Tantalum-incorporated hydroxyapatite coating on titanium implants: its mechanical and in vitro osteogenic properties.

OBJECTIVE: The fabrication of bioactive coatings on metallic implants to enhance osseointegration has become a topic of general interest in orthopedics and dentistry. Hydroxyapatite (HA) coating has been shown to induce bone formation and promote bone-implant integration. Unfortunately, poor mechanical performance has hindered this from becoming a favorable coating material. The majority of present studies have focused in incorporating different elements into HA coatings to improve mechanical properties. In recent years, tantalum (Ta) has received increasing attention due to its excellent biocompatibility and corrosion resistance. The aim of on the present study was to investigate the fabrication and biological performance of Ta-incorporated HA coatings. METHODS: Ta-incorporated HA coatings were fabricated using the plasma spray technique on a titanium substrate, and the surface characteristics and mechanical properties were examined. In addition, the effects of Ta-incorporated HA coatings on the biological behavior of mesenchymal stem cells (BMSCs) were investigated. RESULTS: Ta-incorporated HA coatings with microporous structure had higher roughness and wettability. In addition, the bonding strength of Ta/HA coatings with the substrate was substantially superior to HA coatings. Furthermore, Ta-incorporated HA coatings not only facilitated initial cell adhesion and faster proliferation, but also promoted the osteogenic differentiation of BMSCs. CONCLUSION: These results indicate that the incorporation of Ta could improve mechanical performance and increase the osteogenic activity of HA coatings. The Ta-incorporated HA coating fabricated by plasma spraying is expected to be a promising bio-coating material for metallic implants.

Lipofuscin in saliva and plasma and its association with age in healthy adults.

BACKGROUND AND AIM: To compare blood and salivary levels of lipofuscin in healthy adults and to analyze the relationship between the lipofuscin level and the healthy adults' age. METHODS: One hundred and twenty-two healthy volunteers were recruited and divided into three groups according to their age: young (n = 42, 20-44 years old), middle-aged (n = 51, 45-59 years old), and elderly (n = 29, 60-74 years old). One ml saliva and 5 ml whole blood were collected from each person. An ELISA kit was used to measure both the plasma and salivary lipofuscin levels. The differences between the groups were compared with independent-sample t test, and the relationship between the salivary lipofuscin level and the age was assessed with linear regression analysis. RESULTS: The mean ± SD of the lipofuscin level in the saliva and plasma of 122 subjects was 68.93 ± 1.32 and 78.05 ± 1.75 µmol/l, respectively. No gender-dependent differences were observed in either the salivary or the plasma lipofuscin level (saliva: p = 0.443, plasma: p = 0.459). The salivary and plasma lipofuscin levels of the elderly subjects were significantly higher than those of the young (saliva: 80.72 ± 13.53 mmol/l versus 59.12 ± 1.92 mmol/l, p = 0.0003; plasma: 93.31 ± 3.14 mmol/l versus 67.43 ± 2.54 mmol/l, p = 0.0002) and middle-aged (saliva: 80.72 ± 13.53 mmol/l versus 70.31 ± 11.17 mmol/l, p = 0.0004; plasma: 93.31 ± 3.14 mmol/l versus 78.12 ± 2.40 mmol/l, p = 0.0002) subjects. Similarly, the salivary and plasma lipofuscin levels of the middle-aged subjects were significantly higher than those of the young subjects (saliva: 70.31 ± 11.17 mmol/l versus 59.12 ± 1.92 mmol/l, p < 0.0001; plasma: 78.12 ± 2.40 mmol/l versus 67.43 ± 2.54 mmol/l, p = 0.0019). The lipofuscin levels in the saliva and plasma were significantly positively correlated with the subject age (r = 0.551, p = 0.0001; r = 0.528, p < 0.0001). Furthermore, the salivary lipofuscin level and plasma lipofuscin level also were found to have a positive correlation (r = 0.621, p < 0.0001). CONCLUSION: No gender-dependent differences were observed in either the salivary or plasma lipofuscin levels. The salivary and plasma lipofuscin levels were positively correlated, and the age is positively correlated with lipofuscin content in saliva.

[Observing the effect of high glucose on proliferation of bone marrow stromal stem cells through Wnt/Β-catenin pathway].

