Higher education has gradually become essential in the economical society with the coming knowledge economic time. Cultivation of innovative dental talents is highly requested by modernization of China. Textbooks are crucial in cultivating high quality students of stomatology. A completely new epoch proposition appeared on how to construct an innovative teaching textbook system. The countermeasures, which are aiming at such aspects as the textbook evaluation system, author groups and textbook systems, are discussed in this paper.

According to the reviews of some critical factors, such as incidence rate of oral maxillofacial neoplasm, influence factors of molecular- biology and pathology, and advancement of comprehensive treatments, a new treatment idea- balancing therapeutic idea（BTI）has been put forward to improve the patients′life quality, prolong their survival, and decrease their psychological and physiological pains. The key point of the BTI is that the doctors should pay much attention to the patients′overall benefit and keep away from the risk of over- treatment based on the fact that it is impossible that cancer cells are killed out at the biological level. It is important for doctors to let the residual tumor cells be monitored and restricted with body′s immune defense system under the condition of normal physiological function and not being destroyed by improper treatment. This is the most important purpose of BTI that let oral cancer become chronic disease authentically and improve the therapeutic safety and efficiency.

Objective To detect the methods and experience of CT guided interstitial 125I seed implantation treatment for head and neck malignant tumor. Methods 5 patients with head and neck malignant tumor were treated by interstitial 125I seed implantation with CT guide, 3 of them were treated with operation and adjunct seeds implantation, the other two patients were implanted seed only. According the treatment plan, register needles were punctured firstly, based on CT scan, these needle′s position and depth were adjusted, then the seeds were implanted into the target area. Another CT scan was done for the dose verification. Results The procedure of 125I seeds implantation of five patients was successful. 5 of twelve register needles were adjusted. The dose distribution of the instant verification was the same as that of treatment plan. Conclusion The CT guided seeds implantation of the head neck malignant tumors can practice the treatment plan accurately, and the dose verification can be done instantly.

Objective To study the effects of TiO2 blasted and acid- etched surfaces of cp- titanium on changing composition of oxide- film and attachment and proliferation of osteoblasts in vitro. Methods cp- titanium discs were prepared and divided into 4 groups：TiO2 blasted（SB）, sandblasted and acid- etching（SLA1 and SLA2） and machinepolished surface（S0）. Scanning electron microscopy（SEM）, X- ray diffraction（XRD） and electron probe microanalysis （EPMA） were used to test surface morphology and composition of oxide - film. Osteoblasts were cultured on the titanium surface of 4 groups. MTT assay was used to measure the attachment and proliferation. Results In regard to surface roughness, average roughness for SB, SLA1 and SLA2 was obviously higher than S0. Oxygen ratio increased on SB,contrarily, it decreased on SLA. A mixture of anatase and rutile- type crystals were observed in the SB. Smaller anatase were observed in the SLA1 and SLA2. The   ide thickness on SLA surface was thiner than that on the SB surface. After 1, 4, 24 hours′culture, the number of osteoblast attachment on SB surfaces was the highest（P<0.05）. The number of cells osteoblast proliferation was the highest on SB after 1 , 3, 5 and 7 days′culture（P<0.05）. Conclusion The thickness and chemical composition of oxide film play an important role in osteoblast attachment and proliferation at the same roughness surface. It is concluded that osteoblast attachment and proliferation are better on SB surfaces than on SLA1 and SLA2 surfaces.

Objective To evaluate wear resistance and hardness of three kinds of new composite resins. Methods Three kinds of new composite resins, Solidex， Spectrum, FiltekTM Z350, were tested. Enamel as control group. A refited MG- 200 wear machine was used in this study. Scanning electron microscope（SEM）was used to observe the friction surface of each tested material. Hardness of each tested material was determined by Vickers indentation technique. The data of wear and hardness were analyzed by Mann-Whitney test and 1- way ANOVA. The relationship between the hardness of the composites and the amount of wear of them was determined by a regression analysis method. Results FiltekTM Z350 showed the lowest volumetric wear and highest Vickers hardness in the composites （P<0.05）. No significant differences in wear and hardness were observed between Solidex and Spectrum（P >0.05）. Significant relationships were observed between the hardness of the composites and the amount of wear of them （r=- 0.968 6）（P<0.05）. Different wear characters of the friction surface of the tested materials were observed by SEM. Conclusion Nanofilled composite was superior to the hybrid composite in wear resistance and hardness.

