砄bjective: To study the mineralization and related differential phenotype of human dental papilla cells in vitro . Methods: Human dental papilla cells were primarily cultured with explant technique, the cells of third passage were incubated for a long term in the presence of 10 mmol/L ? glycerophosphate(? GP)and 50 ?g/ml of ascorbic acid (L AA) in DMEM containing 5% FBS. Alkaline phosphatase (ALP) and osteocalcin(OC) were measured at different culture time. Cell growth was observed under inverted microscope and mineralization was tested with Von Kossa stainning. Results: Cultured papilla cells were growing in multilayer. Cells exposed to ? GP and L AA exhibited higher ALP activity in 14 days and increased OC in 21 days with certain amount of secreted matrix. After 35 days of culture, mineralized tubercles were formed. ALP activity and synthesized OC began to decrease after 42 days of culture. Conclusion: Human dental papilla cells may show odontoblast phenotype in vitro .

砄bjective: To determine the effects of interleukin 1 receptor antagonist( IL lra) on the production of IL 6 induced by IL 1? in human gingival fibroblasts(HGFs). Methods:HGFs at passage 5 were exposed to various concentrations of IL 1? with or without IL 1r? . IL 6 in the culture medium was measured with a sandwish ELISA assay. Results:IL 6(?g/L) produced by HGFs exposed to IL 1? at the concentrations (?g/L) of 0.1, 1.0, 10 and 100 were 207?40.29, 235?80.78, 370?40.62, 570?68.17 and 737.5?83.47 respectively. While that by HGFs exposed to IL 1? at 10 ?g/L with IL 1r?(?g/L) at 1, 10, 100 and 1 000 were 387.5?49.69, 312.5?26.81, 242.5?25.86 and 217.5?21.65 respectively. Conclusion: IL lra can inhibite the IL 1? induced IL 6 production in HGFs.

Objective:To investigate if transforming growth factor-?1 (TGF-?1) induces apoptosis in odontoblast cell line MDPC-23. Methods:MDPC-23 cells were treated with TGF-?1 at 0.5,2.5 or 10 ng/ml for 48 h,apoptosis of MDPC-23 cells was detected by annexin V and propidium iodide (PI) staining, cell death detection ELISA and DNA electrophoretic analysis. Results: Consistent results were obtained from three different methods.TGF-?1 at 0.5-10 ng/ml induced apoptosis of MDPC-23 cells in a dose-dependent manner. Conclusion:TGF-?1 may paly a role in apoptosis of odontoblasts.

To assess the roles of glutamate and its ionotropic receptor in processing noxious sensory input from dental pulp,glutamate NMDA receptor subtype antagonist,MK-801 and non-NMDA receptor subtype antagonist,CNQX were administrated separately into left lateral cerebral ventricle prior to exposing pulp cavity of left maxillary first molar tooth.The number of Fos-positive neurons in medulla oblongata was measured and compared with that of the group with simple exposure of dental after same survival time pulp.Fos protein expression was reduced dose-dependently by an administration of MK-801,but CNQX had little effect.The results showed that glutamate may be an excitatory transmitter of noxious dental pulp sensory input to neurons in medulla oblongata.In pain nodel of mechanical exposing dental pulp,NMDA receptor subtype has an important role in this process.

Objective:To investigate the correlation between root and root canal diameter of maxillary central incisors and age by cone-beam computed tomography(CBCT).Methods:CBCT images of 420 cases of Chinese Han population were divided into 7 age groups as follows:1 5 -24,25 -34,35 -44,45 -54,55 -64,65 -74 and 75 -84(n =60).Root diameter and root canal diameter of maxillary central incisors at the 3 /4 level from the cemenal-enamel junction(CEJ)to root apical were measured.Linear-regression a-nalysis was used to analyze the correlation between root and root canal diameter of the teeth and age,T-test was used to examine the gender difference.Results:Mean root diameter(mm)of the teeth in males and females were 5.81 ±0.445 and 5.53 ±0.489(P <0.05),mean root canal diameter(mm)1 .20 ±0.396 and 0.96 ±0.236(P <0.05),mean of the ratio of root canal diameter and root diameter of the teeth 0.21 ±0.072 and 0.1 7 ±0.043(P <0.05)respectively.There were negative correlations between the ratio of root canal diameter and root diameter of the teeth with age (R2 =0.576,P <0.05).Conclusion:The ratio of root canal diameter and root diameter of maxillary central incisors is negitively correlated with age in Chinese Han population.The decrease of root canal diame-ter in males is more significant than that in females.

