Current perspectives of nanoparticles in medical and dental biomaterials

Nanotechnology is gaining tremendous impetus due to its capability of modulating metals into their nanosize, which drastically changes the chemical, physical and optical properties of metals. Nanoparticles have been intro- duced as materials with good potential to be extensively used in biological and medical applications. Nanoparticles are clusters of atoms in the size range of 1-100 nm. Inorganic nanoparticles and their nano-composites are applied as good antibacterial agents. Due to the outbreak of infectious diseases caused by different pathogenic bacteria and the development of antibiotic resistance, pharmaceutical companies and researchers are searching for new antibacterial agents. The metallic nanoparticles are the most promising as they show good antibacterial properties due to their large surface area to volume ratios, which draw growing interest from researchers due to increasing microbial resistance against metal ions, antibiotics and the development of resistant strains. Metallic nanoparticles can be used as effective growth inhibitors in various microorganisms and thereby are applicable to diverse medical devices. Nanotechnology discloses the use of elemental nanoparticles as active antibacterial ingredient for dental materials. In dentistry, both restorative materials and oral bacteria are believed to be responsible for restoration failure. Secondary caries is found to be the main reason to restoration failure. Secondary caries is primarily caused by invasion of plaque bacteria （acid-producing bacteria） such as Streptococcus mutans and lactobacilli in the presence of fermentable carbohydrates. To make long-lasting restorations, antibacterial materials should be made. The potential of nanoparticles to control the formation of biofilms within the oral cavity is also coming under in- creasing scrutiny. Possible uses of nanoparticles as topically applied agents within dental materials and the appli- cation of nanoparticles in the control of oral infections are also reviewed.

PHOTOCURING STUDY OF NEW DENTAL RESINS BASED ON MULTIFUNCTIONAL ACRYLIC ISOCYANURATE BY PHOTOCALORIMETRY

Photocuring of new dental resins composed of tri(2-hydroxyethyl) isocyanurate triacrylate (THITA) alone and its mixtures with trimethylolpropane triacrylate (TMPTA) or pentaerythritol triacrylate (PETA) initiated by camphorquinone/amine system was studied by photocalorimetry. Among several different amines as coinitiators, 2-ethyl-4-dimethylaminobenzoate (AM-3), N,N-dimethylbenzylamine (AM-5) and 2,4,6-[tri(dimethylaminomethyl)]phenol (AM-6) are most effective. Upon irradiation, photopolymerization can occur immediately and no induction period appears in N-2 nor in air. Comparing the THITA/TMPTA and THITA/PETA mixtures, the parameters of photopolymerization and hardness of photocured samples show a small difference and only change slightly with varying molar ratios of mixture. In the presence of inorganic filler, the hardness of photocuring resins is almost the same as that for commercial products.

Cone-beam computed tomography analysis of curved root canals after mechanical preparation with three nickel-titanium rotary instruments

Cone beam computed tomography is a 3-dimensional high resolution imaging method. The purpose of this study was to compare the effects of 3 different NiTi rotary instruments used to prepare curved root canals on the final shape of the curved canals and total amount of root canal transportation by using cone-beam computed tomography. A total of 81 mesial root canals from 42 extracted human mandibular molars, with a curvature ranging from 15 to 45 degrees, were selected. Canals were randomly divided into 3 groups of 27 each. After preparation with Protaper, Revo-S and Hero Shaper, the amount of transportation and centering ability that occurred were assessed by using cone beam computed tomography. Utilizing preand post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. Canals were metrically assessed for changes （surface area, changes in curvature and transportation） during canal preparation by using software SimPlant; instrument failures were also recorded. Mean total widths and outer and inner width measurements were determined on each central canal path and differences were statistically analyzed. The results showed that all instruments maintained the original canal curvature well with no significant differences between the different files （P=0.226）. During preparation there was failure of only one file （the protaper group）. In conclusion, under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. Areas of uninstrumented root canal wall were left in all regions using the various systems.

