Objective　To establish a standardized rat model of autotransplantation of teeth and to analyze its advantages and disadvantages. Methods Five-week-old SD rats were extracted for left upper third molar and second molar firstly. Then, the left upper second molar tooth socket was prepared until it could hold the third molar. After the transplantation, the direction and bite were adjusted. Finally, the fixation was done through resin adhesive. Postoperative oral healing, imaging and histological examination were detected. Results Rats were eligible for autologous tooth transplantation surgery. After 8 weeks, the mouth of the transplanted teeth was still well-fixed, and there was no swelling in the soft tissue. Tissue HE staining showed that the donor teeth and alveolar bone were initially healed. CT scan showed that there was a small amount of bone formation. It had the advantages of short test period, low cost, good repeatability, and acceptable variety of inspection and detection. The shortcomings included: the individual was small, the experimental operation space was small, the degree of refinement was higher, and some operation could not be carried out completely or could not be completed. Conclusion The rats can be used as a standardized animal model of autotransplantation of teeth.

Objective To explore the compositions of oral flora from edentulous individuals. Methods Bacteria plaque samples were collected from mouth floor/tongue abdomen, tongue back, labial/buccal vestibule, hard palate/alveolar ridge crest and saliva of 11 edentulous individuals. The microbial 16S rRNA gene clone libraries were then constructed. Using pryosequencing, sequencing analysis of the V2-V3 variable zone of 16S rDNA was performed to execute species identification of oral flora from 11 edentulous individuals. Results A total of 51,091 sequences, which were classified into Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria phyla, were identified by pyrosequening in the 11 edentulous subjects. Predominant genera included Streptococcus, Neisseria, Porphyromonas, Rothia, etc. Streptococcus mitis, Granulicatella adiacens, Veillonella dispar, Pseudomonas citronellolis, Haemophilus pittmaniae, Neisseria zoodegmatis, Porphyromonas sp and Rothia mucilaginosa were dominant species. Conclusion Complete absence of dentitions had an impact on the oral flora compositions of edentulous individuals.

Abstract：Objective To establish a murine oral mucosal candidiasis model, observe oral mucosal infection and examine the corresponding systemic infectiondynamically, and to analyzethe changes of the infection. MethodsImmuno-suppressed mice were inoculated with C.albicansinfectionusing the oral swabs. Lesions in the murine tongue were observed using macroscopic observation. The viable cells of the C. albicans in the oral cavity were calculated and the histological study of the murine tongues was analyzed to determine C. albicans infections of the oral mucosal. Weight and fungal burdens in the kidney, liver and feces from the descending colon were examined to assess the severity of the systemic infections. The above indicators in the infected mice were examined and recorded for a week after inoculation. In the blank group immunosuppressed mice were swabbed with saline. Results①The number of viable C. albicans cells in the oral cavity was low on the 1st day after inoculation，then rapidly grew and tended to be stable between the range of 106-107CFU / ml from day 3 to day 7 after inoculation . Oral tongue lesions had a similar trend. There was no obvious pseudomembranous on day 1 and visible tongue dorsal pseudomembranous could be seen from day 3 to day 7 after inoculation .②Histopathological sections stained by PAS revealed that C. albicans had developed a mycelial form, penetrated into the mucosal epithelium and destroyed the epithelium within 3-5 days after inoculation. There were visible yeast cells on the mucosal epithelium on day 7 after inoculation.③The weight of the mice gradually decreased after inoculation. Candida cells that recovered from feces gradually increased and reached to the highest level on the 5th day afterinoculation, but in kidneys and livers , there were no viable Candida cells . The blank group was not infected with C. albicans . Conclusions：Inoculating C. albicans in the oral cavity of mice using oral swabs can establish a murine oral mucosal candidiasis model. The oral candidiasis of the infected mice has changes in a week. The appropriate time of animal experiments should have been chosen depending on the infection status

