The physiological, biochemical and behavioral periodic oscillations of the living organisms are called circadian rhythm, which is regulated by the clock genes. Recently, dozens of core clock genes have been found. As the earliest known clock genes，Clock and Bmal1 are the starting factors of the entire circadian system. On the other side, bone remodeling is an effective method to solve bone defect, which is one of the most important issues in prosthodontics nowadays. Thus this review summarized the basic mechanism of the clock genes, and explored the regulatory mechanism of clock gene（Clock and Bmal1） on bone remodeling in recent research progress.

Objective　To investigate the effect of CKIP-1 gene on the changes of trabecular bone of femur and mandibular at different time. Methods: 3-month- and 6-month-old mice with CKIP-1 knockout (CKIP-1-/-) were selected as the experimental group, wild type mice (WT) as the control group (n=5, same litter and gender, male). Femurs and mandibulars at 3 months and 6 months were harvested for micro-CT scanning. Quantitative analysis was performed to analyze the trabecular bone of the femur and the mandible. The effect of CKIP-1 on bone metabolism balance in adults with the increase of age was evaluated. Results: At 3 months, compared with the control group, the BV/TV of the femur and the mandible in the experimental group increased by 2.54% and 1.69%, and at 6 months increased by 3.77% and 2.82%（P<0.05）, respectively. During the period from 3 months to 6 months, BV/TV of the femur and mandible decreased by 4.42% and 1.1% (P<0.05) respectively. Conclusion: The femur is more sensitive than the mandible to the CKIP-1 gene regulation of bone mass, and it is more obvious with the time.

Objective　 To establish animal model of TMJ ankylosis secondary to complex trauma and to provide the experimental carrier for the further research on its mechanism . Methods Five sheep were used in this study. Four were included in the operation group, while one was left as control. In the operation, bilateral TMJ osteotomies were performed on the four sheep to induce sagittal fractures of the mandibular condyle, the glenoid fossa was damaged and the lateral one-fourth segment of the disc was removed. At the end of the 12th week postoperatively, spiral CT scanning, gross observation and histological observation were used to evaluate the changes of the TMJ. Results Bilateral TMJ of the four sheep occurred bone ankylosis. CT scanning detected calcified callus formation in the joint space. Articular surfaces were roughened after the formation of new bone, which protruded into the joint space. Histological observation showed that joint space was filled with abundant new cartilaginous matrix, cartilage cells, and a small amount of fibrous tissue. Conclusions This study successfully establishes the animal model of s TMJ ankylosis resulting from complex trauma, which conforms to the clinical damage modes and disease process, and provides a stable and practical animal model for the further study of traumatic TMJ.

Objective　 To discuss the biological effect of tumor necrosis factor-α on the proliferation and osteogenic/dentinogenic differentiation ability of stem cells from rat apical papilla. Method: Root nipple tissue in rat was separated and SCAP was extracted by combining enzyme digestion method with tissue block method. The cells were identified by fluorescence immunoassay. The cells were divided into experimental groups (TNF-α 5, 10, 15, 20, 30, 40, 50 ng/mL) and control group (TNF-α 0 ng/mL).The proliferation of SCAP was evaluated by CCK-8 method, and alkaline phosphatase activity, alizarin red staining and quantitative real-time PCR were applied to evaluate the effect of tumor necrosis factor-α on the ability of osteogenic/dentinogenic differentiation of SCAP. Result: SCAP was consistent with the characteristics of mesenchymal stem cells and had the ability of multi-directional differentiation. The proliferation of SCAP results showed that each concentration group could promote the proliferation of SCAP, the difference was statistically significant(P<0.05).The ALP activity showed that each concentration of TNF-α could significantly reduce the activity of ALP, and the difference was statistically significant(P<0.05). The alizarin red staining showed that with the increase of the concentration of TNF-α, the staining gradually became lighter, the red nodule gradually became smaller, and the number of the formation decreased gradually. The quantitative real-time PCR showed that the expressions of OC, DMP-1 in the experimental groups were significantly lower than the control group in 3 days(P<0.05), the expression of DSPP was significantly lower (P>0.05), while the expression of BSP was slightly higher(P<0.05). In 7days, the expressions of OC, DSPP in the experimental groups were significantly lower than the control group(P>0.05), the expression of DMP-1 was significantly lower(P<0.05), while the expression of BSP was slightly higher (P<0.05). In 14 days, the expressions of OC, DMP-1 and BSP in the experimental groups were significantly lower than the control group(P<0.05), while the expression of DSPP was slightly higher(P<0.05). Conclusion: TNF-α can promote the proliferation and inhibit the osteogenic/dentinogenic differentiation of SCAP in different degrees.