Antibacterial activity of calcium hydroxide combined with chitosan solutions and the outcomes on the bond strength of RealSeal sealer to radicular dentin

The purpose of this study was to investigate the antibacterial activity of calcium hydroxide [Ca（OH）2] combined with chitosan solutions against Enterococcus faecalis-infected root canal dentin and the effect of this new intraca- nal medicament on the bond strength of RealSeal sealer to radicular dentin. An experimental intracanal medicament was prepared by mixing different concentrations of chitosan solution （25%, 50%, and 100%, W/V） to Ca（OH）2 powder. Antibacterial activity was evaluated and the total numbers of colony forming units were determined. Bonding ability of RealSeal sealer to radicular dentin was evaluated using push-out bond strength test. Data were analyzed using one-way analysis of variance （ANOVA） and Tukey＇s multiple comparison tests. We found that Ca（OH）2 combined with different concentrations of chitosan solutions showed better antibacterial activity than Ca（OH）2 mixed with saline, without significantly affecting the bond strength of RealSeal sealer to radicular dentin （P 〉 0.05）. The findings suggest that Ca（OH）2 combined with chitosan is a promising intracanal medicament and may be effective in endodontic therapy.

A simple,sensitive and non-destructive technique for characterizing bovine dental enamel erosion:attenuated total reflection Fourier transform infrared spectroscopy

Although many techniques are available to assess enamel erosion in vitro, a simple, non-destructive method with sufficient sensitivity for quantifying dental erosion is required. This study characterized the bovine dental enamel erosion induced by various acidic beverages in vitro using attenuated total reflection Fourier transform infrared （ATR-FTIR） spectroscopy. Deionized water （control） and 10 acidic beverages were selected to study erosion, and the pH and neutralizable acidity were measured. Bovine anterior teeth （110） were polished with up to 1 200-grit silicon carbide paper to produce flat enamel surfaces, which were then immersed in 20 mL of the beverages for 30 min at 37 ℃. The degree of erosion was evaluated using ATR-FTIR spectroscopy and Vickers＇ microhardness measurements. The spectra obtained were interpreted in two ways that focused on the ~1, ~3 phosphate contour： the ratio of the height amplitude of ~3 P04 to that of/11 P04 （Method 1） and the shift of the v3 P04 peak to a higher wavenumber （Method 2）. The percentage changes in microhardness after the erosion treatments were primarily affected by the pH of the immersion media. Regression analyses revealed highly significant correlations between the surface hardness change and the degree of erosion, as detected by ATR-FTIR spectroscopy （P〈0.001）. Method 1 was the most sensitive to these changes, followed by surface hardness change measurements and Method 2. This study suggests that ATR- FTIR spectroscopy is potentially advantageous over the microhardness test as a simple, non-destructive, sensitive technique for the quantification of enamel erosion.

Comparison of the rheological properties of four root canal sealers

The flowability of a root canal sealer is clinically important because it improves the penetration of the sealer into the complex root canal system. The purpose of this study was to compare the flowabilities of four root canal sealers, measured using the simple press method （ISO 6876）, and their viscosities, measured using a strain-controlled rheometer. A newly developed, calcium phosphate-based root canal sealer （Capseal） and three commercial root canal sealers （AH Plus, Sealapex and Pulp Canal Sealer EWT） were used in this study. The flowabilities of the four root canal sealers were measured using the simple press method （n= 5） and their viscosities were measured using a strain-controlled rheometer （n=5）. The correlation between these two values was statistically analysed using Spearman＇s correlation test. The flow diameters and the viscosities of the root canal sealers were strongly negatively correlated （p= -0.8618）. The viscosity of Pulp Canal Sealer EWT was the lowest and increased in the following order： AH Plus〈Sealapex〈Capseal （P〈0.05）. All of the tested root canal sealers showed characteristic time- and temperature-dependent changes in their rheological properties. The viscosities measured using the strain-controlled rheometer were more precise than the flowabilities measured using the simple press method, suggesting that the rheometer can accurately measure the rheological properties of root canal sealers.

Immediate and delayed micro-tensile bond strength of different luting resin cements to different regional dentin