Objective: To construct RAS1 gene knockout strain in Candida albicans using HIS-LEU-ARG knocking-out strategy and URA-Blaster methodology respectively and compare the success rate of the two strategies. Methods: In the HIS-LEU-ARG knocking-out strategy, the genomic DNA of SN152 strains were amplified and fused with DNA of auxotrophic markers to construct homologous fusion fragments using fusion PCR. For URA-Blaster methodology, the genomic DNA of CAI4 strains were inserted into sides of hisG-URA3-hisG knockout cassette to construct knockout plasmid using seamless cloning. Fusion gene fragments and plasmid linearization product were then introduced into Candida albicans SN152 and CAI4, respectively. Positive colonies were screened on the nutritional defect medium and performed homologous recombination two times to knock out both alleles in the RAS1 gene. Results: The Candida albicans RAS1 double allelic deletion strains were successfully constructed using HIS-LEU-ARG knocking-out strategy. However, URA-Blaster methodology was repeated more than three times and failed to construct RAS1 double allelic deletion strains. Conclusion: HIS-LEU-ARG knocking-out strategy is more suitable for the construction of RAS1 gene knockout strain in Candida albicans than the URA-Blaster methodology.

Abstract： Objective This study was undertaken to detect variation of CCR6-CCL20 expression in tissue from OLP patients and healthy controls. Methods Real-time quantitative PCR was used to detect the mRNA expression of CCR6 and CCL20 in oral mucosal tissue and immunohistochemistry was used for the detection and localization of CCR6 and CCL20. Results Tissue from OLP patients had markedly up-regulated levels of CCR6 and CCL20 mRNA compared to healthy tissue (P < 0.001). Moreover, immunohistochemical staining showed that in OLP patients, CCR6 and CCL20 expression was obviously higher than that in the control patients. Conclusion The CCR6CCL20 axis may play a role in the immunological mechanism of OLP. [Key words] oral lichen planus; CCR6; CCL20

Objective The aim of this study was to evaluate the effects of Asperosaponin D(ASD) on periodontium remodeling as well as the mechanism of effects on osteoclast. Methods In all, forty Wistar rats were selected and randomly divided to four groups (n=10). The control group (Group A) received no drug, the experimental Group B received a low concentration ASD (5 mg/kg) injection, the experimental Group C received a high concentration ASD (10 mg/kg) injection and group D received an appropriate concentration PGE2 (25μg/kg). The 5 groups of rats were sacrificed in batch on the 3st, 7th, 14th, 21st and 28th day with cardiac perfusion. Osteoclastic activity in the first molar periodontal tissue was evaluated by TRAP stainings and immunohistochemical staining. All statistical analysis was performed using SPSS software version 13.0. Results From 3rd to 21st, TRAP staining and immunohistochemical analysis of periodontium by the expression of ODF showed that the osteoclast numbers of every groups increased. From 7th days to 28th days, compared with group A, the number of osteoclast in the experimental group(Group B, C, D) increased. the number of osteoclast in group B was less than in group C and group D, and there were similar with group C and group D. Conclusions Local injection of both low and high concentrations of ASD and PGE2 may promote OTM by enhancing osteoclastic activity. The effect of local injection of high concentrations of ASD and PGE2 is similar, however The effect of high concentrations of ASD solution is more obvious than the effect of concentrations of ASD solition.

Objective　To evaluate the antimicrobial effect of Nd:YAG laser, Er:YAG laser and their combination on enterococcus faecalis in root canals. Methods　Teeth infected with enterococcus faecalis were randomly divided into five groups. Group A: normal saline (NS) irrigation; Group B: 1%NaClO irrigation; Group C: Nd:YAG laser; Group D: Er:YAG laser; Group E: Nd:YAG + Er:YAG laser. After treatment, teeth selected randomly from each group were observed using scanning electron microscopy (SEM). Bacteria were collected from the remaining root canals and cultured. Results　Among five groups, group A achieved least bacteria reduction while group B had best antimicrobial effect, followed by group E. Except for the similar bactericidal rate between group C and group D (P> 0.05), there was a significant difference among the groups (P <0.05). Conclusions　Nd:YAG laser, Er:YAG laser and their combination are effective in root canal disinfection and can been seen as supplements to routine methods.

