brackets, self?ligating brackets have lower frictional resistance and can provide persistent low force. Meanwhile, they help with better torque control, pain alleviation, chair time reduction, fewer visits and better periodontal health. However, self?ligating brackets have a problem that they are not in favor of correcting rotation and they have no obvious in terms of arch expansion. Based on clinical applica? tion and the authors?? experience, this article presents the advantages, limitations and development trend of self?ligating brackets, in or? der to provide reference for its clinical application.

Objective To fabricate scaffolds containing superparamagnetic iron oxide nanoparticles（SPIONs） by 3D printing technology in order to make scaffolds with better biocompatibility for tissue engineering. Methods Gelatin-alginate hydrogel scaffolds adding SPIONs and not adding SPIONs were both fabricated by 3D printing technology. Stereomicroscope, transmission electron microscope（TEM）,vibrating sample magnetometer（VSM）and flow cytometry（FCM）were used to characterize the surface topography, internal structure, magnetic properties and biological properties. Results Stereomicroscope showed that scaffolds with regular structure and uniform pore could be successfully fabricated by 3D printing technology, and TEM showed that SPIONs were distributed evenly in the hydrogel matrix .The VSM results showed that scaffolds containing SPIONs exhibited superparamagnetism. The FCM results showed that compared with the control scaffolds, the cell proliferation index in the scaffolds in experimental group elevated, and the magnetic scaffolds could promote cell proliferation, which indicated that the magnetic ones had better biocompatibility. Conclusion Tissue engineering scaffolds can be successfully fabricated by 3D printing technology and scaffolds with SPIONs show better compatibility compared with those without SPIONs.

Abstract: Objective To observe the influence of molar-missing on apoptosis of hippocampus CA1 neurons and expression of casepase-3 in hippocampus neurons of young rats ,and to investigate the possible mechanism of juvenile molar-missing on hippocampus neural cell apoptosis in young rats. Methods 60 male SD rats(at the age of 4~5 weeks) were randomly divided into control group and experimental group, 30 in each group .And then 30 rats were randomly divided into three groups(4-week group, 8-week group and 20-week group) based on when the modeling ends down to observe the expression of casepase-3 protein by using HE staining and immunohistochemistry, and to observe the dynamic changes of nerve cell apoptosis in rat hippocampus by using TUNEL method. Results: 1. The morphology and structure of hippocampus CA1 cells were normal in the control group, and there were no significant pathological changes. The cells in the experimental group were swollen, vacuoles appeared, the structural arrangement became disordered, and the neuron cells were significantly reduced.2. With time variation(4,8,20 weeks), positive cells in hippocampus CA1 region of experimental group by the number increased, and the difference was statistically significant (P = 0.000), while in the control group there was no statistical difference (P = 0.301) in casepase-3 expression. The differences were statistically significant in casepase-3 expression between any two groups (P < 0.001). 3.The TUNEL positive cells in experimental group had a statistically significant difference (P = 0.000). The TUNEL positive cells in control group had no significant difference (P = 0.276) . There was a statistically significant difference in the number of TUNEL positive cells between any two groups (P < 0.001).Conclusion: Longrun chewing stimulation decrease may increase apoptosis in hippocampus of rats and may increase the expression of casepase-3 protein at the same time. The results suggest that the long-term molar deletion in rat hippocampus induces the development of apoptosis of hippocampus tissue cells.

Objective　 To study the effect of minimally invasive tooth extraction in rats. Methods Twenty SD female rats were randomly divided into two groups，the left six molars were extracted by conventional methods(control group) and minimally invasive method(experimental group) respectively. Postoperative survival rates, teeth intactness and the injury of soft tissue in extraction sites were observed. Results Compared with control group, the rat survival rates increased in experimental group, the incidence of crown and root fracture decreased, and the degree of soft tissue injury in dental sockets were milder than the control group. Conclusion The minimally invasive extraction method can effectively save time and resources of animal experiments, which can ensure the following experiments to carry on smoothly.

