Objective　To investigate the relationship of vascular endothelial growth factor c(VEGF-C) and induced nitride ox- ide synthesizase(iNOS) expression in lymph node micrometastasis of oral squamous cell carcinoma.Methods　Samples were ob- tained from 47 cases of oral squamous cell carcinoma and 15 caseswith normal oral mucosa, VEGF-C and iNOSmRNA expression were detected by RT-PCR method. Lymph node micrometastasis of 10 normal lymph nodes and 355 lymph nodes from 47 cases of oral squamous cell carcinoma was detected with immunohistochemical reaction in cytokeratin antibody.Results　The percentages in tumorswith higher expressionwere 57·4% forVEGF-C, 68·1% for iNOS(P<0·05). Theywere significantly higherthan that of normal groups. Significant positive relationshipwas found between VEGF-C and iNOS(P<0·01). The positive rate of cytoker- atin(CK) was 48·9%. Significant positive relationship was found between VEGF-C and CK, iNOS and CK(P<0·01). The ex- pression rates of CK in positive group of VEGF-C and iNOS were 63·0%,65·6% respectively,and were significant higher than negative groups.Conclusion　Expression of VEGF-C and iNOS in lymph node micrometastasis of oral squamous cell carcinoma is significant related.

Objective　To investigate the effect of pulse Nd:YAG laser combined with NaF on caries resistance of human enamelin vitro.Methods　24 caries-free, constant premolares were cut into enamel mass. Surface ultrastructure and fluoride distribution of enamel in laser-NaFtreated group, lasertreated group, NaFtreated group and control groupwere observed by scan- ning electron microscope (SEM) and electron probe microanalyzer.Results　①SEMobservation: In laser-NaFtreated group, the smear layer was almost removed, the enamel surface showed partially melted-like and bubble-like appearance, diffuse white-small particles distributed on enamel surface, and melted position, microcrack and microhole appeared whitely blocking-reflection. ②Electron probe microanalyzer analysis: In enamel samples, the highest average Ci of F-and the hightest depth which F-en- tered in enamel were recorded in the laser-NaF treated group. The average Ci of F-in laser-NaF treated group was significantly increased compared with that in NaF-treated group or laser-treated group or control group (P<0·001).Conclusion　The pulsed Nd:YAG laser combined with sodium fluoride could make the enamel surface partially melt, change the structure of the crystal, enhance the absorption of fluoride, and clear smear layer. This technology may resist the caries.

Objective　To study glycyrrhizin′s anticancer effect and its mechanism.Methods　3-methylcholanthrene were in- jected into mice′s submandibular glands to induce tumor, then transplanted the tumor pieces(1 mm3) to mice. The transplanted tumors were measured, and flow cytometry analysis and cytomorphology observation were conducted.Results　Glycyrrhizin (GL) inhibited the transplanted mandibular gland fibro-sarcoma of mice and the suitable GL dose for inhibiting fibrosarcoma of mice was 1.61 mg per20 gweight. The GLdose below3.22 mg per20 gweight didn′t produce remarkable toxicity and side effects. GL in- duced cytomorphological changes of tumor cells and enhanced immunosuppression of macrophage on fibrosarcoma. The result of flow cytometry showed that tumor cell counts of GL1 and GL2 groups increased remarkably in DNA synthetic prophase, and de- creased in DNA synthetic phase.Conclusion　GL can inhibit transplanted mandibular gland fibro-sarcoma of mice. The antican- cer mechanism of GLmay be acting on related enzymes with phagocytosis. The result of flow cytometry showed that the shift of fi- brosarcoma cells fromG1 phase to S phase was blocked. This suggests that the anticancer action of GL is related to its inhibition of ribonucleotide reductase, a rate-limiting enzyme in DNA synthesis.