OBJECTIVE: To explore the effect of high glucose on proliferation of bone marrow stromal stem cells through Wnt/Β-catenin pathway. METHODS: Bone marrow stormal cells were obtained from the mandible of Wistar rats and stimulated with different concentrations of glucose (5.5 and 16.5 mmol/L). Cell proliferation was evaluated with methyl thiazolyl tetrazolium assay (1, 3, 5, and 7 d)and cell cycle analysis by flow cytometry (5 d). Β-catenin and cyclin D1 protein levels were determined by Western blot. The mRNA expression of lymphoid enhancer binding factor-1 (LEF-1) and cyclin D1 were tested by real-time polymerase chain reaction. RESULTS: The results of methyl thiazolyl tetrazolium assay indicated that the optical density values of two different concentrations of the glucose had no statistical difference on day 1 (P=0.700). On days 3, 5, and 7, the optical density values of the 16.5 mmol/L group were significantly lower than those in the 5.5 mmol/L group (P=0.006, P=0.002, and P=0.003). Cell cycle analysis indicated that high glucose concentration could reduced the progression from phase G1 to S, and the proliferation index values of the 16.5 mmol/L group were significantly lower than those of the 5.5 mmol/L group (P=0.014). The Β-catenin and cyclin D1 levels were lower in the 16.5 mmol/L group when compared with the 5.5 mmol/L group. High glucose condition also reduced the mRNA expressions of LEF-1 and cyclin D1. CONCLUSION: High glucose can inhibit the proliferation of bone marrow stormal cells by suppressing the expressions of Β-catenin, LEF-1, and cyclin D1 in the Wnt/Β-catenin pathway.

Measurement of cortical bone thickness in adults by cone-beam computerized tomography for orthodontic miniscrews placement.

The purpose of this study was to investigate the cortical bone thickness of the inter-dental area of both jaws for orthodontic miniscrew placement. The cone-beam computerized tomography images of 32 non-orthodontic adults with normal occlusion were taken to measure the cortical bone thickness in both jaws. One-way analysis of variance (ANOVA) was used to analyze the differences in cortical bone thickness. Buccal cortical bone in the mandible was thicker than that in the maxilla. In the maxilla, cortical bone thickness was thicker in the buccal side than in the palatal side. Buccal cortical bone thickness in the mandible was thickest at the site distal to the first molar, and in the maxilla it was thickest at the site mesial to the first molar, while in the palatal side of maxilla it was thickest at the site mesial to the second premolar. The changing pattern of cortical bone thickness varies at different sites. In the buccal side of maxilla, the thinnest cortical bone thickness was found to be at 4 mm level from the alveolar crest, while the thickest was at 10 mm level (except for the site mesial to the first premolar). The buccal cortical bone thickness at the sites mesial or distal to the first molar in the mandible and palatal cortical bone thickness of maxilla tended to increase with increasing distance from the alveolar bone.

Clinical effect of Tip-Edge plus appliance in children with angle II(1) malocclusion.

The effects of Tip-Edge plus appliance in the treatment of Angle II(1) malocclusion and the mechanism were investigated. Fifty-two Angle II(1) children, aged from 12.3-14.2 years, with mandibular retrusion in permanent dentition were selected and treated with Tip-Edge plus appliance. Lateral cephalometric films taken before and after treatment were analyzed. The arithmetic mean and standard deviation were calculated for each variable. Paired t-test was performed to evaluate the significant treatment change. Results showed that the average treatment time was 16 months. Normal overjet and overbite were established with retroclination of upper incisors and proclination of lower incisors. U1-NA was decreased by 15.4° (P<0.01). ANB and Y axial angle were decreased significantly (P<0.05). Soft tissue measurements showed that FCA and UL-E were decreased dramatically (P<0.05), and LL-E was increased significantly (P<0.05). Remarkable soft tissue change was noted after the treatment and convex facial profile changed to the straight profile. In conclusion, Tip-Edge plus technique can quickly and efficiently correct anterior bite and lateral outlook.

Effects of rhBMP-2 on Bone Formation Capacity of Rat Dental Stem/Progenitor Cells from Dental Follicle and Alveolar Bone Marrow.

