Tooth or dentition missing compromises human health physically and psychiatrically. Although several prosthesis methods are used to restore tooth loss, these restorations are still non- biological methods. It is a dream for human being to regenerate a real tooth for hundreds years. There are two ways to regenerate the tooth. One is application of conventional tissue engineering techniques including seed cells and scaffold. The other is regeneration tooth using dental epithelium and dental mesenchymal cells based on the knowledge of tooth initiation and development. Marked progress has been achieved in these two ways, while there is still a long way to go. Recently a new concept has been proposed for regeneration of a biological tooth root based on tooth- related stem cells and tissue engineering technique. A biological tooth root has been regenerated in swine. It may be a valuable method for restoration of tooth loss before successful whole tooth regeneration. A latest research showed that a subpopulation in bone marrow cells can give rise to ameloblast- like cells when mixed with embryonic epithelium and reassociation with integrated mesenchyme, which may provide a new seed cell source for tooth regeneration.

Objective To investigate the effects of basic fibroblast growth factor（bFGF） on the proliferation of human salivary adenoid cystic carcinoma（ACC）cell line ACC- 2 in vitro. Methods The effect of ectogenic bFGF on proliferation of ACC- 2 was observed by MTT assay. Extracellular signal- regulated kinase（ERK）activity was measured by immuno- precipitation. p- ERK1/2, Cyclin D1 and p21waf/cip1 expression were assessed by Western blot. Results bFGF could enhance the proliferation of ACC- 2. Stimulated by bFGF, the proliferation ratio increased significantly. The intracellular ERK activity, p- ERK1/2 and Cyclin D1 expression were increased, while p21waf/cip1 expression was inhibited by different concentrations of bFGF. The above effects of bFGF could be attenuated by MEK inhibitor U0126. Conclusion bFGF stimulates the proliferation of ACC- 2 in a dose dependent manner. The proliferation effect of bFGF may be due to up- regulating ERK, Cyclin D1 and p21waf/cip1 signaling pathway. This research can help us to explore a new pathogenesis and therapy of the ACC.

Objective The purpose of this study was to establish the computer - assisted Delaire cephalometric analysis system with WinCeph8.0 in order to simplify the procedure of manual Delaire cephalometric analysis. Methods On the basis of the theory of Delaire cephalometric analysis and the program module of WinCeph8.0, the landmark points and the auxiliary line were defined, the measurement and analysis program were written, then the computer- assisted Delaire cephalometric analysis system was established. Paired t- test and dispersion analysis of the computer - assisted and manual measurements were taken. Results Computer - assisted Delaire cephalometric analysis system was convenient and accurate to trace the landmark points and the auxiliary line. It was able to proceed the measurement and calculation automatically and display the analysis results. Statistical analysis showed that computerassisted analysis was more accurate than manual analysis. Conclusion This study provided a convenient, simplified, accurate computer- assisted analysis platform for Delaire cephalometric analysis which facilitated its clinical application.

Objective To evaluate the effect of Zinc oxide- eugenol cement and Gluma desensitizer on the sheer bond strength of three kinds of dentin bonding agents. The three dentin bonding agents were Zinc phosphate cement, Glass ionomer cement and Super - Bond C&B. To find the theory depending for the using of different protective methods and the selecting of different kinds of dentin bonding agents in prepared abutment teeth. Methods The buccal surfaces of ninety freshly extracted human premolars were flattened to expose an adequate area of lower dentin. Followed by wet- grinding on a series of silicon carbide paper from number 320, 400, 600 grit to produce the dentin bonding surface. The teeth roots were embedded in self- curing resin with the crown out of the resin. The embedded ninety teeth were divided randomly into three groups. The group A was control and the dentin surfaces were not treated. The group B was covered with a paste of Zinc oxide- eugenol cement. The group C was covered with Gluma desensitizer. Calculating the sheer strength between three bonding agents and dentin after the two treatments of dentin surface. The results were statistically assessed with SPSS software. Dentin surfaces were observed with scanning electron microscope（SEM）. Results The sheer bond strengths of Zinc phosphate cement had significant decrease （P<0.05）, especially the C1 group. The sheer bond strengths of Glass ionomer cement and Super- Bond C&B had no significant difference. Conclusion Zinc oxide- eugenol cement and Gluma desensitizer could reduce the sheer bond strength of Zinc phosphate cement with dentin surface. Zinc oxide- eugenol cement and the Gluma desensitizer could not effect Glass ionomer cement and the Super- Bond C&B with dentin.

