Objective　To observe the distribution of Annexin I and cytosolic phospholipose A2(cPLA2) in the palatal process of dexamethasome teratogenerated mice.Methods　Cutting along the coronary plane of the heads of fetal mice to obtain palate in the 14th, 15th, 16th day of gestation by 10-week-old in-bred mice. The distribution of Annexin I and cPLA2was checked by im- munohistochemical staining.Results　Duringthe fusing of the palatal processes, the staining ofAnnexin I and cPLA2 was positive in the epithelial and mesenchymal cells of the palatal process, and the intensity of staining changed with time.Conclusion　An- nexin I and cPLA2can modulate the development of fetal palate to some extent, and theymay be importantmediators in the devel- opment of cleft palate induced by dexamethasone.

Objective　The purpose of this study was to investigate the distribution of collagenⅠ,Ⅱ,Ⅹ,alkaline phosphatase (ALP) and their roles during initiation of condylar cartilage of the fetal mouse.Methods　Coronary sections of mandible of mouse embryo aged from14thto 18thdaywere studied under lightmicroscope after stained by immunohistochemical methodwith an- tibody of typesⅠ,Ⅱ,Ⅹcollagen and ALP.Results　On the 14th day ofmouse embryo, itwas found thatmesenchymal cells con- densation continuous with the periosteum. TypeⅠcollagen and ALP were positive behind the terminal of the ossifying mandibular periosteumwhere future condylarwill form. On the 15th day, positive staining for typesⅠ,Ⅱcollagenwas found in mesenchymal cells around hypertrophic cells and typeⅩcollagenwas detected in hypertrophic cells. ALPwas positive in bothmesenchymal cells and hypertrophic cells. On the 16th day, typeⅠcollagen was observed from periosteal osteogenic cells and mesenchymal cells of the fibrous cell layer to the upper hypertrophic cell layerwhileTypeⅡcollagenwas restricted fromthe lower polymorphic cell layer to the bottom of the hypertropic cell layer. TypeⅩcollagenwas positive in the hypertrophic cell layer. ALPwas positive in perios- teal osteogenic cells and hypertrophic chondral cells, but not in the polymorphic cell layer.Conclusion　Development of condylar cartilage is different from that of limb bone. TypesⅠ,Ⅱ,Ⅹcollagen are expressed in the condylar chondrocyte on the early stage of endochondral ossification. The histology evidence supports the conjecture that condylar cartilage is derived from differentiated mesenchymal cells of the preperiosteum or periosteum of the mandible where ALP is positively expressed.

Objective　To discuss the effects of titanium nickel shape memory alloy (TiNi-SMA) distractor with different stretching force and different distance between two fixed ends on the height of alveolar ridge augmentation.Methods　The mini distractors were all made of TiNi-SMAwire. The maximum stretching force and the distance between two fixed ends according to different distractors (A, B and C) were 20 mm, 700 g; 15 mm, 1 000 g; 20 mm, 1 000 g. 15 adultmongrel canineswere divid- ed into three groups randomly and extracted the mandibular premolars and first molar. One month later, box-shaped osteotomies of the alveolar bone were carried out in the left mandible and the TiNi-SMA distractors were buried. The bone height was measured and the radiographswere taken before and five weeks post operation continuously.Results　One week post operation, the vertical ridge augmentation of group A, B and C averaged (7·55±1·02)mm, (4·97±0·34)mm, (8·54±0·82)mm and the height re- mained (7·20±1·05)mm, (4·93±0·21)mm, (8·04±0·78)mm five weeks post operation. There was no statistic difference in the height of alveolar ridge augmentation between Group A and C, but Group B showed significant difference with the other two groups. In each group, the height did not changed significantlywith the time. The radiographs showed obvious distraction gap post operation, and the new bone regenerated five weeks later.Conclusion　It suggests that in the scope of suitable stretching force, the height of alveolar ridge augmentationwas determined by the size ofTiNi-SMAdistractor, that is to say, determined by the dis- tance between the two fixed ends.