Objective To analyze stress around the impacted tooth by constituting a 3- dimensional finite element model of impacted tooth, consequently offer reference basis for clinic traction treatment. Methods The 3- dimensional finite element model of the impacted tooth was constituted by CT scan, append pericementum and alveolar bone model was used to constitute impacted model. 3 forces were loaded to 3- dimensional finite element model and the periodontal stress of impacted tooth was calculated. Results When force 1 was loaded to the model, the maximum stress was smaller, but the stress distribution was more average. When force 3 was loaded to the model, the maximum stress was larger, but the stress concentrated at the side of the force. When force 2 was loaded to the model, the stress distribution was medium. Conclusion When the direction of the force is in line with the central axis, the maximum stress is smaller, and the stress distribution is more average, while this has advantage to the eruption of the impacted tooth. When the direction of the force has angle with the central axis of the impacted tooth, the angle is larger, the maximum stress is larger and the stress distribution is more concentrate, and this goes against the eruption of the impacted tooth. The angle between the orientation of the traction and central axis of the impacted tooth is smaller, there are more advantages to the eruption of the impacted tooth. So the angle should be properly selected in order to make sure of the eruption of the impacted tooth. When the angle is quite large, more anchorage is needed to resist to the large force.

Objective To observe the effect of the chitosan thermosensitive hydrogel loading recombinant human bone morphogenetic protein- 2（rhBMP- 2） on repairing periodontal defects. Methods To prepare artificial furcation defects model in the posterior area in 3 healthy male dogs, and then to inject chitosan thermosensitive hydrogel loading of rhBMP- 2 after fast suturing tissue flap. The groups filled with nothing or filled only with chitosan thermosensitive hydrogel were the controls. The dogs were sacrificed after 8 weeks and the periodontal regeneration was observed histologically. Results The histological observation showed that the chitosan thermosensitive hydrogel loading rhBMP- 2 group achieved apparent periodontal tissue regeneration occupying the majority of the defects and the control groups got only a small amount of periodontal tissue regeneration. Conclusion The chitosan thermosensitive hydrogel loading rhBMP- 2 can effectively promote the periodontal tissue regeneration, while simplifying the surgical operation. It might be a potential means for periodontal regeneration.

Objective To establish the expression and purification route for the gene encoding human amelogenin（AMG） mature peptide in Escherichia coli（E.coli）. Methods Recombined plasmid pGEX- 4T- 1/AMG was identified by double endonuclease digestion electrophoretogram and DNA sequence analysis. The recombined plasmid was transformed to E.coli BL21. The inducing time, isopropyl- beta- D- thiogalactopyranoside（IPTG） concentration and inducing temperature were optimized for the express system. Under the optimized condition, the target fusing protein in supernatant,periplasm, plasm and inclusion body was analyzed separately. A great amount of target fusing protein was found in the dissoluble protein. AMG fusing protein was purified by the GSTrapFF affinity column. Results Double endonuclease digestion electrophoretogram and DNA sequence analysis were done to identify the recombined vector pGEX- 4T- 1/AMG. The results were consistent with the anticipation. The optimum inducing time was 14.5 hours. The optimum IPTG concentration was 1.0 mmol/L. The optimum inducing temperature was 20 ℃. Under this condition, the target protein was expressed to a maximum. Plentiful target protein was expressed in plasm and inclusion body under the optimized condition. A mount of plasm protein was obtained and purified by the GSTrapFF affinity column. The purified liquid was collected and analyzed by SDS- polyacrylamide gel electrophoresis（SDSPAGE）. The protein electrophoresis map showed that AMG fusing protein was purified successfully. After twice elution, high pure fusing protein was obtained. Conclusion pGEX- 4T- 1/AMG system is used successfully to express human AMG fusing protein.

