This article is to explore how to participate disaster medical rescue. Specific cases, concerned experiences and effects obtained from the big earthquake occurred in Wenchuan, Sichuan Province May 12, 2008 were presented for researching consideration. According to conclusion of this report, it is urgently necessary and vitally important for stomatologists to study disaster medicine rescue.

A study of the dental professional action to the struggle for the mass casualty and disaster events was reported. The dental professional first aid and care, triage of casualties, maxillofacial surgery, forensic odontology to the struggle for the mass casualty and disaster events were discussed. The dental profession personals must make the more specific contribution in the mass casualty and disaster events in the future.

目的研究碱性成纤维细胞生长因子（bFGF）对人牙周膜成纤维细胞内核心蛋白多糖（decorin）的影响，探讨bFGF在牙周再生中的意义。方法体外原代培养人牙周膜成纤维细胞，用外源性bFGF刺激细胞，半定量RTPCR法检测牙周膜成纤维细胞内decorin基因表达的变化。结果电泳结果表明，bFGF抑制人牙周膜成纤维细胞内decorin的mRNA合成，并且随着质量浓度的增加抑制作用减弱。结论decorin具有很多生物学功能，bFGF对decorin的抑制作用很可能是牙周炎损伤修复过程中一个重要的调节因素，为bFGF在牙周组织再生中的作用提供理论基础。

Objective To explore the change of bone density of children′s mandible measured by quantitative computed tomography（QCT）. Methods 71 children aged between 10- 16 years were measured by QCT in left mandible angle, middle of mandible and right mandible angle. The differences were analyzed according to the age and sex respectively. Results The density of mandible of left mandible angle, middle of mandible, right mandible angle were 44.29, 89.70, 54.31 mg/dL in the 10 - 12 ages group, and 63.85, 122.47, 70.23 mg/dL in the 13 - 16 ages group. Conclusion Male youngster′s mandible density was increased with the age between 10- 12 and 13- 16 ages. There were significant differences between left mandible angle, middle of mandible and right mandible angle. There were significant differences of mandible density between male and female.

Objective Undried silver- hydroxyapatite- titania（Ag- nHA- nTiO2）nanoparticles slurry was used to make membrane with polyamide 66（PA66） by co- polymerization method. The purpose of this study is to test the physical and chemical characteristics and antibacterial ability. Methods The morphology, chemical components and structures of the membrane were characterized by atomic absorption spectrometer（AAS）, X- ray diffraction（XRD）, scanning electron microscope（SEM） and energy- dispersive X- ray analysis（EDX）. Staphylococcus aureus（S.aureus）, Escherichia coli（E.coli）, Porphyromonas gingivalis（P.gingivalis）, Fusobacterium nucleatum（F.nucleatum）and Streptococcus mutans （S.mutans）were utilized to test the antibacterial effect. Results XRD results demonstrated that the membrane have characteristic diffraction peaks of pure hydroxyapatite（HA）. A homogeneous distribution of the Ca, P, Ti and Ag element in the membrane was confirmed by EDX. Both surface and section showed porous structure which was confirmed by SEM and the average hole size was 20- 30 μm. The bacteria assay reflected to the antibacterial effect, 50.10% of S. aureus and 56.31% of E.coli were killed. However, 91.84% of P.gingivalis, 90.64% of F.nucleatum and 90.49% of S. mutans were killed and pictures of SEM showed obviously fewer cells on the surface. Conclusion The nanocomposite membrane could be one of the bioactive materials with antibacterial properties for oral guided bone regeneration technique.