Abstract: Objective To explore the relation between precision of intraoral scanning digitized model's evaluation on gingival parenchyma, and pocket depth, gingivitis inflammation degree, arch width, and anatomical position, thereby providing experimental reference for clinical application. Method 30 patients with chronic periodontitis having undergone supragingival scaling and periodontal probing examination were selected to obtain traditional plaster models. 3Shape Trios intraoral scanner was used for intraoral scanning to obtain digitized models. 3Shape D810 scanned plaster model and the scanning result was translated into STL-format file, which was imported into Geomagic Qualify 2012 software, to compare the 3D deviation value between two types of models for gingival of probed sites, incisor, premolar teeth, molar and gingival parenchyma of full dentition. The one-sample T-test, chi-square test, Pearson correlation coefficient were used to analyze the relation between 3D deviation magnitude of gingival and pocket depth (PD), gingivitis inflammation degree and arch width of each probed site. The variance analysis in method of randomized blocks design was adopted to analyze whether digitized models for anatomical position are different in gingival accuracy, and Tukey test was used to make a further pairwise analysis. Result The 3D deviation magnitude between intraoral scanning digitized model and traditional plaster model was not correlated to pocket depth, gingivitis inflammation degree or arch width (P>0.05), but was correlated to anatomical position of teeth. The precision for molar region was lower compared with incisor and premolar region (0.381±0.137). Conclusion The intraoral scanning digitized model can be an alternative to traditional plaster model in terms of gingival tissue and is clinically applicable.

Objective Prior to the use of nano-BGs desensitizers in teeth bleaching operation, to observe the content of H2O2 in dentine pulp with or without the application of desensitizers by smearing method or transparent tray. Methods: 48 dentin disks were collected from human first molars and divided into 6 groups. Group A: without desensitizing treatment, the crown ends of the disks were soaked into deionized water for 30minutes. Group B：without desensitizing treatment, the crown ends of the disks were soaked into 30% H2O2 for 30minutes; Group C: smearing application of BGs desensitizers for 2min, twice/day, after soaking disks into artificial saliva (AS) for 24 hours, the crown ends of the disks were put into 30% H2O2 for 30minutes; Group D: transparent tray application of BGs desensitizers 1 hour, after soaking disks into artificial saliva for 24 hours, the crown end of the disks were put into 30% H2O2 for 30minutes; Group E: smearing application of BGs desensitizers for 2min, twice/day, after soaking disks into artificial saliva for 24 hours, the crown ends of the disk were put into deionized water for 30minutes; Group F: transparent tray application of BGs desensitizers for 1 hour, after soaking disks into artificial saliva for 24 hours, the crown ends of the disk were put into deionized water for 30minutes. Tthe fluid in dentin pulp of each group was extracted and the content of H2O2 was calculated by the measurement of absorbance with UV-visspectrophotometry. Results: The contents of H2O2 in each group were: 0μg (A group)，21.149μg± 0.489μg (B group)， 9.813μg ±0.426μg(C group)，4.065μg ±0.268 μg( D group), 0μg( E group)，0μg( F group). ANOVA results indicated that statistically significant difference existed between B, C and D（F=459.748,P<0.05）. Multiple comparison results indicated that significant difference also existed between B, C and D. Conclusion: The application of BGs desensitizers can reduce the penetration of H2O2 into dentin pulp so as to reduce the occurrence of BH during or post bleaching operation. The effects can be enhanced when applied in combination with transparent-tray.

