IADR Abstract Archives
Phase Transformation in An Injection-Moulded Zirconia Implant Material
Objectives: This study aimed to investigate tetragonal-monoclinic phase transformation (t→m) and associated surface, morphological changes in a zirconia implant material following hydrothermal ageing.
Methods: A high pressure hydrothermal reactor was used to simulate10-15 years of in vivo ageing (cycle: 5 hours,134°C, 2 bars). As-received and aged, discs and implants (n=3 p/g) were studied using Raman spectroscopy to quantify t→m. Four discs were mirror-polished, two of them were aged according to the above protocol. All samples were studied using optical profilometer in order to investigate surface, morphological changes and to determine differences in roughness parameters.
Results: Analysis of Raman spectra obtained from point scans revealed pure tetragonal phase composition of as-received disc and implant samples. Aged discs and implants had mean monoclinic phase volume fraction of 3.52±1.32% and 4.82±0.19%, respectively. Polished samples exhibited mean Sa and Pa values of 19.23±1.24 nm and 19.83±0.81 nm, respectively. Polished aged samples have had significantly higher mean Sa and Pa values as indicated by one-way ANOVA test, p-value <0.05 (23.11±0.88 nm and 23.74±1.27 nm, respectively). In contrast to polished samples, scans from polished-aged samples revealed 3-10, bead-like structures. Such structures may represent the uplifts or crystalline pull-outs associated with the hydrothermally induced t→m.
Conclusions: The findings of this investigation indicated that the studied material was not drastically affected by the ageing process. ISO standard 13356:2008 specifies that zirconia implant materials should retain less than 25% monoclinic phase following the used ageing cycle, which is the case in this investigation. The observed surface, morphological changes should be further investigated in terms of their effect on durability of this material.
Methods: A high pressure hydrothermal reactor was used to simulate10-15 years of in vivo ageing (cycle: 5 hours,134°C, 2 bars). As-received and aged, discs and implants (n=3 p/g) were studied using Raman spectroscopy to quantify t→m. Four discs were mirror-polished, two of them were aged according to the above protocol. All samples were studied using optical profilometer in order to investigate surface, morphological changes and to determine differences in roughness parameters.
Results: Analysis of Raman spectra obtained from point scans revealed pure tetragonal phase composition of as-received disc and implant samples. Aged discs and implants had mean monoclinic phase volume fraction of 3.52±1.32% and 4.82±0.19%, respectively. Polished samples exhibited mean Sa and Pa values of 19.23±1.24 nm and 19.83±0.81 nm, respectively. Polished aged samples have had significantly higher mean Sa and Pa values as indicated by one-way ANOVA test, p-value <0.05 (23.11±0.88 nm and 23.74±1.27 nm, respectively). In contrast to polished samples, scans from polished-aged samples revealed 3-10, bead-like structures. Such structures may represent the uplifts or crystalline pull-outs associated with the hydrothermally induced t→m.
Conclusions: The findings of this investigation indicated that the studied material was not drastically affected by the ageing process. ISO standard 13356:2008 specifies that zirconia implant materials should retain less than 25% monoclinic phase following the used ageing cycle, which is the case in this investigation. The observed surface, morphological changes should be further investigated in terms of their effect on durability of this material.
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