We sought to evaluate immediate and delayed micro-tensile bond strength of Panavia F2.0 and Multilink Sprint resin cement to superficial, deep and cervical dentin. Thirty-six freshly extracted non-carious human molars were sectioned in the mesiodistal direction to expose three different dentin regions including superficial dentin （1 mm below the dentine-enamel junction）, deep dentin （1 mm above the highest pulp horn） and cervical dentin （0.5 mm above the cemento-enamel junction and 0.5 mm below the dentine-enamel junction）. Resin cements were applied on dentin surfaces and composite blocks were luted under constant seating pressure. Each group was divided into three subgroups according to time intervals. Specimens were sectioned to obtain sticks of 1 mm2 in diameter and subjected to microtensile bond strength testing at a cross head speed of 1 mrn/min. Both resin cements showed higher micro-tensile bond strength to superficial dentin than that to deep or cervical dentin （P 〈 0.001）. Micro-ten- sile bond strengths of Panavia F2.0 were higher than those of Multilink Sprint at different dentin regions （P 〈 0.001）. Immediate ＂micro-tensile bond strengths were higher than those of delayed micro-tensile bond strengths for both resin cements （P 〈 0.001）. It was concluded that resin cements with different chemical formulations and applications yield significantly different micro-tensile bond strengths to different dentin regions.

Effect of addition of chitosan to self-etching primer:antibacterial activity and push-out bond strength to radicular dentin

The purpose of this study was to evaluate the antibacterial activity of a modified self-etching primer incorporating chitosan and whether this modification affected the bond strength to radicular dentin.A modified self-etching primer was prepared by adding chitosan solutions at 0.03%,0.06%,0.12% and 0.25%（W/W） to RealSeal selfetching primer.RealSeal primer without chitosan was used as the control.The antibacterial activity of the modified self-etching primer was evaluated using the direct contact test against Enterococcus faecalis.The bonding ability of the RealSeal system to radicular dentin was evaluated using the push-out bond strength test.The modes of failure were examined under a stereomicroscope.Data were analyzed using analysis of variance（ANOVA） and Tukey’s test,with a P-value 〈 0.05 indicating statistical significance.The results showed that the antibacterial properties of the freshly prepared and aged modified self-etching primer incorporating chitosan exhibited potent antibacterial effect against Enterococcus faecalis compared with the unmodified primer.The RealSeal system with the aged modified self-etching primer incorporating chitosan showed no significant differences in the bond strength as compared with the control（P = 0.99）.The findings suggest that modified self-etching primer incorporating chitosan is a promising antibacterial primer which does not adversely affect the bond strength of the RealSeal system to radicular dentin.

Effect of water storage on fluoride release and mechanical properties of a polyacid-modified composite resin (compomer)

We evaluated the effect of water storage on fluoride release and mechanical properties of compomer restorative material. Fluoride release was recorded using a specific fluoride electrode. Flexural properties and fracture toughness were measured using a universal testing machine. Vickers hardness was measured using a micro-hardness tester. There was initial burst of fluoride release up to 1 w, which was diminished to a low level in 1 mon and remained relatively constant over 6 mon. Flexural strength and hardness were increased up to 1 mon followed by a gradual decrease up to 6 mon. Flexural modulus was decreased gradually up to 6 mon. Fracture toughness was increased during the first week and gradually decreased over the storage period. We concluded that flexural properties, fracture toughness, Vickers hardness and fluoride release of compomer were sensitive to water as well as storage time. There was a significant effect of fluoride release on the studied mechanical properties.

Surface Characteristics of Mussel-inspired Polydopamine Coating on Titanium Substrates

Mussel adhesive proteins are non-toxic, biodegradable and have low immunogenic qualities that make them highly attractive for medical purposes compared with man-made materials. 3,4-DOPA, which is a dopamine precursor, is a critical element for achieving mussel-like adhesive properties. In present study, polydopamine was coated onto the titanium surfaces by dipping in a 2 mg/mL dopamine solution in 10 mM Tris- HCl buffer at pH 8.5. EDX element analysis and Raman spectroscopic analysis of the surface were conducted to verify the formation of polydopamine. The surface characteristics of polydopamine-coated titanium plates were observed by SEM and AFM. Hydrophilicity and corrosion-resistance were also evaluated by static contact angle measurements and potentiodynamic polarization corrosion tests. The absorption intensity for pH-induced polymerization rapidly increased for the initial four hours and thereafter smoothly increased. EDX element analyses revealed that the content of carbon and oxygen increased and the content of titanium decreased after the coating process. In the Raman spectra, polydopamine resulted in two new peaks at approximately 1 370 and 1 570 cm^-1 resulting from the stretching and deformation of catechol. Microstructural features revealed that nanometer-sized bright granules were randomly distributed after coating, and these nanoparticles grew with increased coating time. The Ra values of polydopamine-coated titanium plates were showed to increase with coating time. Compared to the pure titanium curve, the inflection point of polydopamine-coated titanium was located at a higher corrosion potential and lower corrosion current density. Findings from our research suggested that polydopamine coatings offer a versatile approach for titanium surface modification.