Dental stem/progenitor cells are a promising cell sources for alveolar bone (AB) regeneration because of their same embryonic origin and superior osteogenic potential. However, their molecular processes during osteogenic differentiation remain unclear. The objective of this study was to identify the responsiveness of dental follicle cells (DFCs) and AB marrow-derived mesenchymal stem cells (ABM-MSCs) to recombinant human bone morphogenetic protein-2 (rhBMP-2). These cells expressed vimentin and MSC markers and did not express cytokeratin and hematopoietic stem cell markers and showed multilineage differentiation potential under specific culture conditions. DFCs exhibited higher proliferation and colony-forming unit-fibroblast efficiency than ABM-MSCs; rhBMP-2 induced DFCs to differentiate toward a cementoblast/osteoblast phenotype and ABM-MSCs to differentiate only toward a osteoblast phenotype; and rhBMP-2-induced DFCs exhibited higher osteogenic differentiation potential than ABM-MSCs. These cells adhered, grew, and produced extracellular matrix on nanohydroxyapatite/collagen/poly(l-lactide) (nHAC/PLA). During a 14-day culture on nHAC/PLA, the extracellular alkaline phosphatase (ALP) activity of DFCs decreased gradually and that of ABM-MSCs increased gradually; rhBMP-2 enhanced their extracellular ALP activity, intracellular osteocalcin (OCN), and osteopontin (OPN) protein expression; and DFCs exhibited higher extracellular ALP activity and intracellular OCN protein expression than ABM-MSCs. When implanted subcutaneously in severe combined immunodeficient mice for 3 months, DFCs+nHAC/PLA+rhBMP-2 obtained higher percentage of bone formation area, OCN, and cementum attachment protein expression and lower OPN expression than ABM-MSCs+nHAC/PLA+rhBMP-2. These results showed that DFCs possessed superior proliferation and osteogenic differentiation potential in vitro, and formed higher quantity and quality bones in vivo. It suggested that DFCs might exhibit a more sensitive responsiveness to rhBMP-2, so that DFCs enter a relatively mature stage of osteogenic differentiation earlier than ABM-MSCs after rhBMP-2 induction. The findings imply that these dental stem/progenitor cells are alternative sources for AB engineering in regenerative medicine, and developing dental tissue may provide better source for stem/progenitor cells.

Combined Use of Recombinant Human BMP-7 and Osteogenic Media May Have No Ideal Synergistic Effect on Leporine Bone Regeneration of Human Umbilical Cord Mesenchymal Stem Cells Seeded on Nanohydroxyapatite/Collagen/Poly (l-Lactide).

Human umbilical cord mesenchymal stem cells (hUC-MSCs) are a promising alternative source of mesenchymal stem cells (MSCs) that are enormously attractive for clinical use. This study was designed to investigate the effect of recombinant human bone morphogenetic protein-7 (rhBMP-7) and/or osteogenic media (OMD) on bone regeneration of hUC-MSCs seeded on nanohydroxyapatite/collagen/poly(l-lactide) (nHAC/PLA) in a rabbit model. The characteristics of stem cells were analyzed by plastic adherence, cell phenotype, and multilineage differentiation potential. Cell proliferation was examined using cell counting kit-8 assay. Osteogenic differentiation was evaluated by quantitative Ca2+ concentration, PO43- concentration, alkaline phosphatase (ALP) activity, osteocalcin (OCN) secretion, and mineralized matrix formation. Bone regeneration was investigated in jaw bone defect repair in rabbit by microcomputed tomography, fluorescent labeling, and hematoxylin and eosin staining. Except for initial stress response, OMD and OMD + rhBMP-7 inhibited the proliferation of hUC-MSCs seeded on nHAC/PLA; rhBMP-7 inhibited cell proliferation in the nonlogarithmic phase and attenuated the inhibitory effect of OMD on cell proliferation. The inhibitory effects of OMD, rhBMP-7, and OMD + rhBMP-7 on cell proliferation were ranked as OMD > OMD + rhBMP-7 > rhBMP-7. OMD, rhBMP-7, and OMD + rhBMP-7 promoted Ca2+ concentration, PO43- concentration, ALP activity, OCN secretion, and mineralized matrix formation of hUC-MSCs seeded on nHAC/PLA. The promoting effects of OMD, rhBMP-7, and OMD+rhBMP-7 on Ca2+ concentration, PO43- concentration, ALP activity, OCN secretion, and mineralized matrix formation were ranked as rhBMP-7 > OMD > OMD + rhBMP-7, OMD > OMD + rhBMP-7 > rhBMP-7, OMD > rhBMP-7 > OMD + rhBMP-7, rhBMP-7 > OMD + rhBMP-7 > OMD, and OMD > rhBMP-7 > OMD + rhBMP-7, respectively. In rabbit jaw bone defect repair, OMD, rhBMP-7, and OMD + rhBMP-7 enhanced bone regeneration of hUC-MSCs seeded on nHAC/PLA, but the largest bone mineral apposition rate and bone formation were presented in cultures with rhBMP-7. These findings suggested that the combined use of rhBMP-7 and OMD may have no ideal synergistic effect on bone regeneration of hUC-MSCs seeded on nHAC/PLA in rabbit jaw bone defect.

