Zirconia has been established as a promising material for dental implants. Various surface treatment methods have been utilized to promote better osseointegration and improve the success rate of dental implants. However, a better understanding of the influences of topographic characteristics on cell attachment, proliferation, and differentiation is needed.
Different surface topographic zirconia specimens, As sintered, Mild rough, Moderate rough, and Rough zirconia groups were fabricated with sandblasting method in various distances and stages. The surface texture, microstructure, and wettability were inspected with the optical profiler, SEM, and contact angle measurement respectfully. Human primary osteoblast cells were cultured on the four groups of zirconia with different surface modifications in 24 well plates and on plates without test material as control. Crystal violet and triton X-100 solution were used to evaluate cell attachment efficiency at 9 hours and proliferation rate at 7, 14, and 21 days after seeding. ALP activity was measured with fluorometric assay. The expression of osteocalcin was measured with an ELISA kit. Alizarin red staining was conducted to evaluate the mineralization. The cell morphologies were inspected under SEM after cell fixation and critical point drying process. The data were analyzed with one-way ANOVA for experiment on each time interval and two-way ANOVA for all time points. Tukey post hoc test was used for pairwise comparison. P value < 0.05 was considered statistically significant.
Topographic parameters and contact angle measured in As sintered, Mild rough, Moderate rough, and Rough surface groups were as follow: Sa = 0.23, 0.50, 2.13, 5 µm, Sal = 49.88, 21.20, 30.42, 49.87 µm, Sdq = 64.64, 248.60, 511, 734.66 µm/mm, Sk = 0.7, 1.54, 4.19,16 µm, Spk = 0.31, 0.64, 1.47, 5.13 µm, Svk = 0.35, 0.71, 5.96, 6.18 µm respectively, and contact angle = 64.6°, 55.2°, 43.5°, 38.6° respectively.
The result showed that Rough zirconia group induced the highest cell attachment efficiency at 9 hours (p<.001). As sintered zirconia group promoted significant cell proliferation rate at 21 days (p<.001) while Rough zirconia group drastically down-regulated cell proliferation (p<0.001). The most elevated levels of ALP, osteocalcin, and mineralization expressions at 21 days were found in the Moderate rough group with significant differences (p<.001, p<.001, p<.001 accordingly)
Within the limitations of this in vitro study, it can be concluded 1) the modified microroughened zirconia surfaces of Sa 5 µm would promote human osteoblast attachment but down-regulate cell proliferation, 2) the As sintered zirconia surface would stimulate cell proliferation, and 3) the microroughened surfaces of Sa 2 µm would up-regulate osteoblast differentiation. These findings could be incorporated into designing and fabricating the dental implant surfaces for optimal osseointegration.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/46670 |
| Date | 01 September 2023 |
| Creators | Namano, Sunporn |
| Contributors | Chou, Laisheng |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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