Accurate skeletal age evaluation can assess the stage of individual development,and therefore provide the important reference for orthodontists to choose proper treatment timing and predict the growth potential. This paper explores three aspects,including the research status of the assessment of craniofacial growth and development,the influencing factors of skeletal age evaluation accuracy,and the improvement and development of skelatal age evaluation. The views are summarized as follows:1.The hand-wrist skeletal age, especially Fishman Skeletal Maturity Indicators (SMI),is organic, simple and reliable. The method of Cervical Vertebrae Maturation(CVM), especially Quantitative Cervical Vertebral Maturation (QCVM) which adapts to today's digital image trend, has attracted more and more attention with the obvious advantages, no need for additional x-ray exposure and easy to observe the mandibular growth peak. 2.The accuracy of skeletal age evaluation are affected by several factors,such as race、gender and evaluation methods. Therefore, it’s necessary to find the proper evaluation method for specific patients.3. Environmental factors can lead to abnormal bone development, especially the long-term disorders of biological clock,which influences the accuracy of skeletal age evaluation.It reminds us the importance of maintaining the normal biological rhythm. The new methods is proposed by regulating the biological clock to modify the abnormal craniofacial development and improve the assessment accuracy with skeletal age.

Abstract：　Objective　 The purpose of this study was to establish a mechanical-stress-induced OA model of the rat TMJ. Methods　 Six-week-old female SD rats were divided into control group and OA group at random. Each group had 5 rats. Passive mouth opening (3h/day, last for 5 days) was used to build up the TMJOA animal model. Toluidine blue staining and collagen II immunohistochemical staining were used to analyze the structural change of condyle cartilage. Micro-ct was used to evaluate the subchondral bone remodeling.Results　 Expression of proteoglycan and collagen II decreased in cartilage and bone mineral density (BMD) of subchondral bone decreased in OA group. Conclusions　 Forced jaw opening without surgical intervention can induce evident OA-like lesions in the rat TMJ, and this OA model may contribute to the elucidation of the cartilage degradation mechanism in TMJ OA.

Abstract: Objective To investigate the potential of odontogenic differentiation of placenta-derived mesenchymal stem cells (PMSCs). Methods PMSCs were obtained from SD rat placental tissues with collagenase and trypsin digestion. Immunocytochemistry was used to identify their phenotype. Osteogenic and adipogenic induction were used to identify their multilineage differentiation. SD fetal rat tooth germ cell-conditioned medium (TGC-CM) was used to induce PMSCs for 14 days. The specific proteins (DMP-1 and DSP) of odontoblast were detected by Immunocytochemistry. The specific genes (DMP-1and DSPP) of odontoblast were detected by RT-PCR and gel electrophoresis. Results PMSCs were positive for CD105, CD44 and CD29, negative for CD31, C34 and CD45. Calcium nodules and lipid droplets were formed respectively after osteogenic and adipogenic induction. After 14 days’ odontogenic induction, the morphology of PMSCs had no obvious change, and they expressed the specific proteins (DSP and DMP-1) and the specific genes (DMP-1 and DSPP), which were specifically expressed in odontoblast. Conclusion PMSCs have the potential to be induced to odontoblast-like cells.

Abstract: Objective To investigate the effect of RhoA-Rho kinase signaling pathway on differentiation of human dental pulp stem cells (hDPSCs) in simulated microgravity (SMG). Methods HDPSCs were seeded in the PLGA scaffolds, and divided into normal gravity group and microgravity group. After 72 hours’ culture, cells were seeded in plate and divided randomly into mineralization induced with or without Y-27632 groups. AKPase activity test was established after 3, 5, 7, 10 days. DMP-1 (dentin matrix protein-1), DSP (dentin sialoprotetin) and DSPP (dentin sialophosphoprotein) were detected by Western Blot for 10d, and mineralized nodules were detected by Alizarin red staining for 21d. Results The expression level of RhoA was down-regulated under microgravity. Treated with Y-27632 in normal gravity after 3, 5, 7 and 10 days, the AKPase activity was significantly lower than control. After 21 days’ culture, the Alizarin red staining showed that the positive granules were hardly detected. The expression levels of DSP, DSPP and DMP-1 were lower than those in the control group after 10 days of culture. Conclusion Simulated microgravity inhibited the expression of RhoA. Inactivation of Rho kinase by addition of inhibitor Y-27632 caused lower mineralization ability of hDPSCs. It is possible that RhoA-Rho kinase signaling pathway is involved in the effect of simulated microgravity on mineralization process of hDPSCs.

