Fracture resistance and failure location of zirconium and metallic implant abutments.

AIM

The purpose of this study was to evaluate the fracture resistance and failure location of single-tooth, implant-supported, all-ceramic restorations on different implant abutments subjected to a maximum load.

METHODS AND MATERIALS

Forty Certain 3i implants and 20 ITI Straumann implants were used in this study in combination with 20 UCLA abutments, 20 ZiReal abutments, and 20 synOcta Ceramic Blanks to form three groups according to abutment type. All 60 abutments were prepared with standard measurements: a 1.0 mm deep chamfer, 2.0 mm of incisal reduction, and a total height of 7 mm. Sixty IPS Empress 2 full ceramic crowns were fabricated and cemented on each abutment with a resin cement. Static loading was simulated under maximum loading and fracture locations were noted.

RESULTS

The mean load to failure data and standard deviations for the three groups were as follows: Group 1 (792.7 N +/- 122.5) and Group 3 (793.6 +/- 162.3) showed no significant difference in fracture resistance while the values for specimens in Group 2 (604 N +/- 191.1) had the lowest mean value and were significantly lower. In Group 1, 16 crowns and four abutment fractures were reported, while in Group 3, 17 crowns and three abutments fractured. Group 2 actually showed three types of fractures. Two specimen fractures were located at the implant level, six with fractures occuring within the Empress 2 all-ceramic crown, and the remaining 12 failures were located at the abutment level.

CONCLUSION

Within the limitations of this laboratory study, the following conclusions were drawn: The mean load-to-failure values for all three groups were well above the reported normal maximal incisal load range. The load to failure for both the zirconium oxide (ZrO2) abutments (ZiReal on 3i Certain implants and synOcta Ceramic Blanks on SLA ITI Straumann implants) had mean fracture loads of 792.7 N (+122.6) and 604.2 N (+191.2), respectively. The zirconium oxide (ZrO2) ZiReal and titanium (UCLA) abutments on the 3i Certain implants had statistically significantly higher fracture loads (792.7 N and 703.7 N, respectively) than those recorded for the 3i Ceramic Blank abutments on the SLA ITI Straumann implant (604.2 N). The ITI Straumann Ceramic Blank abutments showed uniform fracture behavior. Fracture mainly emanated from the cervical buccal aspect of the abutment.

CLINICAL SIGNIFICANCE

The three abutments tested showed they can withstand clinical loads above the normal range of mastication.