the implant. Lower stress levels were found in the cancellous bone than the cortical bone in different loading conditions.

Lower Von Mises stress values were found in the models with up to 2 mm difference in implant height, and higher stress values were noted in the cortical bone and the implant neck compared with trabecular bone.