Objective To investigate the effects of ovariectomy on genioglossus（GG） electromyography and myofibre phenotype in female rats and to explore the proposal mechanisms underling ovarian hormone protecting to the patency of upper airway（UA）. Methods 30 female Sprague- Dawley rats were randomly assigned to three groups: normal group（NORMAL）, sham group（SHAM） and ovariectomized group（OVX）. Six weeks later, electromyography activity of the genioglossus（EMGgg）was obtained from inserted bipolar electrodes. The integrated EMG（iEMG）was analyed. Genioglossus was stained with ATPase staining. The fibre phenotype composition and cross sectional area （CSA）of type ⅡA and ⅡB/ⅡX fibres were measured. Results EMGgg had no significant variety between the normal and sham group（P>0.05）. Compared to normal group, iEMG was significantly decreased in OVX group（P<0.05）. GG myofibres were composed of Ⅱ phenotye, including Ⅱ A（40.27 ±1.01）% and Ⅱ B/Ⅱ X（59.73 ±1.01）%, fibres composition and CSA of types ⅡA and ⅡB/ⅡX had no significant variety between the normal and sham group. Compared to normal group, fibres composition had no significant variety in OVX group（P>0.05）, but the CSA of type ⅡA was significantly decreased（P<0.05）. Conclusion The decreased EMGgg of ovariectomized rat maybe relates to the decrease of CSA in type ⅡA fibre. Ovarian hormone may protect the patency of upper airway through affecting muscle function of UA dilator.

Objective To evaluate the biologic effects of simulating static magnetic field of magnetic attachment on human periodontal ligament fibroblasts（HPDLF）. Methods HPDLF were cultured in vitro and exposed to simulating static magnetic fields of magnetic attachments for 4 days with magnetic flux density of 12.5, 125 and 250 mT respectively, while the control group free of additional static magnetic field was also set up. The activities of cellular alkaline phosphatase（ALP） and superoxide dismutase（SOD）were measured with a spectrophotometer, and cell cycle was analyzed by flow cytometry. Results An increase were detected, induced by 250 mT static magnetic field exposure for 4 days in terms of activity of ALP in HPDLF, as compared with the control group（P<0.05）. However, no corresponding effects were found in activity measurements of SOD（P >0.05）. Also there were no statistical differences observed on cell cycle distribution（P >0.05） or cell proliferation index（P >0.05） under such static magnetic fields. Conclusion The static magnetic fields of magnetic attachment used in this study have improved the activity of ALP, and do little inference to the activity of SOD and the cell cycle distribution.

Objective To determine the biomechanical characteristics of mandibular fractures in different site. Methods Nine adult mandibular specimens were measured precisely. The data was used to establish a three - dimensional model. When mandibular was under functional loading, the bending and torsion moment as well as shear force of angle, body and symphyseal fracture was calculated. The data were analyzed by Origin 6.0 software. Results Angle fracture had relatively high positive bending moment and high shear force. Body fracture had positive as well as negative bending moment and the highest torsion moments. Symphyseal fracture had only negative bending moment and relatively low shear force. Conclusion Angle, body and symphyseal fractures each have a biomechanics characteristic. These biomechanics characteristic should have an important meaning in the treatment of mandibular fractures and instructing patient how to bite correctly.

Objective To investigate new bone formation of alveolar augmentation with recombinant human bone morphogenetic protein- 7（rhBMP- 7） expressed in prokaryocyte. Methods To create the model of rabbit extraction socket into which the composites of rhBMP- 7 and the gelatin sponge was immediately implanted, then the samples were investigated 2, 4, 8 and 12 weeks postoperatively by gross observation, scanning electron microscope（SEM）, quantitative measurement of calcium content and alkaline phosphatase（ALP） activity. Results There was significant difference in height of alveolar ridge absorpted between the experimental groups and the carrier control groups through gross observation. The result of SEM showed that bone healing in rhBMP- 7 groups was 4- 6 weeks earlier than that of control groups. ALP activity in rhBMP- 7 groups were obviously high compared with that of control groups. Conclusion The BMP- 7 has a satisfactory osteoinduction ability to promote new bone formation and prevent alveolar bone absorption.

