DNA coating on dental titanium (Ti) implants is attracting attention due to its osteogenic properties. The aim of the present study was to evaluate in vitro and in vivo bioactivities of a multilayered DNA/protamine (D/P) coating on Ti implant by simulated body fluid (SBF) immersion experiments and implantation experiments into extracted sockets of rat molars. Two types of DNA, 300 base pair (bp) and 7000 bp fragments, were used. Protamine was initially immobilized onto Ti implants using a tresyl chloride-activated method and DNA and protamine were then alternatively deposited after the immobilization of protamine by a layer-by-layer technique. A multilayered D/P-coating was confirmed by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy measurements. The deposition of apatite progressed more on the surfaces of multilayered D/P-coated Ti implants than on those of nontreated Ti implants in SBF immersion experiments. Animal implantation experiments showed that multilayered D/P-coated Ti implants provided a significantly higher bone-to-implant (BIC) contact ratio 3 weeks after implantation. No significant difference was observed in the BIC ratio 9 weeks after implantation. The results of the present study demonstrated that a multilayered D/P-coating promoted new bone formation at the early stages of the bone healing process. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1500-1509, 2016.

We aimed to evaluate in vivo bone response and in vitro apatite formation to titanium (Ti) implants, coated with double-stranded DNA (DNA-d) or single-stranded DNA (DNA-s), and to compare the influence in different structure of DNA, double strand and single strand on bone response and apatite formation. The bone responses to multilayered DNA-d/protamine or DNA-s/protamine coating implants were evaluated after implantation into the extracted sockets of rat maxillary molars. Apatite formation on either coating surface after immersion in simulated body fluid (SBF) was evaluated using the quartz crystal microbalance (QCM) method. DNA-d/protamine and DNA-s/protamine coatings produced more roughened and hydrophilic surfaces than untreated Ti. Animal experiments showed that higher bone-to-implant ratios were achieved 3 and 6 weeks after implantation using DNA-d/protamine and DNA-s/protamine coatings compared with Ti. QCM measurements revealed that each coating contributed to significant earlier apatite formation in SBF. We conclude that both DNA-d/protamine and DNA-s/protamine coatings enhanced early bone formation. We suggest that a DNA-multilayer coating is useful for the surface modification of a Ti implant.

Nano-apatite could be prepared from a homogeneous solution of calcium (Ca)-aspartic acid (Asp) and Caglutamic acid (Glu) chelate complex with a high yield. Asp and Glu are components of non-collagenous proteins. Arginine is used to adjust pH to obtain precipitation from a Ca complex solution. Apatite from a Ca-ethylenediaminetetraacetic acid (EDTA) chelate complex was also prepared. These apatites are referred to as Asp-HA, Glu-HA, and EDTA-HA, respectively. Nano-apatite paste was obtained after mixing with water. Synthesized nano-apatite was characterized by X-ray diff raction and Fourier transform infrared measurements. It was revealed that Asp-HA and Glu-HA showed smaller crystal sizes with nano-scale, higher lattice distortion and greater degree of consistency as compared to EDTA-HA. The elution of Ca ion forms Asp-HA and Glu-HA were smaller than that of EDTA-HA. To investigate the infl uence of the diff erent amino acid ligands for calcium on bone response, bone responses to each nano-apatite paste were evaluated after transplantation into the subperiosteal pocket of the rat calvarial skeleton. Asp-HA and Glu-HA showed greater amounts of new bone formation than EDTA-HA. New bone formation progressed at an especially early stage after implantation with Asp-HA. It is suggested that Asp-HA paste will be useful for bone regeneration.

Denture plaque control for the prevention of aspiration pneumonia is very important. The pellicle is the major cause of denture plaque adhesion. Few basic studies have evaluated the effectiveness of denture cleansers for pellicles composed of salivary proteins. The adhesion of salivary proteins formed on denture base metal and the removal rate were quantitatively analyzed using the QCM method after denture cleanser injection. This is the first study to compare the cleaning effects of denture cleanser on denture base metal using the QCM method. Au and Ti sensors were employed as the denture base metals. Albumin was used for the adsorption of salivary proteins. The results showed that no significant difference was found between Au and Ti in the amounts of albumin adsorbed, and the rate of albumin removal from Ti was significantly higher than that of Au. In this study, the cleaning effectiveness of denture cleanser was confirmed based on the adsorbed amount and the removal rate of salivary proteins adsorbed onto denture base metals. Thus, the QCM method was suggested to be a useful tool for removing the effects of salivary proteins from denture cleaning agents on denture base metal.