OBJECTIVE: To investigate the preparation and properties of the novel silica (SiO ₂)/hydroxyapatite (HAP) whiskers porous ceramics scaffold. METHODS: The HAP whiskers were modified by the SiO ₂ microspheres using the Stöber method. Three types of SiO ₂/HAP whiskers were fabricated under different factors (for the No.1 samples, the content of tetraethoxysilane, stirring time, calcination temperature, and soaking time were 10 mL, 12 hours, 560℃, and 0.5 hours, respectively; and in the No.2 samples, those were 15 mL, 24 hours, 650℃, and 2 hours, respectively; while those in the No.3 samples were 20 mL, 48 hours, 750℃, and 4 hours, respectively). The phase and morphology of the self-made HAP whisker and 3 types of SiO ₂/HAP whiskers were detected by the X-ray diffraction analysis and scanning electron microscopy. Taken the self-made HAP whisker and 3 types of SiO ₂/HAP whiskers as raw materials, various porous ceramic materials were prepared using the mechanical foaming method combined with extrusion molding method, and the low-temperature heat treatment. The pore structure of porous ceramics was observed by scanning electron microscopy. Its porosity and pore size distribution were measured. And further the axial compressive strength was measured, and the biodegradability was detected by simulated body fluid. Cell counting kit 8 method was used to conduct cytotoxicity experiments on the extract of porous ceramics. RESULTS: The SiO ₂ microspheres modified HAP whiskers and its porous ceramic materials were prepared successfully, respectively. In the SiO ₂/HAP whiskers, the amorphous SiO ₂ microspheres with a diameter of 200 nm, uniform distribution and good adhesion were attached to the surface of the whiskers, and the number of microspheres was controllable. The apparent porosity of the porous ceramic scaffold was about 78%, and its pore structure was composed of neatly arranged longitudinal through-holes and a large number of micro/nano through-holes. Compared with HAP whisker porous ceramic, the axial compressive strength of the SiO ₂/HAP whisker porous ceramics could reach 1.0 MPa, which increased the strength by nearly 4 times. Among them, the axial compressive strength of the No.2 SiO ₂/HAP whisker porous ceramic was the highest. The SiO ₂ microspheres attached to the surface of the whiskers could provide sites for the deposition of apatite. With the content of SiO ₂ microspheres increased, the deposition rate of apatite accelerated. The cytotoxicity level of the prepared porous ceramics ranged from 0 to 1, without cytotoxicity. CONCLUSION SiO ₂/HAP whisker porous ceramics have good biological activity, high porosity, three-dimensional complex pore structure, good axial compressive strength, and no cytotoxicity, which make it a promising scaffold material for bone tissue engineering.
Animals ; Durapatite ; Porosity ; Vibrissae ; Apatites ; Ceramics ; Silicon Dioxide

Ameloblasts are specialized cells derived from the dental epithelium that produce enamel, a hierarchically structured tissue comprised of highly elongated hydroxylapatite (OHAp) crystallites. The unique function of the epithelial cells synthesizing crystallites and assembling them in a mechanically robust structure is not fully elucidated yet, partly due to limitations with in vitro experimental models. Herein, we demonstrate the ability to generate mineralizing dental epithelial organoids (DEOs) from adult dental epithelial stem cells (aDESCs) isolated from mouse incisor tissues. DEOs expressed ameloblast markers, could be maintained for more than five months (11 passages) in vitro in media containing modulators of Wnt, Egf, Bmp, Fgf and Notch signaling pathways, and were amenable to cryostorage. When transplanted underneath murine kidney capsules, organoids produced OHAp crystallites similar in composition, size, and shape to mineralized dental tissues, including some enamel-like elongated crystals. DEOs are thus a powerful in vitro model to study mineralization process by dental epithelium, which can pave the way to understanding amelogenesis and developing regenerative therapy of enamel.
Mice ; Animals ; Durapatite/metabolism* ; Dental Enamel/metabolism* ; Ameloblasts/metabolism* ; Amelogenesis ; Stem Cells ; Organoids

