Objective　To culture human dental papilla cells(HDPCs)and to study its cytobiological charactersin vitro.Meth- ods　HDPCswere isolated and cultured with explant culture techniquein vitro; TypeⅠcollagen, fibronection and lamininwere detected in HDPCs and its secreted matrix with the immunocyto-chemical stain; HDPCs were incubated in mineralized promoting solution containing 10 mmol/Lβ-glycerophosphate, 100 mg/L of ascorbic acid and 10 nmol/L dexamethasone supplemented with 10% FBS and the form of mineralized nodules was tested with Alizarin Red S stainning.Results　Cultured HDPCsin vitrowere well growing in DMEM/F12. TypeⅠcollagen, fibronection and laminin stainingwere all positive in bothHDPCs and its secreted matrix, and laminin was stained with bunchiness in matrix. Mineralized nodules formed after cultured 27 days by Alizarin Red S stainning.Conclusion　HDPCs isolated and cultured are well growingin vitro, have a capability of synthesizing and secreting matrix and in mineralized promoting solution, are able to formmineralizer, so, HDPCs have a capacity of seed cell of tissue engi- neering regeneration tooth.

Objective　To observe the expression of cyclin D1 in human adnoid cystic carcinoma and its correlation with clini- cal characters.Methods　The expression of cycline D1 was evaluated with immunohistochemical method in forty-one cases of human adnoid cystic carcinoma, 15 cases of PA and 12 cases of normal salivary gland tissue.Results　The expression of cyclin D1 in normal tissue was negative, significantly different from PA and ACC (P<0·05). The expression level of PA was signifi- cantly lower than ACC (P<0·05). High expression of cyclin D1 was correlated with clinical stage and histological classification (P<0·05), but notwith sex, age, tumor site, recurrence, metastasis.Conclusion　High expression of cyclin D1 promotes the formation and development of ACC.

Objective　The aims of the present studywere to assess the characteristics ofMSCswhichwere induced and prolif- eratedin vitro, then to learn the interfaces between them and metal materials.Methods　Adult dogswere selected as experimen- tal animals, the MSCs (marrow stem cells) were aspirated from the femur, which were induced to the phenotype of OB (osteo- blast), then to proliferatedin vitrowith metal materials. Using biochemical tests, phase contrast microscopy, transmit electromi- croscope, scanning electromicroscope to detect MSCs and the image of interface.Results　MSCs had powerful osteogenic pheno- type when they were inducedin vitro, and they also attached to the metal materials. And there were more cellswhich attached on tensile stress area than other areas.Conclusion　The MSCs inducedin vitrocould be used as source of osteoblast. The affects of air-abrasion with alumina are not significant, but they have relation to the extent of strain and property of stress. [Key words]　marrow stem cells|cell culture|osteogenisis|interface|strain

Objective　to studythe effect of hepatocyte growth factor on the proliferation of dental pulp cell.Methods　the 4th generation dental pulp cell cultured in vitro was used as target cell. 1~200μg/L hepatocyte growth factor was added in the test group while the pure cell culture DMEMas control. TheMTTmethod and flowcytometrywere applied to assay the proliferation and cell cycle of dental pulp cell of different groups.Results　1~200μg/L hepatocyte growth factor showed promoting effect to the proliferation of pulp cell since the 5th day (P<0·05). 100μg/Lwas found to be the optimal concentration. Also on the 5th day, 100μg/L hepatocyte growth factor decreased the G1 subcycle and increased the S subcycle of dental pulp cell (P<0·05). While on the 3rd day, it had no effect on the cell cycle.Conclusion　hepatocyte growth factor had positive effect on the proliferation of dental pulp cell, with 100μg/L as the optimal concentration.

Objective　In order to determine the influence of bFGF on the biological characteristics of osteoblasts and periodon- tal ligament cells, the author investigate the influence of bFGF on the migration, proliferation of osteoblasts and periodontal liga- ment fibroblasts between osteoblasts and fibroblasts.Methods　The forth generation of osteoblasts and periodontal ligament fibro- blast were obtained and the woundingmodelin vitroof themwas founded. The cellswere cultured in mediumswith orwithout bF- GF. Their migration and proliferation were observed and measured.Results　Osteoblasts migrated faster than fibroblasts in com- mon culture mediumwithout bFGF and the periodontal ligament fibroblasts in culture mediumwith bFGF had higher migration rate than other groups. bFGF promoted the proliferation of both two kinds of cells.Conclusion　bFGF could accelerate periodontal fi- broblasts′proliferation and migration.