Objective To study the microstructue of acellular dermal matrix（ADM） and the attachment and proliferation of MG63 osteoblast - like cells on the membrane. Methods ADM was experimental group and expanded polytetrafluoroethylene（e- PTFE） membrane was control group. Light microscope and scanning electronic microscope （SEM）were used to observe the microstructure of the two kinds of membrane. MG63 osteoblast- like cells were cultured on the two kinds of membrane and the blank group. The cell viability was checked by cell viability analyzer （CVA） and alkaline phosphatase（ALP） activity was detected by ELISA. SEM was used to observe the adhesion and proliferation of the MG63 osteoblast- like cells on the two kinds of membrane. Results The ADM was composed of the tissular side and basal lamina side. The tissue side showed scale- shaped structure and the basal lamina side demonstrated many digitations and some pores of folliculus pili. The e- PTFE showed many tiny lined cracks in elliptic structure. The viability of the MG63 osteoblast- like cells on the two kinds of membranes and ALP measurement showed that there was no significant difference between each of the two membrane groups and the blank. The adhesion and proliferation of osteoblast- like cells on the two kinks of membranes were both well. Conclusion ADM has no negative effects on the growth of osteoblast - like cells. ADM is biocompatibile and its microstructure is appropriate for guided bone regeneration materials.

Objective A novel biological piezoelectric ceramic was made by beta- tricalcium phosphate（β- TCP） and lithium sodium potassium niobate（LNK） piezoelectric ceramics. To study its biocompatibility to osteoblast isolated from the cranium of 1- day- old Sprague- Dawley mice. Methods The biological piezoelectric ceramic TCPLNK1/10, TCPLNK5/5 respectively mixed by β- TCP and LNK piezoelectric ceramic at the ratio of 1/10 and 5/5. Then osteoblasts were used and seeded respectively on the negative and positive surfaces of TCPLNK1/10 and TCPLNK5/5. Growth and proliferation of the osteoblasts on TCPLNK1/10 and TCPLNK5/5 surfaces were evaluated in vitro by means of scanning electron microscopy（SEM）examination, fluorescence dyeing of osteoblast skeleton protein and MTT assay. Results Cell morphology of osteoblast on positive and negative surfaces of TCPLNK1/10 and TCPLNK5/5 was normal, and both adhesion and growth characteristics showed better than control group. The growing osteoblasts on the TCPLNK1/10 negative surface were significantly higher than others. The negative surface of TCPLNK1/10 possessed better osteogenesis potential than others in vitro. Conclusion The surface of TCPLNK may permit the imitation piezoelectric effect of natural bone for bone regeneration.

Objective To evaluate the chemical composition of the modified surface of fluoride ion - implanted titanium and assess the effect on the formation of focal adhesion plaque in vitro. Methods Pure commercial titanium discs were treated with fluoride ion implantation by plasma immersion ion implantation technique（PIII） and chemical composition and value of the surface modification layer were characterized by X- ray photoelectron spectrometer（XPS）. In order to investigate the formation of focal adhesion plaque, MG- 63 cells were seeded onto the surfaces of the modified Ti discs and quantified by morphometric analysis using an immunofluorescence microscope. Results The full range XPS spectra and fitting results indicated that the surface of fluoride ion- implanted titanium was the mixture of titanium dioxide and titanium trifluoride. Meanwhile, the quantity of focal adhesion plaque on fluoride ion- implanted titanium was more than that on the non- implanted titanium after 6 hours′cell culture. Conclusion The XPS data revealed that the modified surface layer of fluoride ion- implanted titanium contained titanium dioxide and titanium trifluoride, which could enhance the formation of focal adhesion plaque.

Objective To investigate the method of the three - dimensional reconstruction of temporomandibular joint（TMJ） on the basis of CT and MRI medical image fusion technology, which establishes good foundation for a series biomechanical studies and clinical analysis. Methods The geometric data for the TMJ model were obtained from a young and healthy male volunteer. Twelve spherical markers were located on the regions of both TMJ and mental tubercles, where CT and MRI scans can reach. The three- dimensional geometric of the hard and soft tissues of TMJ was reconstructed by CT and MRI scans data, which was based on the registration procedures of spherical markers located on the face of the volunteer. Results The three- dimensional geometric model of TMJ was obtained, including hibateral articular disc, mandible, glenoid fossa and inferior teeth, and it had better geometric similarity. The results showed that the methods of three- dimensional reconstruction of TMJ with CT and MRI medical image fusion technology can be operated easily and promptly. The constructed model had good morphology. Conclusion It is feasible to construct the three - dimensional model of TMJ on the basis of the registration procedures of spherical markers and CT-MRI medical image fusion technology. It has the advantage of simulating both hard and soft tissues reasonably. The model well expresses the shape of the TMJ.

