Abstract: Objective Hedgehog pathway play a vital role in bone development. This study investigated the expression of Hedgehog pathway signals in orthodontic bone remodeling. Methods We established the mice orthodontic model and observed on day 0, day 7, day 14 after orthodontic treatment. Tooth movement distance measured by micro-CT. HE&TRAP staining were used to investigated the orthodontic bone remodeling and osteoclastogenesis. Immunofluorescence staining was used for the expression of Gli1 positive cells in bone remodeling. Hedgehog pathway molecules mRNA expression levels and the expression changes of Intraflagellar transport(IFT) protein detected by Real time-PCR. Results The orthodontic tooth movement distance gradually increased. HE&TRAP staining showed the alveolar bone remodeling is obviously and osteoclastogenesis actively after treatment. Immunofluorescence showed a significant increased in the expression of Gli1 positive cells, which was mainly expressed in the alveolar bone pressure side, and peaked on the 7th day of orthodontic force(P<0.05). The mRNA expression of Hedgehog pathway vital molecules Shh, Smo, Gli were higher than control group(P<0.05). The changes of intraflagellar transport protein mRNA expression levels at each time point were statistically significant (P<0.05). Conclusion The Hedgehog pathway signals and Intraflagellar transport (IFT) protein participate in the orthodontic alveolar bone remolding.

Objective　Studying the changes of structural properties and cytological behavior of these microspheres modified with different concentrations of type I collagen (COLI), to guide the preparation of scaffold conducive to bone tissue regeneration. Methods　PCL microspheres were prepared (as the control group), then modified with COLI of different concentrations (as experimental groups). The surface morphology was observed by field emission scanning electron microscope (FESEM). Water absorption rate of materials was measured by dry-wet mass method. The proliferation of BMSCs was tested by Cell counting Kit-8 (CCK-8) assay, while the adhesion of cells was estimated by confocal laser scanning microscopy (CLSM) and Alkaline phosphatase (ALP) activity of cells was measured at 3 and 7 days. Results　FESEM pictures showed that collagen fibers were crisscross arranged to wrap the surface of microspheres in collagen modified groups. The water absorption rate of collagen modified group was higher than that of control group (P<0.05). CCK-8 results showed that BMSCs in all groups were proliferating continuously within 7 days, and the proliferation rate of the 0.1% COLI group was higher than other groups (P<0.05). Cells in the 0.1% and 0.5% COLI groups spread better than the other two groups at 6 h by CLSM. ALP activity of BMSCs cells in 0.1% COLI group was higher than that of other groups (P<0.05).Conclusions　The 0.1% COLI modified microspheres prepared in this study can promote adhesion, proliferation and early osteogenic differentiation of BMSCs in vitro.

Objective　To evaluate the effect of aging in vitro on the flexural strength of a novel transparent Y-TZP ceramic product and Weibull analysis. Methods　Sixteen transparent Y-TZP ceramic Katana UTML (KU) specimens were prepared and Lava Plus (LP) was selected as the control group, a transparent Y-TZP product commonly used in the dental market. The specimens were subjected to hydrothermal aging treatment according to the following methods: in an autoclave at 134℃ under 0.2MPa for 20h. The flexural strength of the samples before and after aging was tested by a universal tester, and then the value of flexural strength was analyzed by Weibull analysis. Besides, Scanning electron microscope (SEM) was applied to analyze the surface microstructure of the two zirconia ceramics before and after aging. Results　There was no significant difference in the flexural strength of KU before and after aging, but it was significantly lower than that of LP. The results of Weibull analysis showed that the Weibull modulus (m) of KU increased after aging, while the m value of LP decreased. The results of SEM showed that there was no significant changes on the surface morphology of KU after aging, while the grain continuity of LP was destroyed. Conclusions　Aging in vitro had no adverse effect on the flexural strength of the novel transparent Y-TZP ceramic product KU. Compared with LP, hydrothermal aging treatment didn’t reduce the reliability and structural integrity of KU, which indicated that KU has a better aging resistance than LP.