Objective To evaluate the influence of incorporating inorganic antibacterial agents on the systemic toxicity and cytotoxicity of an experimental self- etching primer（ESP）. Methods Six kinds of inorganic agents were incorporated respectively into the primer. Systemic toxicity in vivo tests in rats and direct contact in vitro cytotoxicity tests with NIH fibroblasts were conducted. Results Systemic toxicity tests revealed neither toxic manifestations nor significant differences in body weight gain between control and other groups. There were no significant differences between experimental groups and empty control on cell vitality and cell proliferation rates. Toxicity was only observed in areas beneath the specimens and/or in the direct vicinity of the specimen edge. There was no influence on the cell density over the limit of specimens. Conclusion The incorporation of tested inorganic antibacterial agents with a proper concentration had no significant influence on the systemic toxicity and cytotoxicity of the tested selfetching primer.

Objective To examine the change of epidermal growth factor（EGF）concentration in saliva of recurrent aphthous ulcer（RAU） patients during the ulcerous and interval period and epidermal growth factor receptor（EGFR） in ulcer biopsy samples. Methods EGF data of the samples, which were 27 saliva samples from RAU gained not only in the ulcerous period but also in interval period and 33 ones from normal persons, were acquired through enzyme linked immunosorbent assay（ELISA） and EGF standard curve. EGFR- RNA date of RAU biopsies, which were 31 biopsy samples from RAU got during the ulcerous period and 35 ones from normal persons, were surveyed by QF- RT- PCR. All RAU samples were obtained under the same level, which were the whole patients were minor aphthous ulcers and their ulcers occurred not over the first four days. All patients and normal persons were selected seriously under the rule of physical situations without any other diseases and histories of using medicines. Results The EGF concentration of saliva in RAU group at ulcer occurrence was higher than that in the interval period and the normal control with a significant test（F=3.24, P<0.05）. The EGF concentration of saliva in RAU group during the interval period was lower than that in the control, which was significant on statistics（t =2.73, P<0.05）. The EGFR- RNA in RAU group at ulcer occurrence was higher than the normal control with a significant test （t=3.15, P<0.05）. Conclusion It was suggested that the ulcer occasion of RAU patients could be related with the decreasing of EGF in saliva during interval period, and that the ulcer self- cure of RAU patients would be contributed to the increasing of EGF in saliva and EGFR in ulcer tissues during ulcer occurrence.

Objective To evaluate the efficiency of micro- implant anchorage（MIA） for posterior teeth intruded and the result of the treatment of scissors bite on one- side posterior teeth. Methods The study included 3 females and 1 male. All the overextruding upper posterior teeth were intruded by the MIA. The micro- implant screws were inserted into the buccal and lingual alveolar bone of the maxillary posterior teeth or the buccal alveolar bone of mandibular posterior teeth. About 0.833 N force was used to intrude the overgrowthing upper posterior teeth, and about 0.559 N force was used to draw buccally the low posterior teeth tilting lingually. Results The overextruding upper posterior teeth were intruded 2.0 mm on average, the low posterior teeth tilting lingually were upreared buccally. All the MIA screws kept stable during the treatment, but there was a slight inflammation around the implant screws. Conclusion MIA could be used as an efficient method to correct scissors bite on one- side posterior teeth with intruding overgrowth upper posterior teeth, or uprearing buccally the tilting low posterior teeth.

Objective To approach the correlation of upper airway and surrounding tissues with body mass index （BMI） of non- apnea aged males. Methods Thirty- one non- apnea aged from 70 years to 84 years males（all were inspected by polysomnography and apnea hyponea index<10 times/hour） had magnetic resonance imaging scanned. In images of MRI, the upper airway was divided into four sections, including nasopharynx, velopharynx, glossopharynx and laryn - gopharynx. The sizes, forms and surrounding tissues were measured and correlation analysis of duality variable about upper airway and surrounding tissues with BMI were carried out. Results 1）The volume of nasopharynx had negative correlation with body mass（P<0.05）. 2）The min anterior- posterior diameter of velopharynx had positive correlation with body mass and BMI. The max value of anterior- posterior diameter/transverse diameter of velopharynx had positive correlation with body mass. The min value of distance of fatpads had negative correlation with body mass and BMI. The min and average value of distance of ascending ramus had positive correlation with body mass and BMI. The min value of distance of fatpads/distance of ascending ramus had negative correlation with body mass and BMI. The transverse diameter/lateral velopharyngeal wall of velopharynx had positive correlation with BMI. All of above results had statistic significance（P<0.05）. 3）The volume of soft palate, tongue and fatpads had no correlation with body mass and BMI（P>0.05）. Conclusion The forms of sectional areas of velopharynx are subjected to body mass, and with the increasing of body mass they tend to round. In non- apnea aged males, the distance of fatpads and ascending rami have intimate relationship with body mass and BMI. The volume of soft palate, tongue, fatpads and velopharyngeal walls has little things with body mass and BMI.