New nano-sized Al2O3-BN coating 3Y-TZP ceramic composites for CAD/CAM-produced all-ceramic dental restorations. Part I. Fabrication of powders.

Partially sintered 3 mol % yttria-stabilized tetragonal zirconium dioxide (ZrO(2), zirconia) polycrystal (3Y-TZP) ceramics are used in dental posterior restorations with computer-aided design-computer-aided manufacturing (CAD/CAM) techniques. High strength is acquired after sintering, but shape distortion of preshaped compacts during their sintering is inevitable. The aim of this study is to fabricate new machinable ceramic composites with strong mechanical properties that are fit for all-ceramic dental restorations. Aluminum oxide (Al(2)O(3))-coated 3Y-TZP powders were first prepared by the heterogeneous precipitation method starting with 3Y-TZP, Al(NO(3))(3) . 9H(2)O, and ammonia, then amorphous boron nitride (BN) was produced and the as-received composite powders were coated via in situ reaction with boric acid and urea. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to analyze the status of Al(2)O(3)-BN on the surface of the 3Y-TZP particles. TEM micrographs show an abundance of Al(2)O(3) particles and amorphous BN appearing uniformly on the surface of the 3Y-TZP particles after the coating process. The size of the Al(2)O(3) particles is about 20 nm. The XRD pattern shows clearly the peak of amorphous BN among the peaks of ZrO(2).

Brain activation patterns during unilateral premolar occlusion.

OBJECTIVE: To observe the characteristics of brain activation during unilateral premolar occlusion. METHODS: Functional magnetic resonance imaging was collected from 10 healthy volunteers during occlusion of the left first premolar (L1), left second premolar (L2), and right first premolar (R1). The brain activation patterns were analyzed, and the primary sensorimotor cortex, supplementary motor area, insula, thalamus, and prefrontal cortex were chosen as regions of interest. RESULTS: Single premolar occlusion activated the precentral gyrus, postcentral gyrus, cerebellum, thalamus, frontal lobe, hippocampus, cingulate gyrus, and parietal lobe. The brain areas showing activation during single premolar occlusion were similar to those activated by chewing. The activation pattern of L1 was more similar to that of L2 than R1. No significant left and right hemisphere differences in signal intensity were detected within the regions of interest. CONCLUSION: Brain activation patterns from two ipsilateral premolars were more similar than the pattern from a contralateral premolar.

[Minimal invasive microscopic tooth preparation based on endodontic, periodontal and functional health].

Tooth preparation is the primary and core operation technique for dental esthetic restoration treatment, due to its effect of providing restoration space, bonding interfaces and marginal lines for dental rehabilitation after tooth tissue reduction. The concept of microscopic minimal invasive dentistry put forward the issue of conducting high-quality tooth preparation, conserve tooth-structure, protect vital pulp and periodontal tissue simultaneously. This study reviewed the concepts, physiology background, design and minimal invasive microscopic tooth preparation, and in the meantime, individualized strategies and the two core elements of tooth preparation (quantity and shape) are listed.

Reconstruction of caprine mandibular segmental defect by tissue engineered bone reinforced by titanium reticulum.