Objective　To investigate a kind of Co-Cr-Mo alloys used for both porcelain fused to metal (PFM) restorations and casting framework of removable partial dentures.Methods　The Co-Cr-Mo alloy underwent the design for elementary compositions of the alloys and the production from the rawmaterials by means of a vacuummelt furnace. The strength, hardness, plasticity and casting ability of the alloywere examined with metal tensile test. Vickers hardness test and grid castingwere examined respective- ly. The microstructure of the Co-Cr-Mo alloy was also inspected by scanning electron microscope and X-ray diffraction analysis. Results　The elementary composition of DA9-4 alloy mainly consisted of Co 54%~67%, Cr 21%~26%, Mo 5%~8%, W 5%~8%, Si 1%~3%, Mn 0.1%~0.25% and trace elements. The yield strength of the alloywas 584 MPa, while the ten- sile strengthwas 736 MPa. The coefficient of expansionwas 15.0%, the Vickers hardness reached 322, and the casting ratio exi- bited 100%.Conclusion　The DA9-4 Co-Cr-Mo alloy used for PFMand framework shown in this paper can meet the clinical de- mands and have reached the objects of the experiment plan.

Objective　To investigate the effect of two different ring liner thickness on the deformation of resulted castings. Methods　GC No.2 casting rings (50 mm in height and 39.5 mm in diameter) were lined with two dry ceramic fiber linerswith thickness of 0.70 mm and 0.45 mm. Plate-like wax patterns with pre-marked points were invested with a gypsum-bonded invest- ment and the rings were cast with a silver-based dental alloy. The difference between the castings and the wax patterns at corre- sponding points was calculated to represent the dimensional change of the investment in the rings at different directions.Results　 The expansion of the investment in the ringwas non-isotropic, with larger radial direction expansion than the axial direction expan- sion(P<0.01). In the scope of this study, the effect of two different ring liner thickness on the casting precisionwas statistically non-significant (P>0.05).Conclusion　The liners with two different thickness failed to eliminate non-isotropic deformation of the castings under the testing conditions of this study.

Objective　To clone the recombinant fusion gene ofEscherichia coliheat-liable enterotoxin B subunit (Ltb) and Actinobacillus actinomycetemcomitansfimbria associative protein (Fap).Methods　Two couples of primerswere designed for PCR according to the known sequence of ltb and fap. The ltb and fap gene were obtained by amplification PCR technique from plasmid EWD299 ofEscherichia coliandActinobacillus actinomycetemcomitans310 DNArespectively, and fused them by PCR. The fusion gene ltb-fap were cloning into plasmid pET28a(+). The recombined plasmid pET28a ltb-fapwas transformed intoEscherichia coli DH5α. The recombinant was screened and identified by restriction enzyme and PCR. The cloned gene was sequenced.Results　 The ltb-fap about 531bp in sizewas obtained successfully , and identified by PCR, restrictive enzyme and sequence analysis.Con- clusion　The vector of pET28a ltb-fap was obstained.

Objective　To detect and distinguishStreptococcus mutans(S.mutans) andStreptococcus sobrinus(S.sobrinus) quickly in epidemiology and investigate the distribution ofS.mutansin the oral of children with rampant caries.Methods　De- signed minor groove binder (MGB) probes according to the gtf gene ofS.mutansandS.sobrinus. Detected 9 reference strains of Streptococcus mutansgroup byMGB probes in real time and after cultivation. Evaluated the results of these twomethods. 92 dental plaques from pre-school children with rampant caries were detected in real time with MGB probes.Results　The primers could amplify the target sequences specificity and distinguishedS.mutansandS.sobrinusfrom each other using MGB probes. Though the fluorescence occurred earlier inS.mutansthan inS.sobrinus, they had the same results in nature. In 92 children with ram- pant caries, the detective ratio ofS.mutanswas 96.7% and that ofS.sobrinuswas 32.6%. All the sampleswhich could detect S.sobrinuswere positive forS.mutans.Conclusion　The primers and probe designed fromgtf genes ofS.mutansandS.sobri- nuscan amplify the target sequence and distinguish them from each other in real time.

Objective　To evaluate the mastication function of the patientwhose maxilla was reconstructed with individual tita- nium mesh and Chinese flap or combinedwith fibularflap. The superiority of thismethod onmaxillary functional reconstructionwas testified.Methods　Since March of 2001, 10 cases of maxillary defectwere reconstructed with individual titaniummesh and Chi- nese flap or combinedwith fibular flap, and routine removal partial dentureswere fixed after 3~6 months postoperatively. Assess- ment of occlusal force was proceeded byT-Scan II system (Tekscan company, USA).Results　The occlusal force analysis results indicated the asymmetry index of bite force and asymmetry index of occlusal contact area differed significantly between preoperation and postopertion (P<0.05). The recovery rate of total occlusal force was between 27.05%~74.06%, and the average was 50·15%.Conclusion　This new three-dimensional maxillary functional reconstruction method had a satisfactory recovery in both of contour and function recently, especially restored the mastication function effectively.

