Influences of internal tapered abutment designs on bone stresses around a dental implant: three-dimensional finite element method with statistical evaluation.

BACKGROUND

The aim of this study is to determine the effects of various designs of internal tapered abutment joints on the stress induced in peri-implant crestal bone by using the three-dimensional finite element method and statistical analyses.

METHODS

Thirty-six models with various internal tapered abutment-implant interface designs including different abutment diameters (3.0, 3.5, and 4.0 mm), connection depths (4, 6, and 8 mm), and tapers (2°, 4°, 6°, and 8°) were constructed. A force of 170 N was applied to the top surface of the abutment either vertically or 45° obliquely. The maximum von Mises bone-stress values in the crestal bone surrounding the implant were statistically analyzed using analysis of variance. In addition, patterns of bone stress around the implant were examined.

RESULTS

The results demonstrate that a smaller abutment diameter and a longer abutment connection significantly reduced the bone stresses (P <0.0001) in vertical and oblique loading conditions. Moreover, when the tapered abutment-implant interfaced connection was more parallel, bone stresses under vertical loading were less (P = 0.0002), whereas the abutment taper did not show significant effects on bone stresses under oblique loading (P = 0.83). Bone stresses were mainly influenced by the abutment diameter, followed by the abutment connection depth and the abutment taper.

CONCLUSION

For an internal tapered abutment design, it was suggested that a narrower and deeper abutment-implant interface produced the biomechanical advantage of reducing the stress concentration in the crestal region around an implant.