Objective To study the role that vascular endothelial growth factorC plays in the lymph node metastasis of the squamous cell carcinoma （SCC） of tongue.Methods An established VEGFC transfected Tca8113 cell strain （VcTca） was heterotransplanted into BALB/C nude mice subcutaneously. The expression of VEGFC and VEGFR3 was detected. The property of tumorigenesis and metastasis of the transfected cell was investigated.Results Jugular lymphatic metastases developed in 4/6 mice of VcTca group in 6 weeks after transplantation, while no lymph node metastasis was found in mice with tumors of nontransfected Tca8113 cell （Tca） and mock transfected cell（pDTca） at the same time. There was no difference in tumor weight among VcTca, pDTca and Tca （P>0 05）.Conclusion\ It is suggested that VEGFC could promote lymph node metastatic ability of Tca8113 cell, and could be utilized as a target of new regimen in prevention and treatment for lymphatic metastasis of oral carcinomas.

Objective Streptococcus mutans has been proved as a causative bacteria of human dental caries. The surface protein antigen is one of the important pathogenic factors. The A region of the surface protein antigen pac gene (pacA) can enrich T-cells and B-cells epitope. In this study, a DNA vaccine carrying pacA and gfp gene (a reporter gene) for caries prevention was constructed. The DNA vaccine was liable to be traced in vitro and in vivo.Methods The fragment of pacA (1 3 kb) was amplified by PCR with the plasmid pPC41 as template, and inserted into a pEGFP-C1 vector. The recombinant plasmid produced was named as pEGFPC1-pacA. After the COS1 cell line was transfected by the recombinant plasmid, the expression of gfp was detected by observing the green fluorescence and measuring the fluorescence intensity, and the expression of pacA was detected by RT-PCR.Results Restricted analyzing, sequencing and PCR technique were employed to identify the recombinant plasmid. The phase and orientation of the pacA gene inserted into the vector pEGFPC1 were correct and no changes of their open reading frames were discovered. The transfected COS1 carrying green fluorescent protein (GFP) was observed; the GFP expression level of transfected cells was higher than that of controlled cell. The transcript of pacA gene was confirmed by RT-PCR.Conclusion Construction of the recombinant plasmid was successful. The gfp gene and pacA gene in the plasmid was transcribed and expressed simultaneously in the transfected cells. Moreover, detection of GFP is simple, safe and effective for living cells.

Objective To investigate the age-related changes of histological structure and DNA repair capacity (P53 protein expression) in oral mucous membrane and try to explain why the elders are prone to oral squamous cell carcinoma.Methods\ The routine HE staining and an immunohistochemical technical (SP method) were used respectively to study the changes of histological structure and P53 expression in normal oral mucosa of different age groups. The SP staining results were evaluated by semi-quantity method.Results ①With aging, a series of histological changes were observed in the oral mucosa; ② With aging, an elevating tendency of P53 protein level emerged in the oral mucosa (P<0 05).Conclusion The sensitivity to carcinogenic agents in elder people may be accentuated by the age-related histological changes and DNA repair capacity changes of the normal oral mucosa.

Objective The purpose of this study was to establish a stable, high-efficient and low-toxic way of transfecting nm23-H1 into Tca8113 line cells, and then to find out whether nm23-H1 could affect the invasion and metastases ability of Tca8113 line cells.Methods nm23-H1 was transfected into Tca8113 line cells with Lipofect. The different expressions of nm23-H1 between transfected and non-transfected line cells were detected by the method of immunohistochemistry. The difference of the invasion and metastases ability between transfected and non-transfected line cells was detected by transwell-room and wash techniques. The change of chemo-sensitivity was evaluated by MTT.Results Using pCMV-NEO-BAM system to keep stable expression of nm23-H1, the significant difference of NDPKA expression between transfected and non-transfected Tca8113 line cells was discovered; The metastases ability of transfected Tca8113 line cells decreased significantly;The chemo-sensitivity of transfected Tca8113 line cells to CDDP increased significantly.Conclusion nm23-H1 can inhibit the metastases of Tca8113 line cells and increase the chemo-sensitivity to CDDP significantly.

Objective The purpose of this study was to introduce cryotreat technique into prosthetic dentistry by investigating the wear resistance changes of SDA-Ⅱ medium melting-point castable alloy before and after cryotreat.Methods 15 samples were divided into three groups, i.e. control group, cryotreat group, cryotreated plus post-cryogenic treat group. Weight loss measurement was used to examine the wear resistance.Results For SDA-Ⅱ medium melting-point castable alloy, cryotreat effectively improved its wearing resistance; so far as the wear resistance was concerned, the post-cryogenic treatment was unnecessary. Conclusion The results obtained above suggest that cryotreat was an effective method in enhancing the wear resistance of SDA-Ⅱ medium melting-point castable alloy.

