Objective　To study the effects of inducible NOS inhibitor aminoguanidine on the expression of NOS in facial nerve and surrounding tissue of traumatic facial paralysis rats.Methods　Asmall dose of aminoguanidine were intraperitoneally injected into rats before and after facial paralysis. The facial nerve and surrounding tissues were cut at different time point. Immunohisto- chemical ABC method was used to study the changes of NOS expression in facial nerve and surrounding tissues.Results　The in- ducible NOS immunoreactivity was obvious inhibited in the facial nerve and surrounding tissues in aminoguanidine group.Conclu- sion　Aminoguanidine chronic treatment can obvious inhibit the inducible NOS expression in the facial nerve and surrounding tis- sues. Aminoguanidine can improve the regeneration of facial nerve and the recovery of traumatic tissues.

Objective　To evaluate the expression of recombinant plasmid pcDNA3·1/GBD of glucan binding protein ofStrepto- coccus mutansin mammalian cells COS-7.Methods　Eukaryotic plasmid carrying encoding gene of GBD ofStreptococcus mutans gbpAwas constructed and the plasmid was introduced into COS-7 cells by Lipofectamine reagent. The transient expressed protein in COS-7 cells was detected by immunochemistry technique.Results　The positive expression was detected in plasma of the cells which were transfected with recombinant plasmid pcDNA3·1/GBD. The cells which were transfected with pcDNA3·1 were nega- tive.Conclusion　GBD can translate and express in COS-7 cells aftertransfectedwith recombinant plasmid pcDNA3·1/GBD. The expressed protein locates in the plasma and the protein is able to combine with anti-GbpA antibody. The expressed protein has the antigenicity and is a candidate gene vaccine.

Objective　To confirm if denuded bone on lateral aspects of the hard palate of surgical repairs of the cleft palate is the main reason of causing disturbance of facial growth and to investigate the mechanism.Methods　48 SD ratswere employed in the study. Among them 40 animalswere divided into normal control and experimental group randomly. Normal controlwas not op- erated. Hard palate mucoperiosteum on the left side in experimental group were excised. Left hard palate mucoperiosteum in an- other 8 female three-week-old SD ratswere excisedwith same method andwere sacrificed at 2nd, 5th, 8th, and 12th day, respec- tively. The 8 rats were used for histological research.Results　The width of all left sides hard palates in experimental group was significantly narrower than right side, and demonstrated statistical difference. Chronic osteomyelitis on the denuded hard palatewas observed.Conclusion　The denuded bone wound might be a principal factor for the following maxillary growth deformity in cleft palate patients who received palatoplasty in childhood. The mechanism of causing the deformity might be wound and scar contrac- tion, decreased blood flow and nutrition plus chronic osteomyelitis.

Objective　To investigate the condensability of mandibular length.Methods　In six goats were used in the study. Corticotomy at right mandibular angleswas performed via extral-oral accession. Special deviceswere applied to shorten the mandi- ble by 0·5 mm per three days respectively.Results　①Mandibular angles of the six goatswere shorten by 0·8 cm to 1·3 cm re- spectively in 48 days to 78 days;②In spite of the lower ascending ramus moving forward and angles being blunt, the occulusion scarcely varied because of contralateral bite-lock;③X-ray demonstrated that, at first, bone density in contracted areas declined , and then increased gradually to almost normal density;④Under microscope there were three tissues layers from central to lateral within the bone gap: fiber layer, cartilage layer and bone layer, and fiber layer gradually transform into cartilage layer with the fixed time. At the end of fixation they all transform into bone tissue.Conclusion　Contraction osteogenesis is actually a process of compression, absorption and rebuilding. It is feasible that using contraction osteogenesis to shorten the mandible via cortcotomy.

Objective　To establish a method for culturing dental follicle cells of rat and observe the growth characteristics of the cultured cellsin vitro.Methods　Dental follicle and associated enamel organs were dissected from the first and second man- dibular molars of 6-7-day-old rats, and then culturedin vitro. Purified dental follicle cells derived fromthe third orthe fourth pas- sage cells were utilized in the following experiments. The shape and ultrastructure of dental follicle cellswere observed by light-mi- croscopy and transmission electron microscopy. Immunocytochemistrywas used to detect the expression of vimentin, typeⅠcolla- gen and fibronectin.Results　The cultured cells were fibroblastic in shape, elongate with processes, and transmission electron microscopy revealed that they contained electron-dense granules, an abundant rough endoplasmic reticulum, but did not form desmosomes. Vimentin, typeⅠcollagen and fibronectinwere present in dental follicle cell.Conclusion　The dental follicle cells of rat could be successfully culturedin vitroand the cultured cells had the same characteristics of dental follicle cells of normal rat.

