Objective To study the effect of gradually induced occlusal disorders on the expression of basic fibroblast growth factor（bFGF）of condylar cartilage in rat. Methods The model of gradually induced occlusal disorders was established in rat. The expression of bFGF was examined by SABC technique of immunohistochemistry. The expression of bFGF was analyzed by amount of positive cells. Results bFGF was expressed positively in the proliferative cell layer, maturative layer and hypertrophical cell layer in the rat mandibular condyle cartilage. In control group, expression of bFGF increased from 2- week- old to 6- week- old, then it had a decrease during experiment. Compared with the control group, bFGF of experiment group was increasing at 2 week, 6 week and 8 week during experiment. But there was decreaseing at 4 week. There was no difference between young experiment group and the adult experiment group. Conclusion The gradually induced occlusal disorders may lead to significant increase of expressiong of bFGF in condyle cartilage，which suggests that the bFGF may be involve in the procedure of repairing process of articular cartilage.

Objective To examine cytokeratin 18（CK18）and it′s gene in jaw odontogenic keratocyst （OKC）epithelial lining. Methods The epithelial linings of 32 cases were subject to monoclonal antibody immunohistochemical staining for CK18, CK8 and CK19. RT- PCR and in situ hybridization for CK18 mRNA were conducted in 12 of 32 cases in keratocyst epithelial cell linings. Results In 17 cases, CK18 were observed in keratinized surface layers, though weakly positive. In 27 cases, CK18 were positive in the granular cell layers. CK18 were also positive in the spinous cell layers in 14 cases. In all cases, CK18 was negative in basal cell layers. By RT- PCR, 4 cases expressed CK18 strongly, 8 cases weakly. By in situ hybridization, 8 cases expressed CK18 mRNA positively in both spinous and granular cell layers, and 4 cases positively in basal and keratinized cell layers. CK8 were expressed in basal cell layers of keratocyst epithelial linings. In 23 cases, CK19 were expressed in surface cell layers of keratocyst epithelial linings. Conclusion The expression of CK18 in keratocyst epithelial linings transfers from basal cell layer to spinous layer. The expression of CK18 immunohistochemical staining and CK18 mRNA in situ hybridization are different, which shows CK18 might be related to proliferation of OKC epithelial linings. That suggests the existence of regulation of CK18 and CK18 mRNA expression.

Objective To study the expression of P63 in human salivary gland development and the existing of salivary gland stem cells. Methods 24 embryonic salivary gland samples in different stage, 10 normal salivary gland samples were collected. HE- stained and immunochemistry stain were used. Results It could be seen on the HE- stained sections that the epithelial buds proliferated to form the epithelial branches and duct systems, finally the terminal cells differentiated into ductal, myoepithelial and acinous. During the development of salivary gland, the expression of P63 was gradually reduced. In normal adult salivary gland samples, the positive cell interspersed in the basal layer of intercalated duct, secretory duct and excretory duct. Conclusion P63 plays an important role in human salivary gland development. The result of our experiment shows the distributive characteristic of salivary gland stem cells, which exist abroad in bud stage, but decrease and only exist in the basal layer of ducts in normal adult salivary gland.

Objective To investigate the effect of FAK on biological characteristics of tongue squamous cell carcinoma cell Tca8113. Methods Lipofect was used to transfect FAK into Tca8113 cell lines. The difference in expression of FAK between the transfected and non- transfected cell lines was detected by immunofluorescence assay. Then by use of transwell room and wash way, the difference in invasion and adhesion ability between the transfected and non- transfected cell lines was tested. MTT method was adopted in finding the change of proliferation. Results RT- PCR analysis showed that the FAK gene was downregulated by Tca8113 cells. FAK expression was significantly down regulated by the transfection of FAK ASODN（P<0.05）. Antisense FAK ODN significantly inhibited proliferation, adhesion and the invasion of Tca8113 cells. Conclusion FAK plays an important role on biological characteristics of tongue squamous cell carcinoma cell Tca8113.