Effects of Chairside Polishing and Brushing on SurfaceRoughness of Acrylic Denture Base Resins

The effects of 3 chairside polishing kits and mechanical brushing on the surface roughness of 3 different acrylic denture base resins were compared. Acrylic denture base resins （auto-polymerizing, heat-polymerizing, injected heat-polymerizing resins） were examined after a tungsten carbide bur, and after chairside polishing using 3 polishing kits and pumice. The specimens were subjected to mechanical brushing using a wear tester to simulate 30 000 strokes of brushing. The surface roughness of the acrylic denture base resin specimens was measured using a contact pro-filometer. After the test, the random polished acrylic resins were evaluated by scanning electron mi-croscopy （SEM） and atomic force microscopy （AFM）. Acrylic denture base resins polished using the 3 types of polishing kits had a smoother surface than those finished with the tungsten carbide bur （p〈0.05）. The surface of the resin polished by a TC cutter exceeded the Ra of 0.2 μm （p〈0.05）. The auto-polymerizing resin showed a significantly higher surface roughness than the heat-polymerizing resin and injected heat-polymerizing resin （p〉0.05）. In the case of polishing step wise, there was almost no change in surface roughness after brushing （p〉0.05）.

Comparative Study of Visual and Instrumental Analyses of Shade Selection

The difference between visual and instrumental analyses of a shade selection on natural teeth was investigated. With visual analysis, five prosthodontist examined the middle third of the unrestored maxillary right central incisor of a patient using VITAPEN classical and Vita Toothguide 3D-MASTER tooth shade guide. In instrumental analysis, one prosthodontist examined the same teeth using a spectrophotometer （ShadepilotTM, Degudent, Hanau-Wolfgang, Germany, software 2.40）. Overall, instrumental analysis is more accurate and reproducible than a visual assessment. However, the difference is clinically acceptable.

The Influence of Ceramic Surface Treatments on the Microtensile Bond Strength of Resin Cements to Y-TZP Ceramic

The effects of surface conditioning methods on the microtensile bond strength of Y-TZP ceramic were studied based on airborne particle abrasion and resin cements.Eight square-shaped（φ12 mm×5 mm high） Y-TZP ceramic were studied blocks（LAVATM,3M ESPE,USA） and flat occlusal dentin blocks were fabricated,pre-treated（airborne abrasion with 125μm Al2O3 particles,tribochemical silica coating with 110 μm Al2O3 particles modified by silica oxide）,and bonded to each other using resin cements（Panavia F 2.0,RelyX Unicem）.Thereafter the trilayer specimens were cut into microbar specimens with a bonding area of approximately 1.0±0.1 mm2 and then microtensile bond strength tests were performed.The Y-TZP ceramic following airborne particle abrasion with 125μm Al2O3 and silicoating,the surface roughness of Y-TZP and its surface silica content were confirmed to increase.Overall,the Y-TZP ceramic surface treatment with a tribochemical silica coating showed the highest microtensile bond strength of the phosphate monomer-based resin cement to Y-TZP ceramic（mean MPa=18.11±0.27（Panavia F 2.0）,17.45±0.39（Rely X Unicem）.In cases in which a silica coating was applied,there was no significant difference in the bonding strength depending on resin cements（P0.05）.

External apical root resorption and the release of interleukin-6 in the gingival crevucular fluid induced by a self-ligating system

The aim of this study was to investigate the amount of external apical root resorption (EARR) and the release of interleukin (IL)-6 in the gingival crevicular fluid (GCF) in subjects treated with a low-force low-friction system. Sixty patients were assigned to two groups of thirty patients for each: one group received treatment with self-ligating brackets and the other with conventional ligated edgewise brackets. All patients were treated with extraction of the maxillary first premolars. The EARR of the maxillary central incisors was evaluated on the periapical radiographs and cephalograms, taken before and after orthodontic treatment. The GCF was also collected non-invasively from the mesial and distal sides of central incisors by using filter paper strips before and after orthodontic treatment. Enzyme-linked immunosorbent assay (ELISA) kits were used to determine the IL-6 levels in the GCF samples. A significant difference was found in the amount of EARR between the patients with self-ligating brackets and conventional brackets. The mean amount of EARR was significantly lower for self-ligating brackets than conventional brackets (p < 0.05). The GCF levels of IL-6 for the patients with self-ligating brackets appliance were significantly lower than for those with the conventional brackets (p < 0.05). These results show that the mean amount of EARR and the GCF levels of IL-6 were significantly lower in the patients treated using low-force low-friction appliances than conventional brackets. Therefore, self-ligating brackets may be a useful system for reducing inflammation and EARR.

