IADR Abstract Archives
Biodegradation of Zirconia by Fusobacterium Nucleatum
Objectives: The current study was to investigate the degradation of zirconia with Fusobacterium nucleatum.
Methods: Eighty of polished and sintered zirconia discs (IPS e.max®ZirCAD MT A2, Ivoclar Vivadent, Liechtenstein) in round shape (20mm in diameter) with Ra=0.55±0.04μm were prepared. Fusobacterium nucleatum (F.n.) was inoculated on the zirconia discs for either 3 or 7 days. Specimens without bacteria incubation were served as control group. Inductive coupled plasma-optical emission spectroscopy (ICP-OES) test was applied to quantify the Zr element concentration in the medium with and without F.n. bacteria incubation. The surface characteristics of zirconia were evaluated by water contact angle (WCA), biaxial flexural strength (BFS) test and X-ray diffraction (XRD) measurements. The statistical analysis was performed with one-way ANOVA with α=0.05.
Results: The BFS values of the zirconia after incubated with F.n. for 3 (654.50±112.18MPa) and 7 (660.02±106.64MPa) days were significantly lower (p<0.05) than zirconia without any bacteria incubation (765.01±20.12MPa), and stored in pure broth for 3 (719.02±32.01MPa) and 7 (716.11±58.12MPa) days. XRD showed no tetragonal (T) to monoclinic (M) phase change of zirconia in all the groups. ICP-OES detected no significant difference (p>0.05) for Zr release for broth only or with F.n. groups. WCA of zirconia surfaces after incubated in the broth with F.n. for 3 (10.51±4.13°) and 7 (10.35±1.14°) days were higher than zirconia surfaces after immersed in pure broth without bacteria (15.72±2.12° and 21.15±4.43° for 3 and days, respectively); however, they were significantly lower (p<0.05) than those on the zirconia surfaces without any treatment in the control group (73.46±8.57°).
Conclusions: Fusobacterium nucleatum might lead to zirconia biodegradation, and the reasons are yet to be found.
Methods: Eighty of polished and sintered zirconia discs (IPS e.max®ZirCAD MT A2, Ivoclar Vivadent, Liechtenstein) in round shape (20mm in diameter) with Ra=0.55±0.04μm were prepared. Fusobacterium nucleatum (F.n.) was inoculated on the zirconia discs for either 3 or 7 days. Specimens without bacteria incubation were served as control group. Inductive coupled plasma-optical emission spectroscopy (ICP-OES) test was applied to quantify the Zr element concentration in the medium with and without F.n. bacteria incubation. The surface characteristics of zirconia were evaluated by water contact angle (WCA), biaxial flexural strength (BFS) test and X-ray diffraction (XRD) measurements. The statistical analysis was performed with one-way ANOVA with α=0.05.
Results: The BFS values of the zirconia after incubated with F.n. for 3 (654.50±112.18MPa) and 7 (660.02±106.64MPa) days were significantly lower (p<0.05) than zirconia without any bacteria incubation (765.01±20.12MPa), and stored in pure broth for 3 (719.02±32.01MPa) and 7 (716.11±58.12MPa) days. XRD showed no tetragonal (T) to monoclinic (M) phase change of zirconia in all the groups. ICP-OES detected no significant difference (p>0.05) for Zr release for broth only or with F.n. groups. WCA of zirconia surfaces after incubated in the broth with F.n. for 3 (10.51±4.13°) and 7 (10.35±1.14°) days were higher than zirconia surfaces after immersed in pure broth without bacteria (15.72±2.12° and 21.15±4.43° for 3 and days, respectively); however, they were significantly lower (p<0.05) than those on the zirconia surfaces without any treatment in the control group (73.46±8.57°).
Conclusions: Fusobacterium nucleatum might lead to zirconia biodegradation, and the reasons are yet to be found.