Objective To investigate the apoptosis induction effect of vitamin E succinate（VES） on Tca8113 cells and its possible mechanisms. Methods The proliferative activity of Tca8113 was assessed by methyl thiazolyl tetrazolium（MTT） assay. After Tca8113 cells were treated with different concentrations of VES, apoptotic rates were analyzed by flow cytometry（FCM）. Fas monoclonal antibody was used for the blocking test. Fas expression was detected by immuocytochemistry（SABC assay） and FCM. Results VES demonstrated a significant growth inhibitory effect and apoptosis induced effect on the Tca8113 cells in a dose- and time- dependent manner. Fas neutralizing antibody can block the apoptosis induced by VES. After the administration of VES, the expression of Fas protein increased and the kytoplasm staining enhanced. Proteinum quantitative analysis showed that the mean fluorescence intensity increased. Conclusion VES can induce apoptosis in human tongue cancer cells, and the up- regulation of the cell surface Fas protein may play an important role in the process.

Objective The purpose of this study was to evaluate the maximum binding（Bmax） and affinity Kd value changes of acetylcholine receptor（n- AchR）on rat′s superficial masseter muscles after functional mandibular advancement. Methods Forty 5- week- old male SD rats were randomly divided into experimental and control groups. The mimic functional appliances were only used in experimental groups, and the rats of two groups were killed after 1, 3, 7, 14 days. Radio- ligand binding assay（RBA）was applied to determine the Bmax and Kd value of n- AchR on the superficial masseter muscles. Results The Bmax of n- AchR in experimental groups was higher than that in the control groups at all time points, and the differences had statistical significance. The Kd value of n- AchR was higher in experimental group than that in control groups in 1, 3, 7 days, while Kd value in experimental group of n- AchR was lower than that in control groups in 14 days. The differences had statistical significance in 7 and 14 days, but the differences had no statistical significance in 1 and 3 days. Conclusion The functional orthopedics can increase the Bmax and affinity of n- AchR on rapid growing rat′s superficial masseter muscles.

Objective To evaluated the bonding strength between pure titanium and Solidex after deposition by magnetron sputtering TiSiN with different content of Si（9%, 19%） and analyzed the surface component by electron probe micro- analysis（EPMA）. Methods All pure titanium samples divided into 3 groups according to different surface treatment, then bonded with Solidex light- cured composite. Material test machine was used to measure bonding strength and the surface was analyzed by EPMA. Results The bonding strength of deposition with TiSiN groups were higher than unfilming group, increasing the content of Si could enhance the bonding strength between pure titanium and Solidex in TiSiN groups（P<0.05）. EPMA showed amorphous materials like TiN, SiN gathered on the surface in TiSiN groups. There were obvious interspaces between unfilming pure titanium and Solidex, contrary no interspaces was observed in TiSiN groups. Conclusion The bonding strength of filming groups was higher than unfilming group, amorphous material like TiN, SiN gathering on the surface may prevent the microleakage and stop metal ion leaking.

Objective To evaluate the abutment periodontium condition after restored with the distal - extension extracoronal attachment dentures. Methods 20 mandibular distal- extension cases were followed up, to measure the gingival index（GI） and plaque index（PLI） of the distant - abutments before restored with attachment dentures and after restored for one month, six months and one year; to compare the length of distant alveolar bone before restored with that after restored one year by taking digital stomatology tomogram photos. Results There were not significantly different in the PLI of distant- abutment between before repaired and after repaired one month, six months, one year （P>0.05）. There were not significantly different in the GI of distant - abutment between before repaired and after repaired one month, six months（P>0.05）, but the GI of distant - abutment after repaired one year was significantly higher than that before repaired（P<0.05）. There were no significant differences on the length of distant alveolar bone in distant- abutment before repaired and after repaired one year（P>0.05）. Conclusion It is important to protect the periodontal health of the abutment when restored with distal- extension extracoronal attachment dentures. It is necessary to examine periodically after restored in order to keep the periodontal health of the abutment.

