Effect of Axial Wall Height and Total Occlusal Convergence of 3Y-TZP Zirconia Implant Abutments on the Retention of Adhesively Bonded 3Y-TZP Zirconia Crowns
Abstract
Currently, no published data exists to provide clinical guidance on decisions relative to total occlusal convergence (TOC) and axial wall height (AWH) regarding a 3Y-TZP zirconia crown bonded to a zirconia abutment. This study quantified the effect of total occlusal convergence and axial wall height on the resistance form of a milled 3Y-TZP zirconia crown adhesively bonded to a milled 3Y-TZP zirconia custom implant abutment. Eight groups of ten 3Y-TZP zirconia (Sagemax NexxZR T, Washington, U.S.A) crown and 3Y-TZP zirconia abutment (Sagemax NexxZR S, Washington, USA) pairs (n=10) were fabricated. Each group differed in AWH (H-4mm, H-3mm, H-2mm, H1mm) and TOC (C-7 deg, C-15 deg) of the abutment and corresponding crown. 3Y-TZP zirconia crowns and abutments were air abraded with aluminum oxide (50 microns, 20-30psi, steam-cleaned) and adhesively bonded to each other using the Panavia V5 (Kuraray North America, Houston, TX) resin cement system. After cementation, samples were artificially aged with thermocycling (500 cycles, 5-55 deg C, dwelling time 30 seconds), mounted into the Instron Universal Testing Machine (Instron, Norwood, MA) and forces directed at 45 deg to the long axis of the sample were applied to failure (debonding or fracture). The mode of failure and the load at which failure occurred was recorded. 98.75% (79/80) of crowns debonded from their respective abutments and 1.25% (1/80) of crowns fractured. The fractured samples were from the C-7 deg group with 4mm AWH. Statistically significant difference of load at failure between C-15 deg group was found within the H1mm and H-3/H-4 groups. Results of this in vitro study indicate that, when bonded with resin cement, milled 3Y-TZP zirconia crowns will dislodge from milled 3Y-TZP zirconia implant abutments due to lack of conventional resistance form in regard of AWH or TOC. At least 3mm AWH and a maximum of 15 deg TOC are required to resist crown debonding within the average maximum biting forces.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 24, 2021
- Accession Number
- AD1183061
Entities
People
- Jens D. Nelson
Organizations
- Uniformed Services University of the Health Sciences