Objective To observe the drug resistance and drug efflux pumps gene mRNA of Saccharomyces albicans, including CDR1 gene and MDR1 gene, at different stage of biofilm formation in chemostat, furthermore to analysis the relationship between the drug efflux pump gene expression and the biofilm related drug resistance. Methods To form the mature biofilm in vitro in chemostat, then collect the biofilm strains at different development stages（2, 12, 24, 48 h）to semi- quantified mRNA amount of CDR1 gene and MDR1 gene by one step RT- PCR method. Using XTT reduction method to test the dynamic change of Saccharomyces albicans drug resistance in biofilm. Results Antifungal resistance of biofilm- grown cells increased conjunction with the biofilm maturation. Compared with earth stage of biofiom strains, the amount of CDR1 mRNA gene in mature biofilm strains increased, while MDR1 gene did not. Conclusion There is positive correlation between drug resistance and biofilm maturation of Saccharomyces albicans. Biofilm related drug resistance appears to be partially associated with the upregulation of drug efflux pumps, although the variation is not shown coincidence. During the biofilm formation, CDR1 gene expression is actively up- regulated, but MDR1 gene expression is stable.

Objective To explore the multi - differentiated capability of human dental pulp stem cells（hDPSCs） obtained by cell - clone culture approach and to determine the appropriate induced medium. Methods The cloned isolation and expansion of hDPSCs were preinduced for 24 h, and were subsequently replaced with neural- inductive medium containing certain concentration of dimethylsulfoxide（DMSO）, butylated hydroxyanisode（BHA）, forskolin, β- mercaptoethanol（β-ME） and hydrocortisone for 4 days. Then induced cells were analyzed by morphological observation, immnocytochemical staining for non- specific esterase（NSE） and glial fibrillary acidic protein（GFAP） expression, RT- PCR for GFAP mRNA. Meanwhile, the uninduced hDPSCs were used as negative control. Results The morphology of induced cells changed at the initial 12 h, and displayed a typical neuron- like cells at 24 h. There was a gradual increase in the number of these neuronal differentiated cells with continuous induction. Furthermore, immnocytochemical staining showed that the induced cell expressed NSE and GFAP, two marked enzymes of neuron cell. The GFAP mRNA was also detected in induced cells by RT- PCR assay. In contrast, the uninduced cells maintained its original appearance and had no expression on them. Conclusion hDPSCs may possess potential of multiple- differentiation and may differentiate into neuron- like cells on certain inductive condition.

Objective To investigate the effects of transforming growth factor- β1（TGF- β1） gene therapy on bone defect and bone rarefaction around endosseous implant. Methods The primary cultured bone marrow derived stroma cells（BMSCs）was transfected by plasmid pCDNA3.1（+）- TGF- β1, and was adhered with polylactic- co- glycolic acid （PLGA） for constructing TGF- β1 gene- modified artificial bone. The model of rats with placed titanium implants in the proximal metaphyses of the tibiae after ovariectomy was made. The TGF- β1 gene- modified artificial bone（experimental group）, BMSCs- PLGA compound artificial bone（control group） and nothing（blank control group）were placed in the bone defect around implant. The tibiae were examined by decalcified sections with immunohistochemical method and histological analysis methods at intervals of 4 and 8 weeks after implant surgery in order to detect the expression of TGF- β1 in new bone adjacent to the implant and the healing of the bone defect around the implant. Results The expression level of TGF- β1 of experimental group was higher than that of control group and blank control group at the 4th week. The histological analysis indicated that the gene- modified artificial bone had stronger osetogenic potential than others. Conclusion TGF- β1 gene- modified artificial bone promotes the repair of the bone defect around titanium implants in osteoporotic rats.

Objective To investigate the effects of Porphyromonas gingivalis（P.gingivalis） lipopolysaccharide（LPS） on collagen phagocytosis of human periodontal ligament fibroblasts（hPDLF）. Methods Fluorescence localization and flow cytometry was used to test the collagen phygocytosis of hPDLF stimulated by the various concentration of LPS for 48 hours in vitro. Results The collagen phygocytosis of hPDLF was increased significantly by 0.1 μg/mL LPS （P <0.05）. Conclusion This study indicates that P.gingivalis LPS may enhance the degradation of collagen by stimulating the phagocytic activity of the hPDLF in periodontitis.

