Analysis of resistance to fracture between straight and angled abutments of Morse taper system

Objective

The aim of this study was to verify the fatigue fracture resistance of the implant-abutment joint, in straight and angled types, subject to cyclic loads similar to chewing.

Material and method

It was used 32 implants system (3.75 × 11mm) with Morse taper and 32 abutment, divided in two groups: abutment straight and angled (n = 16) (Neodent, Curitiba, PR, Brazil). The sets were submitted to cyclic testing using servo-hydraulic equipment, fixing the number of cycles at 5 million. It was evaluated the number of cycles, load and moment force of the samples. The Fisher test and ANOVA were applied (p<0,005). Fractured samples were analyzed in the scanning electron microscopy (SEM).

Result

Straight abutment, four resisted the cycles number established, supporting loads between 470N and 510N. Angled abutment: nine resisted to loads between 570N and 890N. Regarding the fractured samples below the number of cycles, in the straight abutment, nine fractured with loads between 470N and 630N. In the angled abutment, five fractured with loads ranging from 760N and 890N. The moment of the force was calculated for each joint implant-abutment (Averages: Straight Group - 4335,23Nmm, angled Group - 3923,37Nmm).

Conclusion

Two types of abutments (straight and angled), in vitro conditions, statistically behaved similarly, and accepts the null hypothesis that there is no difference in fracture resistance between groups.

Dental implants; material resistance; mechanical phenomena