Objective To study the relation on overfilling with gutta- percha point or paste and acute periapical periodontitis. Methods Collected sixty cases of acute periapical periodontitis which had been filled with gutta- percha point and paste within 1 week, and took dental radiographs. The cases that dental radiographs showed only guttapercha point was overfilling were assigned to group A（34 cases）, and the cases that dental radiographs showed only paste was overfilling were assigned to group B（26 cases）. The cases that dental radiographs showed both gutta- percha point and paste were overfilling were excluded. Sixty cases were divided into light group and severe group according to clinical sign. Measured gutta- percha point length or paste areas over apex. Took out the obturation material completely, adjusted occlusion when necessary and changed root canal medicament every day until clinical sign disappeared completely. Recorded the time of clinical sign disappeared completely. Results In group A, gutta - percha point length over apex averaged 1.01 mm on light cases, and 1.79 mm on severe cases. In group B, the paste areas over apex averaged 2.45 mm2 on light cases, and 8.26 mm2 on severe cases. Group A had 13 light cases and 21 severe cases, and group B had 18 light cases and 8 severe cases. In group A, the average time of clinical sign disappeared completely was 3.56 days, and in group B the average time was 6.19 days. The statistical test showed there were significant differences among these four couples. Conclusion The more overfilling, the more severe clinical sign was. Clinical sign caused by gutta- percha point overfilling was more severe. The time of clinical sign which caused by gutta- percha point overfilling disappeared completely was shorter.

Objective To choose the best retraction agent for the clinic by evaluating the gingival inflammation related to three kinds of retraction agents. Methods 40 maxillary premolars were divided into four groups according to the randomized block design: Ferric sulfate group, aluminum chloride group, epinephrine group, sodium chloride group（control group）, each 10 teeth, respectively used 25% AlCl3, 15.5% Fe2 （SO4）3, 0.1% HCl- epinephrine, sodium chloride as retraction agents. The quantity of gingival crevicular fluid（GCF） and the active level of aspartate aminotransferase（AST） in gingival crevicular fluid were measured before and 1, 3, 5, 7, 9 days after retracting gingiva by four kinds retraction agents. The changes of GCF were calculated. Results The change of the GCF from the smallest to the largest was sodium chloride, 0.1% HCl - epinephrine, 25% AlCl3 , 15.5% Fe2 （SO4）3. Compared withsodium chloride, only 15.5% Fe2 （SO4）3 in AST was the significant difference in the first day and the third day（P<0.05）. AST of ferric sulfate group after 1, 3 days greater than 800 IU. Conclusion 0.1% HCl - epinephrine is suggested in patient without cardiovascular disease. For patient with cardiovascular disease, the better substitute is 25% AlCl3. 15.5% Fe2 （SO4）3 will not be used until its concentration is fallen.

Objective The study was designed to investigate the relationship between the accuracy of Root ZX and the size of apical foramen, when the apical constrictions were intact or not. Methods Lengths were taken when the needle reached the‘0.5’mark and‘APEX’mark on the Root ZX. The electronic apex locator（EAL）- measured canal working length（L2） and EAL- measured canal length（L1） were then compared with the actual canal working length（L′） and actual canal length（L）. Besides, the areas of apical foramens（S） were measured when the apical constriction were intact or not. Then the measurement deviations and the areas of apical foramens were analyzed by linear correlation and linear regression using the software SPSS 12.0. Statistical significance was considered at P< 0.05. Results There were no significantly correlations between the area of apical foramen and the accuracy of Root ZX if the apical constriction was intact（P>0.05）. However, the accuracy of Root ZX and the size of apical foramen had significant negative correlation when the apical constriction was destroyed（P<0.001）. Then the linear regression was completed, and the linear regression equation was ΔL2=- 0.623+6.596S, so the critical area of the apical foramen was 0.135 mm2 if the tolerant error was set at 0.5 mm according to the statistic control. Conclusion The size of apical foramen has little effect on the accuracy of Root ZX if the apical constriction is intact. However the measurements of Root ZX should be used carefully when the apical constriction was destroyed.