OBJECTIVE: To investigate the feasibility of using natural poritos as scaffolds in bone tissue engineering (TE) and repair of caprine mandibular segmental defect with titanium reticulum reinforced. METHODS: Natural poritos with a pore of 190-230 microm in size and porosity of about 50percent-65percent was molded into the shape of granules 5 mm x 5 mm x 5 mm in size. Expanded autologous caprine marrow mesenchymal stem cells were induced by recombinant human morphogenetic protein-2 (rhBMP2) to improve osteoblastic phenotype. Then marrow derived osteoblasts were seeded into poritos in density of 4 x 10(7)/ml and incubated in vitro for 48 hours prior to implantation. Then osteoblastic cells/poritos complexes were implanted into mandibular defect and the defect was reinforced by titanium reticulum. Implantation of poritos alone acted as the control. Bone regeneration was assessed 4, 8, 16 weeks after implantation using roentgenographic analysis and histological observation was done after 16 weeks. RESULTS: New bone could be observed histologically on the surface and in the pores of natural coral in all specimens in the cell-seeding group, whereas in the control group there was no evidence of osteogenesis process in the center of the construction. The results showed that new bone grafts were successfully restored 16 weeks after implantation. CONCLUSIONS: This study suggests the feasibility of using porous coral as scaffold material transplanted with marrow derived osteoblasts by TE method. By means of titanium reticulum reinforcement, mandibular defect could be successfully restored. It shows the potentiality of using this method for the reconstruction of bone defect in clinic.

[Comparative study on bilateral temporomandibular joint of patients with unilateral multiple symptoms in cone-beam computed tomography].

PURPOSE: To investigate bilateral temporomandibular joint of patients with unilateral multiple symptoms in cone-beam computed tomography (CBCT) and explore the reference planes that may be different,providing reference for the diagnosis of temporomandibular disorders and comparative study. METHODS: 50 cases with unilateral multiple symptoms（except for cases with unilateral single symptom）were examined by CBCT and the following indexes were observed and analyzed,including horizontal angles of the cross-sectional condyle after the reconstruction in the same patient, joint space, macroaxis diameter of condyle and vertical angles of condyle, which were commonly used at oblique position parallelled to the long axis of condyle, the gradient of articular tubercle and the joint space,which could be obtained at sagittal and oblique position vertical to the long axis of condyle.The data obtained was analyzed by paired t test with SPSS13.0 software package. RESULTS: There was significant difference between the bilateral measured value of joint space when the angle was 60° in sagittal plane (P<0.05).The difference was more significant when the angle was 120° in parallel plane and 90° in sagittal plane (P<0.01). The other measured parameters were not significant different. CONCLUSIONS: For patients with TMD, it is more easily to observe differences between the bilateral measured value of joint space in the sagittal or vertical plane,where the increase of the front joint space can be seen and construction was more significant.

The effect of calcium phosphate composite scaffolds on the osteogenic differentiation of rabbit dental pulp stem cells.

The objective of this study is to compare the effects of the two calcium phosphate composite scaffolds on the attachment, proliferation, and osteogenic differentiation of rabbit dental pulp stem cells (DPSCs). One nano-hydroxyapatite/collagen/poly (l-lactide) (nHAC/PLA), imitating the composition and the micro-structure characteristics of the natural bone, was made by Beijing Allgens Medical Science & Technology Co., Ltd. (China). The other beta-tricalcium phosphate (ß-TCP), being fully interoperability globular pore structure, was provided by Shanghai Bio-lu Biomaterials Co, Ltd. (China). We compared the absorption water rate and the protein adsorption rate of two scaffolds and the characterization of DPSCs cultured on the culture plate and both scaffolds under osteogenic differentiation media (ODM) treatment. The constructs were then implanted subcutaneously into the back of severely combined immunodeficient (SCID) mice for 8 and 12 weeks to compare their bone formation capacity. The results showed that the ODM-treated DPSCs expressed osteocalcin (OCN), bone sialoprotein (BSP), type I collagen (COLI) and osteopontin (OPN) by immunofluorescence staining. Positive alkaline phosphatase (ALP) staining, calcium deposition and calcium nodules were also observed on the ODM-treated DPSCs. The absorption water rate and protein adsorption rate of nHAC/PLA was significantly higher than ß-TCP. The initial attachment of DPSCs seeded onto nHAC/PLA was significantly higher than that onto ß-TCP; and the proliferation rate of the cells was also significantly higher than that of ß-TCP on 1, 3, and 7 days of cell culture. The ALP activity, calcium/phosphorus content and mineral formation of DPSCs + ß-TCP were significantly higher than DPSCs + nHAC/LA. When implanted into the back of SCID mice, nHAC/PLA alone had no new bone formation, newly formed mature bone and osteoid were only observed in ß-TCP alone, DPSCs + nHAC/PLA and DPSCs + ß-TCP, and this three groups displayed increased bone formation over the 12-week period. The percentage of total bone formation area had no difference between DPSCs + ß-TCP and DPSCs + nHAC/PLA at each time point, but the percentage of mature bone formation area of DPSCs + ß-TCP was significantly higher than that of DPSCs + nHAC/PLA. Our results demonstrated that the DPSCs on nHAC/PLA had a better proliferation, and that the DPSCs on ß-TCP had a more mineralization in vitro, much more newly formed mature bones in vivo were presented in DPSCs + ß-TCP group. These findings have provided a further knowledge that scaffold architecture has different influence on the attachment, proliferation and differentiation of cells. This study may provide insight into the clinical periodontal bone tissue repair with DPSCs + ß-TCP construct.