Objective To observe the expression and distribution of matrix mentallproteinase- 2（MMP- 2） in the periodontal tissues of diabetes mellitus（DM） rats during tooth movement, and to observe the affection of diabetes mellitus on the collagen metabolism. Methods Eighty male Sprague- Dawley rats were used. Mesial force was applied to pull the maxillary first molar. Forty rats were rendered diabetic by injection of streptozotocin. In 3 weeks after the injection, rats were subjected to lateral tooth movement. The animals were sacrificed after 0, 3, 7, 14 and 21 days respectively. Two- step immunohistochemical method was applied to localize and examine the expression of MMP- 2 in periodontal tissue of rats. Results MMP- 2 immunohistochemical results indicated that the MMP- 2 expression increased and was observed on both sides periodontium of movement tooth, osteoclast, cementoblast, osteocyte, fibroblast and osteoblast appeared positive. According to the immunohistochemistry image analysis, experiment group changes was less obvious than control group. Dynamic changes of OD occured, reaching the minimum on the 7th day and then increasing slowly. IOD increased steadily, up to the peak on the 7th day, and then decreased, which still remained a high level on the 21st day. Conclusion DM alveolar bone collagen metabolism increases. DM alveolar bone reactive potency decreases in orthodontic tooth movement, weak collagen metabolism. MMP- 2′s activity changes regularly, in close relation to bone remodeling, and plays an important role during the orthodontic tooth movement.

Objective To investigate the effects of alveolar bone resorption on stress of tooth/implant- supported restoration connected by precision attachment using three- dimensional finite element（FEM）approach. Methods The FEM was applied to analyze the stress distribution of tooth/implant- supported restoration connected by precision attachment under various loading conditions when the alveolar bone was absorbed to different level. Results The stress values of the tooth, implant and their surrounding bone increased when their surrounding bone decreased by bone absorption. Conclusion The stress values of the tooth, implant and their surrounding bone were closely related with the bone resorption.

Objective To estimate the diagnostic potential of the dental operating microscope used for locating the second mesiobuccal canal（MB2） orifice in maxillary first molars. Methods 120 extracted maxillary first molars were used, all the access cavities were prepared and fixed on the dental study model. MB2 orifices were examined with naked eye and under a dental operating microscope（DOM）. The examination was repeated by another dentist with the same methods. Then Indian ink was injected into the pulp chamber and all the teeth were treated to be transparent to determine if it had a real MB2. Results The sensitivity and accuracy of the DOM group were 0.78 and 0.76, higher than 0.61 and 0.65 of the naked eye group（P<0.05）. The correspondency of Kappa index between observers by naked eye and DOM was 0.701 and 0.819, respectively. Conclusion The use of DOM can increase the detection rate of MB2.

Objective To study the clinical effects of insertion- type separate post and post - crown on ceramic restoration of molar residual root and crown with low occlusogingival distance and large root bifurcation angle. Methods 19 molar residual roots and crowns with low occlusogingival distance（<3 mm） and large root bifurcation angle were involved in this study. Firstly, the root canals were prepared according to their natural directions without concerning about the common path of insertion. Accurate impression were taken with silicone. Insertion- type separate post and core- ceramic crown were fabricated respectively. Finally, the two parts were cemented together in patient after try- in, and the upper post cavity were filled with light- sensitive composite resin. Results None of prostheses was loose and no abutment teeth fractured for 6 - 38 months. All of the fixed restorations were found with good marginal fitness and well masticatory function without sign of gingivitis. Conclusion Insertion- type separate post and post- crown is a better method to restore molar residual root and crown with low occlusogingival distance and large root bifurcation angle.

Objective To investigate the clinical effects of the maxillary molar distalization with modified Distal- Jet appliance. Methods 15 patients（average age 12.3 year- old）with maxillary molars shifting mesially were selected as the subjects. Maxillary molars of all patients were distalized with modified Distal- Jet appliance. Results All patients achieved good occlusion, normal overjet and overbite with modified Distal- Jet appliance. Conclusion Modified Distal-Jet appliance can distalize maxillary molars effectively.