Objective To compare the mandibular indices differences between periodontitis and non- periodontitis subjects by digital panoramic tomograms in order to find a simple and effective method to evaluate the density of alveolar bone and study the relativity between local bone loss and systemic bone loss. Methods Standard digital panoramic tomograms of sixty periodontitis subjects and sixty non- periodontitis subjects were taken. Density and height cortical width（CW） and panoramic mandibular index（PMI） of alveolar bone were measured on the digital panoramic tomograms. SPSS 12.0 was used for statistics analyses. Results The periodontitis subjects had lower height of alveolar bone（8.76 mm vs. 11.85 mm, P=0.000）, lower density of alveolar bone（106.08 vs. 113.33, P=0.034）, thinner cortical width（3.80 mm vs. 4.27 mm, P=0.008）, while the difference of PMI between the two groups was not significant （P>0.05）. The relativity between both density and height of alveolar bone with CW was significant（P<0.05）, but not significant with PMI（P>0.05）. Conclusion The optical method is a simple and effective method to measure the density of the alveolar bone. Compared with the non- periodontitis subjects, the periodontitis subjects not only have alveolar bone changed significantly but also have thinner cortical width.

Objective The purpose of this study is to evaluate the quality level of Chinese clinical research about dental caries in 1950- 2005. Methods The Chinese clinical research literatures about dental caries in 1950- 2005 were collected. All the literatures were evaluated by Jadad scale. The score of Jadad scale was form 0 to 5. Score 2 and below was poor quality literature, and score 3 and more was high quality literature. The full marks of Jadad scale was 5. Results 3 201 clinical research papers about dental caries were collected, in which 46 articles were high quality literature. In 3 201 papers, random allocation methods were mentioned in 142 papers, double- blind measure were performed in 26 papers, the withdrawn and missing cases were described in 256 papers. Conclusion The high quality literature of Chinese clinical research about dental caries in scientific research design is less. The scientific research design should be strength to enhance the total quality of Chinese clinical research about dental caries.

Objective To study the dental caries status in the primary dentition of 5- year- old children and analyze the difference of oral health behavior of family between urban and rural in Liaoning province. Methods The representative samples were selected by multi- stage, stratified and random sampling from Liaoning province. Dental caries of 792 children at five years were recorded according to World Health Organization criteria. The questionnaries were finished by 396 parents of the children and analyzed the oral health behavior of family in urban and rural by chisqure test. Results The prevalence and dmft of dental caries of 5 - year - old children in Liaoning province was 73.86% and 4.38, respectively. The prevalence of dental caries in 5- year - old children was 64.14% in urban and 83.59% in rural. There was significant difference on the consumption of sweets, chocolate, water with sugar and beverage between the children in urban and rural. More urban children had good toothbrushing behavior such as the time of beginning brush tooth, the frequency of brushing and daily use of fluoridated toothpaste compared with the rural children. The parents in urban had high level of education and incomes and there were more children in urban have regular dental visit pattern than in rural. Conclusion This study has shown that there is an urgent need for the implementation of a systematic education on oral health behavior of family on rural children in Liaoning province.