Objective　To study the bracket placement and archwire bending based on ethnic differences and individual differ- ences of normal occlusion.Methods　The prominence, tip, torque, upper first molar offset of crown and arch form between Chi- nese and Caucasian normal occlusion were compared.Results　The results showed the ethnic differences of prominence, tip, torque, upperfirstmolar offset of crown and arch form between Chinese and Caucasian normal occlusion. The placement of bracket was influenced by the crown morphology.Conclusion　The adjustments of the bracket placement and arch wire bending with Edgewise and pre-adjusted appliance are necessary to adapt to ethnic difference and individual difference.

Objective　The aim of this studywas to investigate the effects of the pendulum appliance in treating dental ClassⅡ patients with various vertical growth patterns.Methods　The samples (n=30) were divided into three groups equally based on their FMA. Pretreatment and post-treatment cephalometric radiographs were taken to measure the changes.Results　The amount of upper molar distalization in the low-angle group was the fewest, and that in the high-angle group was the most. Upper molars had been intruded insignificantly. The amount of anchorage loss at the first premolars and overjet increased at incisorswas different in the three groups. The biggest change happened in the low-angle group, and the smallest in the high-angle group.Conclusion　 The results of this study showed that pendulum appliance could move the uppermolars distally in a short period of time. The upper molars in different groups were intruded insignificantly. Pendulum appliance could be used to move the upper molars distally in high-angle cases.

Objective　To study the severity of periodontitis and risk factors in Chengdu.Methods　202 periodontitis patients (65 male, 137 female), aged from 25 to 60, were requested to fill a questionnaire. Probing depth(PD),clinical attachment level (CAL),gingival recession and bleeding on probing(BOP) on 6 sites of each tooth were measured and recorded.Results　The mean PD, AL, gingival recession and BOP% of 202 subjects was (3·2±0·31) mm,(3·5±0·37) mm,(0·3±0·02) mm and 21·16%·59% of subjects missed at least one tooth. 129 subjects suffered with initial to moderate periodontitis. 73 subject suf- fered with advanced periodontitis. 40, 86, 55 and 21 subjects had received college education, high school education, middle school education and primary school education. 18% of subjects had smoking history, 67% subjects had tea/coffee history, 66% of subjects had psychosocial problem, and only 8% of subjects had received regular periodontal treatment. There is no relationship between the severity of periodontitis and education.Conclusion　It is very important to develop an education program on oral healthy for people in Chengdu.

Objective　The study aims to find outthe fluctuating curve of the intra-articular pressure in temporomandibular joint with sudden-onset, persistent, severe closed lock and discuss the mechanism of its formation. We also investigate the effects of the arthrocentesis.Methods　20 affected sides in 16 patientswere collected. ANo.8 syringe needlewas used to pierce intothe upper compartment of TMJ. The pre-arthrocentesis intra-articular pressure was measured by the pressure transducer via the flexural rigid tubing at open and close bite. The curve and mean value were documented during the operation.Results　The patientswith sud- den-onset, persistent, severe closed lock had significantly low negative intra-articular pressure in their affected temporomandible joints. The average pressureswas (-9.947±8.854) kPa at open bite and (-6.475±4.147) kPa at close bite.Conclusion　The TMJs with sudden-onset, persistene, severe closed lock has particular characters on etiology and clinical behavior. Arthrocentesis is one of the effective treatments to the diseases.

Objective　To reveal the correlation between personal anxiety (PA) and dental fear (DF) among the junior college students in Southwest China.Methods　The Corah′s questionnaire and personal anxietymeasuring indicator (SAS) were conduct- ed on 1 975 junior college students in Chengdu. The collected datawas analyzed by Software SPSS 10.Results　A correlationwas found between DF and PA (χ2=3.97,P<0.05). The score of DF was well related with the score of the 15 questions designed (r=0.913,P=0.000). The side affections during dental treatment process had significant effects on DF (r=0.409,P= 0·000).Conclusion　A correlation was found between DF and PA among the junior college students in Southwest China.