Effects of Danggui-Shaoyao-San on the Influence of Spatial Learning and Memory Induced by Experimental Tooth Movement.

BACKGROUND: The pain caused by orthodontic treatment has been considered as tough problems in orthodontic practice. There is substantial literature on pain which has exactly effected on learning and memory; orthodontic tooth movement affected the emotional status has been showed positive outcomes. Danggui-Shaoyao-San (DSS) is a Traditional Chinese Medicine prescription that has been used for pain treatment and analgesic effect for orthodontic pain via inhibiting the activations of neuron and glia. We raised the hypothesis that DSS could restore the impaired abilities of spatial learning and memory via regulating neuron or glia expression in the hippocampus. METHODS: A total of 36 rats were randomly divided into three groups: (1) Sham group (n = 12), rats underwent all the operation procedure except for the placement of orthodontic forces and received saline treatment; (2) experimental tooth movement (ETM) group (n = 12), rats received saline treatment and ETM; (3) DSS + ETM (DETM) group (n = 12), rats received DSS treatment and ETM. All DETM group animals were administered with DSS at a dose of 150 mg/kg. Morris water maze test was evaluated; immunofluorescent histochemistry was used to identify astrocytes activation, and immunofluorescent dendritic spine analysis was used to identify the dendritic spines morphological characteristics expression levels in hippocampus. RESULTS: Maze training sessions during the 5 successive days revealed that ETM significantly deficits in progressive learning in rats, DSS that was given from day 5 prior to ETM enhanced progressive learning. The ETM group rats took longer to cross target quadrant during the probe trial and got less times to cross-platform than DETM group. The spine density in hippocampus in ETM group was significantly decreased compared to the sham group. In addition, thin and mature spine density were decreased too. However, the DSS administration could reverse the dendritic shrinkage and increase the spine density compared to the ETM group. Astrocytes activation showed the opposite trend in hippocampus dentate gyrus (DG). CONCLUSIONS: Treatment with DSS could restore the impaired abilities on ETM-induced decrease of learning and memory behavior. The decreased spines density in the hippocampus and astrocytes activation in DG of hippocampus in the ETM group rats may be related with the decline of the ability of learning and memory. The ability to change the synaptic plasticity in hippocampus after DSS administration may be correlated with the alleviation of impairment of learn and memory after ETM treatment.

Enhancement of periodontal tissue regeneration by transplantation of osteoprotegerin-engineered periodontal ligament stem cells.

INTRODUCTION: The objective of the present study was to evaluate the capacity of a tissue-engineered complex of human osteoprotegerin (hOPG)-transfected periodontal ligament stem cells (PDLSCs) seeding on beta-tricalcium phosphate (ß-TCP) to regenerate alveolar bone defects in New Zealand rabbits. METHODS: PDLSCs were isolated from rabbit periodontal ligament tissues and expanded in vitro to enrich PDLSC numbers, and their proliferative activities and differentiation capability were evaluated under specific induction conditions. Lentiviral vector containing hOPG and enhanced green fluorescent protein (EGFP) was constructed by using Gateway technology and transfected into rabbit PDLSCs. The expression of hOPG was determined with quantitative real-time reverse transcription-polymerase chain reaction and Western blot. The PDLSCs with or without engineered hOPG were seeded on ß-TCP scaffolds prior to transplantation. Morphological characterization of cells and materials was done by scanning electron microscope. Twenty rabbits with alveolar bone defects were randomly allocated into four groups and transplanted with ß-TCP, PDLSCs/ß-TCP, and hOPG-transfected PDLSCs/ß-TCP or were left untreated as a control. Animals were sacrificed 12 weeks after operation for histological observation and histomorphometric analysis. RESULTS: PDLSCs expressed STRO-1 and vementin and favored osteogenesis and adipogenesis in conditioned media. Expressions of hOPG were significantly upregulated after transfection of the lentiviral vector into PDLSCs. PDLSCs attached and spread well on ß-TCP, and there was no significant difference in growth of PDLSCs on ß-TCP between the hOPG transfection group and the non-transfection group. The histological observation and histomorphometric analysis showed that the hOPG-transfected PDLSCs/ß-TCP complex exhibited an earlier mineralization and more bone formation inside the scaffold than control, ß-TCP, and PDLSCs/ß-TCP complexes. Implantation of hOPG-transfected PDLSCs contributed to new bone formation as determined by EGFP gene expression under circularly polarized light microscopy. CONCLUSIONS: The present study demonstrated the feasibility of ß-TCP scaffolds for primary PDLSC culture and expression of hOPG gene in vitro and in vivo, and hOPG-transfected PDLSCs could serve as a potential cell source for periodontal bone regeneration, which may shed light on the potential of systemic hOPG gene therapy in combination with PDLSC tissue engineering as a good candidate in periodontal tissue engineering for alveolar bone regeneration.