Objective To develop a method to construct a three- dimensional finite element model of the dentulous mandibular body of a normal person. Methods A series of pictures with the interval of 0.1 mm were taken by CT scanning. After extracting the coordinates of key points of some pictures by the procedure, we used a C program to process the useful data, and constructed a platform of the three- dimensional finite element model of the dentulous  mandibular body with the Ansys software for finite element analysis. Results The experimental results showed that the platform of the three- dimensional finite element model of the dentulous mandibular body was more accurate and applicable. The exact three- dimensional shape of model was well constructed, and each part of this model, such as one single tooth, can be deleted, which can be used to emulate various tooth- loss clinical cases. Conclusion The three- dimensional finite element model is constructed with life- like shapes of dental cusps. Each part of this model can be easily removed. In conclusion, this experiment provides a good platform of biomechanical analysis on various tooth- loss clinical cases.

Objective Porphyromonas gingivalis（P. gingivalis）is considered to be major putative periodontal pathogens. The purpose of the study was to evaluate P. gingivalis and clinical effects of scaling and root planning（SRP） in 20 subjects after 3 months. Methods Twenty periodontitis patients were selected. The mean age was（44.33 ± 13.86） years old. Clinical assessments of probing depth（PD）, clinical attachment loss（CAL） and bleeding on probing （BOP）were made prior to SRP and at 3 months post- therapy. Subgingival plaque samples were taken at each visit and analyzed using TaqMan real - time polymerase chain reaction for the presence and levels of P. gingivalis. The quantification for P. gingivalis was also performed with the help of the species- specific primers/probes and the serial dilution of the plasmid standards. Results Mean probing depth, mean clinical attachment loss and bleeding on probing showed sig- nificant reduction at 3 months（P<0.001）. The prevalence and level of P. gingivalis were significantly reduced after SRP（P<0.001）. A positive correlation was found between the numbers of P. gingivalis and PD at baseline（P<0.001）. There were no correlation between the initial level of P. gingivalis at baseline and the clinical improvement after therapy. But the number of P. gingivalis at responding sites was more decreased than non- responding sites after SRP（P <0.05）. Conclusion SRP produced a good clinical improvement. The prevalence and level of P. gingivalis were significantly reduced after SRP. The effect of SRP may be determined by the degree of P. gingivalis decreased. The real- time polymerase chain reaction can be used to evaluate the effect of periodontal therapy.

Objective To study the properties of orthodontic rectangular arch wires in torsion. Methods By using the torsion measurement apparatus, torsion moments and angles of four kinds of orthodontic wires（0.46mm×0.63mm and 0.48 mm×0.63 mm stainless steel wires, and the same size nickel- titanium wires）were tested respectively in a 0.56 mm- slot first maxillary incisor bracket. According to the torsion moments and angles, scatter graphs were drawn to fit the load- deflection curves of four kinds of wires and their linear equations were calculated. According to the equations, the torsion stiffness and the play angles of the wires at 20 N·mm correspondingly were calculated. Results The torsion stiffness of four kinds of wires were 4.909, 6.417, 1.325 and 1.363 N·mm/°, the torsion angles of different wires were 19.14°, 15.33°, 36.83°and 35.07°at 20 N·mm respectively. Conclusion The torsion stiffness of stainless steel wires was bigger than that of the same cross- section dimensional nickel- titanium wires. The difference of torsion stiffness between two dimensional nickel- titanium wires is smaller, while the difference of torsion stiffness between two stainless steel wires is larger.

Objective The aim of the study was to establish a cephalometric normal standard value for Korean in Yanbian China by means of Steiner analysis. Methods 72 cases of Korean adults in Yanbian with normal occlusion were selected, standard lateral cranial X- ray films were taken and cephalometric Steiner analysis was performed. The data was compared with Korean in Soul of Republic of Korea with normal occlusion. Results 1）Cephalometric Steiner normal standard values, standard deviation and Cheveron analysis chart were established. 2）1- NB angle of male was significantly bigger than that of female, while GoGn- SN angle of female was significantly bigger than that of male（P<0.05）, respectively. 3）There were significant differences on SNA, SNB, ANB, SND, 1- NA（mm）, 1- NB （except woman） compared with same age group Korean presented by In- Chool Park（P<0.05）. Conclusion There is a significantly different between male and female Koreans with normal occlusions in Yanbian China. This experiment filled in the blank of stomatology research in Yanbian Korean autonomous region. In the mean while, it completed and supplemented the normal occlude data of different nations in China. The present paper also provided the reference for clinic and scientific research on orthognathic surgeon. At the same time, the experiment provided the evidence for the further research.