Ginsenoside Rb1, the effective constituent of ginseng, has been demonstrated to play favorable roles in improving the immunity system. However, there is little study on the osteogenesis and angiogenesis effect of Ginsenoside Rb1. Moreover, how to establish a delivery system of Ginsenoside Rb1 and its repairment ability in bone defect remains elusive. In this study, the role of Ginsenoside Rb1 in cell viability, proliferation, apoptosis, osteogenic genes expression, ALP activity of rat BMSCs were evaluated firstly. Then, micro-nano HAp granules combined with silk were prepared to establish a delivery system of Ginsenoside Rb1, and the osteogenic and angiogenic effect of Ginsenoside Rb1 loaded on micro-nano HAp/silk in rat calvarial defect models were assessed by sequential fluorescence labeling, and histology analysis, respectively. It revealed that Ginsenoside Rb1 could maintain cell viability, significantly increased ALP activity, osteogenic and angiogenic genes expression. Meanwhile, micro-nano HAp granules combined with silk were fabricated smoothly and were a delivery carrier for Ginsenoside Rb1. Significantly, Ginsenoside Rb1 loaded on micro-nano HAp/silk could facilitate osteogenesis and angiogenesis. All the outcomes hint that Ginsenoside Rb1 could reinforce the osteogenesis differentiation and angiogenesis factor's expression of BMSCs. Moreover, micro-nano HAp combined with silk could act as a carrier for Ginsenoside Rb1 to repair bone defect.
Alginates/pharmacology* ; Animals ; Bone Regeneration ; Cell Differentiation ; Durapatite/pharmacology* ; Ginsenosides ; Osteogenesis ; Rats ; Silk/pharmacology* ; Tissue Scaffolds

Objective: To study the effect of hydroxyapatite (HA) based agents on the bonding properties of universal adhesive with different application modes, and to provide evidence for the use of adhesives after desensitization treatment. Methods: Sixty impacted third molars were extracted and selected (acquired from Department of Oral and Maxillofacial Surgery, College of Stomatology, Xi'an Jiaotong University). Four third molars were used to prepare 1 mm thick dentin disks and treated with 1% citric acid to simulate sensitive tooth models. The dentin surfaces were observed by scanning electron microscope (SEM) after treating with no desensitization (control group), desensitized by HA based toothpaste Biorepair and Dontodent Sensitive respectively (desensitizing toothpaste A group and B group), or HA paste treatment (desensitizing paste group ) (n=2 per group). The remaining teeth were selected to expose the mid-coronal dentin and establish dentin sensitivity models. Then, the specimens were divided into 4 former groups and received corresponding treatment. Each group was randomly divided into 2 subgroups, and intermediately strong universal adhesive (G-Premio Bond) was applied on the desensitized dentin by either etch-and-rinse mode or self-etch mode. Resin-dentin slice specimens (n=4 per subgroup), microtensile specimens (n=20 per subgroup) and slice specimens (n=6 per subgroup) were prepared. The microstructure and nanoleakage of the adhesive interfaces were observed by scanning electron microscopy (SEM). The microtensile strength (bond strength) and fracture mode were tested and recorded. The water permeability of the adhesive interface was observed by laser scanning confocal microscopy (LSCM). Results: SEM showed that desensitizing toothpaste and desensitizing paste could partially or entirely occlude most of the dentin tubules. For the etch-and-rinse mode, the bond strength of specimens treated with toothpaste A [(40.98±4.60) MPa], toothpaste B [(40.89±4.64) MPa] and HA paste [(41.48±3.65) MPa] was significantly higher than that of the control group [(38.58±4.28) MPa] (F=3.89,P<0.05). There was no statistically significant difference in bond strength among the 4 subgroups for self-etch modes (F=0.48,P>0.05). After desensitization, the bond strength of the control group and desensitizing groups in the self-etch mode was significantly higher than that in the etch-and-rinse mode (P<0.05). The overall fracture modes were mixed failure and interfacial failure in the control group and desensitizing groups. SEM showed speckled silver-stained particles deposited along the bottom of the hybrid layer on the bond interface of etch-and-rinse mode, and there were few silver-stained particles deposited on the bond interface of self-etch mode. LSCM showed continuous linear penetration in the hybrid layer of etch-and-rinse mode subgroups and discontinuous linear penetration in the hybrid layer of self-etch mode subgroups. Conclusions: HA based desensitizers have no adverse effect on the bond strength of intermediately strong universal adhesive and show good bonding performance accompanied with the self-etch mode.
Adhesives ; Dental Bonding ; Dental Cements ; Dentin ; Dentin-Bonding Agents ; Durapatite ; Humans ; Materials Testing ; Microscopy, Electron, Scanning ; Resin Cements ; Tensile Strength