[Effect of the peri-implantitis on the biological function of osteoblasts obtained from the mandibles].

OBJECTIVE: To study the effect of peri-implantitis inflammatory microenvironment on the biological function of jaw bone osteoblasts. METHODS: Primary mandible osteoblasts from peri-implantitis and normal tissue were isolated and cultured. Third-generation purified osteoblasts were identified and detected. The proliferative activity of osteoblasts was evaluated through MTT assay. Osteocalcin (OCN), Runx2, and collagen I (Col I) mRNA levels were examined by real-time quantitative polymerase chain reaction. OCN protein levels were determined by Western blot. RESULTS: : After 4 d of culture, the proliferative activity of osteoblasts from peri-implantitis became lower than that of normal tissue ( P <0.05). After 7 d of culture, OCN, Runx2, and Col I mRNA expression decreased ( P <0.05). The OCN protein levels also decreased ( P <0.05). CONCLUSION: Peri-implantitis inflammatory microenvironment can decrease the proliferation and differentiation activity of mandible osteoblasts.

[The effect of different factors on forming-dentin differentiation of rat dental mesenchymal cells].

PURPOSE: To investigate the effects of combined use of bFGF, IGF1, BMP4 and TGF-ß1 on forming-dentin differentiation of rat dental mesenchymal cells (rDMCs). METHODS: Enzyme and differential digestions were performed to isolate and culture rDECs and rDMCs, and immunofluorescence staining against cytokeratin and vimentin were carried out to identify cell sources. Then alizarin red staining and Gomori calcium-cobalt method were used to detect the mineralization ability of rDMCs after mineralized induction. Immunohistochemistry, image analysis, real-time PCR and Western blot were utilized to determine the expression differences of DSPP/CAP/OPN/OCN in rDMCs after induction by bFGF+IGF1 (group 1), TGF-ß1+BMP4 (group 2) and bFGF+IGF1+TGF-ß1+BMP4 (group 3), respectively. Statistical analysis was performed with SPSS 14.0 software package. RESULTS: The rDECs and rDMCs were isolated, cultured and identified successfully. Calcium nodus and ALP staining were positive in cytoplasms of rDMCs after being induced by mineralization liquid. In groups 1 and 2, the expression levels of DSPP/CAP/OPN/OCN mRNA and protein were notably higher than those of control group, significant differences were found between groups (P<0.01). Among them, the expression levels of CAP/OCN in group 1 and DSPP/OPN in group 2 were the highest, respectively. CONCLUSIONS: The rDMCs possess osteogenesis property after mineralization induction. bFGF+IGF1 can notably promote the expressions of CAP/OCN, and accelerate rDMCs to differentiate into cementoblast and osteoblast, and the mineralization of cementum matrix and bone matrix. TGF-ß1+BMP4 can markedly increase the expressions of DSPP/OPN, and quicken rDMCs to differentiate into odontoblast and osteoblast, and the mineralization of dentinal matrix and bone matrix which display osteogenesis trend. Combined use of four factors had no significant synergism.

[Effect of high glucose on migration of BMSCs through inhibiting CXCR-4].