Objective The aim of this study was to examine the effects of deep branches of cervical plexus on trapezius muscle.Methods The evoked electromyography of 32 trapezius of 16 SD rats was examined in different time and results obtained were processed by statistical methods.Results After cutting the accessory nerves, stimulating the deep branches of cervical plexus evoked the myoelectricity, the myoelectricity results varied according to different time.Conclusion The deep branches of cervical plexus are another important motorial supply to trapezius muscles. After cutting the accessory nerves, if the branches were undamaged, the shoulder′s function would be greatly preserved.

Objective The aim of this study was to investigate the effect of short enamel etching time on bonding strength.Methods 80 healthy premolars were randomly divided into two equal groups, one was etched for 15 seconds, the other for 60 seconds, after normally bonding Edgewise brackets, the tooth specimen was stored in water at room temperature for 24 hours. An MTS NEW810 100KN testing machine was used to examine the shear force.Results Although the bonding strength for 15 seconds etching time was weaker than that for 60 seconds, the means of the bonding strength in 15 seconds group reached 5 862 5 MPa.Conclusion Etching for 15 seconds could provide enough bond strength for orthodontic practice. Furthermore, the adhesive remained on tooth after debonding was less by comparison with 60 seconds etching group, therefore brackets could be removed easily and the work efficiency could be increased in clinic by means of 15 seconds etching time.

Objective To study the clinico pathologic factors influencing postoperative survival rate in mucoepidermoid carcinoma of salivary glands.Methods A retrospective study of seventy patients with mucoepidermoid carcinoma of salivary glands has been carried out. All cases underwent primary surgical resection in our hospital were followed up and clinicopathologic factors influencing the postoperative survival rate of patients were investigated. Statistical analysis was conducted using a computer program (SPSS). The data were statistically treated according to the Kaplan-Meier method. The Log rank tests were employed to assess the statistical significance of various groups.Results The 3-, 5- and 10-year overall survival rate were 90 66%, 88 85% and 86 63%, respectively. The patients with tumors′ diameter less than 4 cm, early clinical stage (stage Ⅰand Ⅱ), well differentiated tumor cells, without lymph nodes involvement, without local recurrence and metastasis after primary surgical resection had a long survival term. The patients with tumors′ diameter more than 4 cm, with lymph nodes involvement, advanced clinical stage (stage Ⅲ and Ⅳ), poor differentiated, with local recurrence and metastasis after primary surgical resection demonstrated a short survival term.Conclusion TNM and clinical stage, the degree of differentiation, with or without local recurrence and metastasis after primary surgical resection are the important factors influencing the postoperative survival time.

Objective The purpose of this study was to discuss the principle in neck treatment of cN\-0 patients with squamous cell carcinoma of buccal mucosa.Methods 101 patients of squamous cell carcinoma of buccal mucosa at the stage of cN\-0, who had hospitalized in West China College of Stomatology, Sichuan University from 1980 to 2000, were investigated retrospectively. All the patients received a comprehensive therapy consisting of surgical procedures combined with chemotherapy and radiotherapy. The combining radical therapy of buccal, mandible and neck was the main surgical method. Lymph nodes were cleared after operation and examined by pathological method. The patients had been followed up for more than 3 years.Results 17 patients had lymph nodes metastasis, the occult metastasis (OM) rate was 16.83%. It increased in the high stage of original lesion, the OM rate of T\-3 and T\-4 was 18 18% and 52.00%, respectively. The metastasized lymph nodes were mainly located in submandible and superior deep cervix lymph nodes, their respective metastasis rate was 41 18% and 29 41%.Conclusion The rate of occult metastasis of squamous cell carcinoma of buccal mucosa is high, and then we should adopt actively selective neck dissection for the cN\-0 patients of squamous cell carcinoma of buccal mucosa.

Objective To evaluate the clinical efficacy of intra-articular injection with 2% chitosan as a treatment for irreducible anterior disc displacement of the TMJ.Methods Total 30 patients with irreducible anterior disc displacement were divided into two groups according to quasi-randomizaion. The patients in test group received intra-articular injection with 1 0 ml of 2% chitosan into upper cavities of the suffered joints,in control group with 12 5 mg of prednisolone. The patients were followed up at the 1st day and 14th day after injection and the maximal mouth opening was measured.Results The maximal mouth opening at 14th day was (36 73±4 69) mm in test group, with 11 73 mm increase from baseline; and (28 53±5 81) mm in control group, with 3 86 mm increase, respectively. The increase of maximal mouth opening in test group was significantly higher than that of control group (P<0 05).Conclusion Chitosan is an effective biomaterial in curing irreducible anterior disc displacement of TMJs.