Objective To study the effect of Er: YAG laser preparation and xtra power mode of curing light on the microleakage of the composite resin filling. Methods 40 extracted molars were randomly divided into 4 groups for cavity preparation, filling and curing: Group A—High speed handpiece and ANTHOS therapy unit attached LED light (550 mW/cm2, 20 s); Group B—high speed handpiece and VALO light curing unit (xtra power mode 3200 mW/cm2, 3 s ); Group C—Er: YAG laser and ANTHOS therapy unit attached LED light; Group D—Er: YAG laser and VALO light curing unit. All the samples were prepared for class V cavities thereupon resin filling and placed in the normal saline at 37 ℃ for 24 h. After thermocycling, all samples were stained by methylene blue solution, and then sectioned longitudinally in buccolingual direction. Microleakage of the composite resin was observed under stereomicroscope and statistically analyzed. Results Microleakage of gingival wall in all samples was higher than that of the occlusal wall; Microleakage of group A was lower than in group B and group C, with a statistically significant difference (P ＜ 0.05). Group D had the largest microleakage compared with other groups, and the difference was statistically significant (P＜0.05). Conclusion The Er: YAG laser preparation and xtra power mode of the light curing unit will increase the risk of the resin filling leakage.

Objective To evaluate the effect of sandblasting on the shear bond strength and durability of three resin cements bonded to titanium. Methods Titanium in two sizes (φ5 mm×5 mm, φ4 mm×2 mm) were fabricated with titanium casting technology for dentistry, each size consisted of 96 specimens, and the two sizes were paired up to 96 pairs. The paired specimens were divided into the experiment group and the control group. The experiment group was sandblasted with 50 μm Al2O3 particle，the control group was untreated. The paired titanium specimens were bonded by Super-Bond C&B (SB), Panavia F (PF) and Rely X Unicem (RU), according to manufacturer’s recommendations. The specimens were divided into 6 groups (SB sandblasted, SB un-sandblasted, PF sandblasted, PF un-sandblasted, RU sandblasted, RU un-sandblasted), each of which consisted of 16 pairs of specimens. 8 pairs of each group were immersed in water bath at 37 ℃ for 24 hours, the other 8 pairs were treated with 5 000 cycles of thermocycling after being immersed in water at 37 ℃ for 24 hours. The shear bond strength was evaluated by the MTS testing machine. The values of each group were compared by two- factor ANOVA with interaction analysis. Results Before thermocycling, the shear bond strength of RU un-sandblasted group was the lowest, and the highest results were obtained in SB sandblasted group (28.03±8.40) MPa. After thermocycling, the highest strengths were obtained in PF sandblasted group (27.12±8.68) MPa, and the lowest results were obtained in RU un-sandblasted group. Before thermocycling, the shear bond strengths of SB sandblasted and SB un-sandblasted groups were statistically different (P＜0.05), which was also true for RU sandblasted and RU un-sandblasted groups. After thermocycling, the results of RU sandblasted and RU un-sandblasted were still different (P＜0.05). Thermocycling statistically affected the shear bond strengths in SB sandblasted and SB un-sandblasted groups (P＜0.05). Other results were not statistically different (P＞0.05). Conclusion Sandblasting can significantly increase the shear bond strength and durability of SB and RU bonded to titanium, but it isn’t positively correlated with the shear bond strength and durability of all resin cements bonded to titanium.

Abstract Objective To investigate the expression of the matrix metalloproteinase-2 (MMP-2)-tryptase double positive mast cells (MCs) in periodontal tissues in different stages of chronic periodontitis using double immunofluorescence staining. Methods A total of 45 patients including healthy controls (n = 15), those with slight chronic periodontitis (n = 15), and those with severe chronic periodontitis (n = 15) were involved. The gingival specimens were fixed in 10% buffered formalin for 48h, stained with hematoxylin and eosin for the observation of histological changes under optical microscope, and stained with double immunofluorescence for the identification of MMP-2-tryptase double positive MCs in gingival tissues under fluorescence microscope. Results Compared with the healthy controls, the densities (cells/mm2) of MMP-2-tryptase double positive MCs were significantly increased in chronic periodontitis groups (P <0.01). In addition, the density of MMP-2-tryptase double positive MCs in severe chronic periodontitis group was significantly higher than that of the slight chronic periodontitis group (P <0.05). Conclusion The density of MMP-2-tryptase double positive MCs is positively correlated with the severity of periodontitis inflammation. MMP-2-tryptase double positive MCs may play a positive role in the development of periodontitis.