Objective　 LIM mineralization protein-1 is non-secret protein in the cell, widely existing in various tissues, which not only affects the mineralization of bone matrix but also is the important regulatory factor in the process of osteoblast differentiation and bone formation. This experiment evaluates the effect of intracellular signal transduction molecules LIM mineralization protein 1on dental pulp stem cells in vitro mineralization by detecting the process of mineralization. It can provide the reference for evaluating the LMP-1 as osteogenesis adjustment factor and affecting bone matrix mineralization research. Methods　 Dental pulp stem cells were cultured in vitro，purified and then subcultured . Bone marrow mesenchymal stem cells were cultured in vitro by density gradient centrifugation method. Two kinds of cells were set up respectively into the experimental group and the control group. In the experimental group, the induction fluid was added to the culture medium, but in the control group it was not added. They were detected in 3, 5, 7 and 14 days respectively. Fluorescence quantitative PCR method was used to detect the culture period expression of osteogenic marker genes LIM mineralization protein-1、BMP-2、DSPP、COL-1、RUNX-2. The results were statistically analyzed by SPSS17.0. Results　The activity of alkaline phosphatase increased and the activity of alkaline phosphatase in the experimental group was significantly higher than that in the control group at 5, 3, 7 and 14 days. The formation of mineralized nodules was seen in the experimental group at 21 days. Fluorescent quantitative PCR was used in both the experimental and control groups, and the expression of the experimental group was significantly higher than that of the control group. Conclusions　LIM mineralization protein -1 is associated with the mineralization of dental pulp stem cells in vitro and bone marrow mesenchymal stem cells. It’s speculated that LIM mineralization protein 1 May as the detection of dental pulp stem cells and bone marrow mesenchymal stem cells is an indicator of mineralization.

Abstract: Objective To study the protective effect of tea polyphenols (TP) on H2O2 induced human periodontal ligament cell injury and its mechanism. Methods Human periodontal ligament cell injury model was established using H2O2. Cells were randomly divided into three groups: control group, H2O2 group, and H2O2+ TP group. Cell viability was detected using MTT method and cell apoptosis was detected by flow cytometry. The MDA content and SOD activity were measured by the MDA and SOD detection kit. Protein expression levels of caspase-3, caspase-12, Bcl-2 and Bax were examined by western blot. The expression of IL-1β and IL-6 was detected by ELISA method. Results The cell viability was decreased with H2O2 treatment in a dose dependent manner. TP reversed the effect of H2O2 in human periodontal ligament cells, which included decrease of cell viability, increase of cell apoptosis, elevation of MDA, reduction of SOD activity, increase of expression levels of caspase-3, caspase-12, and Bax, decrease of Bcl-2 expression, and elevation of IL-1β and IL-6 expression. Conclusion The TP treatment protects H2O2 induced human periodontal ligament cell injury via inhibiting oxidative stress, mitochondrial apoptotic pathways and inflammation.

Objective To evaluate the effect of different sandblasting conditions including sandblasting time, sandblasting pressure and sandblasting alumina powder size on surface loss of dental zirconia. Methods 250 zirconia bars were randomly divided into 25 groups according to different sandblasting pressures (0.1 MPa, 0.2 MPa, 0.4 MPa, 0.6 MPa), sandblasting times (7 s, 14 s and 21 s) and alumina powder sizes (50 μm and 110 μm). The control group did not receive sandblasting. The volume loss, height loss and roughness on zirconia surface after sandblasting were measured and compared for each group. Results The volume loss and height loss were increased with higher sandblasting pressure and longer sandblasting time, but they decreased with larger powder size (all P＜0.05). The surface roughness were increased with higher sandblasting pressure, longer sandblasting time and larger powder size (all P＜0.05). Conclusion Considering the clinical adaptation and surface roughness after sandblasting, sandblasting with alumina particles at 0.2 MPa, 21 s and the powder size of 110 μm is recommended for dental application.

Objective To evaluate the effect of chair-side heating bleaching on teeth with different positions. Methods 6 patients were selected to join in the test according to the inclusion criteria. Three sessions for 15 minutes using a chair-side heating bleaching system were performed as one bleaching treatment, and the interval between each two sessions was one day. Colors of maxillary central incisor, lateral incisor, and canine were registered each session and 1 week or 1 month after completing the treatment by a dental colorimeter, registering parameters L*, a*, b*, color difference values, and whiteness values. Results There was no significant difference of color difference values and whiteness difference values among the three different teeth positions (P?0.05). Color difference values and whiteness difference values also showed no difference among the three bleaching sessions, and 1 week or 1 month after completing the bleaching treatment (P?0.05). Conclusion Chair-side heating bleaching exerts the same effect on teeth with different positions.