Objective To evaluate the clinical effect of fluoride varnish in preventing caries of primary teeth, and to compare the caries prevention effects of fluoride varnish with two different concentrations. Methods 150 children whose ages were three year- old were randomly chosen from one of nurseries of Chongqing, and were randomly divided into four groups with 37 children in 0.5% fluoride varnish group, 38 children in 0.1% fluoride varnish group, 39 children in 0.5% sodium fluoride group and 36 children in blank group. The groups included 71 girls and 79 boys. Protective measure was applied every half an year and the research has lasted for two years. The research was designed by double- blinded methods, and was carried out with the dental caries standard suggested by World Health Organization. All the data were collected and the clinical effects of four groups were compared. Results The average caries index and caries surface index of 0.1% fluoride varnish group and those of control groups were significantly higher than that of 0.5% fluoride varnish group. There were no significant difference between the average caries index and caries surface index of 0.1% fluoride varnish group and those of control groups. Conclusion 0.5% fluoride varnish was effective in preventing caries of primary teeth.

Objective To evaluate the clinical effects of Fu Fang Ya Tong Ding on treatment of gingivitis and pericoronitis. Methods 120 clinical patients with gingivitis or pericoronitis were randomly divided into 3 groups（40 patients in each group）. After routine rinse treatment for all patients, patients in the test group were treated with Fu Fang Ya Tong Ding, patients in the positive group were treated with iodine glycerol, while that time patients in the negative group received no treatment anymore. Ten minutes after treatment, visual analogue scale（VAS）was used to record the severity of pain for each patient. 3 days and 7 days later, pain and inflammation degree were also recorded by pain three - degree scoring method and index of gingivitis. The total treatment effects were evaluated under a comprehensive clinical treatment standard. Results 10 minutes after treatment, 40.0% of patients in the test group had almost no pain, while no obvious reduction of pain was found in the control group. 3 days, 7 days after the treatment, 92.5%, 95.0% of patients in the test group had no pain, and 55.0%, 90.0% of patients in the positive group had no pain. In the negative group, there were 47.5% of patients which pain was still remained in 7 days. 7 days after treatment, gingival index in the test group reduced by 25.0% and 42.8% compared with the positive and negative groups（P<0.05）. 3 days after treatment, 62.5%, 45.0% and 30.0% patients separately in the test, positive and negative groups manifested good effects under the comprehensive clinical treatment standard; after 7 days, 97.5%, 92.5% and 77.5% patients in the 3 groups manifested good effect. The group using Fu Fang Ya Tong Ding had better effects than groups using iodine glycerol or only applying routine rinsing treatment group（P<0.05）. Conclusion Fu Fang Ya Tong Ding can treat gingivitis and pericoronitis through significantly reducing inflammation and pain.

Objective The study was to evaluate the method of early laser intervention of hemangioma in facial and neck regions of infant. Methods Between January 1999 and December 2006, twelve patients, aged 6 days to 3 months, with cutaneous hemangioma in facial and neck regions, were treated with laser, eight cases with Nd:YAG laser therapy and four cases with Venus laser therapy. Four cases with hemangioma in facial and neck regions of infant treated with oral corticosteroid were as control. The outcome was recorded with 1 to 6 years of follow- up. Results Total resolution was obtained in twelve patients with laser intervention. Atrophic scars occurred in eight patients with Nd:YAG laser therapy, without other complications, such as ulceration, life- threatening hemorrhage and et al. No scar occurred in four patients with Venus laser therapy. Recurrence was not seen in twelve cases with laser therapy with follow- up. Hemangiomas enlarged continuously in four cases with oral corticosteroid therapy. Conclusion Early laser intervention is an excellent management of cutaneous hemangioma in facial and neck regions of infant.

Objective To evaluate the deformation of ProTaper rotary instruments using in root canals of different curvature in vitro. Methods Extracted first mandibular molars were divided into two experimental groups according to the curvature of mesial buccal canals: group A with moderate curvature and group B with severe curvature. Only the mesial buccal canals of all these teeth were prepared with 6 sets of new ProTaper rotary instruments individually. Additionally, the control group was established with a set of new ProTaper rotary instruments. After finishing each canal preparation, the instruments accompanied by control were examined under the stereomicroscope by an inspector without knowing the group. If distortion, unwinding, abrasion or fracture occurred within one set of instruments, then the whole set was disposed. The sets without problems were in use until 30 times. After 5, 10, 20 times canal preparation, S1, F1 files without deformation under stereomicroscope were examined under scanning electron microscope （SEM）. Results Deformation of ProTaper rotary instruments happened after 12 times in group A and after 7 times in group B. In these two experimental groups, microcracks were found increasing with the times of use under SEM in the instruments without deformation under stereomicroscope. The microcracks on tip of instruments were deep in the early use and became smoother after 10 times. Similar changes happened on knife- edge of instruments, and the microcracks extended over the edge after 20 times use. Conclusion Root canals with severe curvature tend to damage ProTaper rotary instruments more frequently than moderately curved canals. ProTaper rotary instruments are appropriate to treat less than 7 root canals with severe curvature or 12 root canals with moderate curvature. Stereomicroscope is recommended to detect early damages on Ni- Ti rotary instruments, for preventing instruments fracture in clinic.