Objective　To investigate the effect of in vitro low temperature aging treatment on the crystalline phase, structure and flexural property of a CAD/CAM composite resin block containing zirconia fillers. Methods Sixteen Lava Ultimate (LU) bars with the same size were prepared. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to evaluate the crystalline phase and structure stability of LU before and after low temperature aging (in an autoclave at 134℃ and 0.2 MPa for 20 hours). Meanwhile, the flexural property of specimens was tested by the universal testing machine, and then the statistical analysis of flexural strength and flexural modulus was performed using the SPSS 22.0 statistical software package to evaluate the flexural stability of LU after low temperature aging. Results　The flexural strengths of LU were (185.33±19.22）, (220.89±20.88） MPa and the flexural moduli were (14.16±0.92), (20.93±0.97） GPa before and after low temperature aging. They were significantly higher than those before aging (P＜0.05). XRD patterns showed that zirconia crystal phase of LU did not change after low temperature aging, and the results of SEM showed that the microstructure of LU after aging was more compact. Conclusion Lava Ultimate performs good crystalline phase, structure and flexural stability under low temperature aging treatment.

Objective：To design experimental conditions via nano-indentation test, in order to investigate the viscoelastic properties of the human periodontal ligament（PDL）. Methods：After preparation of human PDL samples, the nano-indentation creep test and conventional reduced elastic modulus test were carried out by a flat punch in a moistful environment. The experimental scheme was set up according to the control variable method, and the influence of different experimental conditions on the experimental outcomes were analyzed. Results：The optimum parameters were obtained as follows: the nano-indentation creep test demanded the loading rate as 0.3-0.5 mN/s; the holding time of 25s and peak load of 2-3 mN were suitable for the conventional nano-indentation test. The nano-indentation creep curve of human periodontal ligament and the reduced elastic modulus range of 0.0121-6.84 MPa were obtained. Conclusion：The viscoelastic properties of human periodontal ligament were verified. We obtained the experimental conditions that were applicable to nano-indentation test for human periodontal ligament.

0008) [Abstract] Objective: To investigate the short-term clinical application of CAD/CAM porcelain veneer for anterior teeth. Methods: 52 cases of anterior teeth esthetic restorations in 12 patients, including anterior teeth scattered in space, incisor defect, dental fluorosis and mild to moderate tetracycline teeth. After teeth preparation by the same doctor, all patients used 3-shape scanner to obtain optical impression, CAD (3Shape software) to design veneers, Roland Dental Cutting System of Japan to cut VITABLOCS RTriLuxe three-layer ceramic blocks(VITA Company,Germany), and instantly completed the production of digital porcelain veneer in one day. According to the modified USPHS prosthesis evaluation criteria, the digital porcelain veneers were followed up on the baseline and 1, 3，6, 12 months after restorations. The results were analyzed by the chi-square test. Result: The anatomical form, marginal fitness, gingival condition, secondary caries and proximal contact points of digital porcelain veneer were good during the observation period. There were 2 cases of gingival inflammation in digital porcelain veneer after 1 month of bonding, which was caused by residual bonding agent. There was no discomfort in the follow-up after removing the residual bonding agent. But chi-square test shows there is no significant difference between the different time points. Within 12 months, the success rate of grade A was more than 90%. CONCLUSION: Digital porcelain veneer has good short-term effect in esthetic restorations for anterior teeth. It has the advantages of fast, minimally invasive, beautiful looking and good adaptability. It is a new esthetic and minimally invasive dentistry method for anterior teeth, but its long-term effect remains to be further observed.

Objective　 To observe the clinical application of computer aided design and computer aided manufacturing (CAD/CAM) in the functional reconstruction of mandible defects with fibular musculocutaneous flap transplantation. Methods The data of 9 patients with mandibular segmental defect resulting from mandibular lesion were analyzed. (CAD/CAM) technology was used to design fibula shaping to create favorable bone conditions for dental implant repair. The surgical guide plate was made by rapid prototyping. The titanium plate was reconstructed by preforming on the reconstructed solid model. Among them, 5 patients completed the implantation and restoration one year after surgery. The patients' facial shape, mouth width/type, temporomandibular joint, occlusal function, peri-implant soft tissue and bone tissue were followed up and observed. Bone level at the edge of the implant was measured 6 to 12 months after the restoration. Result All the flaps survived in 9 cases. Under the guidance of the surgical guide plate, the osteotomy and fibula were shaped smoothly and the time consumption was reduced. The 5 patients who completed the implantation and restoration were followed up at 6 and 12 months after the implantation. The patients showed full lateral shape, bilateral symmetry, and mouth width of 3.1-3.9mm. The soft tissue color around the implant was normal without obvious gingivitis around the implant. The occlusal relationship and masticatory function were normal. CBCT showed that there was no obvious absorption of bone tissue around the implant.Conclusion CAD/CAM can guide the shaping of fibula more accurately and create favorable bone conditions for the reconstruction of dental defects.