Objective　To investigate the oral health knowledge, attitudes and behavior of urban, rural and suburban adults in Deyang, PR China, and analyze the influence of several variables on the utilization of dental services.Methods　1 010 adults with 35-44 years old from urban, rural and suburban areaswere interviewed byQuestionnaire forAdults, WHO Integrated Package for Basic Oral Care.Results　More than half of the surveyed adults claimed“having pain of mouth during the last 1 year”. More urban adults(61.3%) used fluoridate toothpaste than suburban and rural adults(6·9%、16·8%)·61·0% and 71·5% of rural and suburban adults had never seen a dentist, compared with 32·0% of urban adults. Logistic regression analysis showed that ur- ban adults having pain in mouth during the last yearwere more likely to visit a dentist in the last 2 years.Conclusion　Although the oral health attitude is good among the people in Deyang, the knowledge is poor. Dental service utilization was not enough and the situation was also worse for rural adults.

Objective　The relationship between the mode of tumor invasion in the tumor-host borderline and the frequency of cervical lymph node metastasiswas investigated in squamous cell carcinoma of the oral cavity.Methods　200 caseswith histologi- cally proven squamous cell carcinoma of the oral cavitywere studied by histological methodwithHE stained. The mode of invasion in the tumor-host relationship was classified into five grades by Yamamoto′s criteria.Results　With regard to the relationship be- tween the mode of invasion and metastasis, the more invasive the tumor tissue was, the more frequent the metastasis formed (P< 0·001). The frequency of metastasis in grades 1 and 2 was low (0 and 5·9%, respectively),The frequency of metastasis in grades 3 was moderate (14·3%), and that in grades 4c and 4d was highly rapid (63·0% and 82·9%, respectively). Single node metastases were frequent in grade 3 and grade 4c (66·7% and 58·8%, respectively), while plural node metastases were frequent in grade 4d (70·6%,P<0·05 ). Moreover, the distribution of metastasized lymph nodes was focused on level 1 (41·2%)or level 1 and 2 (79·4%) in grade 4c and was dispersed from level 1 to 4 in grade 4d (P<0·05). In the present study, the degree of differentiation did not correlate wellwith the frequency of metastasis.Conclusion　These results indicate that the more invasive the tumor cells were to the host, the more frequent the metastasis formed. The different mode of invasion would accompany with different frequency of metastasis, different number and distribution of metastasized lymph nodes.

Objective　A retrospective clinic study is presented of surgical patients undergoing a modified parotidectomy with conserving the sub-superficial musculoaponeurotic system (sub-SMAS) and great auricular nerve and reconstructing by the sterno- cleidomastoid flap(SF). The incidence of clinical complications was observed after the parotidectomy.Methods　226 patients were divided randomly into fourgroups. Group 1 (94 cases) were operated bythe conservingthe sub-SMAS. Group 2 were operat- ed by the sub-SMAS and constructed by SF. Group 3 (57 cases) were treated by the subcutaneous flap (sub-CF). Group 4 (33 cases) were received by sub-CF and SF. The surgical technique was described and the incidence of clinical Frey′s syndrome was evaluated by minor test(starch-iodine test)and observed gustatory sweating syndrome. The feeling and concave of the region of au- ricular lobule were followed up.Results　The incidence of Frey′s syndrome in group 1 (5·32%) or group 2 (4·76%) was sig- nificantly lower than that of group 3 (49·1%) or group 4 (51·5%) through by subjective observation and minor test(P< 0·005). The significance between group with SF and group without SF existed in protecting the concave of the region of auricular lobule(P<0·05). The feeling of the region of auricular lobule had no change by preserving the great auricular nerve.Conclusion 　There was good effect to prevent gustatory sweating syndrome in parotidectomy of reserve parotid fascia. The aesthetics and sense of the region of auricular lobule could be prevented by using SF and reserving the great auricular nerve.

　Objective　Using functional magnetic resonance imaging (fMRI) to detect the cerebral cortical somatotopy during maximum voluntary clenching with soft occlusal pad in healthy adults. By comparing with the cerebral cortical activation during clenching with andwithout soft occlusal padwe try to detect the central mechanism of the rule of the occlusal pad.Methods　Ten healthy subjects were selected and scanned by Elscint/GE 2.0 TeslaMR system. Block designwas used and the movement pattern was maximum voluntary clenchingwith soft occlusal pad. The fMRI datawere analyzed by SPM99 software and group map analysis was done.Results　The activation areas were found in bilateral or unilateral motor cortex, somatosensory cortex, prefrontal cor- tex, temporal cortex, premotor cortex, insula, frontal operculum, basal ganglia (putamen), parietal cortex and cingulate. Group map analysis showed activation in bilateral motor cortex, right somatosensory cortex, bilateral basal ganglia, and bilateral insula. The activation of left motor cortex was significantly higher than right side. Compared with cortical activation without occlusal pad, the motor and somatosensory cortex changed a lot.Conclusion　The changes of the activation of motor and somatosensory cortex during clenching after wearing the soft occlusal pad might be the central mechanism of the rule of the occlusal pad.