Objective To investigate the correlation of the prevalence of periodontitis with age and course of disease in patients with type 2 diabetes.Methods A total of 884 patients with diabetes (both sexes,aged 35-79 yr) were involved in present study.Diagnosis of periodontitis was made according to the 1999 WHO standard,and of type 2 diabetes to the 1997 WHO standard.Age,gender,course of diabetes and periodontal state of those patients were recorded.The patients were grouped according to their age (10 yr interval) and course of disease (5 years interval).Based on the grouping,the collected data were input into ACCESS data bank and statistically analyzed with SAS software,and the prevalence of periodontitis were then compared.Results The prevalence of periodontitis in patients with type 2 diabetes increased with the increasing of age and with the prolonging of disease course (P

Objective:To clone and sequence cDNA of MH2 domain of Smad1 gene from human dental papilla cells. Methods:Total RNA was isolated from primarily cultured human dental papilla cells and reversely transcribed into single stranded cDNA.The desired DNA product was obtained by PCR with two gene specific primers.The segment was inserted into PUC19 vector and the plasmid was transformed into E.coli JM109.The double stranded cDNA of positive clone was sequenced.Results:The sequence of MHz domain of Smad1 cloned from human dental papilla cells was consistent with that reported by Hoodless et al. Conclusion:Smad1 exists in human dental papilla cells,BMP signaling may be mediated by smad1 in human dental papilla cells.

Objective:To observe the clinical effect of apical barrier and perforation repair with mineral trioxide aggregate.Methods:Selected 23 samples from out-patients of the department of conservative dentistry of oral disease treatment center of 306 Hospital of PLA.Among them,7 samples were with unshaped root apical,6 samples were with lateral perforation from root canal internal absorption or root fracture,10 samples were iatrogenic lateral perforation.The course of the disease was 0.5-24 months.The images of dental films showed that there was shadow around the root or apical area in all the samples.All the samples received regular root canal treatment.Under root canal microscope,the open sites were sealed with MTA.After the barrier formed,filled the root canal with warm gutta-percha vertical compaction technique.Patients were ordered to re-check on 6 months and 12 months respectively.Results:1 sample dropped out.On 6 months visit,1 sample showed enlarged shadow at the apical area,20 samples showed shrinked shadow,1 sample showed no significant change.On 12 months visit,the shadow vanished in 9 samples;the shadow decreased in 5 samples,and there were 2 samples showed no significant changes.Conclusion:The treatment with MTA on apical barrier and perforation shows acceptable effect in short term observation.The use of microscope helps to enhance the accuracy and leak tightness of MTA filling.

Objective: To observe the expression of proteins Rb and P 53 in leukoplakia (LK) and squamous cell carcinoma (SCC) of oral muco sa. Methods: The expression of proteins Rb and P 53 was determined by immunohistochemical S-P method. Paraffin sections of 33 s amples of SCC and 20 of LK were immunohistochemically stained and analyzed. Results: (1)The expression of Rb in OLK, OSCC was not si gnificantly different from that in normal oral mucosa ;(2)the overexpression of mutant P 53 were found in OLK and its expression was increasing with dysp hasia degree (P

Objective: To study the relationship between human herpes vi rus 6 (HHV-6) infection and oral squamors cell carcinoma. Methods: The serum anti-HHV-6 antibody titers from 16 cases of oral squamors cell carcinoma (OSCC) and 16 control subjects were detected by indirect immunofluores cence assay. HHV-6 DNA in peripheral blood mononuclear cells was amplified by P CR and the specificity was confirmed by Southern-blot hybridization with an int ernal probe oligonuclotide. An immunohistochemical staining was used to detect H HV-6 antigen in OSCC tissues. Results: Positive expression of s erum HHV-6 IgG antibody was found in all the cases of OSCC and in 12 of the 16 controls. Geometric mean titer of OSCC group and control group was 1∶118 and 1 ∶64 respectively (P