Objective To study the clinical manifestation and its pathogenesis of the developmental enamel defects in primary dentition of children with low birth weight and premature birth history.Methods One hundred and seventysix children （aged 38 years old） were studied about the clinical manifestation of the developmental enamel defects in the primary dentition and its relationship with their medical history.Results The prevalence of enamel defects in primary dentition in these children was 77.3%. There was no significant correlation between enamel defects and gender. Enamel opacity mostly affected the upper and lower second primary molars. Enamel hypoplasia mostly affected the maxillary and mandibular primary incisors and the maxillary first primary molars.Conclusion Enamel defects mainly result from children′s general disorder at birth or within one year after birth.

Objective To examine the effect of nickel-titanium rotary instruments in reducing post-operative pain.Methods 95 molars with pulpal and/or periapical involvement were randomly assigned to two groups for root canal preparation. One group was treated with ProFile nickel-titanium rotary instruments; the other was treated by using stainless steel hand files-FlexoFile. The incidence and degree of post-operative pain after root canal preparation in the two groups were recorded.Results In ProFile group, the incidence of post-operative pain was 27.7%, while 62.5% of the teeth developed post-operative pain after hand preparation. The difference between two groups was statistically significant (P<0.01).Conclusion Root canal preparation on molars with stainless steel hand files resulted in relatively high incidence of post-operative pain. Mechanical preparation using ProFile nickel-titanium instruments generated less post-operative pain and discomfort.

Objective The purpose of this study was to make a comparison between extraction and non-extraction orthodontic treatment results concerning teeth alignment, occlusal relation, facial profile and treatment interval.Methods 39 extraction-non-extraction borderline cases were selected by 5 orthodontic specialists through reviewing their pre-treatment records. 5 specialists were then asked to rank the results by marking the post-treatment record of each case. And then the samples were divided into different groups according to extraction, non-extraction and extraction pattern by reviewing case history.Results No statistically significant difference was found in teeth alignment, overbite and overjet, midline symmetry, lateral occlusal relation and treatment intervals. However, the post-treatment facial profile of extraction groups obtained higher marks from 5 specialists (P=0.001).Conclusion While both extraction and non-extraction treatment can achieve comparable results in teeth alignment and occlusal relation with equivalent time interval in borderline cases, extraction treatment, whatever extraction of four first premolars or second premolars is performed, can achieve better facial profile.

Objective To investigate the development of third molar embryo and establish the normal value of posterior arch length of adolescence in Chengdu.Methods The samples consisted of 40 males and 41 females with Class 1 dentitions, normal second molar occlusion, no history of orthodontic treatment, and good facial balance. Cephalometry and statistic analysis were conducted for all the subjects.Results The normal value of posterior arch length of maxilla in male was(16 52±2 35)mm and in female was(16 42±2 55)mm The normal length of mandible was(13 00±2 44)mm in male and(12 43±2 18)mm in female But statistic analysis showed no gender difference. Most of the third molar embryo had been formed and their tooth crowns had been calcified, the occurrence ratio was 84 0 % in maxilla and 85 2 % in mandible. Most of them located in the middle and inclined mesially.Conclusion The data obtained in this study will be valuable for our clinical practice and be helpful for the study concerning dento-facial growth and development.

Objective To analysis the sum and frequencies of Bolton toothsize discrepancies Angle Class Ⅰ,Ⅱ,Ⅲ malocclusion patients.Methods Measured each tooth crown mesialdistal size between the first molar of 439 dental plaster casts of malocclusion patients and obtained the sums of six anterior toothsize and twelve toothsize between the first molar of upper or lower and calculated the anterior and total toothsize discrepancies by Bolton rate standards, then statistic analysises were done.Results Patients whose sums of anterior toothsize discrepancy were pass 1.5 mm or less than 1.5 mm was 14.02% in Angle Class Ⅰ malocclusion patients and 9.49% in Class Ⅱ and 19.32% in Class Ⅲ. Patients whose sums of tolal toothsize discrepancy were pass 1.5 mm or less than 1.5 mm was 19.63% in Angle Class Ⅰ malocclusion patients and 15.33% in Calss Ⅱ and 20.45% in Class Ⅲ. The upper sum of anterior toothsize of Class I malocclusion patients whose sums of anterior toothsize discrepancies were pass 1.5 mm or less than 1.5 mm was always smaller than normal and the lower sum was always larger The sums of anterior toothsize discrepancy of Class Ⅰ、Ⅱ、Ⅲ and total toothsize discrepancy of Class Ⅰ were always between 1.5 mm～2.5 mm or 2.5 mm～1.5 mm. Patients whose sums of anterior toothsize discrepancy were pass 3.5 mm or less than 3.5 mm was 2.34% in Class Ⅰ malocclusion patients and 0 in class Ⅱ and 0 in class Ⅲ. Patients whose sums of totoal toothsize discrepancy were pass 3.5 mm or less than 3.5 mm was 4.21% in Class Ⅰ and 1.46% in Class Ⅱ and 4.54% in Class Ⅲ.Conclusion Toothsize discrepancy of malocclusion patients was not the general cause of malocclusion.