Objective To investigate the stress intensity and distribution in the dentine of intact endodontically treated mandibular second premolar under three different restorations. Methods Four three- dimensional finite element models were constructed by the data of spiral CT：1）Mandibular second premolar restored directly by full crown；2） Fill the perforating cavity with resin material and full crown restoration；3）Cast nickel chromium（NiCr） alloy post core plus full crown restoration；4）Fiber post and resin core plus full crown restoration. Load was applied on the buccal inclined surface near the top of the buccal cusp and the intensity and distribution of the maximum tensile stress and von Mises stress in the dentine were compared. Results When the tooth was restored with NiCr alloy post core, an obvious stress concentration area was observed in the dentine next to the top of the post. When the fiber post was used, there was little stress concentration area around the top of the post, and the stress distribution in the dentine was almost the same as the control group. No difference of the intensity and distribution of the stress was found with the control group when no post was used and the perforating cavity was just filled with resin material. Conclusion Compared with cast metal post, fiber post is more suitable for post- core crown restorations. In cases with sufficient coronal tooth substance, post is not absolutely necessary and just filling the perforating cavity with resin material followed by crown restoration can be one of the alternative restorations.

Objective To investigate stress distribution in mandibular first premolar restored by composite resin with root screw of different length in different occlusion. Methods An three dimensional finite element model of mandibular first premolar restored by composite resin with root screw was constructed by using spiral CT image reconstruction technique, Mimics, Pro/Engineer, Pro/Mechanica software. Based on this model，stress distribution in dentin, composite resin and root screw was analyzed in the situation of different screw length and different occlusion. Results When the occlusion was tripod contact and cusp tip- ovoid fossa contact, the stress of dentin, composite resin and root screw were all much less than their compressive strength. And also in this situation, the stress of bond surface between the composite resin and dentin was less than the bond strength of composite resin. The screw was longer but no more than 8 mm, the dentin stress distributes better. Conclusion In the restoration of large area mandibular first premolar crown defection, tripod contact and cusp tip- ovoid fossa contact with 8 mm root screw is recommended.

Objective To investigate the neural representations of normal humans intraoral water stimulation using non- invasive functional magnetic resonance imaging（fMRI）measurement, provide information for intraoral thermosensory study. Methods 13 healthy right- handed subjects（of which 6 were males） participated in the study to receive 23 ℃ deionized distilled water stimuli in mouth. The experimental protocol consisted of a block- design using 5 stimulus. Water stimuli were delivered to the subject′s mouth through self- made polythene tubes that were held between lips. Functional MRI scan covering the whole brain was carried out. The fMRI data was analyzed by SPM99 software with statistic t- test to generate the activation map. Results Significant activations existed in peri- sylvian including pre/ post - central gyrus, insular, orbitalfrontal cortex（OFC）, anterior cingulate cortex（ACC）, frontal gyrus, parietal lobule, midbrain and parietal lobule. Conclusion Water′s ability to activate nonspecific somatosensory, thermal or taste processing. The findings highlight the complex and distributed processing of different aspects of intraoral perception, and emphasize the importance of controlling for the effects of water when investigating the functional neuroanatomy of taste or temperature.

Objective The objects of the present study were to construct a computer model and to evaluate the load and stress of denture by means of three dimensional finite element analysis in order to provide evidence for clinic application. Methods The study utilized CT to scan the maxilla of a healthy man to receive the primal data, and then used Materialise Mimics 9.1 to establish a series of two- definite images artificially and automatically. The three dimensional finite element model of partial maxilla, including teeth, bone and softy tissue, could be constructed in Pro/Engineer WF 2.0 software by using related commands. The separated removable partial denture assembly was finally set up according to the denture design in Pro/Engineer WF 2.0. After converting data into Ansys Workbench 9.0, the command of meshing was fulfilled. Applying different loads on artificial teeth, the data about the stress on the periodontium, abutment and supporting tissue were obtained. Results Statistical comparisons showed that the stresses of periodontal membranes had no significant differences, but the periodontium under saddle changed greatly under different loads. Conclusion This study shows that the separated removable partial denture assembly can undertake the retention and load respectively due to special design. It is the two layers of bases that can protect the healthy of abutments. This design may be applicable for the restoration of the tooth with poor periodontium around abutments.