Objective　To explore the correlation of chemotherapy efficacy in tongue squamous cell carcinoma(SCC) with ex- pression level of P-glycoprotein(Pgp), multidrug resistance-associated protein (MRP), lung resistance-related protein (LRP), glutathiones-tranferase (GST-π), DNAtopo-isomeraseⅡα(TopoⅡα).Methods　The expression patterns of Pgp, MRP, LRP, GST-πand TopoⅡαin 40 patients (pre and post-chemotherapy, respectively) with tongue SCC were examined by immunohisto- chemically labelled streptavidin bioein method (LsAB).Results　The expression ratios of Pgp, MRP, LRP, GST-πand TopoⅡ αin pre-chemotherapy cases were 47·5%, 50%, 35%, 45%, 82·5%, respectively. No relations between expression of Pgp, MRP, LRP, GST-π, TopoⅡαand clinic indexes were established (P>0·05). Expression ratios of Pgp, MRP in post-chemo- therapy cases were higher than that in pre-chemotherapy cases (P<0·05). Expression of Pgp and MRP showed relevance with drug resistance (P<0·05). The co-expressionwas common, the ratios of co-expression of Pgp, MRP, GST-πandMRP, GST-π in chemotherapy non-responders were 40% and 50%, respectively, but 0 in responders.Conclusion　The intrinsic multidrug resistance of tongue SCC is relevant to the effects of Pgp, MRP, GST-π.

Objective　To study the expression of MMP-8 in human and rat tooth development.Methods　Immunohis- tochemistry was used to detect the localization of MMP-8 protein while in situ hybridization was used to examine the expression of MMP-8 mRNA.Results　The expression ofMMP-8 proteinwas localized in odontoblast and dentin matrix at the later bell stage in human tooth germ. The dentin was denser close to the pulp cavity. The expression ofMMP-8 mRNAwas found in very few polar- ized odontoblast at the early bell stage and all polarized odontoblast at the later bell stage in rat tooth germ.Conclusion　The re- sults suggested thatMMP-8 involved in dentinmatrix rebuilding in the process of dentin formation in human and rat dental develop- ment.

Objective　To investigate the expressions ofTestosterone in the condylar cartilage of rapid growing rats.Methods　 The mimic functional appliances were used in experiment groups and rats were killed after 3 days , 1week, 2weeks, 3weeks and 4weeks. Immunohistochemical technique was used to detect the expression ofT.Results　Twas expressed throughout the condy- lar cartilage. TheHighest expressionswere in mature layers of both experiment and control groups. Alongwith the maturation, the expressions of T in the condylar cartilage were changed respectively, and the immunostain levels in the mature layer of experiment groups 2 and 3 weekswere higherthan those of control groups (P<0·05).Conclusion　①Tis a member of cartilage growth and development control system.②The orthopedic mechanism of functional appliance may be conducted by T.

Objective　Clinical effects in local application of hyaluronic acid (HA) adjunctive to scaling and root planing (SRP) were evaluated.Methods　In this cross over design study 20 patientswith chronic periodontitiswere included. Plaque in- dex, sulcus-fluid-flow-rate (SFFR), sulcus bleeding index, probing pocket depth and attachment level were monitored. All pa- tients were treated with full mouth SRP, in addition a HA gel was administered subgingivally in the test site every week for 6 weeks.Results　A statistically significant improvement of all clinical test parameters was observed in both groups (P<0·05). Clinically, no significant difference between test and control group could be found. However, the SFFR decreased significantly faster in the test group.Conclusion　No post-inflammatory tissue regeneration could be achieved by the adjunctive use ofHAgel to SRP in the patients with chronic periodontitis. Due to SFFR a control of local inflammation can be achieved quickly.