Objective To discuss the effect of orthodontic treatment on the root development of vertically impacted maxillary incisors. Methods Twenty-four patients with unilaterally vertically impacted maxillary central incisors were selected. The contralateral tooth with the same name was used as the control. Cone-beam CT (CBCT) was taken before and after treatment．Dolphin 11.0 was used to measure the root length before and after the treatment．Results The root lengths of impacted teeth after the treatment (9.79±1.57 mm) were significantly larger than those before treatment (7.50±1.29 mm) (P<0.001). The root lengths of the impacted teeth were significantly smaller than those of the control teeth before and after treatment (P<0.001).Conclusion Orthodontic traction can promote the further root development of the vertically impacted maxillary incisors, but the root length still cannot reach the normal level after treatment.

Objective To analyze the facial changes and the esthetic scores among different groups of evaluators in patients with skeletal class Ⅲ malocclusion before and after orthodontic orthognathic surgical treatment. Methods The study includes forty-five patients with skeletal class III malocclusion who accepted orthodontic orthognathic treatment.37 p ersons were selected by using visual analogy score (VAS) method to score these patients’ frontal and 90-degree-right profile photos of pre and postsurgical orthodontic treatment. Cone Bean CTs(CBCT) were taken before and after treatment. The lateral cephalometric radiographs were rebuilt by Dolphin imaging 11.0 and measured with Holdaway analytical method. Results Patients’VAS scores were greatly improved after orthodontic orthognathic treatment (p < 0.05). There were significant differences between orthodontists and layperson (p < 0.05). Part of values of Holdaway analytical method were different before and after treatment. Conclusion Orthodontic orthognathic treatment can greatly improve the frontal and lateral faces of patients with skeletal class III malocclusion. Orthodontists' aesthetic scores in these patients are generally lower than layperson.

Objective To compare the clinical effects of using two different positions of micro-screw implants in the treatment of dental and skeletal maxillary protrusion patients requiring extraction of premolar orthodontic?therapy. Methods 38 patients with indications were selected. According to the implantable height of micro-screw implants in maxillary molar region, the patients were divided into High position group (20 cases) and Low position group (18 cases) . The data before and after treatment were analyzed statistically. Results The upper anterior teeth of all the patients got obvious retraction and intrusion. The data of U1-SN/(°) ，U1-PP/(°) decreased significantly(P＜0.05)after operation , while the High position group’s decreased more(P＜0.05). The results showed that High position group lost more anterior teeth torque. The distance of U6-PP decreased(P＜0.05) while High position group’s decreased significantly(P＜0.05), indicating that we got posterior teeth intruded, and High position group is effective. Conclusions Both methods could be effective in the treatment of dental and skeletal maxillary protrusion . More retraction of the upper anterior teeth and the maxillary retraction could come out from Low position group.Better vertical control could be got from High position group，from which we obtained more intrusion of posterior teeth, more counter clockwise rotation of the mandible.