Objective To evaluate the feasibility of employing metabonomics method in identification of oral pathogenic bacteria. Methods The Streptococcus mutans ATCC25175 and Actinomyces viscosus ATCC15987 were respectively inoculated in same certain culture medium. The growth curves of the inoculated bacteria were drown by turbidimetry. The culture solutions in four different growth phases of the both bacteria were used to test with the 1H- Nuclear magnetic resonance（1H-NMR） spectroscopy respectively. The data of 1H-NMR spectroscopy results were analyzed by principal components analysis（PCA）. Results The PCA showed the obvious clustering phenomena and the points of two group data stayed differentially together by two clusters. Therefore, the NMR - based metabonomics profiles can discriminate the two different kind of bacteria. Conclusion The metabonomics can be expected to be a kind of promising useful method in quick discrimination of oral pathogenic bacteria.

Objective To analyze the stress and displacement distribution of 3D- FE models in three conjunctive methods of vascularized iliac bone graft for established mandibular body defects. Methods Using computer image process technique, a series of spiral CT images were put into Ansys preprocess programe to establish three 3D- FE models of different conjunctions. Results The three 3D- FE models of established mandibular body defects by vascularized iliac bone graft were built up. The distribution of Von Mises stress and displacement around mandibular segment, grafted ilium, plates and screws was obtained. Conclusion It may be determined successfully that the optimal conjunctive shape be the on- lay conjunction.

Objective To investigate the imagery changes of the upper airway and the surrounding soft tissues of local adults with non- apnea who used snore guard and to provide experimental data for the clinical diagnosis and treatment of obstructive sleep apnea syndrome（OSAS）. Methods Thirty students with non- apnea from Hebei medical university were chosen, and magnetic resonance imaging（MRI） was used to measure the changes of the upper airway and the surrounding soft tissues after snore guards were used. SPSS 10.5 software was used to analyze statistically. Results After the snore guard was put into oral cavity, the change of the average section and volume of the nasopharynx, the palatopharynx, the hypopharynx and the glossopharynx were statistically significant. The average sagittal size, the average horizontal size of the nasopharynx, the palatopharynx, the hypopharynx and the glossopharynx were increased statistically. The ratio of sagittal size, the horizontal size in the hypopharynx and the glossopharynx changed statistically important. There was a decrease of the soft palate, the shape, the height, and the length of the tongue, the difference was statistically significant. The results demonstrated that snore guard affected the upper airway mainly by changing the volume and the shape of the upper airway, there was an obvious increase of the pharynx. The results also showed that snore guard could increase the width（both sagittal and horizontal） of the upper airway and could change the shape of the surrounding soft tissues, which caused air way more smooth. Snore guard could make the indexes of soft palate and tongue change decreasingly, resulted in the straight stand up of the tongue and the forwardness of the soft palate. Conclusion Snore guard is an effective and convenient instrument for treating the patients with OSAS.

Objective To investigate the influence of repeated sintering on the color of two porcelain- fused- totitanium, and the differences between the two porcelains. Methods Thirty samples were prepared and sintered for 9 times. The color of samples were measured following sintering 1, 3, 5, 7, 9 times by ShadeEye NCC colorim eter according to two brands of porcelains with CIE1976L*a*b* color system, and calculated relevant chrome, chromatism and hue, and statistical analysis. Results When two brands of porcelains were sintered 5 times, the color parameters had no significant change and sintered continuely, the color parameters of L* and a* had obvious changes, but can′t be observed by eyes. Conclusion The color parameters of titanium- porcelains have no significant change after repeated sintering.