Objective　To evaluate the cytocompatibility of nanophase hydroxyapatite ceramicsinvitro.Methods　Hydroxyap- atite(HA) was prepared viawetmethod. The grain size of the hydroxyapatite in the studywas determined by scanning electron mi- croscope and atomic force microscope with image analysis software. Primary osteoblast culture was established from rat calvaria. Cell adherence and proliferation on nanophase hydroxyapatite ceramics and conventional hydroxyapatite ceramics were examined at 1, 3, 5, 7 days. Morphology of the cellswas observed bymicroscope.Results　The average grain size of the nanophase and con- ventional HAwas 55 nm and 780 nm, respectively. Throughout 7 days period, osteoblast proliferation on the HA was similar to that on tissue culture borosilicate glass controls, osteoblasts could attach, spread and proliferate on HA. However, compared to conventional ceramics, osteoblast proliferation on nanophase HAwas significantly better after1,3,5 and 7 days.Conclusion　Cy- tocompatibility of nanophase HAwas significantly better than conventional ceramics.

Objective　To investigate the effect of transforming growth factorβ(TGF-β)on ectomesenchymal stem cells differen- tiating to smooth muscle cells.Methods　60 pmol/L TGF-βwas added to the ectomesenchymal stem cells of embryonic facial processes. Immunohistochemistry assay and image analysis were used to value the expression extent ofαsmooth muscle actin (α- SMA) and quantitative RT-PCRwas used to value the quantity ofα-SMA.Results　2 days later, about 95% cells inTGF-βgroup and 65% cells in control groupwithout differentiation inhibitor expressedα-SMA. Expression ofα-SMA inTGF-βgroupwas stron- ger than that of control group after one and two days. Quantitative RT-PCR showed the quantity ofα-SMAmRNA in treated group cells was more than that of in control group.Conclusion　Quantity ofα-SMA in TGF-βgroup is more than that of spontaneous differentiation group. TGF-βhas positive effect on ectomesenchymal stem cells differentiating to smooth muscle cells.

Objective　To study the residual stresses of ceramic-metal bond at viscoelastic and elastic phases during cooling of porcelain-fused-to-metal in order to precisely calculate the ceramic-metal bond strength and improve the restorations.Methods　 The finite element model was set up according the crack initiation test (three-point flexure bond test) based on ISO Standard, ele- ments of viscoelastic and thermal-displacementwere used to part the model. The result at viscoelastic phaseswas used as initiation condition of elastic phases to add up.Results　The compressive stresswas caused bymetal during cooling occurred in the ceram- ic. The shear stress induced by loading was offset by thermal shear stress. Load tensile stress and the thermal compressive stress vertical of interface concentrated at the end of the bond interface, but the tensile was greatly higher.Conclusion　The residual stress is very important to metal-ceramic restorations, and the viscoelastic behavior of porcelain greatly influences it. If the metal and ceramic are compatible,the components stresses of the residual stresses may benefit to ceramic-metal bond, and can be taken as a part of bond stresses.

Objective　The study is to investigate the microbial composition of interdental and subgingival plaques of periodon- titis patientswith orwithoutmalodor, to explore the relationships between periodontitis and oral malodor.Methods　20 patients of periodontitis with malodor were chosen from 210 patients of periodontitis, and the clinical parameter of plaque index (PLI), gingi- val bleeding index (GBI) and probing depth (PD) were measured and compared with the control groupwhich had periodontal dis- ease without malodor. During the experiment, the interdental and subgingival microbial samples in both groups were collected and sent to anaerobic culture for 48 hrs, then the total CFU/ml of each sample were counted, and each type of bacteria was separated and identified. All of the data were analyzed by using the statistical software SPSS 10.0.Results　(1)There were no satistical differences on PLI, GBI, PD between experimental group and control group. (2) The percents of leptospira in both interdental and subgingival plaques of test groupwere significantly higherthan that of the control group (P<0.01). (3) Eitherthe interdental or in subgingival plaques, the count results of CFU/mlwere similar in both groups (P>0.05). (4) The proportions of malodor pro- ducing anaerobic bacteria in interdental gingival plaque, such asP.gingivalisandVeillonella, were singnificantly different be- tween test group and control group.Conclusion　The proportions of VSC′s producing anaerobic bacteria in interdental gingival plaque may be play the significant roles in oral malodor. Further studies should be taken to elucidate the relationship between mal- odor and periodontitis.