Objective To explore the clinical characteristic of functional articulation disorders in children and provide more evidence for differential diagnosis and speech therapy. Methods 172 children with functional articulation disorders were grouped by age. Children aged 4- 5 years were assigned to one group, and those aged 6- 10 years were to another group. Their phonological samples were collected and analyzed. Results In the two groups, substitution and omission（deletion） were the mainly articulation errors in these children, dental consonants were the main wrong sounds, and bilabial and labio- dental were rarely wrong. In age 4- 5 group, sequence according to the error frequency from the highest to lowest was dental, velar, lingual, apical, bilabial, and labio- dental. In age 6- 10 group, the sequence was dental, lingual, apical, velar, bilabial, labio- dental. Lateral misarticulation and palatalized misarticulation occurred more often in age 6- 10 group than age 4- 5 group and were only found in lingual and dental consonants in two groups. Conclusion Misarticulation of functional articulation disorders mainly occurs in dental and rarely in bilabial and labio- dental. Substitution and omission are the most often occurred errors. Lateral misarticulation and palatalized misarticulation occur mainly in lingual and dental consonants.

Objective To analyze the effects about inclinations of the second and the third molars in patients treated with or without premolar extractions. Methods Fifty- six adolescents were chosen and divided into the first premolar extraction and non- extraction groups, 30 and 26 patients respectively. The pre- treatment and post- treatment panoramic radiographs were made. Angles between long axis of the third molar and the occlusal plane（the second molar alike）, and long axis of the second and the third molar were measured and evaluated. Results The maxillary and mandibular third molar angulations were all improved after treatment in two groups. Compared with non - extraction group, the average changes of angle between long axis of the third molar and the occlusal plane increased significantly in maxilla and mandible（P<0.05）. Average changes of angles between long axis of the second and the third molar decreased and had statistically significant difference（P<0.05）. The change of angle between long axis of mandibular second molar and the occlusal plane had statistically significant difference（P<0.05）, but there was no statistically significant difference in maxillary second molar（P >0.05）. Conclusion The first premolar extraction in orthodontic treatment could improve the third molar angulations and it would promote the eruption of the third molar.

alveolar bone thickness. Methods Among 168 cases with malocclusion in early permanent dentition stage, 93 patients were male and 75 patients were female. All patients（aged 10 - 14 years） were divided into 9 groups by different facial skeletal types, mandibular anterior alveolar bone thickness in patients′lateral cephalometric films were measured. ANOVA were performed to measurement results with the SPSS 13.0 statistical software. Results Though sagittal facial skeletal types were the same, there were significant differences between different vertical facial types groups. The order was low- angle group, average- angle group and high- angle group according to the size. A high- angle individual often had a thin anterior alveolar bone while a low- angle individual often had the oppositemorphology character. There was no statistical significance between skeletal type Ⅰ, Ⅱ and Ⅲ. But group of skeletal type Ⅲ also had a thin alveolar bone thickness which had no significant difference with high- angle group. Lowangle group Ⅲ had no significant difference with average- angle groupⅠ and Ⅱ in alveolar bone thickness. Conclusion Sagittal facial skeletal types have little influence on anterior alveolar morphology, but the vertical facial skeletal types have strong connection with anterior alveolar bone thickness.

Objective To investigate the characteristics of pain in temporomandibular disorders（TMD） through analyzing the description of pain by the TMD patients. Methods Ninety TMD pain patients were included and the glossary in description of the intensity, rhythm and degree of disability due to TMD pain were recorded. Results The descriptive pain by 90 patients was slight to moderate. There was no significant difference between males and females or between chronic and acute patients in the description of pain intensity（P>0.05）. The chewing disability was the most often reported complaining, and then was mental status. The probability of pain at rest was not different between in chronic pain patients and acute pain patients（P>0.05）. The acute pain patients often used aching, slight and tingle to describe their pain, while the chronic pain patients used dull, gas and numb more. Conclusion Pain intensity in acute or chronic TMD patients is both low. The pain mainly influences chewing function and mental status in patients. Descriptive characteristic with chronic orofacial pain is different from acute.