Objective The aim of this survey was to obtain some information about the prevalence of deciduous tooth caries of 5 - year - old children in Sichuan province. Methods Based on World Health Organization and national oral health survey standards, dental caries prevalence and treatment needs were investigated randomly in selected children of Sichuan province in 2005. And the differences between this survey result and the dental caries prevalence of 5- year - old children of Sichuan province in 1995 were compared. Results The prevalence rate of deciduous tooth caries of 5- year- old children in Sichuan province was 58.72%. The mean number of dmft of 5- year- old was 2.77. The filling rate was only 2.32%. The prevalence rate and mean dmft of deciduous tooth caries showed no significant difference between different area and gender; but the children came from city showed significant higher filling rate than those from countryside, so did the female children compared with the male children. Compared these results with the dental caries of 5- year - old children in Sichuan province in 1995, the prevalence rate and mean dmft of deciduous tooth caries in Sichuan province in 2005 had no significant difference, but the filling rate decreased significantly. Conclusion The deciduous tooth caries prevalence rate of 5- year - old children is still relatively high in Sichuan province； there remains a proportion of active untreated decays. The dental health care education to the parents and teachers should be emphasized. In order to get the earlier diagnosis and treatment, regular examination and prevention method should be conducted.

Objective To survey the tooth decay of the first molars among the people in area of northeast China in order to provide the foundation for prevention and treatment strategies of caries. Methods According to the third national oral health investigation of epidemiology, the dental caries of first permanent molars were examined among 9 394 people aged 5, 12, 35- 44 and 65- 74 in northeast China. The data were analyzed by SPSS13.0 statistical software. Dental caries prevalence rate and DMFT（dmft）of first permanent molar were calculated. Results The prevalence of crown and root dental caries in northeast China were 26.86% and 3.81% respectively, mean DMFT（dmft） of crown and root dental caries were 0.41 and 0.04 respectively. There were significant differences of dental caries among provinces in northeast China. Mandibular first molar suffered from dental caries easily. The prevalence of caries of female was higher than that of male（P<0.01）, but there was not significant difference of prevalence of root caries between two sexes（P>0.05）. Except Jilin province, there were significant differences of prevalence of crown caries between city and rural area in Liaoning and Heilongjiang provinces（P<0.01）. It was no significant difference of prevalence and mean DMFT（dmft）of root caries between city and rural area in each province（P>0.05）. Conclusion The prevalence of dental caries of the first molar among the people in northeast China is high. The dental caries prevention and cure of first permanent molar should be emphasized in oral health field.

Objective To observe the two- dimensional morphology of microleakage between dentin and adhesives. Methods The occlusal enamel of human third molar was cut out and the dentin exposed, followed by the application of dental adhesive（Prime & Bond NT, Contax and Adper Prompt）, then a composite resin crown was built up. After storage in water（37 ℃）for 24 h, all teeth were vertically serially sectioned into matchstick- shaped specimens through the bond interfaces. Half of the specimens from one tooth were subjected to thermal cycling and another half was stored in water（37 °C）. All specimens were then immersed in ammoniacal silver nitrate solution, followed by developing solution. At last all specimens were subjected to microtensile test at a cross- head speed of 1.0 mm/min and their fractured surfaces were observed under scanning electron microscope. Results The planar contour of all the silver leakage was various branching, treelike shape, spreading from the border of section to the center. Conclusion The planar contour of microleakage is treelike shape and its extent is influenced by adhesives and thermal cycling.

Objective To determine the effects of berberine hydrochloride on the expressions of interleukin- 1β （IL- 1β） and tumor necrosis factor- α（TNF- α） in periodontal tissues in rat periodontitis model. Methods Based on the successful rat periodontitis model, the experimental rats were randomized into different groups followed by oral treatment with berberine hydrochloride for 1, 2, 3, 4 weeks and then the rats were sacrificed and analyzed. Pathological assay and HE staining were used to detect the general conditions and pathological changes of rat periodontal tissues. And immunohistochemical staining was conducted to determine the expressions of IL- 1β and TNF- α in rats periodontitis model periodontal tissues. Results The levels of IL- 1β and TNF- α in the periodontitis tissues were significantly higher than that in the control group. Treatment with berberine hydrochloride decreased the levels of IL- 1βand TNF- αin periodontitis tissues（P<0.05）. Moreover, the general conditions and pathological changes in the control group and groups treated with berberine hydrochloride were much better than that in periodontitis groups. Conclusion Berberine hydrochloride inhibited the expression of IL- 1β and TNF- α in periodontal tissues in rats periodontitis model and promoted the regeneration of the periodontal tissues. This study suggested that berberine hydrochloride may have potential clinical application.