Objective　To estimate the related factors and prophylactic measures of endodontic interappointment emergencies (EIE).Methods　The clinical caseswere divided intothree groups. Cases in the routine groupwere treated accordingtothe rou- tine procedures of root canal therapy. Cases in the medicament group took dexamethasone tablets after the instrumentation. Root canals in the drainage group were prepared at the first visit and had been left open for two or three days. The related factors were recorded. The incidences and flare-up index(FUI) value of EIE were statistically analyzed.Results　The EIE incidence of the routine group was 19·1%. The EIE incidence and FUI value of the overinstrumented teeth were significantly higher than those of other teeth(P<0·05). EIEwere not significantly related to the age, gender, tooth location and pathosis of the pulpal and peria- pical tissue(P>0·05). The FUI value of the medicament groupwas significantly lowerthan that of the routine group(P<0·05). Less severe EIE occurred in the cases of the drainage group than those of the control group(P>0·05).Conclusion　The occur- rence of EIE was significantly related to overinstrumentation. Taking dexamethasone may relieve EIE.

Objective　To evaluate the possibility for removal of resinifying agent, time required for removal and the working length loss by Resosolv or Chloroform.Methods　40 human teeth (80 root canals) obturated with FR phenolaldehyde agentwere divided into four groups, 20 root canals per group. Group A: Resosolv with K file; group B: chloroform with K file; group C: Resosolv with Ultrasonic K file; group D: Chloroform with ultrasonic K file. Calculating the percentage for removal of resinifying agent, time required for removal and theworking length loss.Results　The effectiveness of Resosolv for removing resinifying agent was better than chloroform. 87.5% of canals could be negotiated by Resosolv; 45% of canals be negotiated by chloroform.Con- clusion　Resosolv is an effective solvent for canals obturated with resinifying agent.

Objective　To analyze the reliability and feasibility of free flap transfer for head and neck reconstruction in the pae- diatric patients.Methods　Thirty consecutive free flap transfer performed in 28 patients youngerthan 15 years-oldwere reviewed. Data concerningthe operation included date of surgery, defect description and site, stage and histology of tumor, flap type, recipi- ent vessel and complications.Results　The average age of patientswas 12.3 years-old, with age ranged from5 to 15. Therewere 19 males and 9 females. Four kinds of free flap were used. The free fibula flap was most commonly used, followed by free radial forearm flap, rectus abdominis myocutaneous flap, and free scapular flap. The overall success rate of the flaps was 93.3%. The overall complication ratewas 36.7%. The vessel thrombosis ratewas 6.7%.Conclusion　Free flap transfer in the paediatric pa- tients for head and neck reconstruction is safe and reliable. There is no difference between the normal patients and paediatric pa- tients in the success rate and complication rate.

Objective　To investigate the MR imagine features of TMJ coronal structures.Methods　28 TMJs from 15 cadav- ers dipped in formalin over1 yearwere included. Theirmandibleswere fixed at intercuspal positionwhenTMJs oblique coronalMR scan was taken. Baseline was draw on the oblique coronal imagining along the ramus of mandible through its center. The corre- sponding dimensions and areas were measured with electronic ruler.Results　The dimensions were in accordance from large to small as: lateral-medial dimension of fossa, lateral-medial dimension of condyle, medial dimension of fossa, medial dimension of condyle, lateral dimension of condyle and lateral dimension of fossa. Three significant co-relative relationshipwere found: the lat- eral dimension of condyle with lateral dimension of fossa, the medial dimension of condyle withmedial dimension of fossa, and the lateral-medial dimension of condyle with lateral-medial dimension of fossa. CVof lateral dimension of fossa was higher than that of lateral and medial dimension of condyle, and then all the three were higher than other dimensions. The size of the area of joint space shown on oblique coronal imaginings was positively related to that of the area of coronal disc imaginings.Conclusion　Sig- nificant co-ordinate relationship of condyle and fossa ofTMJ coronallywas existed, and the condyle position to fossa lateral-medial- ly varied in great.