Objective Today metal-ceramic restorations are widely accepted in dental practice because of their good aesthetic and biocompatible properties, but there are still several problems to be resolved, among which the influences of their margins on gingival health is noticeable. The purpose of this study was to investigate the influences of metal-ceramic restoration margin on gingival health.Methods 129 abutments of metal-ceramic restorations, including their margins′ fitness, location and smoothness were examined and their influences on gingival health were analyzed.Results There was a close relation between the metal-ceramic restorations′ margins and the gingival health.Conclusion In order to maintain the gingival health, the margins should be smooth, closely fitted, no overhanging and in a moderate location (i.e. not below the gingival more than 1 mm).

Objective To investigate the color difference between AuPt alloy porcelain and NiCr alloy porcelain.Methods 30 metalceramic specimens with different dentin porcelain thickness were fabricated with two types of metalceramic alloy, each type of alloy had 15 specimens. L\+*, a\+*, b\+* were measured after opaque porcelain was applied, and dentin porcelain was fired 1,3,5,7 times by MINOLTA CR100. Then △E was calculated which reflected the color difference between highgold alloy porcelain and NiCr alloy porcelain. Results Comparing with NiCr alloy porcelain, the color of AuPt alloy porcelain was reddish, yellowish and less bright. The △E between highgold alloy porcelain and NiCr alloy porcelain in shade A2 was largest when opaque porcelain was applied. It decreased when dentin porcelain was applied. It became smallest when fired 3 times, and increased along with the increase of fire times. It was larger than 1 5 except firing 3 times. When dentin porcelain was applied, △E which was larger than 1 5 among different dentin porcelain thickness decreased along with the increase of dentin porcelain thickness. Conclusion The color difference between the two types of metalceramic alloy should be carefully taken into account in order to improve the quality of color matching.

Objective To study the clinical effect of the functional muscular equal pressure zone on complete denture.Methods Artificial teeth were arranged within the functional muscular equal pressure zone. With this technique 35 complete dentures were made to rehabilitate 35 edentulous patients whose alveolar bones were moderately or seriously absorbed. After three months′ following up, the satisfaction of these patients were investigate. Results After prosthesis treatment, 35 patients enunciated well and the aesthetic effect was favorable. 89 percent of these patients satisfied the retention and the stability of the maxillary denture, and 78 percent satisfied the retention and the stability of the mandibular denture. 79 5 percent of these patients satisfied the mastication efficiency.Conclusion With the technique, the complete denture is fairly stable in patient′s mouth. The technique can enhance the denture′s retention and improve the patient′s mastication efficiency, especially to these whose alveolar bones are moderately or seriously absorbed. Clinically the technique is of high practical value to these edentulous patients who are difficult to be rehabilitated.

Objective The purpose of this study was to compare the clinical application and effect of two temporary restorations materials : composite and self-cured acrylic resin.Methods 153 composite temporary crowns (and bridges) placed in 44 patients and 144 self-cured acrylic resin temporary crowns (and bridges) placed in 49 patients were evaluated according to the California Dental Association′s (CDA) criteria and questionnaire.Results It showed that composite temporary crowns (and bridges) had better surface smoothness, marginal integrity and anatomic form than self-cured acrylic resin temporary crowns (and bridges). In the 49 patients with self-cured acrylic resin temporary crowns (and bridges), 67% and 88% of them complained of food impaction and mouth odor, while only 2% and 30% in the 44 patients with composite temporary crowns (and bridges) had the same complaint.Conclusion Between the two temporary restoration materials, composite is better than self-cured acrylic resin.

Objective To evaluate the effect of static magnetic field on the expression of SPmRNA in TG in rats.Methods 44 Wistar rats aged 67 weeks were put into static magnetic field and were sacrificed at 1 h, 2 h, 6 h, 12 h, 24 h, respectively. In situ hybridization method was used to evaluate the changes of SPmRNA expression at different time point.Results Many neurons in TG were marked with SP probes in each group, the expression of SPmRNA increased remarkably in static magnetic field group. In this group, the percentage of SPmRNA positive neurons in TG increased greatly in 1 h, reached its peak in 2 h, from then on, decrease of the percentage started slowly but a moderate percentage was kept until 24 h, which was thought to be enough to maintain orthodontic tooth movement. The tendency of control group was almost the same with that of experimental group. The expression of SPmRNA was higher in experimental group within 2 h but became lower after 2 h as compared with control group, this indicated that magnetic field reduced the SPmRNA expression and exerted restoring effect on trauma. There were significant differences between experimental groups and control group at different time points （P<0 01）.Conclusion The expression of SPmRNA in TG in rats increased significantly in static magnetic field.