Maria H. N. T Pham

• Pham, Thi Ngoc Maria Huong; Haugen, Håvard Jostein & Reseland, Janne Elin (2020). Fluoride Modification of Titanium Surfaces Enhance Complement Activation. Materials. ISSN 1996-1944. 13(3). doi: 10.3390/ma13030684. Full text in Research Archive Show summary

  Immediately after dental implant insertion, blood will be in direct contact and interact with the implant surface and activates inflammatory responses and complement cascades within seconds. The aim of the present study was to determine the ability of fluoride-modified titanium surfaces to activate complement cascades using the human buffy coat as model. The buffy coats were exposed to hydrofluoric acid-modified surfaces for a short time and its responses were compared to controls. Identification and quantification of complement cascade biomarkers were conducted using ELISA kits and multianalyte profiling using Luminex. A lower level of C3 at 30 min and increased levels of C4, MIP-4, CRP, and pigment epithelium-derived factor at 360 min were found on modified surfaces as compared to controls. We found no significant differences in the levels of C3a, C5a, C Factor H, α2M, ApoA1, ApoC3, ApoE, Prealbumin, α1AT, and SAP in modified surfaces in the buffy coats. We conclude that titanium surfaces treated with hydrofluoric acid modify the levels of specific biomarkers related to the complement cascade and angiogenesis and, thus, tissue growth, remodeling and repair, as this may play a role in the enhanced clinical performance of fluoride-modified Ti dental implants.

• Pham, Thi Ngoc Maria Huong; Haugen, Håvard Jostein; Rinna, Alessandra; Ellingsen, Jan Eirik & Reseland, Janne Elin (2019). Hydrofluoric acid treatment of titanium surfaces enhance the proliferation of human gingival fibroblasts. Journal of Tissue Engineering. ISSN 2041-7314. 10. doi: 10.1177/2041731419828950. Full text in Research Archive Show summary

  The attachment of implants rely on bone and soft tissue biocompatibility. The aim was to investigate the effect of fluoride modified metallic titanium (Ti) surfaces (Ti-F) on proliferation and differentiation of human gingival fibroblasts (HGF). HGF cells were exposed to hydrofluoric acid (HF) modified Ti coins (Ti-F) for 1, 3, 7, 14 and 21d, and untreated coins were used as controls. A 5-6 fold increase in the proliferation of HGF on Ti-F compared to Ti surfaces was observed. Enhanced gene expression of IL-6 and OPG was found at 7 d. Increased levels of sclerostin, IL- 6 and OPG in the media from HGF cultured on Ti-F coins were found compared to controls. Our results confirm that HF modified surface may indirectly enhance the firm attachment of implant surface to junction epithelium, soft tissue epithelium, which would give protection for underlying osseous structures making osseointegration of the dental implant possible.

• Pham, Thi Ngoc Maria Huong; Landin, Maria Augusta Dos S Silva; Tiainen, Hanna; Reseland, Janne Elin; Ellingsen, Jan Eirik & Haugen, Håvard Jostein (2014). The effect of hydrofluoric acid treatment of titanium and titanium dioxide surface on primary human osteoblasts. Clinical Oral Implants Research. ISSN 0905-7161. 25(3), p. 385–394. doi: 10.1111/clr.12150. Show summary

  Abstract Objective The aim of the study was to investigate solely the effect of fluoride on the surface chemistry of polycrystalline ceramic titanium dioxide (TiO2) and metallic titanium (Ti) and its effect on proliferation and differentiation of primary human osteoblasts (NHO). Materials and methods The NHO cells were exposed to fluoride-modified and unmodified samples for 1, 3, 7, 14 and 21 days. The fluoride effect on the mRNA expression was quantified and measured. The secretion of cytokines and interleukins in the cell culture medium was measured by Luminex, gene expression by RT-PCR, and compared with untreated controls. The effect on cell growth after 1 and 3 days in culture was measured using [3H]-thymidine incorporation. Fluoride release was measured using an ion-selective electrode. The surfaces were examined by X-ray photoelectron spectroscopy and profilometry. Results The fluoride release study detected that fluoride content easily washed off in TiO2 coins when compared with Ti coins. No increase in cell proliferation was found among fluoride-modified TiO2 surfaces compared with controls, except for washed Ti coins with fluoride modification. The cell differentiation with regard to gene expression showed no significant differences in both fluoride-modified and unmodified samples and less effect on protein release for all groups. Conclusions The fluoride from hydrofluoric acid treatment on Ti and TiO2 surfaces gave no specific effect on primary human osteoblast cells. The study indicates that the released fluoride is not the unique factor for the bioactivity of Ti and TiO2 surfaces.

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• Pham, Thi Ngoc Maria Huong; Rinna, Alessandra; Haugen, Håvard Jostein; Ellingsen, Jan Eirik & Reseland, Janne Elin (2015). Enhanced In Vitro HGF Proliferation and Differentiation on Surface Modified Hydrofluoric Acid treated TiO₂ .
• Pham, Thi Ngoc Maria Huong; Rinna, Alessandra; Ellingsen, Jan Eirik; Haugen, Håvard Jostein & Reseland, Janne Elin (2015). Enhanced In Vitro HGF Proliferation and Differentiation on Surface Modified Hydrofluoric Acid treated TiO₂.
• Pham, Thi Ngoc Maria Huong; Landin, Maria Augusta Dos S Silva; Tiainen, Hanna; Reseland, Janne Elin; Ellingsen, Jan Eirik & Haugen, Håvard Jostein (2013). The Effect Of Hydrofluoric Acid Treatment Of Titanium And Titanium Dioxide Surface on Primary Human Osteoblasts .

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