Objective　 To investigate the expressions and the differences of Slug and E-cadherin in oral squamous cell carcinoma（OSCC）. Methods: The mRNA levels of Slug and E-cadherin in 30 cases of OSCC tissues and 20 cases of oral mucosa tissues were detected by rt-PCR, then the relationship between the expression and pathological features was analyzed. Results: The expression of Slug in OSCC tissues was higher than in oral mucosa tissues （P<0.05）while the expression of E-cadherin in OSCC tissues was lower than in oral mucosa tissues （P<0.05）.The expressions of Slug and E-cadherin had correlation with TNM stage and lymph node metastasis（P<0.05）, but not with gender, age, cell differentiation degree and deeper invasion（P＞0.05）. Conclusion: The expressions of Slug and E-cadherin in OSCC are closely related to the development , invasion and metastasis of the tumor.

Abstract：　Objective To evaluate the microleakage of class I composite resin restorations with and without flowable composite liner. Methods　Cylindrical, Class I, 4-mm× 4-mm ×4-mm preparations were made on 48 recently extracted human molars .The samples were divided into 6 groups randomly.Three groups were applied flowable composite liner,and were filled with Tetric N-Ceram Bulk Fill and Filtek P60 composite resin by two filling techniques respectively.The rest of the three groups were applied no flowable composite liner,and filled with restorations metioned above respectively. All the teeth were kept in methylene blue solution for 24 hours,and were sectioned buccolingual though the midline of the materials and examined with the stereoscopic microscope.Results　The microleakage of group A,B and C was lower than group D,E and F ( P ＜ 0.05) .The microleakage of group A and C was lower than group B ( P ＜ 0.05) ，while there was no significant difference between group A and group C( P >0.05). Conclusions　 Using flowable composite as a liner will reduce microleakage．The bulk-fill technology was the same as the traditional layered filling technology in the microleakage of composite resin restoration.

Objective　 To evaluate the effect of minimally invasive tooth extraction on dental-related quality of life in the elder patients. Methods 161 teeth in elder patients who were treated in our hospital from May 2013 to May 2015 were extracted by minimally invasive tooth extraction. The Chinese version of oral health impact profile-14（OHIP-14）was employed to evaluate the impact of quality of life in these patients before and 1 week after treatment. The higher the scale scores are, the worse the oral health life quality is. Results After the minimally invasive tooth extraction,OHIP-14 total scores were lower than those before with significant difference （P<0.05）. The scores on “functional limitation”, “physiological pain”, “psychological discomforts”, “physiological disorder” and “psychological disorder” after treatment were all significantly lower than those before treatment（P<0.05）.The negative impact on "physiological pain" significantly decreased after treatment（p<0.05）（from 50.8% to 9.5%）. Conclusion Minimally invasive tooth extraction for elder patients has full preparations and good effect, which is an ideal medical treatment and worth of being generalized.

Abstract： Objective　To investigate the optimal treatment timing of CICE appliance for class II malocclusion according to Quantitative Cervical Vertebral Maturation(QCVM). Methods　60 cases of Class II malocclusion (an average age of 12.5 years) with normal maxilla and retruded mandible were selected and the patients were divided into three groups I-II-III according to QCVM. For each group, mandibular protraction was achieved with CICE appliance for 6 months before fixed orthodontic treatment. Cephalometric analysis was compared pre-treatment and post-treatment. Results　After 6 months of CICE appliance therapy, harmany profile and remarkable advancement of the mandible were obtained in all of these cases. Class II occlusions were changed to Class I relationship. During QCVM II, the skeletal parameters were changed more significantly than dental parameters before and post treatment. The order of the parameters variation in different QCVM groups is QCVM II＞QCVM I＞QCVM III. Conclusion　CICE appliance contacts comfortable, invisible, concise, efficient, but the optimal treatment timing of mandibular protraction is also significant.