Objective　To investigate the effect of the treatment of periapical diseaseswith recombinant human bone morphoge- netic protein (rhBMP-2) composite in dog models so as to provide basis for its clinical application.Methods　The endotoxin- bacteria mixed fluid was injected into each root canal of the experimental teeth of dogs and the animal periapical disease models were built. The rhBMP-2 composite was mixed by rhBMP-2,TCP,collagen and metronidazole and used in the treatment of periapi- cal diseases in dogmodels as root apex screen. The imageology and pathology researchwere went on.Results　The effective rate of the experimental group was remarkably higherthan that of the carrier group and the control groupwith remarkable statistical dif- ference(P<0.05). The quality of the repair of tissue was obviously better than the two other groups.Conclusion　The rhBMP- 2 composite is a promising biological root-canal filling material.

Objective　To explore the combined effects of orthodontic force and inflammation on the remodelling of periodontal tissues.Methods　The upper firstmolars underwentmesial orthodontic force on 48 rats suffering experimental periodontitis and 48 rats injected lipopolysaccharide, respectively.Results　TheTNF-αprotein expression in the compressed periodontal tissues fluctu- ated during 0,2,12 hours and 2,7,14 days stages, the OD value got to the peak in the compressed periodontal tissues in 2 days. Conclusion　The mechanical remodelling effectswere hindered due tothe circumstance of acute or chronic inflammation. The re- search suggests that the orthodontic treatment to adult patients with periodontal inflammation should be taken carefully.

Objective　To observe the expression of urokinase-type plasminogen activator (uPA) in human tongue squamous carcinoma cells (Tca8113) under hypoxia, in order to explore the relation between hypoxia and invasion and metastasis of oral cancer.Methods　Under different hypoxic times(0,3,6,12,24 h), the expression of uPA protein was examined quantitatively using immunohistochemical technique (IH) and flow cytometry (FCM).Results　Hypoxia promoted the expression of uPA. The longer hypoxic time was, the higher expression of uPA was.Conclusion　Hypoxia can promote invasion and metastasis of oral squamous carcinoma through stimulating the expression of uPA.

Objective　To evaluate the craniofacial characteristics of the ClassⅡ1malocclusion patientswithmouth-breating by posteroanterior cephalometry.Methods　To measure craniofacial width of the 12 ClassⅡ1malocclusion patients with mouth- breathing, and to compared these measureswith correspondingmeasures in a group of normal children.Results　The width of the maxillary base bone (J-J) was less than that in normal children significantly(P<0·01). The mouth-breathing children′s upper and lower archwidth (at firstmolar and cuspid) were comparatively narrower, and lateronasalwidth (Lap-Lap) was narrowertoo. Conclusion　Mouth breathing may lead to craniofacial morphological abnormal development in craniofacial transverse structures.

Objective　To access the effects of post′s diameter on the retention of post-core restorations.Methods　Thirty- three simulant rootswith same length,taper and different diameter (1·305 mm, 1·830 mm, 2·175 mm and 2·700 mm respective- ly) were made of polymethylmethacrylate and were divided into 4 groups. The wax patterns of post-cores were manufactured and cast. The post-cores were cemented. After that, the adhesion, frictional force and restriction of the post-core restorations were measured.Results　When the proportion of length and diameterwas smaller than 4·372, the linear regression between the post′s diameter and the retention of post-core crown systemwas F=107·98+72·08D. The linear regression between the post′s diameter and the adhesion was P=9·60+2·22D. The linear regression between the post′s diameter and the frictional force and restriction was Q=98·37+69·87D. The statistical analysis of the results indicated significant difference (P<0·05). When the proportion of length and diameter was lager than 4·372, the retention of post-core crown system increased although the post′s diameter de- creased.Conclusion　When the proportion of length and diameter was smaller than 4·372, the retention of post-core crown sys- tem increased withthe decrease of the post′s diameter. While the proportionwas lagerthan a certain value, this rule did not exist.