Objective　To study the epidemiological features of cleft palate (CP) in Chinese perinatals.Methods　Data from 1996 to 2000 were collected through Chinese Birth Defects Monitoring Network a hospital based congenital malformation registry system. During that period all live or still birthswith 28 weeks of gestation ormore were assessed within 7 days after delivery.Re- sults　499 perinatalswith CPwere identified among 2 218 616 births, then the overall prevalence rates of CPwere 2·25/10 000, rates in isolated and syndromic CPwere 1·75/10 000, 0·50/10 000 respectively. The rates in urban and rural area, in male and female births were 2·27/10 000 and 2·19/10 000, 1·93/10 000 and 2·57/10 000 respectively. The highest but nonsignificant rate (2·84/10 000) was found in maternal age group of more than 35 years. An increased trend was found both in overall CP and syn- dromic CP during that period. Geographic variation was found among provinces. The perinatal mortality rate of CP was 14·9%, and the rate of isolated forms was 7·3%, while the rate of syndromic CP was as high as 41·4%.Conclusion　The increasing prevalence rate of syndromic CP can account forthe seculartrend of overall CP. Female predominance was only observed in isolat- ed forms of CP among Chinese perinatals. Geographic variation was identified too. Due to poor birth quality, perinatals suffering from syndromic CP had poor prognosis.

Objective　To studythe Ag-NORs expressive character ofTlymphocyte in patientswith oral and maxillofacial tumor and evaluate its diagnostic value for the patients.Methods　Nucleolar organizer regions(NORs) of T lymphocyte from 86 normal adults, 102 patientswith oral and maxillofacial benign tumors and 87 patientswith oral and maxillofacial malignanttumorswere an- alyzed through KL imaging system.Results　There was significant difference among normal adults, benign and malignant patients (P<0·01). Their average I.S% valueswere 7·87±0·12, 5·72±0·14, 4·19±0·13, respectively.Conclusion　The expres- sion of Ag-NORs of T lymphocyte has definite relation with oral and maxillofacial tumors; detection of Ag-NORs might play valu- able in diagnosis of oral and maxillofacial tumors.

Objective　To investigate the causes and treatment of the asymmetric prominent mandibular angle.Methods　 From 1996 to 2001, mandibular angle osteotomy, mandibular outer cortex osteotomy, mandible,genioplasty and buccal pad exci- sion were selected to treat 70 patients.Results　All the patients had satisfactory results with complications of bleeding, infection and labial scar in three patients.Conclusion　asymmetric prominent mandibular angle should be treated according to the charac- teristics of the deformity. Mandibular angle osteotomy, osteotomy of outer cortex of the mandible, genioplasty and bucal pad exci- sion can provide satisfactory result.

Objective　To study the correlation of prime colonization time ofMutans Streptococciand feeding habits in infants. Methods　One hundred and eighty children(aged 6~24 months) from Shenyang city were examined for the colonization ofMS Related items were registered by completed questionnaires.Results　The study showed a correlation between prime colonization time and feeding mode, breast feeding, feeding frequency during bedtime, asleep habits.Conclusion　Advocating reasonable feeding mode and asleep habits is effective to interdict or delayMS′s colonization and transmission in child to prevent caries.

Objective　Skeletal and dental changes during treatment and six months post-treatment with the headgear-Herbst appliance were evaluated quantitatively.Methods　The sample comprised of 22 treated patients and 31 controls. Lateral cephalo- grams were obtained at start, after 6 months and end of active treatment, and after 6 months of retention.Results　The restraint effect on the maxilla was significant in both initial and late phases, the enhanced growth of the mandible was significant during the initial phase only, while there was effect of reduced increase in lower facial height during the late phase only. During retention pe- riod the jaw base relationshipwas maintained and the effect on the lower facial heightwas reinforced.Conclusion　The Headgear Herbst was effective orthopedic devise.

Objective　The purpose of this article was to observe the effect of by microwave thermocoagulation on oral benign tumor and to provide theoretical basis for clinic treatment of oral benign tumor.Methods　165 patients with oral benign tumor were included. There were 83 patientswith oral bursa cyst, 42 patientswith hemangioma, 19 patientswith papilloma, 14 patients with fibrous hyperplasia and 7 patientswith epulis. All the patientswere treated by WB-100 microwave thermocoagulation.Results 　144 patientswere effective afterthe first treatment and 21 patientswere effective afterthe second treatments. No side effect and reoccurrence were found after 3 years.Conclusion　Microwave thermocoagulation is an effective and safe method in clinic treat- ment of oral benign tumor.