Objective To determine the jaw bone stress variation affected by cylinder implant diameter and length simultaneously in Ansys DesignXplorer module. Methods Finite element model of segment mandible with a cylinder implant was created. The range of the implant diameter（D） and length（L） were set from 2.5 mm to 5.0 mm and from 6.0 mm to 16.0 mm respectively. The maximum Von Mises stresses in jaw bone and sensitivity to D and L were evaluated. Results Under axial（buccolingual） load, when one variable equaled to median, the amplification of maximum Von Mises stresses in cortical bone and cancellous bone were 44.66%（71.32%） and 51.45%（58.50%） respectively with the D increasing. The amplification of maximum Von Mises stresses in cortical bone and cancellous bone were 45.97%（21.66%） and 52.15%（37.75%）  espectively with the L increasing. When D exceeded 3.7 mm and L exceeded 10.0 mm, the response curve curvatures of maximum Von Mises stresses to L and D in jaw bone ranged from - 1 to 0. And the variation of the maximum Von Mises stresses in jaw bone was more sensitive to D than to L. Conclusion Stresses in jaw bone under buccolingual and axial load are apt to be affected by implant diameter and length respectively. And to a cylinder implant, the diameter exceeds 3.7 mm and length exceeds 10.0 mm are optimal selections. Diameter should pay more attention to than to length for cylinder implant. Expanding the width of the jaw bone is more important than expanding the height of the jaw bone in clinical experience.

Objective To evaluate the relationship between children′s temperament and dental fear. Methods 254 children( aged 4- 6 years) during first dental treatment took part in the investigation. Their parents answered the Chinese preschool children′s temperament scales( CPTS) . The Frankl method was used to classify the degree of the children′s dental fear. The K independent samples test and One - way ANOVA test were performed to find the differences of the type of temperament and the scores of temperament dimension among three groups. Results Among the 254 children( aged 4- 6 years) , 104 had no fear, 80 had fear and 70 had extreme fear. The incidence of dental fear in children was 59.06%. There were no statistical differences( P>0.05) of dental fear between boys and girls. There were statistically significant differences for the type of temperament among no fear group, fear group and extreme fear group. The scores of adaptability and quality of mood were higher in the extreme fear group and fear group than that in the no fear group. The differences in scores of adaptability and quality of mood was statistically significant between the extreme fear group and no fear group. But the scores of other seven temperament dimensions had no statistical significant differences among three groups. Conclusion Children′s dental fear is correlated to their temperaments. The tendencies of negative mood and slow adaptability should be considered that the patients were at risk of developing dental fear problem.

Objective To evaluate the sedative effect of continuous intravenous infusion of midazolam in treating severe dental phobia. Methods 31 patients with severe dental phobia were enrolled and all of them had good communication with dentists. Two teeth in each patient were assigned to control group and experiment group seperately. The control group received root canal therapy. The experiment group were sedated by intravenous midazolam and received root canal therapy. The treat dependence and behavior therapy efficacy were evaluated. The vital signs and side effects during treatment were noted. Results Continuous intravenous infusion of midazolam showed a significant good sedative effect on patients with severe dental phobia. There were statistical difference in the Houpt score and the Frankl score between experiment group and control group（z=- 4.846, P=0.000；z=- 4.907, P=0.000）. The total dose of midazolam was（9.58±3.76）mg, and mean infusion rate was（0.28±0.06）mg·kg- 1·h- 1. The blood pressure, heart rate and respiration of experiment group were depressed. But these changes didn′t interfere with the completion of the whole treatment. No severe side effects were detected. Conclusion The single use of midazolam as an intravenous sedation agent has satisfactory effect on patients with severe dental phobia.

Objective To explore the treatment plan in patients with congenital lower incisor missing. Methods Thirty- six patients with congenital lower incisor missing were included in the investigation. The missing location, missing quantity, malocclusion type and treatment method were analyzed. Bolton index of two groups were analyzed. The first group was congenital missing one lower incisor who treated by extracting two upper first premolars and one lower first premolar. The second group was congenital missing two lower incisors who treated by exacting two upper first premolars. Results The therapeutic effect of 36 cases were better. Overall ratio in two groups were 91.70%± 1.85% and 92.83%±2.74%, anterior ratio were 81.69%±2.12% and 85.46%±2.39%, anterior tooth- size discrepancy were（2.16±0.64）mm and（4.27±1.14）mm. There were no significance difference on overall ratio in two groups（P>0.05）. There were significance difference in anterior ratio and anterior tooth- size discrepancy（P<0.01）. Conclusion For patients with congenital missing one lower incisor who need extraction in upper and lower jaws, it is less affection on Bolton index that extracting one premolar at non- missing side than extracting one center incisor in mandibe.