OBJECTIVES: The purpose of the study was to evaluate the effect of hydroxyapatite (HA)-based desensiti-zing agents and determine their influence on the bonding performance of mild universal adhesives. METHODS: Mid-coronal dentin samples were sectioned from human third molars and prepared for a dentin-sensitive model. According to desensitizing applications, they were randomly divided into four groups for the following treatments: no desensitizing treatment (control), Biorepair toothpaste (HA-based desensitizing toothpaste) treatment, Dontodent toothpaste (HA-based desensitizing toothpaste) treatment, and HA paste treatment. Dentin tubular occlusion and occluded area ratios were evaluated by scanning electron microscopy (SEM). Furthermore, All-Bond Universal, Single Bond Universal, and Clearfil Universal Bond were applied to the desensitized dentin in self-etch mode. The wettability and surface free energy (SFE) of desensitized dentin were evaluated by contact angle measurements. Bonded specimens were sectioned into beams and tested for micro-tensile bond strength to analyze the effect of desensitizing treatment on the bond strength to dentin of universal adhesives. RESULTS: SEM revealed that the dentin tubule was occluded by HA-based desensitizing agents, and the area ratios for the occluded dentin tubules were in the following order: HA group>Biorepair group>Dontodent group (P<0.05). Contact angle analysis demonstrated that HA-based desensitizing agents had no statistically significant influence on the wettability of the universal adhesives (P>0.05). The SFE of dentin significantly increased after treatment by HA-based desensitizing agents (P<0.05). The micro-tensile bond strength test showed that HA-based desensitizing toothpastes always decreased the μTBS values (P<0.05), whereas the HA paste group presented similar bond strength to the control group (P>0.05), irrespective of universal adhesive types. CONCLUSIONS HA-based desensitizing agents can occlude the exposed dentinal tubules on sensitive dentin. When mild and ultra-mild universal adhesives were used for subsequent resin restoration, the bond strength was reduced by HA-based desensitizing toothpastes, whereas the pure HA paste had no adverse effect on bond strength.
Humans ; Dental Cements/analysis* ; Dentin/chemistry* ; Durapatite/pharmacology* ; Tensile Strength ; Toothpastes

OBJECTIVES: To investigate the dynamic process of the self-assembly behaviors of a full-length human amelogenin (AM) and its functional fragments tyrosine-rich amelogenin peptide (TRAP) and leucine-rich amelogenin peptide(LRAP) METHODS: The full-length human AM and its functional fragments, TRAP and LRAP, were reassembled and purified RESULTS: When pH=8, the full-length human AM and TRAP assembly started spontaneously and formed "nanospheres" after 15 min.The nanospheres formed by TRAP existed independently, with a uniform size but without obvious internal structures. The full-length AM was assembled hierarchically, which formed "nanospheres" and further extended in all directions, formed a chain structure, and then aggregated into a net. The self-assembly behavior of LRAP was not obvious. Proteins mostly existed in the form of monomers without "nanosphere" formation. Only few oligomers were observed. The full-length AM was induced independently for 3 days to form rod-shaped HA crystals. TRAP and LRAP proteins were added, after 3 days the crystal elongation was obvious in the c axis, but the growth in plane A and plane B was poor. CONCLUSIONS The self-assembly and mineralization behaviors of full-length human AM, TRAP, and LRAP were consistent with the directional growth mechanism of HA crystals
Amelogenin ; Dental Enamel Proteins ; Durapatite ; Humans