Abstract: Objective To compare the changes of enamel micro-cracks before and after debonding with different bracket adhesives. Methods Ninety fresh premolar teeth were collected for orthodontic treatment, which were divided into two groups (45 in each group). The first group:obvious microcracks group (visible to the naked eyes under natural light), and the second group: weak microcracks group(invisible in natural light but visible under scanning electron microscope); each group was further divided into three groups(each group of 15): 3M light-cured adhesive group, 3M chemically-cured adhesive group, control group, each group of 15 . Before and after debonding, microcracks length and width changes were measured by the use of scanning electron microscopy. Results: In the obvious microcrack group, the average microcrack width before and afterthe debonding 3M chemical curing adhesive group and 3M light-cured adhesive group had statistically significant difference (P <0.05); while the average length of the microcrack before and afterde-bonding had no significant difference between the two groups (P> 0.05). The differences in width and length before and after treatment were statistically significant (P <0.05). In the weak microcracks group: the average width and length of microcracks were not statistically significant when comparing with 3M light-cured adhesive group and 3M chemically-cured adhesive group (P>0.05) The differences between the width and the length of the chemically-cured adhesive group before and after treatment with 3M light-cured adhesive group were statistically significant (P <0.05). Conclusion The width and length of the enamel microcracks group before and after removing brackets are both increased. Although 3M light-cured adhesive and 3M chemically-cured can both satisfy the requirements of adhesive strength of the enamel, 3M chemical curing group has more damage to the tooth enamel after removing the brackets. Therefore, it is recommended to use 3M light-cured adhesive to meet the clinical requirements which can minimize its damage to the enamel surface.

Objective To compare the different effects between micro-implant and MEAW technique on the upper airway dimensions in patients with class III malocclusion. Methods 12 patients were selected to distalize the lower dentition with the micro-implant,while 13 patients were treated with MEAW technique. The cephalometric radiographs of the pre- and post-treatment upper airway in two groups were measured ,then the comparision of those changes was statistically analyzed . Results There were statistically differences in LPW (P<0.05), but other comparison had no statistically significance. Conclusion The LPW is decreased using the micro-implant technique in patients with class III malocclusion.

Objective：To investigate the control of the crown and root of maxillary teeth in en-mass retraction with different braces torque. Methods: Choose a normal male's tooth as sample. 3D software: Mimics,Geomagic and Solidworks were used to reconstruct by the CT data, and the maxillary three-dimensional finite element model was established in Ansysworkbench.Using micro-implant as anchorage and referring the Damon bracket data, three different angle displacement loads were applied to the maxillary anterior teeth to simulate different torque brackets: High torque, Standard torque and Low torque, and 150g force of the adduction was added as a whole. The stress distribution in periodontal tissue and the crown and root of initial displacement were calculated．Results ：In the process of adducting anterior teeth, the initial displacement of the crown and root and the stress distribution of the periodontal ligament were varied with different torque braces. The movement of the anterior teeth is different depending on braces torque. The initial displacement of anterior teeth with high torque braces is more likely to labial inclination, while that with low torque braces is prone to tilt the tongue side .Conclusion：In the process of adducting anterior teeth, a better therapeutic effect and better face can be achieved via adjusting the brackets torque angle to control the inclination angle of the anterior teeth.

Abstract: This clinical report presented one case of a skeletal class Ⅲ malocclusion adult patient with mandibular deviation and temporomandibular joint disorder problem. After deprogrammed treatment and subsequent fixed orthodontic treatment,the patient’s anterior teeth set up normal overbite and overjet, the mandibular deviation had been improved, temporomandibular disorder symptoms disappeared.

As a diagnostic tool, cone beam computer tomography (CBCT) has been widely used in dental clinic, especially in periodontal research, due to its low radiation, high image quality and unique three-dimensional reconstruction. In this paper, its application in periodontal research is reviewed.

Anterior open-bite is one common kind of malocclusion which has an adverse effect on oral function and facial aesthetics. Comprehensive etiological factors, complicated therapy as well as ambiguous results make it a puzzling issue. Early intervention makes the most of growth potential to rectify maxillofacial discrepancy in vertical direction and have been widely recognized as a favorable choice due to effectiveness/efficiency, stableness and that it simplifies further treatment. Multiple appliances in practice are designed by blocking bad habits, mediating muscle function and inhibiting vertical skeletal development. This article aims to make an overall review on the appropriate time of early intervention as well as the clinical application，effectiveness and stableness of diverse appliance.