Objective To measure the frictions between FAS bracket and stainless steel wire under different two conditions, and compare two traditional self- ligating brackets. Methods FAS bracket was a new- style self - ligating bracket with a friction adjusting system（FAS） to adjust the friction as the wires slide in the bracket. Firstly, FAS bracket 20 times of original size was made, then the frictions were measured respectively made by the steel round wires of diameters 8.128 0 mm or the steel square wires in size of 9.144 0 mm×12.700 0 mm. It was divided into two adjusting states, and used the same method to measure DamonⅢ and SPEED bracket in 20 times of original size. Results With the shim entirely drew in, all the frictions of the arch wire had no significant difference with the DamonⅢ. When 8.128 0 mm stainless steel round wire was used, SPEED bracket had no significant difference with FAS. When 9.144 0 mm×12.700 0 mm square wire was used, they had significant difference（P<0.05）. On turning half a circle, all the frictions of the arch wire had significant difference with two tradition bracket（P<0.01）. Conclusion The new- style FAS bracket can adjust the friction efficiently. Under no pressure state, the friction force is similar to DamonⅢ. Under pressure state, FAS bracket locks the wires, and provides the sliding of wires.

Objective To study the method of decreasing dental anxiety（DA） on root canal treatment. Methods 360 patients were divided into group A, group B and group C. Parol and written notice about the content of root canal treatment were given to the patients of group A, written notice and psychological communication to group B, written notice, psychological communication and local anesthesia to group C. The change of DA level were measured in patients of three groups during treatment period. The patient′s fear degree were evaluated by means of visual analogue scale（VAS）. The data before and after root canal treatment were analyzed. Results The level of DA decreased along with the increasing of treatment frequency. The decreasing of group C was most obviously, next to group B. There were statistical difference before and after root canal preparation in the DA of same group（P<0.01）. There were statistical difference in DA and VAS among group A, B and C（P <0.05）. Conclusion Psychological communication and anesthesia can obviously decrease dental anxiety level on root canal treatment.

Objective To detect the differentially expressed genes in oral lichen planus（OLP） by cDNA microarray. Methods The PCR products of 4 000 genes were spotted on chemical material coated glass plates in array. The total RNAs were isolated from OLP and normal oral mucosa tissue and were purified to mRNA. Both the mRNA were reversely transcribed to cDNA with the incorporations of fluorescent dUTP, for preparing the hybridization probes. The mixed probes were then hybridized to the cDNA microarray. Microarray was scanned for the fluorescent signals and showed the differences between the two samples. Results The expressions of 122 genes were up regulated while the expressions of 91 genes were down regulated in OLP among the 4 000 target genes. The up- regulated genes were mainly the ones of immunity related genes, metabolize related genes, oncogene, cytokine and cell signal transduction protein. The down- regulated genes were mainly the ones of DNA binding and transcription factors, cell signal transduction protein, immunity related genes, metabolize related genes, and cytokine. Conclusion Two hundred and thirteen differentially expressed genes with different functions were revealed in OLP, which may play some roles in the progression of OLP.

Objective To investigate the relationship between wedge - shaped defects and occlusal interference. Methods Following examination from 46 patients, a total of 157 teeth were identified to have the criteria set for wedge- shaped defects and regarded as the experiment group. Also, 157 adjacent teeth exhibiting no such noncarious cervical lesions were randomly selected from the same group of patients and regarded as the control group. The distribution of occlusal force and time were examined with T- ScanⅡ system in 46 patients with wedge- shaped defects in intercuspal occlusion position, protrusive movement and lateral movement. Occlusal interference and premature contact were evaluated and compared between the two groups. Results The proportion of the teeth with premature contact in experiment group was 6.37%, while the control group was 2.55%, there was no significant difference between the two groups（P>0.05）. The total proportion with occlusal interferences in experiment group was 23.57%, which was significantly higher than that of the control group（10.19%, P<0.05）, in experiment group the proportion with working side interferences was 15.92%, and in control group, the proportion was 3.82%, there was significant difference between the two groups（P<0.01）. At the same time, the teeth with occlusal interferences had more serious degree of the wedge- shape defects than those with no occlusal interference. Conclusion The increased occlusal force has relation to the formation as well as severity of wedge- shaped defects.