【Abstract】 Objective To analyze the skeletal and dental characters between subjects with Class III malocclusions and subjects with normal occlusions by using cone-beam computed tomography. Methods 21 subjects with Class III malocclusions and 20subjects with normal occlusions were assessed with cone-beam computed tomography scans. And the CT images were constructed into 3D model by using medical image processing software Dolphin Imaging 11.0.Anatomical landmarks were located and reference planes were established on the 3D model. The measurements were analyzed by SPSS 17.0. Results The extent of maxillofacial deformity increases from top to bottom in adults with facial asymmetry. Some measurements of Class III malocclusions were found to be different with normal occlusions including Asymmetry index of Orbitale ，Anterior nasal spine and Menton.Conclusions Based on this study, the discrepant jaw growth resulting in a Class III skeletal pattern results in no more skeletal asymmetry than Class I skeletal patterns.

Abstract: Objective Taking traditional layering dental resin as a contrast to compare in vitro microleakage and operation time of the three types of latter teeth filled with chunks of resin. Methods 40 unified in vitro molars were selected, in facies occlusalis of tooth preparation 4mm×4mm×4mm hole of class I, then were randomly divided into A, B, C, D four groups The four groups were filled with SonicFill resin, SureFil SDR flowable resin, Tetric N-Ceram bulk Fill resin, Filtek Z350 resin filling, and each sample filling time of completion was recorded. After the thermal cycle test, the filling samples were put into India ink soak for 24h. After drying the sample was cut along the mesial and distal . Sample dye penetration depth was stereoscopically viewed under a microscope , and then counted and measured and analyzed statistically. Results The operation time difference of four groups : there were no significant differences between group A and B P=0.791（P>0.05）;the rest of the pairwise comparison were significant differences P=0.000（P<0.05）;C group consumed the least ,while traditional layering D group consumed the most. Micro-leakage occurred in four groups, but four groups had no significant differences P=0.727（P>0.05）.Conclusion The three kinds of latter teeth filled with chunks of resin can achieve the same edge of the closed nature compared with conventional layering and its operating time is shorter than the latter, easy to operate.

Objective: The aim is to study the oral health consciousness, knowledge and behavior of undergraduates on campus in Shanghai in order to provide original data for improving oral health education. Method: A survey with a self-designed questionnaire was conducted among 350 undergraduate students in Shanghai. Results: Medical students do better than others in oral health and disease recognition and they can do regular oral examination in time. Half students have gum bleeding in last two weeks. The caries prevalence and wisdom tooth eruption rate are really high. The undergraduates get oral knowledge mainly on the Internet. Conclusions: The undergraduates in Shanghai have poor oral health in general and lack oral health knowledge and consciousness especially the non-medical students. So we should emphasize oral health propaganda and education for boys including caries, gingivitis, wisdom teeth and oral cleaning method.

Abstract: Objective To investigate the status of deciduous caries in 3-6 year-old children in Jinan, Shan dong Province, China; and to assess the caries risk of children using Cariogram software to analyze the factors affecting the caries rate. Methods 493 healthy children from 5 kindergartens in Jinan city were randomly selected for the study. Various caries risk factors were collected by oral examination, caries activity detection and a dietary questionnaire. And then the data were analyzed and all patients were divided into the higher risk group and the lower risk group by Cariogram software. Statistical analysis was carried out to analyze the risk factors of caries. Results The prevalence of dental caries in 3-6 year-old children of Jinan city was 67.95%，DMFT 3.45.The higher risk group was 74.84% of the total, and possessed more Mutans streptococci counts, high plaque index, high carbonhydrate diets compared with lower caries risk group and the differences were statistically significant, but secretion rate and buffer capacity were not significantly different. Conclusions The prevalence of dental caries in 3-6 year-old children in Jinan city is high. Rigid oral hygiene protocols ,controlling the dental plaque and sugar intake are needed to prevent deciduous caries.