Objective　To evaluate the methods of orthognathic treatment for mandibular asymmetry.Methods　110 cases of mandibular asymmetry had been treated in pastthirteen years. The type of deformity, the management of the cases, and the effects of orthognathic treatment were summarized in this paper. Orthodontic therapy was taken before and after operation to keep the treatment effect.Results　Accordingtothe type of the asymmetry deformity, differentmethodswere used. Aftertreatment, all the patients obtained satisfactory facial appearances and oral function.Conclusion　It should be diagnosed before surgerywhether the development of deformity is steady or not. If it is steady, the effects of orthognathic and orthodontic therapywill be satisfactory; if not, we should remove the affected condyles and simulataneously ameliorate facial appearance.

Objective　To analyze the clinical character, diagnosis and treatment of badly necrotic pyogenic infection in cervi- cal part with pneumatosis of vomica.Methods　The clinical character, diagnosis and treatment of badly necrotic pyogenic infec- tion in cervical part with pneumatosis of vomica of 46 cases were investigated retrospectively.Results　Lateral and bilateral neck infection caseswere 38 and 8 respectively. 30 cases formed primary pyogenic infection in cervical partwith pneumatosis of vomica, and 16 did from adjacent sites. Besides the characters of the acute infection, gas storage in deep cervical part abscesswas notable. CT and BUltrasonic examination provided useful informations such as sizes, shapes, capacity, extents of abscess and the relation- ship between the abscess and vessel or vital organ. Diagnosis puncture and germiculturewere performed before and after operation. The results showed that 25 of 46 caseswere infected by staphylococcus or streptococcus, and 21 cases did by other bacterium. Ex- ploration and drainage treatments were performed. All cases were cured except 2 died.Conclusion　Diagnostic puncture, CT and/or B Ultrasonic examination are essential for diagnosis and presurgical planning. Germiculture provides reliable evidence for finding pathogeny and therapy. The most possibilities of pyogenic infection with pneumatosis of vomica in cervical part are the ac- tion of aerogenic bacterium, infection both in cervical part and chest or swallowing movement of pharynx.

Objective　To research the color space of the standard color board, guide the clinic work of color match, and es- tablish an foundation for deeper researching.Methods　Through taking analysis of reflecting spectrum and spectral tristimulus, each parameter of the color on standard boardwas found out. The color difference between border upon colors on boardwasworked out throughmatchingthe color parameters. The number of color space between each border upon color on standard color board, di- vided byΔE=1.5, was found.Results　The number of color space between each border upon colorwas 3~6. The color space was bigger in group B, but smaller in group D. The color space was bigger in high lightness area, but smaller in low lightness ar- ea.Conclusion　Some color space has been found between standard color borders of VINTAGE and UNIBOND. Color of natural teeth is unable to be completely included into standard color border, especially in clinical care.

Objective　To examine the absence of the third molar germs in orthodontic patients and to evaluate the relationship between third molar germs and malocclusion.Methods　The subjects comprised 234 patients (male 92, female 142) from the orthodontic clinic whose ages were 14-18 .The assessments of the third molar germs were made from panoramic radiographs, and the assessments of ANB angle were made from lateral cephalograms. All the data were analyzed by statisticχ2test.Results　The percentage of male who missed one or more third molar gems (37.0%) was higher than that of female (24.6%). There was no significant difference between the absent frequencies of third molar germs on left and right sides in eithermaxilla ormandible. The absent percentage of third molar germs in skeletalⅢsubjectswas higherthan those in both skeletal classⅠandⅡsubjects. The absent difference of third molargermswas in upper arches (P<0.05), but not in lower arches (P>0.05). Therewas no signif- icant difference in absent percentage of third molar germs between skeletal classⅠandⅡsubjects.Conclusion　Male patients have higher absent frequencies of third molargerms than female ones. Skeletal classⅢpatients have higher absence of third molar germs in upper jaws than skeletal classⅠandⅡpatients.

