Collections > Electronic Theses and Dissertations > Fracture resistance and surface treatment of Y-TZP prepable ceramic abutments and bars

Intraoral preparation of zirconia implant abutments creates deep surface defects making abutments susceptible to fracture during loading. Fracture strengths were tested for (1) HIP-processed zirconia bars (Astra-Tech) after preparation and/or surface repair treatments: no preparation (NP), dry-preparation (DP), wet-preparation (WP), or we-tpreparation and 30d water storage (WP+30d), mitigating treatment of bonding agent (WP+B), sandblasting (WP+SB), or polishing (WP+P), and (2) abutment-assemblies (preparations of 0, 0.5, or 1mm margin reduction). NP established the strength for pristine zirconia bars (1634 plus or minus 95MPa). DP (1144 plus or minus 109MPa), WP (1442 plus or minus 89MPa), WP+30d (1193 plus or minus155MPa), and WP+B (1218 plus or minus 77MPa) groups had significantly (p less than or equal to 0.05) reduced strengths. WP+SB (1632 plus or minus 134MPa) or WP+P (1664 plus or minus 176MPa) repairs equally well recovered original strengths (p<0.001). There were no statistically significant differences (p>0.05) among different abutment-assembly groups and no logical relationship of strength to increasing amount of reduction. All fractures occurred at the interface where the abutment was connected to the analog, suggesting that fracture was unrelated to the actual abutment.