Objective To evaluate whether there was any difference on the clinical effects of Twin - block, Activator and Herbst appliances on the clinical effects of growing children with skeletal Class Ⅱ malocclusion. Methods 60 patients with skeletal Angle Class Ⅱ malocclusion were divided into three groups（Twin- block group, Activator group, Herbst group）, 20 in each group. The patients of three groups were respectively treated by Twinblock, Activator and Herbst appliances. The patients were 10- 13 years old（mean 11.6） before treatment, and were mainly with mandibular retrognathia. Data of pre- and post- treatment were measured and analyzed. Results There was statistically significance of ANB, SNB, Go- Gn, Co- Gn, L1-MP in sagittal changes, and N-Me, ANS-Me, S- Go, SN-MP, Co- Go in vertical changes after treatmen of three groups. Herbst group was more effective than Twin- block group and Activator group in the increase of L1-MP, but the effects on maxilla were not significant among them. There was no statisticall significance of Ptm- A, OB, N-Me, ANS-Me, S- Go and Co- Go between 3 groups. Conclusion Treatment effects of three different functional appliances（Twin- block, Activator and Herbst） are similar in the early treatment of skeletal Class Ⅱ malocclusion. Compared with Twin- block and Activator, Herbst has more effects on orthopedic of mandibular and lower anterior teeth.

Objective To evaluate the clinical efficacy of a combined in- office cold light bleaching and nightguard vital bleaching（NGVB） system for treating tetracycline stained teeth（TST）. Methods 90 patients with light, medium and heavy TST were randomly and evenly divided into 3 groups. 30 patients with 472 TST from the treatment group were treated with in - office cold light bleaching and NGVB, 30 patients with 466 TST from the control group 1 were treated with in- office cold light bleaching and 30 patients with 469 TST from control group 2 were treated with NGVB. At the time of treatment completion, after half a year and after one year, Vitalescence esthetic restorative masters shade guide was used to record the change of color. Bleaching efficacy and course of treatment were calculated, and lightening stability were evaluated. Results 1）Three groups had satisfied lightening efficacy for light TST with 100% bleaching efficacy. The overall efficacy of treatment group and control group 2 were superior to the in- office cold light bleaching system（P<0.05）. Though there was no significant lightening efficacy difference between the treatment group and control group 2（P>0.05）, the periods of treatment of the treatment group for light, medium and heavy TST were shortened by 43%, 46% and 49%, respectively, compared to the control group 2. 2）All three groups′treatment efficacy for light, medium and heavy TST became weaker progressively （P<0.05）. 3）For the treatment efficacy between the time of treatment completion and after half a year and one year, there was significant statistical difference（P<0.01） for the control group 1, while there was no significant difference for both the treatment group and the control group 2（P>0.05）. Both treatment group and control group 2 had better performance in treatment stability than control group 1. Conclusion In treating the light and medium tetracycline stained teeth, the combined in- office cold light bleaching and NGVB system can achieve a more satisfied whitening result in much shorter period, and significantly enhance the long term whitening stability.

Objective To compare the effects of penehyclidine hydrochloride, atropine and scopolamine as the preanesthetic medication before operation for patient with cleft lip/palate（CL/P） who would undergo general anesthesia. Methods 120 CL/P patients who would undergo general anesthesia with tracheal intubation as research objects were chosen. The patients were divided into three groups randomly, group of penehyclidine hydrochloride （group PH）, group of atropine（group ATR） and group of scopolamine（group SCO）, 40 patients in each group. Penehyclidine hydrochloride（0.01 mg/kg）, atropine（0.01 mg/kg）or scopolamine（0.006 mg/kg）was given respectively to the patients. The changes of heart rate, temperature, blood pressure and the secretion of respiratory tract were observed before medication, 15 minutes and 30 minutes after medication, after trachea cannula and after operation. Results There were no significant changes in heart rate, temperature and blood pressure in group PH after medication（P > 0.05）. The heart rate and temperature in group ATR and group SCO increased significantly after medication（P<0.05）, however, the blood pressure had no obvious change（P>0.05）. The secretion of respiratory tract was decreased significantly in group PH comparing to group ATR and group SCO when the operation was over（P< 0.05）. Conclusion Penehyclidine hydrochloride has no significant effect on heart rate, temperature and blood pressure to the patients, and it′s effect of secretion inhibition is longer and it is better than atropine and scopolamine.