Objective　To compare the endotoxin levels between acute and chronic periapical periodontitiswith different clinical symptoms.Methods　10 cases of acute periapical priodontitis(Group 1) ,10 cases of chronic periapical periodontitis(group 2, the diameter of apical radiolucency area was less than 2 mm),10 cases of chronic periapical periodontitis with sinus(group 3, the diameter of apical radiolucency area was greater than 2 mm), 10 cases of chronic periapical periodontitis without sinus (group 4, the diameter of apical radiolucency area was greater than 2 mm), were included in the study. Chromogenic substrate method of limulus amebocyte lysate(LAL) test was used to measure the endotoxin level.Results　Endotoxin concentrations in group 2 were significantly lower than those in group 1, group 3 and group 4(P<0·01).Conclusion　Endotoxin plays a very important role in the initiation and development of periapical periodotitis and is closely associatedwith clinical symptoms and apical radiolucency de- gree.

Objective　To investigate the characterization of Notch gene involved in genetic regulatory networks in dental pulp stem cells.Methods　The pulp tissue was separated frommouse teeth and digested by collagenase type I. Single-cell suspensions of dental pulp were seeded into 6-well plates with alpha modification of Eagle′s medium supplemented with ES cell qualified Fetal Bovine Serum. Colony-forming efficiency was assessed in 14ds culture. Transcripts for Notch were detected by reverse transcrip- tion-PCR by using total RNA isolated from cells.Results　There were clonogenic cells in dental pulp cell and the incidence of colony-forming cells derived from mouse dental pulp cells was 1·6~2·5 colonies/104plate. Mouse-specific Notch mRNA ex- pressed in colony-forming cells.Conclusion　Notch mRNA expressing in colony-forming cells provided a more detailed under- standing of mouse dental pulp stem cell biology.

Objective　To study the effect of Radix Scutellariae on the growth, metabolism ofPorphyromonas endodontalis (P.e), as a preparation for studying the mechanism of Radix Scutellariae in treating pulp and periapical diseases.Methods　 P.ewas chosen as the experimental bacteria. Radix Scutellariae was extracted by means of reflux with 80% ethanol. The value of MIC of Radix Scutellariae was measured by minute amount serial dilusion test, and the production of butyrate was measured by high liquid chromatograph(HPLC).Results　Radix Scutellariae could inhibit the growth ofP.e, of which the MICwas 100 mg/ L. Following the increase in concentration of Radix Scutellariae, the amount of butyrate decreased to (3·527±0·009) mg/L, (3·048±0·005) mg/L, (2·490±0·011) mg/L, (2·209±0·016) mg/L, respectively(P<0·05).Conclusion　Radix Scutel- lariae could inhibit the growth and metabolism ofP.eand might be an effective agent in treating pulp and periapical diseases.

Objective　To evaluate the effects of basic fibroblast growth factor(bFGF) on proliferation of periodontal fibroblast- like cellsin vivo.Methods　AU-shaped osseous defectwas produced on the buccal side of the mesial root. Four posterior teeth were conducted in four quadrants. Each quadrant included 4 groups: control, bFGF, expanded polytetrafluoroethylene(ePTFE) membrane, bFGF+ePTFE. Each time the 4 teeth sites in one quadrantwere operatedweekly and each dog experienced 4 times of operations. Bromodeoxyuridine(BrdU) was injected 1 hour priorto sacrificingthe dogs at 4 weeks afterfirst surgery. Immunohisto- chemical method was applied to count the BrdU-labeled fibroblast-like cells.Results　The number of BrdU-labeled cells reached the maximum at the 2nd week among all groups and then, decreased with time. Both bFGF and bFGF+ePTFE treated group had significantly more BrdU+cells than remained control or ePTFE groups (P<0·05) at 1st, 2nd weeks after surgery.Conclusion　 2 weeks after periodontal surgery is active phase of proliferation of periodontal fibroblasts. bFGF enhances fibroblast proliferation in early periodontal wound healing, and in turn accelerate periodontal regeneration.

Objective　To investigate if the Ribbond polyethylene fiber has the effect of reinforcing polymethyl methacylate. Methods　28 specimens were fabricated and divided into 3 groups : group of chemical-cured PMMA, group of chemical-cured PMMA reinforced by stainless steel wire and group of chemical-cured PMMA reinforced by Ribbond polyethylene fiber. A three- point bending test was used to measure the flexural strength and flexural modulus of specimens. Then the data were analyzed with a one-way analysis of variance.Results　The flexural strength of chemical-cured PMMA group was (51·383±2·761) MPa,the flexuralmodulus was (179 1·2±113·760) MPa; The flexural strength of stainless steel wire reinforced group was (58·725± 1·218) MPa, the flexural modulus was (209 2·76±120·28) MPa; The flexural strength of Ribbond polyethylene fiber reinforced group was (80·975±2·58) MPa,the flexural modulus was (286 6·53±107·51) MPa。The one-way analysis of variance showed that the resultswere significant (P<0·001). Newman-Keulsmethod showed thatthe differences among all groupswere significant (P<0·05).Conclusion　The Ribbond polyethylene fiber can raise the flexural strength and flexural modulu of polymethyl methacylate.