Objective　To investigate the chondrogenisis by alginate gelatin and rats′bone marrowstromal cells(BMSCs) chon- drogenicly inducedin vitro.Methods　Thirty-two male adult SD ratswere assigned randomly to experimental and control groups. In experimental group, bone marrowwas obtained from the right tibias of all the rats. After expanding and culturing 3 passages, induced BMSCs by chondrogenic culture medium for 10 days. Suspended induced cells in alginate gelatin, and injected the com- plex into the hypodermic tissue of the backs of rats autogenously. In control group only alginate gelatins were injected. The grafts were taken out for examinations 4 and 8 weeks after the operations.Results　Considerable cartilage appeared in experimental group 8 weeks after operations. RegularHE staining and alcian blue staining showed a great deal of cartilage holding chondrocyte masses surrounded by abundant matrix. Alginate gelatin decompounded obviously, and the rest distributed among newly formed cartilage. No cartilage appeared in control group all through.Conclusion　BMSCs and alginate gelatin have a beautiful future in cartilage tissue engineering.

Objective　To observe the expression of angiopoietins in oral squamous cell carcinoma and relationship between the expression of angiopoietins and pathologic classification.Methods　The expression ofAng-1 and Ang-2 protein in samples from42 oral squamous cell carcinoma and 16 oral normal mucosa were detected by immunohistochemical technique.Results　The expres- sion of Ang-1 and Ang-2 was found in both oral squamous cell carcinoma and normal control. Itwas found Ang-1 expression alike in oral squamous cell carcinoma and control (P>0.05). Ang-2 expressed at low level in control while strongly positive in oral squamous cell caroinoma and the level of Ang-2 expression in oral squamous cell caroinoma was related to pathologic classification (P<0.05).Conclusion　Ang-2 expression in oral squamous cell carcinoma is related to angiogenesis and pathological classifi- cation, which is probably involved in angiogenesis regulation, promotes the development and metastasis of oral squamous cell car- cinoma.

Objective　To studythe therapeutic effects of combined gene therapy ofwild type p53 (wt-p53) and herpes simplex virus thymidine kinase (HSV-tk) gene on pleomorphic adenoma cells of salivary gland.Methods　Wild type p53 and HSV-tk gene were transfected into human pleomorphic adenoma cells of salivary gland by using recombinant adenovirus vector. The effi- ciency of transfection was checked and gene was expressed by RT-PCR methods. The cell inhibition after transfected was verified by light microscope and MTT.Results　The proliferation of the pleomorphic adenoma cells transfected wt-p53 and HSV-tk gene was inhibited and the cell survival rate decreased to 54% and 38% respectively in 5 days. However, whenwt-p53 gene combined withHSV-tk/GCV system, the killing effects was significantly stronger (P<0.05) and the cell survival rate decreased to 20%. Conclusion　Combining p53 gene withHSV-tk/GCV system for gene therapy in pleomorphic adenoma cells of salivary gland is a valuable method.

Objective　The aim of this study was to prepare Pingyangmycin Albumin Microspheres (PYM-AMS) for arterio- venous malformations treatment.Methods　PYM-AMS was prepared at 140℃by the method of emulsification-heat solidification and its characteristicswere evaluated, such as morphosis, particle size, drug loading (DL%), encapsulation efficiency (EE%), stability and drug sustained-releasingin vitro. After being packaged, PYM-AMS were sterilized with 13.7 kGy of60Co. Small samples of PYM-AMS were packaged in small bottles and stored at 3~5℃、15~25℃、37℃for 3 months, then checked the change of morphology、DL、EE and the release rate.Results　The surface of particleswas smooth and integrated. The average di- ameter of PYM-AMS particles was 139.422μm and 80% was in the range of 56~251μm. The mean DL% and EE% were 26·47% and 84.3%, respectively. PYM released fast in 5 h, but then released slowly. 88.65% drugs were released in 24 h, and t50was 1.5 h. There was no obvious change of the morphology、DL、EE and the release rate of PYM-AMS stored at 3~5℃、 15~25℃、37℃for 3 months.Conclusion　PYM-AMS prepared in this study had sustained-release effect, high drug loading and high stability. Albumin is a good carrier of PYM embolization agent.