Objective To study the influence of hand- mixed methods on the compressive strength of the zinc phosphate dental cement. Methods Three skilled nurses used three kinds of common clinical hand- mixed methods （included the unidirectional rotation method, the alternate pro and con bidirectional rotation method and the pulling and pushing with folding method） to mix the zinc phosphate dental cement on the same condition（i.e. same indoor temperature and humidity, the same mixing ratio, mixing time, mixing frequency and the same mixing instruments and so on）. The mixed zinc phosphate cement was packed into the plastic cylinders with 10 mm- high and 5 mmbore. After the mixed zinc phosphate cement coagulated, compressive strength was tested separately. Results The compressive strength of the zinc phosphate dental cement mixed with the alternate pro and con bidirectional rotation method was the best, and the value was （106.11±4.82）MPa. The compressive strength of the zinc phosphate dental cement mixed with the pulling and pushing with folding method was lower, and the value was （77.57±6.26）MPa. The compressive strength of the zinc phosphate dental cement mixed with the unidirectional rotation method was the lowest, and the value was （54.41±5.08）MPa. The compressive strength of the zinc phosphate dental cement mixed with the unidirectional rotation method and the pulling and pushing with folding method could not achieve the clinical required compressive strength（about 100 MPa）, while the compressive strength mixed with the alternate pro and con bidirectional rotation method was above 100 MPa. Conclusion The alternate pro and con bidirectional rotation method to mix the zinc phosphate dental cement is recommended in clinic.

Objective To study the influence of two- step sintering method on the sintering property, mechanical properties and microstructure of zirconia ceramic. Methods The nano- size zirconia powder were compacted and divided into two groups, one group for one- step sintering method, another group for two- step sintering method. All samples sintered at different temperature. The relative density, three- bend strength, HV hardness, fracture toughness and microstructure of sintered block were investigated. Results Two- step sintering method influenced the sintering property and mechanical properties of zirconia ceramic. The maximal relative density was 98.49% at 900 ℃/1 450 ℃ sintering temperature. There were significant difference of mechanical properties between one- step sintering and two- step sintering, the three - bend strength and fracture toughness declined, hardness increased at two - step sintering. The three- bend strength, HV hardness and fracture toughness reached to maximum value as 1 059.08 MPa±75.24 MPa, 1 377.00 MPa±16.37 MPa and 5.92 MPa·m1/2±0.37 MPa·m1/2 at 900 ℃/1 450 ℃ sintering temperature respectively. Microscopy revealed the relationship between the porosity and shapes of grains was correlated to strength of the zirconia ceramics. Conclusion Despite of the two- step sintering method influences the properties of zirconia, it also is a promising esthetic all- ceramic dental material.

Objective To study the effects of different heating timings after mixing the materials and different heating methods on the expansion characters of a quick- heating gypsum- bonded investment. Methods The setting expansion rate of GC Cristoquick Ⅱ gypsum- bonded investment was measured with a setting expansion tester 30, 60, 120 min after mixing the material respectively. The thermal expansion rates of the material at different setting time（30, 60, 120 min after mixing） and under different heating treatment methods（quick and conventional heating techniques）were also determined using a thermal dilatometer for dental investments, the total linear expansion rate were calculated. The effects of heating time and heating methods on the expansion of the investments were statistically analyzed with SPSS 11.0 software, using ANOVA multiple comparison（α=0.05）. Results Statistical differences were found among the setting and thermal expansion rates of the investment at different heating timings after mixing the material（P <0.01）. Setting expansion, thermal expansion and total expansion rates increased with the setting time before heat treatment, while thermal expansion rates under different（quick and conventional） heating methods were not statistically significant（P >0.05）. Conclusion The expansion characters of the quick - heating gypsum- bonded investment are influenced by different heating timings after mixing the material. The heat treatment technique of this quick- heating investment recommended needs to be modified to ensure casting precision.

Objective To investigate the influence of sealer placement on apical sealability in root canal treatment. Methods 100 extracted single root canal teeth were selected. All canals were prepared by manual Protaper instrument in a step- back way. The samples were divided into 5 groups randomly. A group: 30 samples, sealer placement by chief gutta percha; B group: 30 samples, sealer placement by K file; C group: 30 samples, sealer placement by spreader; D group: 5 samples, a positive control; E group: 5 samples, a negative control. There were 2 subsets in each experimental group which were obturated by lateral gutta percha with or without sealer. Glucose oxidase method was used to measure the apical leakage at the 1st, 2nd, 4th, 7th, 10th, 15th, 20th, 25th, 30th day of the experiment. Results Apical sealability varied with different sealer placement methods（F=4.832, P=0.001）. Sealer placement by chief gutta percha（A group） had the best instant apical sealability. However, lateral gutta percha with or without sealer didn′t affect the apical sealibility. Conclusion Placing the same kind sealer in different ways can affect the apical sealability. There were no significant differences of the apical leakage no matter the lateral gutta percha with or without sealer. In order to get better instant apical sealability and simplify the clinic operation, placing the sealer with a chief gutta percha while the lateral gutta percha without sealer is recommended.