Acute Nontraumatic Temporomandibular Joint(TMJ) Dislocation is one common maxillofacial disease in the emergency room, which means condyle comes off the glenoid fossa and surpasses the normal limit of joint movement, thus resulting in the inability to recover automatically . It results in discomfort in everyday life and claims high attention. Delays in accurate treatment can lead to long-term sequelae for the patient. Many new treatment methods using reduction techniques have sprang recently. Different techniques will be reviewed for managing acute nontraumatic TMJ dislocation in this paper.

Localized and continuous osteogenic stimulation to defected site is required for effective bone regeneration. Growth factors are very promising molecules to enhance bone regeneration and enable the recruitment of enough endogenous functional cells to the defect regions and promotion of their committed differentiation at appropriate times to reestablish the destroyed tissues. However, the application of the growth factors to clinical practice has been seriously confined, and the problems derived from the determination of the optimal dose of growth factors and the lack of effective delivery systems. Therefore, new delivery systems allowing better control of the spatiotemporal release need to be developed. At present, the growth factor delivery system includes the following four types: sequential delivery using a collagen membrane, injectable polymeric hydrogel and derivative structures, separate and joint application of different kinds of nanoparticles and the composite system of scaffolds. Different delivery systems have their unique characteristics, degradation and release kinetics, and they can be flexibly combined and adjusted according to the clinical needs.

Abstract: Periodontitis often leads to periodontal bone defect, which is an urgent problem to be solved in clinic. Traditional scaffolds have made some progress in periodontal regeneration, but still with many limitations. Since the mesoporous materials are characterized by their unique physicochemical properties as uniform pore sizes, high porosity and surface area, which have a rather prosperous prospect compared with the nano materials. As mentioned above, more emphasis has been laid on the application of mesoporous materials in periodontal regeneration. In this article, the characteristics of mesoporous materials and their application in periodontal regeneration will be reviewed.

　Burning mouth syndrome is characterized by pain, burning sensation or abnormal sensation of oral mucosa. There is no unified view on its various etiological factors. In recent years, there has been increasing research on the causes of BMS. Many scholars have put forward new points of view on its etiology. This article aims to make a summary of the latest research progress on the etiology and pathogenesis of BMS, thus providing some help for the development of its clinical diagnosis and therapies.

Long non-coding RNAs(lncRNAs) refer to the non-coding RNAs which exceed 200nt in length and lack open reading frames, and they account for a significant proportion of non-coding RNAs. LncRNAs play an important role in regulating the process of epigenetics, transcription, translation and protein modification, thus they widely participate in some important life processes including cell differentiation, individual development and so on. At the same time, more and more studies have found that lncRNAs are also closely related to the occurrence and development of some important human diseases. In this paper, the roles of lncRNAs in bone development will be reviewed.

MicroRNAs(miRNAs) was found in eukaryotes, which has the function of regulation and control of a class of endogenous non-coding RNA, and participates in a variety of important cytobiology processes. Current literature indicates that miRNAs can regulate the differentiation and bone absorption. They also regulate the ossification of cartilage. Therefore, miRNAs are powerful regulators for biological organ development and some metabolic bone diseases. In this paper, the research progress of these aspects is summarized.

Aloe contains a variety of active ingredients, including anthraquinone, sugars, organic acids, minerals and vitamins. These ingredients perform pharmacological effects such as immune regulation, anti-tumor, anti-virus, anti-inflammation and promoting wound healing. Aloe and its extracts can be used for diagnosis and treatment of oral lichen planus, oral submucous fibrosis, oral ulcer, periodontal diseases and so on. The application of aloe in dental clinical medicine shows its potential practical value, yet its mechanism remains to be elucidated.