Objective　To investigate the effect of bilateral mandibular distraction osteogenesis in the condyles.Methods　16 adult hybrid dogs were randomly divided into normal control group and experiment group. Experimental dogs underwent bilateral mandibular osteodistraction at a rate of 1 mm/day. 4 dogs were killed respectively in distraction period, 2 and 8 weeks after com- pletion of 10 days distraction. The bilateral condyles specimens were harvested and examined with histological and immunohisto- chemical methods.Results　Comparedwith normal control group, various degrees of irregularities and erosionwere found in fibro- cartilage of condyle in experiment group, including damage in fibrous layer, hyperplasia layer and proliferative layer and osteogenic activity in cartilage layer. Asignificant increase ofTGF-β1 expressionwas also found in experiment groups. TGF-β1 positive stain- ing was noted in hypertrophic cell, matrix and chondroblast, osteoblast and matrix in osteogenic activity areas. These changeswere the most obvious in 2 weeks after completion of distraction.Conclusion　Gradual bilateral mandibular distraction at a rate of 1 mm/day brought degenerative changes of condyle, but the changes are reversible.

Objective　To isolate and identify human dental pulp stem cells from third molars.Methods　Dental pulps were dissected and digested by collagenase typeⅠand dispase. The obtained single cell supernatant were harvested and cultured. Characterization of the phenotype of DPSCswas detected by immunohistochemical method and RT-PCR assay. Cell cycle was ana- lyzed by FCM. Differentiation potential of DPSCs was evaluated.Results　Colony-forming efficiency of cells derived from dental pulp tissue was 2~15 clones/103cells plated. DPSCswere found to express many different markers, including vimentin, collagen typeⅠ, GFAP, nestin and osteocalcin, while they failed to reactwithMyoD and DSPP. About 64.1% of the cellswere in G0/G1 phases, while only 35.8% in proliferation (S+G2+M). Grown in an adipogenic cocktail medium for three weeks, some DPSCs expressed fat cell markers of PPARγand LPL, and formed oil red O-positive lipid clusters in fiveweeks. After culturewith a myo- genic-inductive medium, DPSCswere found to expressMyoD, desmin and myosin, markers ofmyocyte. Long-term cultures of DP- SCs grown in differentiation inductive medium demonstrated the capacity to form Von Kossa-positive condensed nodules with high levels of calcium.Conclusion　Cells isolated from adult human dental pulp are clonogenic, and have multipotent differentiation potential, satisfying the criteria of postnatal somatic stem cell.

Objective　To investigate the biological effects of the new nano-hydroxyapatite/polyamide 66 biological composites (nHA-PA66) on the dental pulp cells.Methods　After interaction with the nHA-PA66 eluate, the growth, proliferation, and function of theinvitrocultured human dental pulp cellswere studied by cell culture technique, inverted phase-contrastmicroscope observation, MTT assay, flow cytometry, ALP activity assay and quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR) analysis.Results　The cultured pulp cells grewwell and showed nomorphological variation. Moreover, thismaterial had no negative effects on the proliferation, cell cycle, ALP activity and the expression of dentin sialophosphoprotein (DSPP) mR- NA of the pulp cells.Conclusion　As a newnano-biomaterial, nHA-PA66 has good biocompatibilitytothe pulp cells, but no ob- vious bioactivity.

Objective　The purples of this studywas to investigate the role of different components of Galla Chinensis extract on the growth of 6 kinds of cariogenic bacteria, and to find out the most effective components of Galla Chinensis extract.Methods　 Four different components (GCE1, GCE2, GCE3 and GCE4) were separated fromGalla Chinensis and there antibacterial activities toStreptococcus mutansATCC 25175,Streptococcus sanguisATCC 10556,Streptococcus salivariusSS 196,Actinomyces naeslundii WVU627,Actinomyces viscosusATCC 19246 andLactobacillus rhamnosusAC 413 were checked. There effects on the growth curve ofStreptococcus mutansATCC 25175 were also investigated.Results　The most effective part of Galla Chinensis was found to be GCE2 and GCE4, whichwere found to be a mixture of polyphenol-rich fractions. All of the different components had an in- hibitory effect to the growth ofStreptococcus mutansATCC 25175.Conclusion　All of the 4 different components of Galla Chinen- sis extract could inhibit the growth of the tested bacteria. These results suggest that the antibacterial activity of Galla Chinensis ex- tract is caused by a synergistic effect of monomeric polyphenols, which can easily bind to proteins.