Objective To establish a model of intracellular infection of human dental pulp fibroblast（HDPF） by Porphyromonas gingivalis in vitro. Methods HDPF was incubated with live Porphyromonas gingivalis with a multiplicitas of infection（MOI） from 100 for 0.5, 1.0, 2.0 hours. HDPF infected with live Porphyromonas gingivalis were observed by inverted microscope. Metronidazole, Penicillin, Streptomycin were added to the medium to kill any extracellular bacteria. Then the cells were lysed by sterile distilled water, dilutions of the lysates of cells were cultured anaerobically. Colony of invasive bacteria were then observed. HDPF exposed live Porphyromonas gingivalis with a MOI 50 and 100 for 1.0 hour, then cells survival rate were detected by MTT assay. Results After infected with Porphyromonas gingivalis 2.0 hours, cells were eumorphism. Porphyromonas gingivalis of incubation for 1.0, 2.0 hours was invasive cells. MTT assays indicated 99.07% cells survival rate with a MOI from 50 and 74.43% cells survival rate with a MOI from 100. Conclusion A model of HDPF intracellular infection with Porphyromonas gingivalis was successfully established in vitro.

Objective To investigate the role of ataxia telangiectasis mutated（ATM） gene in the oncogenesis and progression of oral squamous cell carcinoma（OSCC）. Methods A total of 61 formalin- fixed and paraffin- embedded samples were obtained from patients with hyperkeratosis, oral leukoplakia, OSCC and normal healthy controls. The expression of ATM protein in all of the samples was investigated by streptavidin- peroxidase immunohistochemistry assay. PCR was also performed to detect the loss of heterozygosity（LOH）in D11s2179 of ATM gene. The correlations between ATM and the clinical and histopathological characteristics were also investigated. Results The results indicated that the ATM expression was increased in oral premalignant lesions（P<0.05）. For OSCC, 68.8% samples showed normal or increased ATM expression, while 31.3% had decreased or absent ATM expression. Significant differences were found between the group of decreased or absent ATM expression and that of normal or increased expression over the histopathological grade and lymph node metastasis state. PCR results displayed that none of the samples from oral premalignant lesions showed abnormal changes, while 3 of the OSCC（9.38%） showed loss of heterozygosity（LOH） and 2（6.25%） with microsatellite instability（MSI）. Those 3 samples of LOH showed absent ATM expression. Conclusion These findings indicated that the over expression of ATM may contribute to prevent carcinogenesis of OSCC. ATM inactivation may be one of the genetic alterations of the molecular progression of OSCC.

Objective To compare and evaluate the biocompatibility of three kinds of dentin bonding agents Xeno Ⅲ（XO）, Adper Prompt（AP）, Single bond2（SB）through cell culture in vitro. Methods Three kinds of dentin bonding agents（XO, AP, SB）were applied on the surface of the dental slices which were 5.0 mm in diameter and 0.5 mm in depth. By immersing the slices into the DMEM culture medium, the maceration extracts were obtained. Normal dental pulps of teenagers were collected and human pulp fibroblast was cultured using tissue explant method. The fifth generation pulp cells were exposed to culture medium containing different concentrations of maceration extracts （100.0%, 50.0%, 25.0%, 12.5%） for 24, 72, 120 h. At last, MTT method was used to evaluate the cytotoxicity of the dentin bonding agents on human pulp fibroblast. Results The results showed that all three kinds of dentin bonding systems had cytotoxicity to human pulp fibroblast in different degree in vitro. The cytotoxicity of XO and AP was less than SB. The difference was statistically significant（P<0.05）. Conclusion The results of cell culture in vitro indicated that total- etching adhesives system has more irritation to pulp than self- etching adhesives system.