Objective To observe the effects of nicotine on the proliferation of odontoblasts and explore the possible mechanism. Methods Odontoblasts MDPC- 23 were cultured, inoculated and divided into two groups randomly. With no stimuli added for the control group, the experimental group was stimulated by 100 μg/mL nicotine. After 8 hours, 10 μmol/L BrdU was added to label cells at S stage in cell cycle. 24 hours later, odontoblasts were fixed and immunofluorescence staining was performed with specific mouse BrdU antibody. After counterstaining with propidium iodide, BrdU positive cells were arbitrarily scored microscopically by an independent estimation conducted three times, and the corresponding total cell number in the same vision were counted in both groups. BrdU positive cell rates were calculated and compared statistically. At the same time, odontoblasts MDPC- 23 were cultured and stimulated by 100 μg/mL nicotine, the dynamic Ca2 + concentration inside the cytoplasm were detected immediately by a confocal laser scanning microscope. Results The ratio of S stage cells in the experimental group was 36.3% significantly lower than that（48.2%） in the control group. After the addition of 100 μg/mL nicotine, the Ca2+ concentration inside the cytoplasm rose rapidly, sustained at a high level for a short time and then relapsed gradually. Conclusion Nicotine had inhibitory effects on the proliferation of odontoblasts MDPC- 23, which might be related to the increased Ca2 +concentration in the cytoplasm.

Objective To investigate the effects of local injections of recombinant soluble human receptors on experimental orthodontic tooth movement in the rat. Methods 64 male Sprague- Dawley rats were observed. Starting at day 1, three groups of animals each received local injections of soluble interleukin- 1 receptorⅡ（sIL- 1- RⅡ）, soluble tumor necrosis factor receptor Ⅰ（sTNF- RⅠ） and their combinations. One group served as the control. The amount of tooth movement was recorded and selected tissue sections were stained with hematoxylin- eosin（HE） to observe the histological morphologic alterations of the periodontal tissues and also were stained with tartrate- resistant acid phosphatase（TRAP） histochemistry to analyze the changes of the amount and distribution of osteoclasts and odontoclasts. Results The time- depended histomorphology changes in each receptor group were similar to those in the control group, but the resorption of alveolar bone was slighter at each time point and the surface of root appeared no or a few cement resorption signs. On day 14, the TRAP- positive cells on the surface of alveolar bone and root were reduced by approximately 50% relative to those in the control group（P<0.05）. Whereas statistical tests revealed there were no significant differences among the experimental groups（P>0.05）. Conclusion Local injections of recombinant human sIL- 1 - R Ⅱ and sTNF - R Ⅰ in the orthodontic tooth of rats could reduce the amount and velocity of orthodontic tooth movement and reduce the incidence of root resorption.

Objective To investigate the effect of different kinds of mechanical stress on the mRNA expression of integrin β1 subunit in cultured human periodontal ligament fibroblasts（hPDLF）. Methods To scalp and remove the periodontal ligament attached to the mid- third part of the fresh root of young premolars extracted for the cause of orthodontics. Cultured hPDLF by the method of digesting by Ⅰ- type collagenase combining with tissue adhering. Then hPDLF was isolated and purified by cells passage. The sixth passage′s cells were selected to be loaded. A new cyclic strain loading apparatus. Forcel four point bending device was used for mechanically loading. Cells were loaded by three levels（1 000, 2 000, 4 000 μstrain） of tensional and compressive forces and collected at different times（0, 0.5, 1, 4, 8, 12 h）course after strain loading. The quantity of integrin β1 mRNA in every group was analyzed by means of quantitative real- time PCR with the special primers of up- and down- regulated genes. Results Dynamic mechanical forces down- regulated the expression of integrin β1 subunit mRNA in hPDLF and the difference in groups by different magnitude, different kinds, and different time of mechanical forces loading were statistically significant. The stronger stimulated forces, the more down- regulated expression. Compression down- regulated the expression of integrin β1 subunit mRNA more than tension did. Conclusion Dynamic mechanical forces could regulate the expression of integrin β1 subunit mRNA. The difference among all the groups by different magnitudes, different kinds, and different time of mechanical forces loading were statistically significant.