Effect of Zirconium Oxide Nano-Fillers Addition on the Flexural Strength, Fracture Toughness, and Hardness of Heat-Polymerized Acrylic Resin

Purpose: The mechanical strength of polymethyl methacrylate (PMMA) remains far from ideal for maintaining the longevity of denture. The purpose of this study was to evaluate the effect of Zirconium oxide (ZrO2) nanofillers powder with different concentration (1.5%, 3%, 5% and 7%) on the flexural strength, fracture toughness, and hardness of heat-polymerized acrylic resin. Materials and methods: Zirconium oxide powders with different concentrations (1.5%, 3%, 5% and 7%) were incorporated into heat-cure acrylic resin (PMMA) and processed with optimal condition (2.5:1 Powder/monomer ratio, conventional packing method and water bath curing for 2 hours at 95。C) to fabricate test specimens of PMMA of dimensions (50 × 30 × 30 mm) for the flexural strength, fracture toughness, and (50 × 30 × 30 mm) were fabricated for measuring hardness. PMMA without additives was prepared as a test control. Three types of mechanical tests;flexural strength, fracture toughness and hardness were carried out on the samples. The recorded values of flexural strength in (MPa), fracture toughness in (MPa.m1/2), and hardness (VHN) were collected, tabulated and statistically analyzed. One way analysis of variance (ANOVA) and Tukey’s tests were used for testing the significance between the means of tested groups which are statistically significant when the P value ≤ 0.05. Results: Addition of Zirconium oxide nanofillers to PMMA significantly increased the flexural strength, fracture toughness and hardness. Conclusion: These results indicate that Zirconium oxide nanofillers added to PMMA has a potential as a reliable denture base material with increased flexural strength, fracture toughness, and hardness. According to the results of the present study, the best mechanical properties were achieved by adding 7%wt ZrO2 concentration.

In-vitro bioactivity evaluation and physical properties of an epoxy-based dental sealer reinforced with synthesized fluorine-substituted hydroxyapatite, hydroxyapatite and bioactive glass nanofillers

The purpose of this study was to evaluate the physical properties and bioactivity potential of epoxy-based dental sealers modified with synthesized bioactive glass(BAG),hydroxyapatite(HA)and fluorine substituted hydroxyapatite(FHA)nanoparticles.The synthesized powders were incorporated at 10%and 20%into the epoxy-based dental sealer.The setting time,flow and solubility and microhardness of the modified and unmodified samples were examined.The bioactivity was evaluated using FESEM-EDX and elemental mapping,ATR-FTIR and XRD.The flow value of all of the experimental groups except the FHA modified samples,was greater than 20 mm.Concerning solubility,no specimens exhibited more than 1%weight loss.The solubility value of the FHA groups was statistically significant lower than other groups(p≤0.001).The mean hardness values of all of the modified samples were significantly higher than the unmodified group(p≤0.001).Regarding bioactivity,in vitro study revealed that after 3 days immersion in SBF a compact and continuous calcium phosphate layer formed on the surface of epoxy sealers containing BAG and HA nanoparticles.Based on these results,the addition of BAG and HA nanoparticles did not adversely alter the physical properties of epoxy sealers.Additionally,they improved the in vitro bioactivity of the epoxy sealer.

Carbon Nanotube Coating on Titanium Substrate Modified with TiO_2 Nanotubes

A combination of carbon nanotubes （CNTs） and titanium （Ti） modified with TiO2 nanotubes （TiO2 NTs） was fulfilled with the aim of improving bioactivity of Ti implant.First,well-ordered TiO2 NTs were prepared by the electrochemical anodization of Ti in an ethylene glycol electrolyte containing 1 wt% NH4F and 10 wt% H2O at 20 V for 50 min,followed by annealing.Then,the carboxylated CNTs were coated onto the TiO2 NTs using electrophoretic deposition （EPD） technique.The growth of hydroxyapatite （HA） on the samples was investigated by soaking them in simulated body fluid （SBF）.The result showed the CNTs-coated Ti with the modification of TiO2 NTs （CNTs-TiO2 NTs） was more efficient to induce HA formation than the CNTs-coated smooth Ti （CNTs-Ti）.The vitro cell response was evaluated using osteoblast cells （MC3T3-E1）.The good cell proliferation and strong cell adhesion could be obtained on the CNTs-TiO2 NTs.These results indicated that CNT coating on the Ti modified with TiO2 NTs could be potentially useful for the periodontal ligament combination on dental implants.