Objective To investigate root canal curvature in maxillary anterior teeth. Methods About 400 human maxillary anterior teeth were examined by indirect digital radiography both from labiolingual and mesiodistal directions. The root canal curvature was analyzed. Results The major sort of maxillary anterior teeth was typeⅠ. The proportion of maxillary center incisors, maxillary lateral incisors, maxillary canines curved in mesiodistal were 11.17%, 16.19% and 21.43%, in labio- lingual were 39.59%, 40.00% and 29.59%, both in labiolingual and mesiodistal directions were 4.60%, 35.24% and 24.49%. About 50% of maxillary anterior teeth were moderate curve, the degree of root canal curvature of maxillary canines was larger than that of maxillary incisors, and radius of curvature and length of the curved part of root canal of maxillary canines were smaller than that of maxillary incisors. Conclusion Root canal curvature in maxillary anterior is complex, especially in maxillary canine. In order to improve quality of root canal therapy, we need to understand types of root canal, degree of root canal curvature and radius of curvature completely.

Objective To evaluate shaping ability of nickel- titanium rotary instruments（ProTaper） in curved root canals. Methods The computer assistant measure system of simulated root canal was used for quantitative analysis of root shape of eight simulated root canals during ProTaper shaping process. Blue ink was injected into the simulated root canals before instrumentation, when F2 reached work length（WL）（F2） and when F3 reached WL（F3）. Orifices and apexes were sealed with adhesive tapes. Root canal images were gained by Mustek BP4800TA scanner. The images before and after preparation were turned into Di - numerical images and fused. The changes of central line positions and curvatures were measured in quantity through this system. Data of seven preestablished point from orifice to apex were recorded and analysed by SPSS 10.0 soft ware. Results ProTaper system reduced the angles of simulated canals. Selecting F2 or F3 as the master apical file（MAF） had no influence on the changing rate of the root angles. ProTaper had excess cutting on the outer wall of orifice and the inner wall of curve part, but the displacement of apex was minimal（only 0.021 mm）. Conclusion ProTaper has preferable shaping ability. To prepare very difficult curved canals, the master apical file（MAF） could be F3. Attention should be taken when preparing some curved canals with hollows in their inner walls, in order to avoid the lateral perforation.

Objective To evaluate whether there is difference with regard to chin morphology in subjects with different vertical skeletal craniofacial pattern and the relationship among them. Methods The sample was composed of 80 adolescents who denied orthodontic treatment history and presented ClassⅠskeletal pattern, aged（12.69±0.70） years. They were divided into three groups according to mandibular plane angle: High angle group（21 cases, FH/MP≥ 32°）, average angle group（43 cases, 22°

Objective To obtain the normal value of Coben analysis for Haerbin with normal occlusion and analyze the different features of cranio- maxilla- facial structure between male and female, between adults and children. Methods 120 Haerbin subjects（60 adults and 60 children） who fulfilled specific normal occlusion were seleceted from primary schools and universities students of Haerbin. They were divided into comparison groups on the basis of age and sex. Lateral cephalograms were taken for all subjects, and the mean and standard deviation for each parameter was recorded and compared between groups. Paired t test was used to assess statistical significance. Results In depth, both sexes exhibited great increment in the middle and lower face. In anterior and posterior face height, the male adults exhibited increment, and in female adults only the posterior face height exhibited increment. The male adults face far exceeded the female in vertical growth, and less than the female in horizontal growth. No statistically significant differences of facial form were found between the sexes in children. Conclusion The normal values of Coben analysis for Haerbin with normal occlusion was established. There were significant differences in normal values of Coben analysis between male and female, between adults and children.