Objective To investigate the related factors of dental caries among 3- to 5-year-old children in Jiangsu Province and to provide information support for oral health care service. Methods The sampling process was conducted with a multistage stratified equal capacity method. A total of 1 337 children were recruited. Their parents or grandparents completed a questionnaire during a face-to-face interview. Related factors of dental caries were statistically analyzed. Results A total of 29.92% children started toothbrushing before 3 years old, 33.13% children brushed their teeth twice a day, 17.27% children used toothpaste with fluoride, 58.26% children had at least one kind of sugary food or drink every day, 9.95% children often had desserts before bedtime. Only 28.05% children never had desserts before sleep. A total of 81.90% parents had positive attitude towards oral health while only 24.08% had a higher level of oral health knowledge, and only 17.13% helped their children brush teeth every day. Logistic regression analysis showed a positive correlation between age and caries risk, and children living in rural areas were associated with a higher probability of caries. Conclusion Preschool children in Jiangsu Province have poor eating habits and oral hygiene behaviors and their parents have insufficient oral health knowledge. Therefore, oral health education should be strengthened among preschool children and their parents, especially in rural areas.

Single-cell sequencing refers to the detection, identification and analysis of cell components especially genetic materials at the single-cell level, which can reach single-molecule resolution. Single-cell sequencing captures and analyzes the information about genome, epigenome (including DNA methylation, chromosome accessibility and chromatin topology, etc.), transcriptome as well as cell topological space to define the cell types and further study cellular function, cell lineage, cell migration and transformation as well as cell the molecular effects on cell fate determination and so on. In recent years, to improve the noise-limited effectiveness of single-cell sequencing and research the interrelationship between different omics, single-cell sequencing has developed from single-omics to multi-omics and has been widely used in many fields of life science such as molecular biology, developmental biology, neuroscience, tumor research and immunology, providing powerful technical support for life science research.

Osteoradionecrosis of the jaws (ORNJ) is one of the most serious and important complications of radiotherapy for head and neck cancer, which often leads to severe pain, pathological fracture, sequestration of devitalized bone, and orocutaneous fistulas, and seriously reduces the patients’ survival quality and is even life-threatening. Although many theories of how it occurs have been formulated, the exact etiology and pathogenesis of ORNJ is not certain. The purpose of this article is to review and summarize the progress of studies on etiology and pathogenesis of ORNJ.

Calcium silicate hydrate biomaterials (CSH) can cure by themselves in wet and blood polluted environment. CSH has excellent biocompatibility, which can nucleate and remineralize the apatite, and finally can induce the formation of new mineralized tissues. These physicochemical and biological characteristics make CSH more and more widely used in the field of stomatology, such as root canal filling, pulp capping, root canal sealing, dentin remineralization, and pulp regeneration. Currently, CSH plays a key role in pulp regeneration, dentin remineralization, bone and cementum regenerative healing. In the future, new regenerative dentistry will continue to innovate with the continuous evolution of CSH.

It is commonly believed that pulp tissue is unable to regenerate once infection and necrosis take place. Now with the development of science and technology, dental pulp revascularization has brought new possibilities for pulp regeneration of immature permanent teeth. And stem cells, growth factors, and scaffolds all play critical roles in the process, especially scaffold materials, have got more and more attention recently. The scaffolds can be mainly divided into natural and synthetic materials. Though they have different characteristics, they all share the functions of acting as supports for three-dimensional structure and providing favorable environment for adhesion, proliferation, and differentiation of stem cells. At present, the scaffolds applied in clinics are mostly natural materials, especially induced bleeding, venous blood, and platelet derivatives. Whereas synthetic materials are still at the research stage, they attract people’s attention by their characteristics of innocuity, good biodegradation, and controllability. This review summarizes the research progress on the classification, features, advantages, and disadvantages of various scaffold materials in the dental pulp revascularization.

iRoot bioceramic materials are emerging silicon-calcium-based bioceramic materials, including iRoot BP Plus, iRoot BP, iRoot SP, iRoot FS and many other dosage forms. Compared with MTA, it has the advantages of easy access, good performance, no discoloration of teeth, and has wide application prospects in clinical practice. This article reviews iRoot BP Plus, iRoot BP composition, performance, and its application in endodontic treatment.

Temporomandibular disorders (TMD) is one of the most common oral and maxillofacial diseases. And malocclusion changes the stress load of masticatory muscles and ligaments due to the abnormal relationship between the upper and lower jaw bone position and the occlusal contact of teeth, which causes the changes of condyle and articular fossa shape and position. As a result, it is easy to induce the occurrence of temporomandibular disorders. This paper reviews the effects of different types of malocclusions on temporomandibular joint.