Objective　To study the coordination of facial soft tissue in Angle′s ClassⅠ、Ⅱ1、Ⅲmalocclusion, providing ref- erence for the clinical practice.Methods　60 lateral cephalometric radiographs of three classes of Angle′s malocclusion were in- cluded. 13 measurements were analyzed by SPSS 10.0.Results　Protrusion of the upper and lower lips increased in Angle′sⅡ1 comparing with Angle′sⅠand protrusion of the upper lipwas larger than the lower lip, no difference was found in the facial conv- exity. Increase of upper lip inclination and underdevelopment of maxillary in Angle′sⅢcomparing with Angle′sⅠ.No significant differentwas found in the form of lower lip,soft tissue facial angle and Z angle. Comparing Angle′sⅡ1with Angle′sⅢ, every measurements were significantly different except upper lip inclination, nasolabial angle, representing the formation mechanism of malocclusion.Conclusion　Some differences were found in form and position of lip in three classes of Angle′s malocclusion. However, the deformity was not obvious in Angle′sⅡ1and Angle′sⅢbecause of compensation mechanism. Nasolabial angle only reflected change of upper lip, but could not reflect characters of facial profile.

Objective　To study the oncogene transcriptor c-myc, stimulatory protein 1 (SP1) expression in ameloblastoma (AB) and their relation with telomerase reverse transcripase (hTERT), and to investigate the clinical biological characteristics of AB.Methods　The expressionwas observed in AB by in situ hybridization and SPmethod.Results　The positive rates of c-myc mRNA, hTERTmRNA and SP1 protein were 81·5%(44/54)、94·4%(51/54) and 83·3%(45/54), respectively. Their positive rates increased as AB recurred and transformed malignantly. A strong correlation was found between hTERT and c-myc, hTERT and SP1 (rs=0·853,P<0·001;rs=0·900,P<0·001).Conclusion　Activity of telomerase plays an important role in the tu- morigenesis development of AB. Increasing of hTERT expression may be related to c-myc and SP1. The expression of these three parameters has a significant correlation with the clinical biological characteristics of AB.

Objective　This study aimed at constructing secretory eukaryotic expression vector ofKGPcdgene encoding whole amino acid residues of mature KGPcd fromPorphyromonas gingivalisand investigating the transcription and expression of recom- bined plasmid VR1020/KGPcdin mammalian cells.Methods　Eukaryotic expression plasmid VR1020/KGPcdwas constructed by using molecular cloning methods. Then, the VR1020/KGPcdwas transfected into mammalian cell COS7 with Lipofectamine 2000 according to the manufacturer′s instruction. The transcription of VR1020/KGPcdwas assayed by reverse transcription polymerase chain reaction (RT-PCR). The expression product of VR1020/KGPcdwas analyzed by using indirect immunofluorescence. The protein secretion in cultural medium was detected by ELISAmethod.Results　It proved that the VR1020/KGPcdcould be tran- scribed and translated into transfected COS7 cells. The expressed targeted protein could be secreted into cultural supernatant and could be detected by ELISA.Conclusion　The eukaryotic expression plasmid of VR1020/KGPcdwas constructed successfully and its product can be expressed in mammalian cells. The results indicated that the recombinant plasmid has antigenicity and may be acted as candidate gene vaccine. This laid a basis for its use as gene vaccine candidates in the development of anti-periodontitis and paved the way for further study.

Objective　To isolate human adipose tissue-derived stromal cells and study the potential of osteogenic differentiation after inductive culture.Methods　Liposuction human adipose tissueswere minced and digested with collagenase typeⅠ. The ob- tained stromal cellswere plated in BGJbmedium as primary culture forten days. The second passage cellswere harvested and plat- ed in DMEM/F12 medium supplemented with 10% FBS, 5% horse serum and 50μmol/L hydrocortisone for myogenic induction culture. The cell-anchored slips were removed and fixed in 4% formaldehydum polymerisatum. Toluidine blue, Mallory′s phos- photungstic hematoxylin staining and monoclonal antibody to human skeletal muscle myosin heavy chain immunocytochemical meth- ods were used to assay the differentiation of cells.Results　It was observed that the size and shape of induced cells were much different from those of non-induced cells. Toluidine blue, Mallory′s phosphotungstic hematoxylin staining demonstrated there were many basophilic striations within cytoplasm and multinucleated myotubes were formed. Immunocytochemical stain indicated that characterastic skeletal myosin heavy chain was positive in myogenic induced cells.Conclusion　It seems that human adipose tis- sue represents an abundant reservoir of adult stem cells that have multi-germline potential to differentiate into myoblasts. Adipose tissue derived stromal cells will be another alternative source for cell-based tissue engineering in skeletal muscle reconstruction.