Objective To investigate root canal curvatures of human maxillary first premolars in buccolingual directions. Methods One hundred extracted permanent maxillary first premolars were used. After access preparation, a K- file was inserted into the canals and gently advanced until it reached the apical foramen. Then standardized periapical radiovisiography（RVG）images were taken from mesiodistal direction. The angle of curvature was determined according to the method described by Schneider. The radiu of curvature and length of the curved part of the root canal were calculated. Results 1）The total 50.00%（88/176） of root canal curves were in buccolingual directions, and 53 curves were showed in apical 1/3 of root region. 11.93%（21/176） of S- shaped canals were detected, and the first curves were mostly showed in middle 1/3 of root region, the secondary curves were totally showed in apical 1/3 of root region. 2）There was no difference of curvatures between buccal and lingual root canals, but the secondary curves of S- shaped canals were more complicated than other root canals. 3）There was no correlation between the angle of curvature and the radius of curvature（r=0.002, P>0.05）, but significantly correlation between the angle of curvature and length of the curved part of the root canal（r=0.489, P<0.01）. Conclusion The occurrence of curved root canals in buccolingual directions may be high in human maxillary first premolars, and the curvatures of S- shaped canals were more complicated than others.

Objective To evaluate the effect of the shade and thickenss of luting agent on the final color of different  thickness Solidex resin in vitro. Methods Five specimens of Solidex resin were fabricated at thickness of 0.5, 1.0 and 1.5 mm. The pieces of Ni- Cr alloy, two shade composite resin and opaque porcelain veneered Ni- Cr alloy were used as backgrounds. The CIE L*a*b* values of specimens were measured by a colorimeter（ShadeEye NCC） to determine the colorimetric difference, when different thickness of specimens were overlaid the different shade and thickness of luting agent at the same backgrounds. Results The final color difference of specimens was significantly influenced by the factors of luting agent and the interaction of specimens thickness, backgrounds and luting agent（P< 0.001）. Regarding the thickness of luting agent, A3 shade luting agents produced clinically unacceptable difference （△E*>2）in the final color of Solidex specimens at the thickness of 0.5 mm. Regarding the shade of luting agent, the color difference was more than 2 when the Solidex specimens at the thickness of 0.5 mm or 1.0 mm were against the 0.2 mm thick luting agent. Conclusion The final color of thinner Solidex specimens was significant affected by the change of the shade and thick of luting agent.

Objective To investigate the efficiency of different angle projection radiograph in diagnosing multiple canals of mandibular first premolars. Methods Eighty- eight mandibular first premolars that needed endodontic treatment in vivo were selected. The radiograph was taken at a horizontal angles of 0, 20 - 30 degrees from mesial or distal direction of the tooth preoperative. According to the different angle projection radiographic evaluation, radiographic diagnosis of multiple canals were suspected. After the root canal orifice were detected and located with K files, the root canals were prepared using crown- down technique and obturated using cold lateral condensation technique. The configurations and numbers of root canals were identified and recorded. The postoperative radiograph was taken. According to configurations and postoperative radiograph, the root canal configuration was classified into typeⅠ - Ⅴ. Results In eighty- eight mandibular first premolars, 31 multiple canals teeth were suspected in preoperative radiographic diagnosis, 30 multiple canal teeth were detected under clinical evaluation. In case of 31 multiple canal teeth suspected by preoperative radiographic diagnosis, 3 teeth were not found multiple canals under clinical evaluation. While in case of 2 teeth of one canal suspected by preoperative radiographic diagnosis, multiple canal was detected under clinical evaluation. In 31 multiple canal teeth suspected by preoperative radiographic diagnosis, 13 teeth were detected at a horizontal angles of 0 degree and 25 teeth were detected at a horizontal angles of 20- 30 degree, 7 teeth were suspected at different angle projection. Clinical detected rate of multiple canal in mandibular first premolar were 34.09%（30/88）, 70.00% of which were type Ⅳ and Ⅴ. Conclusion Different angulation radiograph of preoperative will assist to increase clinical detection rate of multiple canals in mandibular first premolar.