Objective The purpose of this study was to observe the morphological changes of toothmarks in pocket limbs and to explore the durative development of bitemarks. Methods Firstly a toothmark model was established by using a universal testing machine and a self- made incisor nod which was pressed particularly on pocket limbs. The changes of toothmarks were observed on alive and dead animals with time elapsing. The scopes of bruise and inden were analyzed by soft on digital photos. The depth data of inden were collected by three dimensional laser measurement. Results The changes in the alive group were faster than that in dead group. There was no obvious fadeaway of bruise during 24 h. The scopes of inden were decreased remarkably in 1 h, while the decrease slowed down in the following hours. Conclusion The changes of indent are fast in pocket limb. It implies that bitemark evidence should be collected as fast as possible in cases.

目的制备磷灰石- 多孔纤维素复合物，评价该复合物的细胞相容性。方法通过化学修饰将磷酸根接枝于天然多孔纤维素玉米芯表面，经预矿化处理后，在模拟体液中进行仿生矿化，X线衍射检测磷灰石- 多孔纤维素复合物表面磷灰石微晶的形成，扫描电镜（SEM）观察复合物表面形貌。体外分离培养扩增乳鼠颅盖骨成骨细胞，经传代培养作为种子细胞接种于复合物表面进行培养。采用MTT和碱性磷酸酶（ALP）活性检测及SEM观察细胞在复合物表面生长、增殖与分化情况。结果仿生矿化后玉米芯表面形成了磷灰石晶体。成骨细胞在磷灰石- 多孔纤维素复合物表面吸附、铺展，具有较好的增殖及合成ALP的能力。结论磷灰石- 多孔纤维素复合物与成骨细胞具有良好的相容性，在仿生构建骨再生材料方面具有潜在的价值。

Objective This article was to study the effect of induced occlusal disorders and removed occlusal disorders on the expression of bone morphogenetic protein- 2（BMP- 2） of condylar cartilage. Methods Young and adult female Sprague- Dawley rats were divided respectively into induced occlusal disorders group, removed occlusal disorders group and control group, 3 rats every group. For induced occlusal disorders rats, the elastic rubbers were inserted between the first and second molar in the left upper side and right lower side to form the disordered occlusion. They were killed under anaesthesia 8 weeks after the treatment. For removed occlusal disorders rats, the first molars that caused disordered occlusion were extracted 6 weeks after forming disordered occlusion. 2 weeks later , they were killed under anaesthesia. For normal rats, they were killed at the same time with experimental rats. Hibateral temporomandibular joints of each rat were removed and stained with HE and monoclone antibody of BMP- 2. The thickness of condylar cartilage was measured. The expression of BMP- 2 in condylar cartilage was detected by half- quantity immunohistochemical analysis. Results For adult induced occlusal disorders group, the thickness of cartilage in intermediate part of condyle decreased. However, it increased in the posterior part. After removing occlusal disorders, the thickness of posterior condylar cartilage returned to normal level. But it was still thinner than control group in the intermediate part. The expression of BMP- 2 in anterior, intermediate, posterior part of condylar cartilage of young induced occlusal disorders group was higher than that of young removed occlusal disorders group and control group. No difference of the expression of BMP- 2 was found in young removed occlusal  disorders group and control group. For the expression of BMP- 2 in intermediate part of condylar cartilage, both adult induced and removed occlusal disorders groups were higher than adult control group. For the posterior part of adult condyle cartilage, the expression of BMP - 2 showed induced occlusal disorders group was higher than removed occlusal disorders group, which was higher than control group. Conclusion Induced occlusal disorders can lead higher expression of BMP- 2 in condylar cartilage of young and adult rats. Adaptability of condylar cartilage of adult rats is weaker than young rats, especially the intermediate part.

Nevoid basal cell carcinoma syndrome is a rare autosomal dominant genetic disorder characterized by developmental abnormalities and tumorigenesis. In this paper, a case of nevoid basal cell carcinoma syndrome family was reported, and its incidence, pathogenesis, clinical features and methods of treatment were discussed by reviewing relevant literatures.

Combined the elaboration on periodontic- endodontic lesion in the textbook Periodontics with the deficiencies existed in the clinical and teaching work and demonstrated the understanding on the type of the combined periodontic- endodontic lesion, and suggested the viewpoint of no sub- type of combined periodontic- endodontic lesion  Only regard the type of pulp disease that induced by periodontal disease as genuine combined periodontic- endodontic lesion.