Objective This study was to test the feasibility of permanent maxillary tooth removal using articaine without a second palatal injection. Methods Of 104 patients, 38 patients had bilateral extraction and 66 patients had unilateral extraction of maxillary tooth. In the test group, 1.7 mL articaine with 1∶100 000 epinephrine was injected into the buccal vestibule of the tooth and the tooth were extracted after 5 minutes. In the control group, the patients were subjected to both palatal injection with 2% lidocaine hydrochloride and buccal injection with articaine. All patients completed visual analog scales（VAS） after extraction. Results The achievement ratio of permanent maxillary tooth anesthesia of test group was 96.2%. The achievement ratio of permanent maxillary tooth anesthesia of control group was 97.1%. There was no statistical significance between achievement ratio of test group and control group（P>0.05）. Conclusion Permanent maxillary tooth removal without palatal injection is possible by articaine injection to the buccal vestibule of the tooth.

Objective To explore the manufacture and clinical application of IPS - Empress casting ceramic restorations. Methods The problems in manufacture and clinical operation of 215 casting ceramic restorations were analyzed. Results In 215 casting ceramic restorations, 12（5.58%） casting ceramic restorations were affected by clinical design or application, 15（6.98%） casting ceramic restorations were affected by some manufacture problems, and 14（6.51%） casting ceramic restorations were affected by clinical try- in. Through 2 - 3 years′follow- up, the achievement ratio of 215 IPS- Empress casting ceramic restorations was 94.88%, and 11 casting ceramic restorations were affected by some problems. Conclusion Beauty and simultaneous enamel wear are the characteristics of casting ceramic restorations. But because of its brittle, the indications should be strictly selected.

Objective To evaluate in vivo gene delivery of Bio- Oss coated with adeno- associated virus- mediated human bone morphogenetic protein 7（rAAV- BMP7/Bio- Oss） for bone regeneration around dental implants. Methods In vitro rAAV- BMP7 were constructed and compounded with Bio- Oss. In 6 male New Zealand rabbits, two hydroxyapatite（HA）coated titanium dental implants were placed respectively to each animal in the bilateral tibia metaphysis. Before implantation, a standardized gap（8 mm in width, 4 mm in depth） was created between the implant surface and the surrounding bone walls. Rabbits were randomly divided into three groups（group A, B, C）. Gaps of group A were filled with rAAV- BMP7/Bio- Oss（n=4）, gaps of group B were filled with Bio- Oss alone（n=4）, and gaps of group C were filled with nothing（n=4）. The rabbits were sacrificed at 4 and 8 weeks respectively, and the sclerous tissue slices obtained, then histology and histomorphometric analysis were conducted. Results Histological and histomorphometric analysis revealed an enlarged bone- forming area in the bone defects of group A and B at 4 and 8 weeks after implantation. Greater bone- implant contact was achieved with rAAV- BMP7/Bio- Oss than with Bio- Oss alone and this difference was statistically significant（P <0.05）. Conclusion rAAV - BMP7/Bio - Oss can induce a stronger peri- implant bone reaction and larger new bone formation than Bio- Oss alone in the treatment of bone defects adjacent to titanium dental implants.