Objective To study the effective method of early treatment on cracked tooth. Methods Sixty cracked teeth were randomly divided into Group A and Group B. Teeth of Group A were treated by means of occlusal adjustment and filling. Teeth of Group B were treated by employing porcelain complete veneer crown. Curative effect was evaluated every half a year and last 2 years. Results The achievement ratio of Group A and Group B was 53.33% and 83.33%. There was significant difference between them（P<0.01）. Conclusion Porcelain complete veneer crown is a better method to treat cracked tooth. It can decrease the occurrence of pulpitis and fracture.

Objective To explore the nursing methods during canal obturation in order to improve efficiency and quality of root canal therapy. Methods 112 teeth treated by complete root canal preparation were chosen to fill the root canal, and the main points of nursing during canal obturation were summarized. Results All of 112 teeth nursed strictly during canal obturation obtained satisfactory efficiency. No one failed after root canal therapy. Conclusion The main points of nursing during canal obturation are the aseptic technique, skilled coordination, instrument management, communication between nurses and patients.

Objective To investigate the oral health status of undergraduate university students and to guide their oral hygiene behaviors. Methods 3 516 college students in Northwest University for Nationalities were investigated in this study according to the criterion issued by World Health Organization（WHO） on the basic methods of oral health investigation in 1997. Results The caries prevalence rate among the students investigated was 47.87%. The average decayed teeth were 1.29. The obturation rate of caries was 20.42%. The students came from city showed significant higher caries rate than those from countryside, and so did the female students compared with the male students. Dental calculus rate was 79.78%. The dental segments related were 3.75. The worst situation was among male students and students from countryside. The examined rates were 53.30% of crowded incisor, 42.58% of maximum upper- incisor anomaly, 50.60% of the maximum lower- incisor anomaly and 31.09% of molar malposition, respectively. More rates of dentofacial anomalies showed no differences of significance between different area and gender. Conclusion In general, the oral health status of the college students are not ideal. It is necessary to advocate early examination, early prevention and early treatment among the students in university.

Objective To compare the difference in strength degradation and morphology damage of two dental ceramic materials after Hertzian contact cyclic fatigue. Methods Hertzian contact technique was used to investigate the response of EmpressⅡglass ceramic and GI- Ⅱglass- infiltrated alumina ceramic to cyclic fatigue. Critical loads of specimens after different fatigue cycles were recorded. Results For EmpressⅡglass ceramic, critical load had significantly difference between specimens after 105 cycles loading. No significant difference of critical load was found in GI- Ⅱglass- infiltrated alumina ceramic after cycles loading. Conclusion GI- Ⅱglass- infiltrated alumina ceramic has better capability in resistance to cyclic loading. It may attribute to microstructure of material. EmpressⅡglass ceramic shows a brittle damage model.

Objective To observe the induction of apoptosis of cisplatin（DDP）to oral squamous cell carcinoma cell line （Tca8113） in vitro and study the role of Survivin on the apoptosis of Tca8113 cells induced by cisplatin. Methods The inhibitory effects of different doses of DDP on Tca8113 cells were assayed with MTT test. Apoptosis was determined by flow cytometry. The expression of Survivin was detected by RT- PCR and immunocytochemistry. Results Cisplatin obviously inhibited Tca8113 cells growth in a dose and time dependent manner. The apoptotic index showed the similar trend. Survivin gene expression was decreased with increasing of time and reached the lowest level at 24 hours after DDP treatment, then increased after that time. Conclusion Cisplatin gene can effectively induce apoptosis in Tca8113 cells and the inhibition of Survivin gene expression may play a critical role on Tca8113 cell apoptosis induced by cisplatin.

