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Conference Paper: Recycling Dental Zirconia Wastes: Is It Feasible?
Title | Recycling Dental Zirconia Wastes: Is It Feasible? |
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Authors | |
Issue Date | 2017 |
Publisher | International Association for Dental Research. The Journal's web site is located at http://www.iadr.org/ |
Citation | 2017 Continental European and Scandinavian Divisions Meeting (CED-IADR/NOF) Oral Health Research Congress, Vienna, Austria, 21-23 September 2017. In Journal of Dental Research, 2017, v. 96, Spec Issue B, abstract no. 0244 How to Cite? |
Abstract | Objectives: Dental yttria-stabilized zirconia is a CAD/CAM material that has a good mechanical and aesthetic properties for dental restoration. However, after the milling, a lot of milling dusts and residual of the blocks remains. This is essentially not environmentally friendly and waste of money. Thus, the objective of this study was to design a easy procedure that could recycle pre-fabricated zirconia blocks with optimum mechanical strength.
Methods: Used commercial zirconia blocks (Lava Plus High Translucency, 3M ESPE) were pulverised (10,000rev/min) into powders and screen-sieved (300-mesh). Then, the screened powder was pickled by acid (0.5-mol/L HNO3, 55°C for 5 minute). Next, the powder was dry pressed into green body blocks (80kN) in a mould (35.0×30.0×3.0-mm3). Finally, the green body was pre-sintered in different temperatures in 800, 850, 900, 950, 1000, 1050 and 1100°C. These pre-sintered blocks, together with the control block, i.e. new zirconia block with the same batch, were then fully sintered at 1450°C according to manufacturer instruction. XRD was used to evaluate the crystalline structure. SEM/EDX was used to study the element composition, surface and particle topography. Relative density and knoop microhardness were tested before and after full sintering. Four-point bending were tested for flexural strength of fully sintered beams (n=7, 24.0×4.0×2.0-mm3). One-way ANOVA was used to analyze the results (α=0.05).
Results: Only tetragonal phase was detected by XRD for both new and recycled zirconia blocks, and similar elemental contents were confirmed by EDX. SEM results showed the pre-sintered samples at 900-1000°C had a smooth and flat surface and evenly distributed particles. No statistical significant difference (p>0.05) was found between new and 900°C to 1050°C recycled fully sintered zirconia for relative density. In terms of hardness, only green blank that was pre-sintered at 1000°C showed no statistically significant difference (p=0.586) than new. Four-point bending test results showed that recycled zirconia pre-sintered at 950-1050°C had no statistical significant difference (p>0.05) than new one .
Conclusions: Recycling of commercial zirconia block deemed to be feasible, and 1000oC seems to be the best pre-sintering temperature for such a recycling process. |
Description | Oral Session: Dental Zirconia Hosted by the Continental European & Scandinavian divisions (CED-IADR/NOF) of the International Association for Dental Research (IADR) |
Persistent Identifier | http://hdl.handle.net/10722/260647 |
DC Field | Value | Language |
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dc.contributor.author | Tsoi, KH | - |
dc.contributor.author | Ding, H | - |
dc.contributor.author | Matinlinna, JP | - |
dc.date.accessioned | 2018-09-14T08:45:03Z | - |
dc.date.available | 2018-09-14T08:45:03Z | - |
dc.date.issued | 2017 | - |
dc.identifier.citation | 2017 Continental European and Scandinavian Divisions Meeting (CED-IADR/NOF) Oral Health Research Congress, Vienna, Austria, 21-23 September 2017. In Journal of Dental Research, 2017, v. 96, Spec Issue B, abstract no. 0244 | - |
dc.identifier.uri | http://hdl.handle.net/10722/260647 | - |
dc.description | Oral Session: Dental Zirconia | - |
dc.description | Hosted by the Continental European & Scandinavian divisions (CED-IADR/NOF) of the International Association for Dental Research (IADR) | - |
dc.description.abstract | Objectives: Dental yttria-stabilized zirconia is a CAD/CAM material that has a good mechanical and aesthetic properties for dental restoration. However, after the milling, a lot of milling dusts and residual of the blocks remains. This is essentially not environmentally friendly and waste of money. Thus, the objective of this study was to design a easy procedure that could recycle pre-fabricated zirconia blocks with optimum mechanical strength. Methods: Used commercial zirconia blocks (Lava Plus High Translucency, 3M ESPE) were pulverised (10,000rev/min) into powders and screen-sieved (300-mesh). Then, the screened powder was pickled by acid (0.5-mol/L HNO3, 55°C for 5 minute). Next, the powder was dry pressed into green body blocks (80kN) in a mould (35.0×30.0×3.0-mm3). Finally, the green body was pre-sintered in different temperatures in 800, 850, 900, 950, 1000, 1050 and 1100°C. These pre-sintered blocks, together with the control block, i.e. new zirconia block with the same batch, were then fully sintered at 1450°C according to manufacturer instruction. XRD was used to evaluate the crystalline structure. SEM/EDX was used to study the element composition, surface and particle topography. Relative density and knoop microhardness were tested before and after full sintering. Four-point bending were tested for flexural strength of fully sintered beams (n=7, 24.0×4.0×2.0-mm3). One-way ANOVA was used to analyze the results (α=0.05). Results: Only tetragonal phase was detected by XRD for both new and recycled zirconia blocks, and similar elemental contents were confirmed by EDX. SEM results showed the pre-sintered samples at 900-1000°C had a smooth and flat surface and evenly distributed particles. No statistical significant difference (p>0.05) was found between new and 900°C to 1050°C recycled fully sintered zirconia for relative density. In terms of hardness, only green blank that was pre-sintered at 1000°C showed no statistically significant difference (p=0.586) than new. Four-point bending test results showed that recycled zirconia pre-sintered at 950-1050°C had no statistical significant difference (p>0.05) than new one . Conclusions: Recycling of commercial zirconia block deemed to be feasible, and 1000oC seems to be the best pre-sintering temperature for such a recycling process. | - |
dc.language | eng | - |
dc.publisher | International Association for Dental Research. The Journal's web site is located at http://www.iadr.org/ | - |
dc.relation.ispartof | Journal of Dental Research (Spec Issue) | - |
dc.relation.ispartof | CED-IADR/NOF Oral Health Research Congress, 2017 | - |
dc.title | Recycling Dental Zirconia Wastes: Is It Feasible? | - |
dc.type | Conference_Paper | - |
dc.identifier.email | Tsoi, KH: jkhtsoi@hku.hk | - |
dc.identifier.email | Matinlinna, JP: jpmat@hku.hk | - |
dc.identifier.authority | Tsoi, KH=rp01609 | - |
dc.identifier.authority | Matinlinna, JP=rp00052 | - |
dc.identifier.hkuros | 290433 | - |
dc.identifier.volume | 96 | - |
dc.identifier.issue | Spec Issue B | - |
dc.identifier.spage | abstract no. 0244 | - |
dc.identifier.epage | abstract no. 0244 | - |
dc.publisher.place | United States | - |