Objective　To discuss the skeletal and dentoalveolar characteristics of asymmetric mandibular excess malocclusions and to discuss the procedures of combined orthodontic-orthonganthic surgery treatments of asymmetric mandibular excess malocclu- sions.Methods　25 cases treated by combined orthodontic-orthognathic surgery treatments were reviewed to find out the special- ties of this kind of therapy.Results　The asymmetric of mandible presents anterior and posterior teeth tipped both sagitally and horizontally, as well as upper and lower jaws incompatibility. The pre-surgical orthodontic treatments included decomposition of anterior and posterior teeth, leveling and aligning the teeth etc. The post-surgical orthodontic treatments were to detail the occlu- sions. The patients all got functional and aesthetic good results after the combined orthodontic-orthognathic surgery treatments. Conclusion　The asymmetric mandibular excess affects the harmony of the face badly, and the correction of itmust be carried out by the combined orthodontic-orthognathic surgery treatments. The pre-and post-surgical orthodontic treatments are the key stages to make the skeletal corrections stable.

Objective　The research aimed to analyze the significance of Pont Index in the dental crowding.Methods　Re- spectively selected 91 normal occlusion persons and 101 dental crowding patients, measured every item of Pont Index of these two sample groups, and compared the results.Results　①The premolar index and molar index of dental crowding patientswere obvi- ously bigger than that of normal occlusion, and there was apparent significant difference.②There was no significant gender differ- ence of Pont Index either in normal occlusion or dental crowding patients. Whereas there was significant gender difference of pre- molar arch width and molar arch width in normal occlusion.Conclusion　The occurrence of dental crowding is clearly related to Pont Index.

Objective　To discuss the unsuccessful reasons and the preventive methods of the unsuccessful clinic cases.Meth- ods　The retrospective analysiswas carried on the 80 prosthesis in 70 patients from 1994 to 2001 whichwere sufferedwith unsuc- cessful results after the restoration of the metal crowns and bridges.Results　Therewere 68 teethwhich had collapsed or broken. 20 teeth had the post loosing or shedding. Root breaking, food impaction, unharmony colors of porcelain and the changing color of gingival were 3,3,6 and 2 teeth.Conclusion　It is necessary to select suitable repairing materials and operate correctly for pre- venting the occurring of the unsuccessful results in the porcelain-fused-to-metal-corwns and bridges.

Objective　To observe the differentmRNAlevels ofCandida albicansALS gene family between planktonic and bio- film-grown cells.Methods　ATCC 90038 and a wild strain of Candida albicans, biofilm modelsin vitrowere formed on glass slides. After 48 hours′incubation, the biofilm-grown cells were harvested. Half-quantification of ALS1 and ALS4 mRNA was based on the amplification by one-step RT-PCR.Results　The amounts ofALS1 and ALS4 mRNAof thewild strain in biofilm in- creased comparing with planktonic cells, while ATCC 90038 didn′t.Conclusion　The members ofALS gene familymay play im- portant roles in the course ofCandida albicansbiofilm formation.

Objective　To determine the dynamic release of tinidazole from the degradable poly-lactic acid (PLLA)-tinidazole blend gel (a periodontal local drug delivery) by high-performance liquid chromatography (HPLC)in vitroand to observe the poly- lactic acid (as a vector of tinidazole) howto affect the release of tinidazole.Methods　HPLC analysiswas conducted. The oper- ating conditions were C18-ODS-A column, water-methanol-acetic acid as mobile phase at a flowrate of 1·5 ml/min and a detection wavelength at 310 nm and a column temperature at 30℃.Results　①The retention time of tinidazole was about 12 min. ②There was good linear relationship between the concentrations of tinidazole in blend gel and their peak areas in the ranges of 5~ 500 mg/L. The regression reactionwasy=0·836+8·452 2×10-5x(r=0·998 6). RSDwas 0·2%.③Polylactic acid had no influence on the determination of tinidazole. The daily average release of tinidazole was 5·60%.The cumulative release of tini- dazole was about 78·40% in 14 days.Conclusion　Thein vitrodrug release analysis is an useful method in evaluating the per- formance of local drug delivery system. HPLC analysis is a simple and accurate method with good reproducibility.

