Applying Multiple Surface Treatments to Enhance Osseointegration of Titanium Dental Implant through Regulating Bone Remodeling(1/3)

The bone remodeling process during the healing stage of dental implants requires a balanced osteoblast/osteoclast reaction. However, with an increase in age, the seniors have lower osteoblast activity while relatively higher osteoclast activity. This imbalanced bone remodeling process may lead to a decrease in bone quality and then prolong the healing time after implants implantation. The purpose of this study is to further regulate the above-mentioned imbalanced osteoblast/osteoclast reaction in order to shorten the healing time of the senior patients with dental implant in poor bone quality region, and then achieve rapid and good osseointegration of dental implant. Therefore, this study intends to develop a multiple surface treatment process over a period of three years to regulate bone remodeling of osteoblast/osteoclast and promote the ability of osseointegration of titanium dental implants. In the first year, a three-dimensional structure capable of good mechanical interlocking, good corrosion resistance, and good cell growth environment will be prepared on the roughened titanium surface through combining simple sandblasting, acid etching, and then electrochemical anodization treatment. Three different concentrations of natural cross-linker epigallocatechin-3-gallate (EGCG), which can also downregulate osteoclastogenesis and upregulate osteogenesis, will be subsequently selected to immobilize three different concentrations of type I collagen, which can enhance osteogenesis, to the titanium surface. The surface physical/chemical properties, corrosion resistance, and initial biological reactions will be analyzed. In the second year, according to the results of the first year, the surface treatment parameters capable of getting good stable immobilized collagen layer, good corrosion resistance, and non-cytotoxicity, and good initial cell response will be selected. Then, we will systematically investigate the effects of this multiple surface treatment on in vitro cell responses, including the osteogenesis of osteoblasts, osteoclastogenesis of macrophages, and bone remodeling (using co-culture system containing osteoblasts and macrophages). In the third year, according to the results of the second year, the surface treatment parameters capable of getting better bone remodeling will be selected, and applied to the surface of the screw-type titanium dental implants for the following in vivo animal tests using osteoporosis model: the dental implants will be implanted in the mandibular anterior teeth of New Zealand white rabbits with low bone density and quality. After 4 and 12 weeks of implantation, we will analyze the bone density change, bone formation ability, and osseointegration ability. Most previous studies related to osseointegration of dental implants have focused on promoting osteogenesis. This study further explores to investigate the effects of surface treatments on the osteogenesis, osteoclastogenesis, and bone remodeling processes. We seek to shorten the healing time and then improve the osseointegration of titanium dental implants for senior patients who have an imbalanced osteoblast/osteoclast reaction, through regulating the bone remodeling process (i.e., downregulating osteoclastogenesis while upregulating osteogenesis) by natural and cost-effective multiple surface treatments. The results of this study are expected to provide a new generation of titanium dental implant surface treatment technology for the future international market competitiveness of the elderly society.