Objective To observe the antibody responses induced by recombinant plasmid pIRES- fimA:IL15 via nasal immunization to BABL/c mice and the regulation of IL- 15 to sIgA. Methods BABL/c mice were immunized with recombinant plasmids pIRES- fimA:IL15 and pIRES- fimA via nasal or intramuscular route. Serum IgG and salivary sIgA levels after immunization were analyzed by ELISA. Results Nasal immunization with plasmids pIRESfimA: IL15 or pIRES- fimA elicited significant higher level of salivary FimA- specific sIgA responses compared with intramuscular immunization. There was no significant difference of the serum IgG responses between nasal immunization mice and intramuscular immunization mice. Nasal immunization with plasmid pIRES - fimA:IL15 elicited significant higher level of salivary sIgA response than with pIRES- fimA（P<0.05）. Conclusion Nasal dropping may be an effective mucosal immunization route of anti- Porphyromonas gingivalis DNA vaccine to elicit specific antibody responses in serum and oral region. IL- 15 has a positive regulation effect to sIgA response.

Objective To analyze the expression of foreign gene in the filial generation of the transgenic plants on the base of the original transgenic tomatoes seeds carrying the gene encoding saliva- binding region（SBR） in PAc of Streptococcus mutans（S. mutans）gained. Methods The tomatoes total DNA was extracted by CTAB methods, and the filial generation transgenic tomatoes carrying the gene encoding SBR in PAc of S. mutans were selected by PCR. The tomatoes total RNA was extracted by trizol and the transcription of the foreign gene was analyzed by RTPCR. Protein was extracted from fruit tissue and the content of the total protein was determined by Bradford′s methods G250. The expression of foreign protein was analyzed by Western blot and the lever of the foreign protein was analyzed by ELISA. Results The fragment encoding SBR in S. mutans PAc gene integrated in the tomato genomic DNA and was expressed. The foreign protein lever was up to 1.2% of the total soluble protein in tomato fruit tissue. Conclusion The foreign protein gene in the filial generation of the transgenic plants could express the foreign protein.

Objective To study the drug resistance changes in Tca8113 cell lines by exposing to carboplatin. Methods The concentration of carboplatin added to Tca8113 cells was increased gradually and continually, which was to induce the carboplatin- resistance in Tca8113 cells. The sensibility to drugs of the cells was analyzed by MTT method. Immunocytochemistry and RT- PCR were utilized to examine the expression of multidrug resistance proteins and genes. Results After exposing to carboplatin, the Tca8113/CBP cells had higher drug- resistance to CBP, MTX, PYM, VCR and higher expression of MRP, GST - π than Tca8113 cells. Conclusion Multidrug resistance of Tca8113/CBP is associated with over expression of MRP, GST- π and MDR. Tca8113/CBP can provide an ideal model for multidrug resistance research.

Objective To investigate the green fluorescent protein（GFP） expression and the bionomics of skeletal muscles satellite cells（SMSCs） in vitro in GFP transgenic mouse. Methods The newborn transgenic mice were acquired to separate skeletal muscles satellite cells with enzyme digestion method. Cells were cultured and subcultured in vitro. Morphological observation, growth curve were investigated to evaluate the proliferation and differentiation characteristics of skeletal muscles satellite cells, fluorescence microscope was used to observe the GFP expression. The cells were identified by immunocytochemical stain. In the basis of identification of anti- sarcometric actin anti- body, the combination of anti- desmin antibody and DAPI（4, 6- diamidino- 2- phenylindole） were used to detect the purification of skeletal muscles satellite cells. Results Immunocytofluorescence suggested the good retain of GFP fluorescence in skeletal muscles satellite cells. The cells showed strong proliferative ability and they were positive with immunocytochemical stain of anti- sarcometric actin antibody and anti- desmin antibody. The combination of anti- desmin and DAPI stain can be used to determine the purification of SMSCs. Conclusion Skeletal muscles satellite cells cultured in vitro showed strong proliferation and differentiation ability. They are fit to construct the cell bank of tissure engineering and to be a useful tool to explore cells fate after transplantation since these cells retain the expression of GFP.