Objective To study the expression of inhibitor- 1 of DNA binding/differentiation- 1（Id- 1） and thrombospondin- 1（TSP- 1） genes in mucoepidermoid carcinoma of different malignant degree and analyze the relationship between them. Methods Using immunohistochemistry（IHC） staining technique, TSP - 1 and Id - 1 proteins in the mucoepidermoid carcinoma of different malignant degree, including well - differentiated, moderately differentiated and poorly differentiated mucoepidermoid carcinoma, and normal salivary gland tissues were detected. Results The positive rate of Id- 1 and TSP- 1 in normal salivary glands were apparently lower than that in malignant mucoepidermoid carcinoma（P=0.000, P=0.013）. The positive rate of Id- 1 in moderately and poorly differentiated mucoepidermoid carcinoma was higher than that of the well- differentiated（P=0.001, P=0.002）. However, the positive expression of Id- 1 showed no relationship between the moderately and poorly differentiated mucoepidermoid carcinoma（P>0.05）.The positive rate of TSP- 1 in poorly differentiated mucoepidermoid carcinoma was less than that of the well- differentiated（P=0.014）. The positive expression of TSP- 1 showed no relationship between the moderately and poorly differentiated mucoepidermoid carcinoma（P>0.05）, and the positive expression of it also showed no relationship between the moderately and well differentiated mucoepidermoid carcinoma（P >0.05）. The expression of Id - 1 and TSP - 1 showed negative correlation（r=- 0.394, P=0.002）. Conclusion The expression of TSP- 1 may inhibit the development of the mucoepidermoid carcinoma, contrarily, the expression of Id- 1 may prompt the development of the mucoepidermoid carcinoma. The expression of Id- 1 and TSP- 1 has negative correlation.

Objective To study the stress changes of maxillary central incisor restored with or without fiber post using three dimensional finite element method, and analysis the role of fiber post in determining the stress distribution in dentin. Methods Three dimensional finite element models of maxillary central incisor with various remaining tooth structure were established by spiral CT, Mimics software and ANSYS software. Test samples were restored with all- ceramic crown and fiber post all- ceramic crown, respectively. The von Mises stress and maximal tensile stress of dentin were recorded. Results The stress level in dentin of maxillary central incisor restored with fiber post all- ceramic crown was smaller than that restored with all - ceramic crown, the stress distribution of both were similar. Conclusion The apply of fiber post can reduce the stress level in dentin of maxillary central incisor and decrease the risk of tooth breakage, but not change the stress pattern.

Objective To investigate the effect of gradually induced disordered occlusion（GIDO） on the expression of tumor necrosis factor- α（TNF- α）in condylar cartilage in rat. Methods Fourty- eight SD rats, aged 8 weeks, were included, and were divided into experimental and control groups randomly, with the same gender distribution. By inserting elastic rubber band the first mandibular lower and maxillary upper molar was moved medially. Four weeks later the third mandibular lower and maxillary upper molars were moved distally with the same method. In this way the GIDO was established in rats. The rats were sacrificed at the end of 2nd, 4th, 6th, 8th week respectively after the application of the GIDO and the temporomandibular joints were stained with HE. The cartilage thickness was measured. The expression of TNF- α in condylar cartilage was examined by immunohistochemistry and calculated by the percentage of positive cells areas. Results The cartilage thickness increased in 4th, 6th, 8th week subgroups of experimental group（P<0.05）. Typical degenerative changes were observed in the experimental group. The expression of TNF- αwas mainly in the hypertrophic layer of the condylar cartilage. Compared with the age- matched control group, the expression of TNF- α in experimental group increased at the end of 2nd, 6th and 8th week（P<0.05）, but kept the same level at the end of 4th week（P>0.05）. Conclusion The present results suggest that TNF- α take part in the procedure of the abnormal remodeling activities of condylar cartilage in GIDO rat model. The catabolism in condylar cartilage in GIDO rats was even obvious when the experimental period was longer with more serious GIDO.