Objective　To observe the morphological changes and the regenerating ability of the fungiform papillae and taste buds after60Co radiation with clinical doses in rats.Methods　The heads, faces and necks of 30 SD rats were radiated with a large dose and one time of60Co in the clinical radiation. The general living condition and the number and shape of the fungiform papillae and taste buds of the tongues were observed after the radiation in rats.Results　In the group of60Co radiation, the ani- mals had wilting, decreasing appetite, losing weight. The heads, faces and necks of animals appeared redness, peeling of hair, increasing of secretions in 5 days afterthe60Co radiation. The changes reached the summit in 10 days and the general living condi- tion of the animals recovered in 60 days. The fungiform papillae and taste buds of the animals appeared degeneration, atrophy and collapsing in 5 days after the60Co radiation. The injuries reached the summit in 10~20 days and the fungiform papillae and taste buds regenerated partially, and the some atrophied fungiform papillae and taste buds were not regenerated in 60 days.Conclusion 　The damage to fungiform papillae and taste buds of tongue following the60Co radiationwith the clinical doseswas very serious. The damaged fungiform papillae and taste buds can regenerate partially, but not completely.

Objective　To clone and sequence the upstream of mouse dentin sialophosphoprotein promoter.Methods　Genom- ic DNAwas obtained from Balb/c mouse blood. The upstream of mouse dentin sialophosphoprotein promoter segmentswas obtained by PCR. Then the segments were inserted into T-vector. The plasmids were identified by digestion with the restriction enzyme analysis. The positive clone was sequenced and compared with Genebank.Results　The upstream of mouse dentin sialophospho- protein promoter was divided into three sequences and three different target segments with 997 bp, 1 004 bp and 674 bp in length were obtained. After identified, sequenced and comparedwithGenebank, the sequences of the segmentswere consistentwiththose displayed on Genebank by 99%.Conclusion　The clone of the upstream of mouse dentin sialophosphoprotein promoterwas suc- cessful. This work will help to study the regulation of DSPP expression.

Objective　To investigate the influence of mold temperature on the mechanical properties of Ti-Zr alloy castings. Methods　Ti-Zr alloywas cast into a moldwhichwas made of a zircon ( ZrO2·SiO2) investmentwith a castingmachine (China) designed as vacuum, pressure and centrifuge. At three mold temperatures (room temperature, 300℃, 600℃) the Ti-Zr alloy was cast separately. The ultimate tensile strength (σb), 0.2% offset yield point strength (σ0.2), and elongation to fracture (δ) were determined by a universal testing machine with 15 mm pre-marked gauge interval. The surface micro-structures ofTi-Zr alloy castings at three mold temperatures were observed by optical microscope.Results　At a higher mold temperature during casting, the tensile strength and yield strength of Ti-Zr alloy were significantly increased, while the elongations were significantly de- creased. The micro-structure of the surface was different from the inner part. There was a reacted layer in the outermost surface. The thickness of reacted layers at the three mold temperatures was about 35.5μm (room temperature), 55.0μm (300℃) and 65.5μm (600℃), respectively. The inner part of microstructure composed of mainαphaseswithin the priorαgrain boundaries. Conclusion　The mold temperature is one of the major factors influencing Ti-Zr alloy mechanical properties. Comparing with Ti6Al4V alloy and Co-Cr alloy castings, Ti-Zr alloy is more suitable for denture frame.

Objective　To investigate the oral health knowledge and habits of freshmen of Sichuan University and promote the prophylactic therapy of dental diseases in the university.Methods　The table and the standard on oral health survey authorized by WHOwere employed in this study.Results　Only 13·1% of all the investigated freshmen had periodic oral health examination. 74·4% brush teeth twice per day, only 7·7% brush teeth over 3 minutes, 16·6% insist in fluoridated toothpaste, and only 6% had applied dental floss. 51·9% do not often take snack food and 94·7% are non-smokers;(4) Tests of prophylactic therapy of dental caries and periodontal diseases and oral health knowledge have poor results.Conclusion　The freshmen have limited knowledge of oral health and lack serious attitude toward oral cleaning behaviors.