Objective To explore a new method to construct the three- dimensional finite element model of microimplant- maxilla using Materialise′s interactive medical image control system（Mimics）. Methods The maxilla with all teeth was scanned with Spiral CT and the images were transferred into the Mimics 9.0 software to obtain the threedimensional images. The Abaqus 6.5 software was used to mesh the three- dimensional model and to establish the finite element model. Results A detachable three- dimensional finite element model of micro- implant- maxilla based on Mimics was constructed rapidly, which can be flexibly re- assembled. Conclusion The method of constructing the three- dimensional finite element model of micro- implant- maxilla is available and effective. The geometrical analogy of the model was greatly improved by using the Mimics system.

Objective The Sonic hedgehog signalling peptide has been demonstrated to play important roles in the growth and patterning of the tooth development. This study aims on whether the antagonist β- transduction repeat containing protein of Sonic hedgehog signal transduction expressed in tooth germs ameloblast and odontoblast or not. Methods The mouse embryo heads of different developmental stages of E10.5, E13.5, E14.5, E16.5, E18.5 and P0, P3, P6 after birth were acquired fixed with 4% paraformaldehyde for 48 hours, embeded with Paraffin and examined using LsAB（labelled streptavidin- biotin）method to observe the β- TrCP expression pattern in tooth germs, ameloblast and odontoblast. Results It was demonstrated that β- TrCP expressed in oral epithelium, tooth bud, mesenchymal cell cytoplasm of ameloblast and odontoblast of different stage of tooth development. Conclusion β- TrCP expressed from early stage to later stage of murine tooth development. And these findings provide the evidence of antagonist regulatory pathways for shh in teeth development.

Objective To investigate the effect of retinoic acid on differentiation of periodontal ligament cells （PDLCs） and gingival fibroblasts（GFs）. Methods The periodontal ligament cells and gingival fibroblasts were cultured, challenged with different concentrations of retinoic acid in medium and detected for the alkaline phosphatase （ALP） activity and its mRNA by biochemical technique, in situ hybridization and RT- PCR. Results ALP activity in normal PDLCs was higher than that in GFs. The mRNA signals were positive in PDLCs, and negative in GFs. After treated with different concentrations of retinoic acid, ALP activity of PDLCs was increased than that of the control, and its mRNA signals were enhanced, especially in 5×10- 6 mol/L. The treated GFs showed a slight increase of ALP activity and a weak band of mRNA signals only in 5×10- 6 mol/L concentration. Conclusion There were differences between PDLCs and GFs in differentiating into osteoblast- like cells.

Objective To investigate the targeting expression of TRAIL gene driven by human telomerase reverse transcriptase（hTERT） promoter in SACC- 83 cell with telomerase activity. Methods Adenovirus vector AdTERTTRAIL was constructed by homologus recombination. After transfecting AdTERT- TRAIL into SACC- 83 cell and HEL cell, its effect on these cells in vitro was investigated using RT- PCR technique, MTT method and flow cytometry. Results After transfection of AdTERT- TRAIL, expression of extrinsic TRAIL gene driven was detected in SACC- 83, the proliferation of SACC- 83 cell showed significant inhibitory effect（the relative cell viability was 49.70%） and its apoptotic rate was promoted（30.49%）, whereas no TRAIL gene was detected in HEL cell, also no inhibitory effect was observed in HEL cell and its apoptotic rate showed little change. Conclusion Adenovirus vector AdTERTTRAIL was successfully constructed, which can be used to induce expression of TRAIL gene in SACC- 83 cell with targeting effect.

A case of a patient with subgingivally fractured incisor was presented. Two weeks after root canal therapy, the subgingival fragment was restored with fiber post, resin core and temporary crown. Gingivoplasty was performed around after the subgingival fragment had been elevated in the axial direction by means of edgewise fixed appliance. Stabilized and held for 6 months, the incisor was restored with all ceramic crown. Optimal esthetic was achieved when restoration was performed after rapid orthodontic extrusion which had lifted up the fracture line above the level of the gingival line within 14 days. At 6- month follow- up, the periodontal tissues were normal and neither luxation nor relapse was noted.