Objective To compare the shaping ability of rotary ProTaper and Flexofile in simulated resin root canals. Methods Forty simulated resin root canals were randomly assigned to two groups, one group for rotaryProTaper with crown- down technique and the other for Flexofile with balanced force technique. Change of working length and incidence of canal aberration and instruments failure were recorded. After preparation, the change of root canal curvature and the amount of resin removed at the inner and outer canal walls were measured with Image Pro Plus 5.0. The centring ability and total amount of resin removed were also assessed. Results In the model of simulated resin canals, ProTaper instruments maintained working length better. Canals prepared with ProTaper instruments remained better curvature and showed fewer aberration compared with those prepared with Flexofile（P<0.01）. ProTaper instruments performed a better centring ability. Conclusion ProTaper instruments have a better shaping ability in simulated resin root canals.

Objective To discuss the diagnose and treatment of puerile cases with serious cellulitis of floor of mouth. Methods The data of 12 cases with serious cellulitis of floor of mouth were retrospectively analyzed. Results 12 cases with serious cellulitis of floor of mouth were all cured by systemic anti- infection and topical incision and drainage. Conclusion The key to treat serious cellulitis of floor of mouth is systemic anti- infection and topical incision and drainage.

Objective To study the expression of chemokine receptor 4（CXCR4） protein and mRNA in oral squamous cell carcinoma（OSCC） and to evaluate the relationship between the expression of CXCR4 protein and the clinicopathology factors, and lymph node metastasis of OSCC. Methods The expression of CXCR4 protein in 64 cases of OSCC was examined by immunohistochemical technique（SABC）, and the expression CXCR4 mRNA in 40 cases of OSCC studied by in situ hybridization, and its relation to cliniopathological parameter was also analyzed. Results CXCR4 mRNA and CXCR4 were positively expressed in OSCC, and the positive expression rate of CXCR4 protein was 62.5%（40/64）. CXCR4 expression was significantly higher in the patients with lymph node metastasis than those without lymph node metastasis（P=0.014 4）, and was also correlated with tumor histological type（P=0.004 2）, depth of invasion（P =0.002 3）and TNM stage（P =0.001 2）, but not with age at surgery, gender and tumor size. Conclusion CXCR4 is highly expressed in OSCC, and its expression is associated with the diverse progression of OSCC, including invasion and lymph node metastasis.

Objective To observe effects of fluid shear stress strength on mRNA expression of ATP6V1a1 in rat polarized osteoclasts. Methods Rat polarized osteoclasts suffered 0.0（control group）, 0.9, 2.9, 8.7 and 26.3 dynes/cm2 fluid shear stress for 30 min. mRNA expression of ATP6V1a1 was detected by Real - Time fluorescent quantitation PCR. Results mRNA expression of ATP6V1a1 in 0.0（control group）, 0.9，2.9，8.7 and 26.3 dynes/cm2 groups was （1.14±0.06）×106, （1.62±0.09）×106, （2.28±0.13）×106, （3.24±0.18）×106, （9.16±0.53）×106 copy numbers, respectively （P<0.05）. Conclusion In the present study, polarized osteoclasts are sensitive to fluid shear stress. mRNA expression of ATP6V1a1 has increscent tendency along with increasing of fluid shear stress strength.

Objective To study the effects of adramycin to disturb telomeric extention reaction mediated by telomerase of Tca8113 cells by inducing oligonucleotides that contain telomeric repeats to form guanine- quadruplex （G4） structures. Methods In the presence of adriamycin, d（TTAGGG）4, d（TTAGAG）4, d（TTAGGG）5 and d（TTAGGGT） were analyzed by electrophoretic mobility shift assay. The mobility of d（TTAGGG）3, d（TTAGGG）4 and d（TTAGGG）5 in native polyacrylamide electrophoresis were observed. Methylation protection experiments were performed to investigate the effects of adriamycin on methylation of guanine in d（TTAGGG）4 and d（TTAGAG）4. The traditional telomeric repeats amplification protocol（TRAP） and modified TRAP- G4 assays were, respectively, used to analyze the different characteristcs of adriamycin′s inhibiting telomeric extension mediated by telomerase of Tca8113 cells. Results At 5.00 μg/mL of adriamycin, conversion of some of linear d（TTAGGG）4 and d（TTAGGG）5 to the new, high-mobility bands formed by complex with special second structures were found in the mobility shift assay. Adriamycin at 1.25 μg/mL protected the G in d（TTAGGG）4 from methylating. Adriamycin at 2.50 μg/mL or 1.25 μg/mL partially inhibited the telomeric extension lengthened by telomerase of Tca8113 cells in TRAP assay, but completely did so in TRAP - G4 assay. Conclusion Adriamycin is able to disturb telomeric extention mediated by telomerase of Tca8113 cells by inducing oligonucleotides that contain telomeric repeats to form intra- molecular G4 structures.