Objective To investigate the transfection efficiency of the recombinant human bone morphogenetic protein- 2（hBMP- 2） gene in targeted cells by ultrasound- mediated microbubble destruction. Methods NIH3T3 cells′ anabiosis was completed and went down to the 3rd or 4th generation, and cultured in 6 well plates. The cells were divided into 2 groups: Plasmid DNA and LipofectamineTM 2000 group（liposome group）, plasmid DNA and ultrasound and microbubble group（ultrasound- mediated microbubble destruction group）. Plasmid DNA was transfected into cells with liposome or ultrasound and microbubble. 24- 48 hours later, the transfection efficiency and the concentrations of hBMP- 2 were measured with fluoresence microscope and enzyme - linked immunosorbent assay（ELISA） respectively. The data were analyzed by curve fitting and t- test of SPSS 11.5. Results The transfection efficiency rate was（7.30± 1.58）% in liposome group, compared with （11.77±3.16）% in ultrasound- mediated microbubble destruction group（P< 0.05）. The concentration of hBMP - 2 after transfection was （1 164.35 ±724.67）pg/mL in liposome group, versus （2 932.70±656.27）pg/mL in ultrasound- mediated microbubble destruction group（P<0.05）. Conclusion Ultrasoundmediated microbubble destruction could significantly improve the transfection efficiency and expression of hBMP- 2 gene in NIH3T3 cells. It may provide a new and effective gene delivery system for gene therapy in periodontal regeneration.

Objective To research the expression of CD31, CD34 and CD105 in squamous cell carcinoma of tongue（TSCC） and discuss their relationships with lymph node metastasis. Methods All the specimens′segments were stained by immunohistochemical method SP, and then the tumor′s microvessel density（MVD）marked by CD31, CD34 and CD105 were counted by the Weidner′s method. Results The expression of CD31, CD34 and CD105 in the tumor′s tissue was much higher than that in the normal tissue（P<0.01）. There was no obvious difference between the MVD values marked by CD31 and CD34（P>0.05）, but they were obviously different from which marked by CD105（P<0.01）. The MVD values between the male and female patients had no statistical difference（P>0.05）. The MVD values marked by CD31 and CD34 had no statistical difference in different pathological grades and clinical stages（P>0.05）, but there was statistical difference in different pathological grades and clinical stages marked by CD105（P<0.05）. Although the MVD value of the cases with lymph node metastasis was different from that without metastasis marked by CD31 and CD34（P<0.05）, there was much higher difference between the cases with lymph node metastasis and those without metastasis marked by CD105（P<0.01）. Conclusion CD105 is a more satisfying vascular endothelial marker than others. It can predict the metastasis possibility of the TSCC patients, thus it may be particularly important in the development of TSCC.

Objective To design and construct the plasmids expressing short hairpin RNA（shRNA）targeting human xylosyltransferase- Ⅰ（XT- Ⅰ）which is the initiating enzyme in the biosynthesis of proteoglycans（PG）. Methods Short chain oligonucleotides were designed according to the sequence of XT- Ⅰ provided by GenBank. The DNA segments were gained through annealing after chemosynthesis, and were cloned into Pgenesil- 1 vector. The recombinant XT- Ⅰ shRNA expression vectors were identified by digestion and sequencing analysis. At last the constructed XT- Ⅰ expression vectors were transfected into salivary adenoid cystic carcinoma cell line（ACC-M） by LipofectomineTM 2000. The expression of green fluorescent protein（GFP） was detected by inverted fluorescent microscope and the rates of  transfection were detected by flow cytometer. Semiquantitative RT- PCR was used to detect the expression of mRNA level of XT- Ⅰin transfected ACC-M cells and the  rotein expression of XT- Ⅰ was detected by Western blot. Results The plasmids expressing shRNA targeting XT- Ⅰgene are called WJ1, WJ2, WJ3, WJ4, WJ5 and  J6. Successful constructions were identified by digestion and sequencing. The mean rate of transfection was 50.26%. ACC-M cells transfected with WJ1 -WJ6  xpressed GFP successfully. And by RT- PCR and Western blot, WJ3 showed the most powerful RNAi gene silencing of inhibitory. The inhibition rate was 72.39% of  RNA level and 70.18% of protein level respectively. Conclusion The XT- Ⅰ shRNA expression vectors were constructed successfully which lays the foundation for  NAi study on the biosynthesis of PG in salivary gland tumors.