Objective　 This paper reported a semi-digital technique to get an optimal fitting custom-made high-density porous Polyethylene (Medpor) for reconstruction of mandibular contour defects with the help of CAD/CAM and reverse engineering technology.Methods　17 patients suffered from defects of mandibular contour registered for the novel techniques adoption to reconstruct the mandibular contour. For each patient, computed tomography (CT) data were collected, CAD/CAM, reverse engineering and rapid prototyping (RP) by three-dimensional (3D) printing were used to fabricate the preoperative individualized geometric model. The mandibular contour defected areas were reconstructed by modelling and implanting Medpor.ResultsAll cases, except one with delayed infection whose implantation material was removed later on, recovered quite well. The follow-up observation showed that the previous defect zones had been accurately reconstructed, and a symmetric bony contour as well as an appealing facial appearance was acquired.Conclusions　Individualized Medpor implant based on CAD/CAM can accurately reconstruct defect of mandibular contour.

Objective To evaluate the clinical application of a self-developed CAD-CAM implant guide template system used in implant restorations for edentulous patients. Methods Five patients with single edentulous jaw were selected. Data were acquired by cone-beam CT scan and imported into the self-developed software to design the digital implant guide templates. Physical guide templates were then rapid-prototyped. ITI implants were implanted guided by the template. After three months, definite prostheses were finished. Postoperative follow-ups were made periodically. Results Five acrylic resin CAD-CAM implant guide templates were fabricated. In the guidance of templates, flapless surgeries were made to place 38 ITI implants with good initial stabilities and small postoperative reactions. After three months, good osseointegrations were generated except one implant off. Fixed implant restorations were made for five patients. Six months and one year follow-ups showed good functional and aesthetic restorations. Conclusion The self-developed CAD-CAM implant guide template system can be applied in the edentulous implant surgery to achieve precise preoperative design and intra-operative accurate control of implant position, which can reduce surgical trauma and postoperative complications, and good effect of edentulous implant restoration can be acquired.

Objective: To investigate the feasibility and effectiveness of combination of Sommerlad and Furlow technique for the treatment of velopharygeal incomplete. Methods: In treatment of VPI after palatoplasty, Sommerlad technique was used to reconstruct veli palatine levator, and Furlow technique was used to lengthen the soft palate. Both techniques were adopted at the same time. After follow-up of The nasopharyngeal fiberscope examination were carried out 1mon after operation to evaluate the results. Results: The improved combined operation design can significantly improve the closure rate of the patients with VPI. Conclusion: The combined application of two different techniques have a strong feasibility and operability. Fine anatomy is the key in this combination procedure. Exact reconstruction of veli palatine lavatory and reliable suture technology is important to ensure the good result. This design could be used for the treatment of VPI after the closure of the cleft palate.

[Abstract] objectve To evaluate the feasibility of palatal?tip intrusion with an artificial appliance. Method 11 patients were selected who were not suitable for the micro-implant . The clinical effect of intrusion were evaluated by CBCT taked before and after treatmen. The palatal?tip distance were measured between before and after. Result The?average?treatment?time?of all patients was 5?months. The comparison between before and after treatment showed that the maximum intrusion 4.13 mm at mesial palatal?tips and 4.04 mm at ?distal palatal?tips. Palatal?tip intrusion with the artificial appliance has a significant effect. ConcIusion This artificial appliance is an useful and simpful treatment method.

Abstract: Objective To investigate the concentration of IL-21 in gingival crevicular fluid (GCF) and the correlation between IL-21 and periodontal clinical parameters to discuss the possible role of IL-21 in different types of periodontitis. Methods 15 healthy people were included as control group, 10 patients with slight periodontitis were selected as slight periodontitis group, and 22 patients with moderate or severe chronic periodontitis were selected as moderate or severe periodontitis group. The basic information was recorded, and probing depth (PD) and clinical attachment level (CAL) were detected by Florida periodontal probes. GCF was collected from patients in each group. The IL-21 protein in GCF was determined by Enzyme Linked Immunosorbent Assay (ELISA). Pearson rank correlation and SPSS19.0 software was used for statistical analysis. Results The mean concentration of IL-21 protein in GCF of each group was (107.20±2.54) pg/mL, (218.90±5.11) pg/mL, and (367.80±7.27 ) pg/mL; The concentration of IL-21 in both periodontitis groups were significantly higher than that in the control group (P < 0.05), and the highest concentration of IL-21 was demonstrated in the moderate or severe periodontitis group. There was significant positive correlation between IL-21 and PD or CAL (P < 0.001). Conclusion The IL-21 protein in GCF of periodontitis is high, especially in moderate or severe chronic periodontitis. IL-21 may play a vital role in periodontal disease, which is related with the destruction of periodontal tissues.