Objective To improve tooth pulp electrical stimulation rat model to study analgesic effect of drugs. Methods Expose lower mandible and incisor and isolate them with rubber dam, two holes with distance 1.5 mm were drilled below the cemento- enamel junction by a thin diamond bur in 22 adult male rats anesthetized with sodium pentobarbital. A pair of insulated stainless stimulating electrodes were inserted through the holes and knotted to fix them. Drilled holes were filled with zinc polycarboxylate cement. Finally, the stimulating electrodes were directed to the top of the skull. Pain threshold of rats was determined by an electrical stimulator under awake, free conditions to evaluate the stability of the model and the analgesic effect of drugs. Results A valid tooth pulp pain model were set up successfully in 22 rats. Rats regain consciousness at 1 to 2 hours after operation. The inserted electrodes keep efficiency for 6 weeks. Neither tissue morphology change nor inflammation cell infiltration can be found in tooth pulp after 6 weeks under the light microscope. Threshold voltages remained constant under the repeat electric stimulations within 300 min（P>0.05，CV<15%） until 4 weeks（P>0.05，CV<15%）. The dose- dependent and time- dependent analgesic effects of capsaicin were showed in this model. Conclusion The improved tooth pulp electrical stimulation rat model is easily performed and shows constant electrical stimulation- induced pain threshold and is suitable for research on analgesic effect of drugs.

Objective To study the effect of platelet - rich plasma（PRP） and latissimus dorsi myofascia with blood vessel on vascularization of tissue engineered bone in dogs. Methods Bone marrow stromal cells（BMSCs） were isolated from iliac bone of dogs. PRP was obtained from the same dog. And demineralized bone matrix（DBM） were prepared from homologuous bone. ABCD 4 areas were divided on the back of dog. PRP/BMSCs/DBM was implanted around the vessels of lattisimus dorsi muscle in the A. PRP/BMSCs/DBM wrapped by superficial fascia in the B. BMSCs/DBM was implanted around vessels of lattisimus dorsi muscle in the C. BMSCs/DBM wrapped by superficial fascia in the D area of the same dog. 4, 8, 12 weeks after implantation, gross specimen and histology examination were made. Results Osteogenesis and blood vessel formation results were A>B>C>D area. Conclusion The results suggested that the PRP and latissimus dorsi myofascia with blood vessels could promote calcification and vascularization in tissue- engineered bone.

Objective To study the change of Ca2+ density in cultured osteoclast- like cells in response to fluid shear stress. Methods Laser scanning confocal microscope and fluorescent probe were used to detect the free Ca2+ in osteoclast- like cells before and after undergoing fluid shear stress. The images were analyzed and compared with image software. Results At 37 ℃ the free Ca2+ in osteoclast- like cells could be labelled effectively with 10 μmol/L Fluo- 3/AM. Compared with contol group, the average intensity of Ca2+ fluorescent signal in osteoclast- like cells undergoing fluid shear stress increased significantly. Conclusion The Ca2+ concentration in bone- marrow derived osteoclast- like cells is sensitive to fluid shear stress, which suggests osteoclast - like cells modulate their function in response to fluid shear stress through the change of free Ca2+ concentration.

3 root canals were found when a left lower first premolar, which preoperative radiograph showing root canal variety, was treated and were verified by postoperative radiograph. The root canal variety of lower premolars should be paied more attention to prevent root canal from losing.

A male patient of 26 years old was received with multiple fracture by tranffic accident. Anesthesia was maintained with inhalation of isoflurance. Malignant hyperthermia（MH）was appeared after operation. The patient rehabilited after physical cooling, bedside persistence hematodialysis, hormone application and so on.