Objective The aim of the present study was to design and fabricate a three dimensional（3D） porous structure of silk fibroin/apatite used as a potential scaffold in bone tissue engineering. Methods With the combining use of non- woven silk fibroin net and biomimetic method, porous non - woven silk fibroin/nano- hydroxyapatite net （NSF/nHAP）was prepared and characterized with X- ray diffraction（XRD）, scanning electron microscope（SEM） and fourier transform infrared spectroscopy（FTIR）. The porosity and swelling ratio of the 3D scaffold were also measured. Besides, the osteoblasts from the cranium of new born SD rat were cultured on the pre - fabricated scaffold to evaluate the biological reaction of the scaffold. Results The nano- sized hydroxyapatite crystals were needle- like with the length of 100- 300 nm and the diameter of 20- 60 nm. The scaffold fabricated in the present study exhibited the porous microstructure with open porosity around 70%- 78%. Its average pore size was about（163.4±42.6）μm. The swelling ratio and water uptaking were 4.56% and 81.93%, respectively, which revealed that the 3D porous scaffold had an excellent hydrophilicity. The rod- shaped apatite crystals could rapidly form on the surface of fibroin fibers throughout the network by immersing the net into calcium and phosphate solutions alternatively. Conclusion A 3D porous NSF/nHAP scaffold can be fabricated by biomimetic mineralization and none- woven silk fibroin method. The novel NSF/nHAP scaffold has an excellent cytocompatibility for the growth of osteoblasts. Porous NSF/nHAP scaffold may be a hopeful biomaterial used in bone tissue engineering.

Objective To study the biological effects of phenytoin（PHT） on cultured human periodontal ligament fibroblasts（hPDLF）, and explore the possibility of its accelerating periodontal regeneration. Methods Increasing concentrations of PHT （1, 5, 20, 100, 500, 2 500 mg/L） were added into the medium of the fourth passage of cultured hPDLF, respectively. After co- incubated for 3 days, cell proliferation activity, the total amount of protein and alkaline phosphatase（ALP） activity were detected. Mineralized sodium and PHT（20, 100, 500 mg/L）were added into the medium of the fourth passage hPDLF. After co- incubated, the mineralized nodules formation were detected by Von Kossa staining. The third passage hPDLF were stimulated by PHT（20, 100 mg/L）, bone morphogenetic protein- 2（BMP- 2）concentration was analyzed by enzyme linked immunosorbent sandwich assay（ELISA）. Results At the concentration of 20 or 100 mg/L, PHT significantly enhanced the proliferating activity and ALP activity of hPDLF （P<0.01）. PHT at 100 mg/L could increase protein synthesis of hPDLF（P<0.05）. The capability of mineralization and BMP- 2 expression of hPDLF were increased significantly（P<0.01） in 100 mg/L group when compared with that in the control group. However, higher concentration（2 500 mg/L） not only changed cell morphology, but also significantly inhibited cell activity. Conclusion The results suggested that proper doses of PHT could promote proliferation and biosynthesis and also enhance osteogenesis by increasing the differentiation, mineralization and BMP- 2 expression of hPDLF while higher concentrations of PHT had cytotoxic effect.

The conventional methods on making double splints in presurgery of skeletal Class Ⅲ were complicated. To find an easy method for the improvement of the production of splints and simplify the making process, 17 severe skeletal Class Ⅲ patients accepted bimaxillary surgery after making double splints were used. According to visual  reatment objective（VTO） forecasting on the lateral cephalometric radiograph of ending presurgical orthodontics and analyzing study models, the surgical methods were designed, the mobile osteotomy bone volume was estimated and the maxillary abnormity was classified. For the patients with right midline and without adjusting their occlusion plane, use the single model method（antedisplace maxillary model twice）or double models method（antedisplace maxillary model firstly, and then retrodisplace mandibular model）to make the double splints which guided the fixtion of bimaxillary surgery through their parallel models and simple articulators. The making process of the double splints was simplified and improved, and the postsurgery effects of all patients were satisfied. Therefore, for making the double splints of skeletal Class Ⅲ bimaxillary surgery, utilizing the proper method on the basis of the specific abnormal conditions of patients can simplify the production process and get twice the result with half the effort.

Skeletal desmoplastic fibroma is an intraosseous neoplasm that is recognized as a very scare benign tumor. It has a propensity for locally aggressive behavior and local recurrence. The aim of this article is to report a case of skeletal desmoplastic fibroma in right mandible of a 4- year- old boy. The patient was found to have a large skeletal desmoplastic fibroma in right mandible, which was resected by surgical intervention. The defect was successfully restored with a titanium plate. In the report, the etiopathogenisis, pathological, radiographic features, clinical diagnosis, therapy and prognosis of skeletal desmoplastic fibroma were diccussed.

融合牙是临床常见的牙发育畸形，根据畸形情况不同可采取不同的治疗措施。本文对1例冠融合牙采用分离牙冠后部分拔除的方法进行正畸治疗，取得了较好效果。

As one of the most common malignancies of the salivary glands, mucoepidermoid carcinoma had a rare frequency in mandible. A case of central mucoepidermoid carcinoma of the mandible was reported and relevant literatures were reviewed. The possible etiology, clinical symptom, radiology, histopathology, diagnosis and treatment of central mucoepidermoid carcinoma were discussed.