OBJECTIVES: This study was performed to evaluate the occlusion of monetite paste on dentine tubule and provide a new potential method for treating dentine hypersensitivity. METHODS: Calcium oxide, strontium chloride, and polyethylene glycol phosphate were mixed in a certain proportion and ground in a planetary ball mill. The reaction was carried out by adjusting the pH to obtain monetite and hydroxyapatite paste. The morphological characteristics of the paste were observed through scanning electron microscope (SEM). The structure and composition were analyzed through X-ray diffraction (XRD) and Fourier transform infrared spectrometer (FTIR). The extracted third molar was selected to undergo demineralization to establish the RESULTS: XRD and FTIR showed that the composition of the paste was mainly monetite, and the composition of hydroxyapatite paste was mainly composed of hydroxyapatite. SEM revealed that the size of the crystal particles of the synthesized paste was tens to hundreds of nanometers. Monetite and hydroxyapatite paste could produce a thicker mineralization layer on the dentin surface, and the mineralization of the dentin tubules of monetite was deeper than that of hydroxyapatite paste. The microhardness of the monetite paste group was significantly less than those of the hydroxyapatite paste groups ( CONCLUSIONS Monetite paste could effectively block the exposed dentin tubules and be used for treating dentin hypersensitivity.
Calcium Phosphates ; Dentin ; Dentin Sensitivity ; Durapatite ; Humans ; Microscopy, Electron, Scanning

Increasing demands for esthetic dental treatment, zirconia, which has high mechanical and esthetic properties, had been applied more and more in clinics. Therefore, assessment of biocompatibility of zirconia is necessary. In this article, a review of in vivo studies of zirconia compatibility was performed. In vivo studies showed zirconia had great biocompatibility both on soft and hard tissue. Studies with various animals and patients reported high biocompatibility of zirconia. In terms of bone synthesis and bone adhesion, zirconia showed similar biocompatible properties to titanium. On the other hand, zirconia could be used as implant. For using as an implant, various methods of Hydroxyapatite (HA) coating had been suggested. Since HA coating on titanium implant showed some problems such as low bonding strength and degeneration of HA, HA-zirconia composite, HA-coated zirconia, and HA-zirconia functionally graded material (FGM) or intermediate layer of alumina had been proposed. These methods showed higher bonding strength and biocompatibility.
Aluminum Oxide ; Animals ; Durapatite ; Hand ; Humans ; Titanium

Acute calcific tendinitis (ACT) is a benign painful inflammatory disorder characterized by resorptive process of calcific deposits following the formation of calcium hydroxyapatite crystals in the tendons. It can occur at various sites, especially in the shoulder or hip joint. ACT involving the lateral epicondyle of the humerus and the cervical spine is very rare. Few reports have demonstrated successive ACT at different sites. We report three cases of successive ACT in women, occurring at the subscapularis followed by the lateral epicondyle, flexor carpi ulnaris followed by the supraspinatus, and longus colli followed by the iliopsoas, respectively.
Durapatite ; Female ; Hip Joint ; Humans ; Humerus ; Shoulder ; Spine ; Tendinopathy ; Tendons

OBJECTIVES: The purpose of this study was to investigate changes in the composition of artificial cariogenic biofilms using a Streptococcus mutans biofilm model over a period of time. METHODS: We analyzed the dry weight, colony forming unit (CFU) number, extracellular polysaccharide (EPS) biovolume, and acid production rate of S. mutans biofilms formed on saliva-coated hydroxyapatite discs after 26 h, 50 h, 74 h, 98 h, 171 h, and 195 h. In addition, we performed a laser scanning confocal fluorescence microscopy to determine the bacterial volume, EPS biovolume, and biofilm thickness. We calculated the biofilm density using dry weight and EPS biovolume. RESULTS: Over a period of time, there was no change in the CFU number and acid production rate of S. mutans biofilms, but there was an increase in the dry weight and EPS biovolume of S. mutans biofilms. The bacterial volume, EPS biovolume, and biofilm thickness only increased in the 50-h-old biofilm; however, no change was observed in 50-195-h-old biofilms. In addition, an increase in the biofilm density was observed over time. CONCLUSIONS: These results suggest that the acid production ability of cariogenic biofilms does not change, but the biofilm density increases over time. However, due to scientific information, further research needs to be conducted in the field of dentistry to get further insights on the progression of cariogenic biofilms over time.
Biofilms ; Dentistry ; Durapatite ; Microscopy, Fluorescence ; Stem Cells ; Streptococcus mutans