Abstract: Objective To evaluate the efficiency of instrumentation and the amount of extruded apical debris with new WaveOne system in preparing root canals. Methods 40 mandible teeth with single root canal were randomly divided into 4 groups and prepared by K-file, BLx, ProTaper Universal and WaveOne, respectively. The extruded apical debris during the preparation were collected and measured. Then combined with the time for preparation, all data were comprehensively compared and evaluated. Results The amount of apical debris of K-File group was the largest, followed by the WaveOne group. There was no significant difference between the BLx and ProTaper groups (P>0.05), and there were significant differences among the other groups (P<0.05). The WaveOne group took the shortest time to prepare, followed by the BLx group, then the ProTaper group, the K-File group needed the most time, and the differences among groups had statistical significance (P < 0.05).Conclusion WaveOne has advantages in the amount of the extruded apical debris compared with the hand K-File, but doesn’t surpass the other two kinds of traditional titanium with Niti instruments. Compared with the other three instruments, WaveOne has the best root canal preparation efficiency.

Abstract：PRF (platelet rich fibrin) is a kind of second generation platelet concentrate with a three dimensional reticular structure which can regulate inflammation, accelerate tissue healing, and release a variety of growth factors slowly and continuously. However, no clinical study has used PRF for the treatment of avulsed tooth. In this study, a delayed and dry-reserved avulsion tooth was replanted with autologous PRF. 12-month follow-up showed that the tooth recovered well, the peridental membrane was healed, no root resorption occurred, and the height of alveolar bone was restored.

GDF-15 (also MIC-1, NAG-1, PLAB, PTGFβ) is a member of the TGF-β superfamily, which is widely distributed in mammalian tissues and has received considerable attention revealing a remarkable multifunctional role in controlling biological events. The progress of bone repair and regeneration is closely associated with angiogenesis. The function of GDF15 on angiogenesis and bone metabolism are diverse, depending on the interaction with their microenvironment, and its signaling pathways remain poorly understood. GDF15 may serve as a therapeutic target for bone regeneration and cancer bone metastases.

Autophagy is a highly conserved cellular process in which organelles, proteins and other cytoplasmic components are delivered to lysosomes for degradation. Recently, there came some studies which had demonstrated that autophagy is essential for bone cell homeostasis. Mutations in autophagy receptors will lead to the imbalance between bone formation and resorption. Altering the state of autophagy may change the differentiation of bone marrow derived mesenchymal stem cells and the construction and function of bone. Moreover, clinical success of dental implantation is critically related to the satisfactory osseointegration in which autophagy plays an important role through influencing the peri-implant bone remodeling and regulating bone homeostasis. This review aims to provide a comprehensive overview of autophagy in bone cells and its role in bone metabolic diseases and dental implantation.

Defect of dentition has become one of the major problems threatening our oral health, and implants are tended to be the first choice of more patients for its harmlessness to the rest teeth、comfort and efficiency in use. However, oral implants have a failure rate, which is often caused by peri-implantitis. Researchers have developed kinds of methods to solve peri-implantitis recently, among which the antimicrobial therapy is most recommended for less damage and convenient process. This article is to review the treatments regarding peri-implantitis with antimicrobial products.

MicroRNAs (miRNAs) are the class of noncoding single-stranded RNA molecules composed of approximately 20–24 nucleotides. These small miRNAs bind to complementary sequences in the 3' untranslated region (UTR) of mRNAs to negatively regulate gene expression. Bone organogenesis is a complex process, which involves the differentiation and crosstalk of multiple cell types for formation and remodeling of the skeleton. The existing evidence indicates that miRNAs control multiple layers of gene regulation for bone development and postnatal functions. Currently, inhibition of mRNA translation by miRNAs has been regarded as an important regulator for bone development and homeostasis. This review focuses on the current knowledge of miRNAs and their involvement in the regulation of bone formation and bone resorption.

Abstract: RNA interference (RNAi) is a sequence-specific gene silencing phenomena mediated by double-stranded RNA which involves siRNA (Small interfering RNA) and miRNA (Micro RNA), and it could block gene expression at the level of transcription, post-transcription and translation, with high efficiency and specificity. This review summarized the pathway and technical route, and the application of RNAi in maxillofacial development, cheilopalatognathus researches, periodontal tissue development and oral tumor researches in stomatology.

Abstract: Flowable composite resin, also known as flowable resin, has been widely used in clinical practice since 1995. It can be used as cavity liner, inner layer for Class II, pit and fissure sealants and so on. Compared with the traditional composite resin, the content of filler in flowable resin is lower, resulting in its different performances. In this paper, the clinical application and performance of flowable resin were extensively reviewed.

Abstract：Human periodontal ligament stem cells (hPDLSCs), which reside in the perivascular space of the periodontium, possess characteristics of mesenchymal stem cells and are able to induce osteogenic differentiation under specific condition.The periodontium exists in a hypoxic microenvironment and the hPDLSCs constitutively receive mechanical stress. The aim of this review is to get the laboratory data of periodontal tissue reconstruction by reviewing relevant literature that assesses the effects of tensile stress on osteogenic differentiation of hPLSCs under hypoxia.