Employ Bio-Inspired Surface Modification to Enhance Biological Response of Dental Implant Materials

  • 劉 嫣婷

Student thesis: Doctoral Thesis


Dental implant a special biocompatible component serving with the rehabilitation of the damaged chewing apparatus due to loss of the natural teeth is currently the most intensively developing field of dentistry Today the increasing demands from patients with missing teeth for masticatory function and aesthetic dissatisfaction of their replaced teeth to be restored and for shortening of the period of osseointegration of the implants Zirconia and titanium have been widely used as a framework material in dental implants due to their excellent mechanical properties and chemical stability However zirconia and titanium are categorized as bio-inert materials which make them difficult to achieve a chemical bond with living tissue and restricts their application in the field of biomedicine Various forms of surface modification have been used to accelerate the initial osseointegration soon after implantation in order to improve the reactions of the tissue and shorten the healing period of the bone In this study a biologically inspired idea from mussels was used to establish a synthetic adhesive platform for medical-implant application Moreover three-dimensional structures with numerous craters were produced to mimic bone morphology and function in order to optimize the integration of the implant In first part of this thesis an easy efficient solvent-free process was proposed for the coating of DOPA film on a zirconia surface which was shown to increase the biocompatibility to osteoblasts Specifically the thickness of the coating and initial cell spreading ability were both enhanced by preparing samples at higher temperatures Then the study was subsequently related to the trace element strontium which we did added into the DOPA polymerization process Strontium has been attracting considerable attention for clinical applications to treat osteoporosis The incorporation of strontium greatly increases osteoblast response such as differentiation and mineralization in DOPA-coated zirconia Interestingly the level of DOPA is highly dependent on the strontium concentration suggesting that strontium may promote DOPA polymerization In the next part of this thesis an organic-inorganic multilayer coating process was developed for the modification of titanium implants A three-dimensional porous structure comprising strontium and micro-arc oxidized (MAO) titanium was covered with a film of DOPA to form a multilayer coating The DOPA film facilitates the initial attachment and proliferation of cells Cell differentiation is sequentially enhanced by the release of strontium from the coatings Moreover MAO process produced a much rougher surface with crater-like structures which provides early fixation and long-term mechanical stability The results demonstrate the efficacy of the proposed coating process in enhancing the multi-biological function of implant surfaces to improve cellular characteristics Moreover the surface properties were simply changed by adjusting the compositions of the electrolyte solutions that alters the local chemistry of the coatings and in so doing changes the biological properties of the MAO coating A porous manganese-calcium-phosphate coating was prepared on titanium through MAO process The manganese in electrolytes can be incorporated within MAO coatings in a dose dependent manner Manganese concentration did not appear to have a significant effect on thickness hydrophilicity pore size or overall porosity of the MAO coatings However the addition of manganese alters the local chemistry of the coatings and improve cell-mediated mineralization All findings in this thesis indicated that combining the beneficial characteristics of both bio-inspired modifications shows considerable promise as a biomaterial for implants These findings may give a new important insight into further advancing the research on exploring the impact of bio-inspired modifications on the degree of osseointegration
Date of Award2014 Aug 14
Original languageEnglish
SupervisorTruan-Sheng Lui (Supervisor)

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