Objective　To investigate the method of enhancing the accuracy of titanium crowns by improving the casting meth- od.Methods　A self-assembled die was used to fabricate 48 standardized wax crowns. The dies were averagely divided into two groups. 21 crownswere successfully fabricated from one group according to the improved techniques. 18 crownswere fabricated by traditional method. A reference mark was scribed 90 degrees apart at four sites on the margin of each wax pattern and respective die. The distance between the margins of the wax pattern and the die was measured under a stereomicroscope. Similarmethodwas also applied to measure the margin of castings. The castings were longitudinally split through midline. The distance between the 4 points(B′、C′、D′、E′)selected in the inner part of the crown and the die was respectively examined.Results　Castings acquired by the improved method were more complete and had smoother surface. Marginal discrepancy value had significant difference be- tween the two groups. Value in experimental groupwas smaller. Distance from B′、E′to die between the two groups had no signifi- cant difference, butthe distance from C′、D′tothe diewas significantly different. The experimental groupwas smaller.Conclusion 　Standardized crowns fabricated by the improved titanium casting technique were more accurate, but special investment for tita- nium crowns and bridges should be developed to compensate the casting shrinkage of metal.

Objective　To investigate the intracellular calcium ion release and the system of calcium channel by 1,25 (OH)2D3stimulus, and the effect of mechanical pressure on it in rabbit mandibular condylar chondrocytes (MCC)in vitro. Methods　In vitrocultured MCC from two-week-old New Zealand rabbits were incubated under 20 g/L heparin, 1 g/L procaine, continuous pressure of 90 kPa for 60 min and 360 min in a hydraulic pressure controlled cellular strain unit. With the Fluo-3/AM probe loaded, 1,25(OH)2D3was added to the medium and then the intracellular calcium level was detected by a laser confocal scanning microscope.Results　Intracellular calcium concentration increased inMCC treated with 1,25(OH)2D3, 1,25(OH)2D3 and procaine, while it didn′t change in heparin treated group. Calcium in group under continuous pressure of 90 kPa for 60 min was also increased, even higher than the group stimulated only with 1,25(OH)2D3. Intracellular calcium in group treated with continuous pressure of 90 kPa for 360 min showed no significant difference compared to the control and even decreased at the end of the recording period.Conclusion　1,25(OH)2D3could stimulate the intracellular calcium release channel of inositol triphos- phate (IP3) receptor open in MCCin vitroand increases the level of intracellular calcium concentration. Pretreatment of definite mechanical pressure could modulate the sensitivity of IP3 channel to 1,25(OH)2D3stimulus.

Objective　To investigate the expression of TGF-β1mRNA in pubescent Rhesus monkeys′condylar under ClassⅢ intermaxillary functional orthopedic force for different lengths of time.Methods　Six pubescent Rhesus monkeywere divided into two test groups and a control group. Monkeys in the test groupsworeTMAⅢwhile the control groups did not. Histological method (HE staining) and in situ hybridization were employed in this study.Results　①The histological results showed that, compared with the control group, the anterior part of the condyle became thickerwhile the median part and the posterior part became thinner in 3 months group. However, in 6 months group,the change was similar to 3 months group.②The results of in situ hybridization showed that, in control group, TGF-β1 mRNAmildly expressed in the anterior part of the condyle while extensively in the median and posterior parts. In 3 months group, TGF-β1 mRNA expressed in all parts of condyle; the most intensive expressionwas in the anterior part. Comparedwith 3 months group, the expression ofTGF-β1 mRNAdecreased in 6 months group, butthe expression in anterior part was stronger than in median and posterior parts.Conclusion　Under ClassⅢOrthopedic therapy, TGF-β1 mRNA probably participated in the endochrondral bone remodeling in the condyle, and the expressionwas closely related to loading time. In 3 months group, the expression ofTGF-β1 mRNAwas stronger than that in 6 months group. Itwas inferred that the remodeling of endochrondral bone was more active in 3 months group.