Objective To elucidate the regulatory bio- mechanism of estrogen and local stress on the bone remodeling activities in vivo. Methods A Wistar rat experimental model was established to apply orthodontic activation during different stages of estrous cycle. In situ hybridization was used to detect the variation of the insulin - like growth factors（IGF）mRNA expression in the periodontal tissues. The data of each group was analyzed with SPSS 11.0 software package for Student-Newman-Keuls（S-N-K）test and one way ANOVA test. Results Both IGF- ⅠmRNA and IGF- Ⅱ mRNA level expressed in the periodontal tissues were increased by orthodontic activation during various stages of the estrous cycle. But a similar pattern emerged that the IGF- Ⅰ mRNA level was the lowest in the estrous stage, whereas its level was the highest in the proestrus stage （P<0.05）. No rhythm of IGF- Ⅱ mRNA expression found during the estrous cycle. Conclusion It was concluded that local mechanical stimulation directly enhanced the IGF expression. In contrast to the IGF- Ⅱ, IGF- I was also influenced by the sex hormone rhythm during the estrous cycle.

Objective To establish a three- dimension finite element model of mandible with two kinds of dental implant and to study the stress of implant- bone interface. Methods Measuring the data of the components of the dental implant and using spiral CT image reconstruction technique to scan the cross section of the mandible. Threedimension finite element analysis software Unigraphics and MSC. Marc/Mentat were used to build the conjunction model and bone model of two implant systems. Loading 200 N axially and 100 N 30°obliquely on the models respectively, the stress distribution patterns of the bone interface of two implant systems were analyzed. Results The stress distribution on the bone interface of two implant systems was similar. The peak stress of oblique loading was higher than that of axial loading. The peak stress district of the bone was concentrated on the stricture of the implant cervix, which was more obviously displayed on the Replace Select implant. The peak stresses on the bone interface of Replace Select implant were higher than that of Replace implant in all loadings. Conclusion To Replace Select especially, oblique force should be avoided in clinical practice in case of the bone absorption.

Objective To investigate the reliability of a newly developed grating projection system 3DSS- STD- Ⅱ by three- dimensional reconstruction of dental cast, so as to offer some evidence for dental computer aided design and computer aided manufacturing（CAD/CAM）. Methods Five groups′data of mandibular dentition cast from different angle: Occlusion, right lateral dentition, anterior dentition, left lateral dentition and posterior of the cast were scanned and acquired by 3DSS- STD- Ⅱ new measuring system. The five groups of acquired data were then under simplification and combination process and the digital dental cast was finally reconstructed by the reverse engineering software Geomagic 6.0. After the reconstruction process, the plaster dental cast and digital reconstructed dental cast were then manually and digitally measured respectively by different items：Width of incisors, width of anterior dental arch, width of buccal segment, length of anterior dental arch and length of buccal segment. The manual process was undergone by vernier caliper and the digital process was by reverse engineering software. The statistical analysis was then undergone in order to evaluate the reliability, repeatability and scan - precision of the new grating projection system. Results With the statistical analysis results, the grating projection system 3DSS- STD- Ⅱ showed its good reliability and repeatability in three- dimensional reconstruction of dental plaster cast. There were no significant differences between the data acquired by 3DSS- STD- Ⅱ digital scanning system and manual measurement by vernier caliper in the precision. Conclusion The new grating projection system of 3DSS- STD- Ⅱ equipped with high reliability and fast speed can meet the need of the fast data acquisition and three- dimensional reconstruction of dental cast and CAD process.

Herpes associated erythema multiforme（HAEM） is an acute exudative dermatic and mucosal disease caused by infecting herpes simplex virus. It has recurrence and idiorestriction, characterized by increasing of CD4+ T leukomonocyte. This article reports a case of herpes associated erythema multiforme, and by way of reviewing relevant literature, discusses the possible mechanism, diagnosis, treatment and prognosis of HAEM.

Alveolar soft part sarcoma is a rare, aggressive malignancy of uncertain histological origin with a propensity for vascular invasion and distant metastasis. The case presented involves a 31- year- old woman with alveolar soft part sarcoma in the tongue root. The clinical features, pathogenesis, diagnosis and treatment were discussed.

The long distance displacement of canine is a rare phenomenon in orthodontic clinic. Its related clinical epidemiology, etiology, diagnosis and treatment methods are briefly summarized, and a case of mandibular canine displaced in chin is reported.