PURPOSE: To explore the effect of high glucose on migration of BMSCs through inhibiting CXCR-4. METHODS: Bone marrow stromal cells (BMSCs) were obtained from the mandible of Wistar rats and stimulated with different concentrations of glucose (5.5, 16.5 mmol/L). The optimum concentration of SDF-1 was evaluated by Transwell assay in physiological glucose concentration (5.5 mmol/L). In the optimum concentration of SDF-1 condition, we detected the effect of SDF-1 and AMD3100 on migration of BMSCs in different concentrations of glucose (5.5, 16.5 mmol/L). CXCR-4 protein levels were determined by Western blot. The mRNA expression of CXCR-4 and MMP-2 were tested by RT-PCR. SPSS 11.0 software package was used for statistical analysis. RESULTS: The optimum concentration of SDF-1 was 100 ng/mL. High glucose could inhibit the migration of BMSCs. In different concentrations of glucose, SDF-1 could promote the migration of BMSCs, but AMD3100 could inhibit this promotion. High glucose condition could inhibit the secretion of CXCR-4 and mRNA expression of CXCR-4 and MMP-2. CONCLUSIONS: High glucose inhibits migration of BMSCs by inhibiting CXCR-4 through SDF-1/CXCR-4 pathway.

[Effect of insulin on peroxiredoxin-6 in the osteogenic differentiation of rat's mandiular bone marrow stromal cells in high glucose].

PURPOSE: To explore the effect of insulin on the expression of peroxiredoxin-6 in osteogenic differentiation of rat's mandibular bone marrow stromal cells(rBMSCs) in high glucose. METHODS: Bone marrow stromal cells were obtained from the mandible of Wistar rats and stimulated in three glucose concentrations mineral medium(5.5 mmol/L, 25 mmol/L and 45 mmol/L) with or without insulin(10-5mol/L) for 1, 3, 7, 14, and 21 days. The expression of prohibitin was quantified via enzyme-linked immuno sorbent assays (ELISA). The mineralization nodules were assessed at day 21 by alizarine red staining. Statistical analysis was performed using SPSS 15.0 soft ware package. RESULTS: High glucose of 45 mmol/L inhibited mineralization of rBMSCs and insulin can improve the mineralization in high glucose. The expression of peroxiredoxin-6 in 45 mmol/L group decreased significantly compared with 5.5 mmol/L group and 25 mmol/L group. The expression of peroxiredoxin-6 in each group achieved maximum at day 21. Insulin (10-5 mol/L) increased the expression of peroxiredoxin-6 in 25 mmol/L group and 45 mmol/L group in osteogenic differentiation of rBMSCs. CONCLUSIONS: High glucose inhibits the expression of peroxiredoxin-6 in osteogenic differentiation of rBMSCs, while insulin upregulates the expression of peroxiredoxin-6 in rBMSCs. Peroxiredoxin-6 may play an important part in later stage in osteogenic differentiation of rBMSCs.

[Effects of glimepiride on proliferation, differentiation and mineralization of rat mandibular osteoblasts in hyperglycemia].

PURPOSE: To evaluate the effects of hyperglycemia and glimepiride on proliferation, differentiation and mineralization of rat mandibular osteoblasts to verify the hypothesis of dental implant administration. METHODS: Primary osteoblasts were isolated and cultured. Then the cells were placed in an osteogenic medium, containing 2 different concentrations of glucose (5.5 mmol/L and 16.5 mmol/L), with or without glimepiride (10 µmol/L). Cell proliferation was evaluated through MTT assay. Alkaline phosphatase (ALP) activity was determined by biochemistric method. Col I protein levels were determined by Western blot. OCN mRNA levels were tested by RT-PCR. SPSS 13.0 software package was used for statistical analysis. RESULTS: Hyperglycemic conditions interfered with the proliferation, ALP activity and OCN mRNA expression of rat osteoblasts, but improved the expression of Col I on day 14. Glimepiride stimulated rat osteoblast proliferation, ALP activity and OCN mRNA expression. The addition of glimepiride to normoglycemic (5.5 mmol/L) cultures registered a significant increase of Col I expression at 7 d and 14 d. Glimepiride significantly increased Col I expression in cells cultured with 16.5 mmol/L glucose for 7 days, but failed to increase at 14 d. CONCLUSIONS: Hyperglycemic conditions interfered with the proliferation, differentiation and mineralization of osteoblasts in rats; however, glimepiride improved the proliferation, differentiation and mineralization of osteoblasts in rats.