Failure modes of Y-TZP abutments with external hex implant-abutment connection determined by fractographic analysis

- The predominant fracture pattern for Y-TZP abutment was at the connecting region.
- Discriminatory landmarks established the reasons why the fracture pattern occurred.
- Failure started where Y-TZP abutment was in contact with the retention screw edges.
- Present findings indicated that the screw head should have a rounded-edge design.
- Present findings may also be used as reference for further fractographic analysis.