Objective　To investgate whether the expression of osteoclast differentiation factor(ODF), intercellular adhesion molecule-1(ICAM-1) depended on the stage of osteoblastic differentiation from rat bone marrow mesenchymal stem cells(BM- SC).Methods　BMSC (4 passage) were selected for osteogenic differentiation by treated with osteogenic supplements(OS). Cells were harvested by day 0, 3, 6, 9, 12, 18 respectively after osteogenic inducement. In each experiment, control and OS- treated cells were processed in parallel. ODF and ICAM-1 mRNAwere analyzed by semiquantitave RT-PCR assay.Results　 Expression of ODFwas enhanced with osteogenic differentiation guadully. whereas, expression of ICAM-1 was activated at OS- treated day 6, then keeping at a stable level.Conclusion　This study indicated that BMSC undergoing osteogenic inducement was an ideal model for studying the differentiation and maturation of osteoblasts. During the early stage of differentiation along os- teoblasts from stem cells to osteocytes, BMSC or osteoprogenitor react somewhat differently from osteoblasts, suggesting the ability of osteoblasts to regulating differentiation and maturation of osteoclasts have been improved with osteogenic culture.

Objective　To investigate the effect of camera control devices of Cerec 2 on the fit of CAD/CAM all-ceramic copy- ings of posterior tooth.Methods　24 all-ceramic copyings were made by Cerec 2 with camera control devices and that without camera control devices. Copyings were embed and sectioned, then SEM and image analyzer was used to measure the space be- tween the copyings and dies atthe marginal opening, the axialwall, and the occlusal adaptation atthe measurement locations.Re- sults　①The marginal fit at buccal space of copyingswith camera control devices groupwas smallerthan thatwithout camera con- trol devices group(P<0·05).②The internal fit of of copyings had statistically significant difference at mesio-axial,disto-axial, bucco-axial,bucco-occlusal,linguo-occlusal and disto-occlusal space between camera control device group andwithout camera con- trol devices group(P<0·05).③There was no statistical difference on the marginal fit and internal fit of copyings between Vita MKⅡand porous alumina oxide(P<0·05).Conclusion　The Cerec 2 with camera control devices reduced effectively the in- accuracy of inner space of copyings which contributed from the technical errors of the operator, and provided well-proportioned space for adhesive. Both the fit of copyings made of Vita MKⅡand porous alumina oxide satisfied the clinical demand.

Objective　The purpose of this study was to evaluate the color changes of gingival porcelain through varying thick- ness and shade of porcelain of ceramometal restorations.Methods　In this study a spectrophotometer (PR-650) was used for col- or analysis. The color changes of dentin porcelain and gingival porcelain with three varied thickness (0·3 mm, 0·6 mm and 0·9 mm) were investigated. In addition, the color variances of Shofu vintage porcelain shade A2, A3and B2were tested.Results 　The results showed that decreased L* value of ceramometal restorations and increased a* value were due to the increase of the gingival porcelain thickness, color measurements showed the same trend as the increased dentin porcelain thickness and the opaque and dentin porcelain with different color affected the appearance of gingival porcelain.Conclusion　The color of gingival porcelain would be changed with the differences of thickness and shade of porcelain of ceramometal restorations.

Objective　To investigate dental caries polarization in 2-5 year-old children.Methods　3 799 random samples of 2-5 year-old children from attending kindergarten in Shenyang were selected. Means of dmft index and SiC index for each age group were calculated by WHO Collaborating Center. The subjects of each age groupwere further divided into subgroups of differ- ent level of dmft: the dmft of subgroup I was 0, the dmft of subgroup II was 1, the dmft of subgroup III was 2, the dmft of sub- group IVwas equal to or more than 3. The obtained data were analyzed statistically with SPSS 10.0.Results　4.5% of 2-year- old children were carriers of 60.0% of the total dmft in that age group, 13.2% of 3-year-old childrenwere carriers of 69.4% of the total dmft in that age group, 34.4% of 4-year-old children were carriers of 86.6% of the total dmft in that age group, and 47.8% of 5-year-old children were carriers of 89.8% of the total dmft of that age group.Conclusion　This study supports the assertion that a small percentage of personswith high dental caries rate and a large percentage of caries-free persons of early child- hood caries.