Evaluation of characteristics on titanium surface treatment for absorption of functional groups

Background In order to bind or fix bioactive materials directly to the surface of a Ti implant, the prior binding process of functional groups （FGs, -COOH and -OH） to the implant surface is necessary. Conventional binding processes are so high-cost and complex, so it is essential to find a simple and effective procedure for Ti-FG binding.Methods Various electrolyte compositions and electrochemical processing were adopted in this study to develop a relatively simple and effective Ti-FG binding process. The ability of Ti-FG binding and calcium （Ca）/phosphorous （P）absorption and corrosion resistance were evaluated according to various titanium surface treatment in electrolyte involving -COOH and -OH ion by using X ray photoelectron spectroscopy （XPS）, field emission scanning electron microscope （FE-SEM） and potentiodynamic scan method respectively.Results In cases of -COOH, the anodic oxidation process （AN） showed an effective binding ability between -COOH and Ti surface. On the other hand, in cases of -OH, there were no significant differences in the result between the conditions used. In regard to the absorption of Ca and P on Ti surface, there was a minimal amount of Ca absorbed but no P was absorbed. The anodic oxidation series showed homogenous corrosion, whereas the electrolyte immersion （EL）series showed unstable corrosion. Although EL-OH showed a novel corrosion potential, the EL-COOH series showed good corrosion resistance over the anodic potential range.Conclusions The ability of binding between FG and the Ti surface and Ca/P absorption were strongly associated with the surface potential （ξ, potential）, which was dependent on the pH of the electrolyte. Accordingly, in order to achieve the effective absorption of various FGs on the Ti surface, it is needed to develop the combination process in addition to the electric affinity, relation with the ξ, potential.

Effect of surface mechanical attrition treatment of titanium using alumina balls： surface roughness, contact angle and apatite forming ability

The effect of surface mechanical attrition treatment （SMAT） of commercially pure titanium （CP-Ti） using 8 mm O alumina balls was studied. SMAT induced plastic deformation, increased the surface roughness, reduced the grain size and decreased the contact angle （from 64° to 43°） with a corresponding increase in surface energy （from 32 to 53 mJ/m2）. Untreated CP-Ti and those treateded using alumina bails for 900 s reveals no apatite growth until the 28th day of immersion whereas those treated for 1800 and 2700 s exhibit apatite growth In selective areas and the extent of growth is increased with increase in immersion time an SBF; The study reveals that SMAT using alumina balls is beneficial in imparting the desired surface Cheracteristics, provided the surface contamination is limited, which would otherwise decrease the apatite forming ability.

Regulation of cell locomotion by nanosecond-laser-induced hydroxyapatite patterning

Hydroxyapatite,an essential mineral in human bones composed mainly of calcium and phosphorus,is widely used to coat bone graft and implant surfaces for enhanced biocompatibility and bone formation.For a strong implant-bone bond,the bone-forming cells must not only adhere to the implant surface but also move to the surface requiring bone formation.However,strong adhesion tends to inhibit cell migration on the surface of hydroxyapatite.Herein,a cell migration highway pattern that can promote cell migration was prepared using a nanosecond laser on hydroxyapatite coating.The developed surface promoted bone-forming cell movement compared with the unpatterned hydroxyapatite surface,and the cell adhesion and movement speed could be controlled by adjusting the pattern width.Live-cell microscopy,cell tracking,and serum protein analysis revealed the fundamental principle of this phenomenon.These findings are applicable to hydroxyapatite-coated biomaterials and can be implemented easily by laser patterning without complicated processes.The cell migration highway can promote and control cell movement while maintaining the existing advantages of hydroxyapatite coatings.Furthermore,it can be applied to the surface treatment of not only implant materials directly bonded to bone but also various implanted biomaterials implanted that require cell movement control.