A fracture strength study of a reinforced internal-implant zirconia abutment with a titanium insert

Abstract

Objectives The weakest part in internal zirconia abutments is the implant-abutment connection area. The aim of this study was to evaluate the effect of a titanium insert on fracture strength of a zirconia abutment under static compressive loading.

Materials and methods Three types of internal abutments were selected for one type of implant with internal connection: internally connected one-piece titanium abutment, internally connected one-piece zirconia abutment, and internally connected two-piece abutment consisting of external zirconia abutment and metal insert (group I, II, and III respectively). 15 abutments and 15 implants were used and divided into three groups of five specimens each. Compressive loading was applied 30 degrees off the axis of the specimens by a hydraulic fatigue test machine MTS (MTS, Minnesota, USA) with dislocation speed of 1mm/min and increased from 0N until deformation occurred. The results were analyzed using SPSS 12.0 for Windows (IBM, New York, USA).

Results 1) The highest mean maximum load was 1401.9(±18.5)N in group I followed by 1233.6(±48.4)N in group III, and 1123.9(±16.2)N in group II was the lowest. Statistical analysis by the one-way ANOVA test and Post-Hoc tests revealed statistically significant differences between the groups. 2) All the abutments were deformed and all the abutment screws were bent in group I. In group II, all the abutments were fractured and all the abutment screws were bent. In group III, all the abutments were fractured and all the abutment screws were deformed

three were fractured and two were bent.

Conclusion Titanium insert, the substitute for the weakest part of internal zirconia abutment, improved the fracture strength of internal zirconia abutments, but not as much as that of titanium abutments