Abstract Objective To systematically evaluate the efficacy and safety of tacrolimus and glucocorticoid for oral lichen planus(OLP)， in order to provide strong basis for clinical rational use of drugs and prevention of adverse reactions.Methods The Cochrane review’s method was adopted manual and computer—based retrieval was performed on The PubMed ,Cochrane Library, MEDLINE，EMbase，CBM，VIP， CNKI and WanFang Data (from their establishment toJune 2016)to collect randomized controlled trials comparing the clinical efficacy of tacrolimus in treating OLP with that of glucocorticoid．The study was selected according to Cochrane system evaluation method． Fifteen literature is recommended by Cochrane was used to complete the Meta analysis of total effective rate ，recurrence rate and rate of adverse reaction. Results Fifteen trials involving 894 patients were included． The results of meta-analyses showed that the total effective rate of tacrolimus was higher than that of triamcinolone acetonide (RR=1．55，95％CI(1．27，1．89)，P＜0.0001) ，mometasone （RR=1．27，95％CI(1．16，1．39)，P＜0.00001) ，and fluorine relaxed (RR=1．33，95％CI(1．05，1．69)，P=0.02)，but there was no significant difference between the tacrolimus group and the propionate group(RR=1．04，95％CI(0.95，1．14)，P=0.44). However,there was no significant difference between the tacrolimus group and the glucocorticoid group in adverse events(RR=0．66，95％CI(0．38，1．15),P=0.14) , there was a significant difference between the experience group and the control group in recurrence rate(RR=0．70，95％CI(0．49，1．00),P=0.05) during the treatment session. Conclusion Current evidence shows that, tacrolimus treated oral lichen planus is a short-term clinical curative effect of better treatment plan. While the diagnosis of pathological examination by pathological examination was less,Due to the limited quality of included studies ,the possibility of selective migration increased.it still needs to be verified by more high quality studies to increase the efficacy and safety of the medicine.

Objective: To evaluate the significance of the AirFloss for plaque control to patients of periodontal diseases. Methods:One hundred and twenty patients of periodontal diseases were randomly assigned to four groups:the manual tooth brushing;the dental floss plus manual tooth brushing;the AirFloss plus manual tooth brushing; the AirFloss. After periodontal initial therapy, oral hygiene tests were performed in four groups of patients at the first month(M1) and third month(M3), and the gingival index GI and Quigley-Hein plaque index were compared between the groups. Results: After one month, the PLI and GI of the AirFloss plus manual tooth brushing were decreased by 47% and 44.9%.And after three month, PLI and GI were decreased by 62.9%和58.4%, and the difference was statistically significant at the two time points(P<0.05).And after one month,the PLI and GI index of the dental floss plus manual tooth brushing respectively decreased by 9% and 10% compared to the baseline examination (P>0.05). After three months ,the PLI and GI were decreased by 15.6% and 16% (P>0.05). Afer one month and three months,the PLI and GI index of simple manual tooth brush group and the airfloss group was no significant baseline examination the difference. Conclusion: The airfloss can significantly reduce plaque in patients with periodontal disease adhesion, improve gingival inflammation, is an effective auxiliary oral cleaning device with periodontal disease.

Objective To investigate the clinical effect of CAD/CAM custom abutment used in posterior region for improving food impaction. Methods 80 cases of 65 patients for implant restoration in posterior region were randomly divided into two groups randomly: Test group included 40 CAD/CAM custom abutments, and control group included 40 stock abutments. 3 months after the completion of restoration, the morphology of gingival papilla was evaluated according to the papilla index score (PIS), the situation of food impaction was observed, and the correlation between them was analyzed. Results There were no cases of PIS 4 in both of the two groups, but there were more cases of PIS2 and PIS 3 in test group( 36 cases,90.00%) than in control group(29 cases,72.50%), while there were fewer cases of PIS 0 and PIS 1 in test group( 4 cases,10.00%) than in control group(11cases,27.50%) , the difference was statistically significant(P<0.05). 4 cases(10.00%) showed food impaction in test group, while 13 cases(32.50%) in control group, the difference was statistically significant(P<0.05). 2 cases(3.07%) showed food impaction in good papilla morphology group, while 15 cases(100%) in poor papilla morphology group, the difference was highly statistically significant(P<0.001). Conclusions When used in posterior region , CAD/CAM custom abutment can help to form better gingival papilla, reduce food impaction, and keep the tissue around the implant healthy.

Abstract Objective To investigate the effect of the periodontal basic therapy on patients with both oral lichen planus(OLP) and periodontitis through observation of the levels of interleukin-10 and transforming growth factor-β (TGF-β) in serum before and after treatment, and to discuss the meaning of periodontal intervention in the treatment of oral lichen plan. Methods: 40 patients with both OLP and periodontitis were divided into two groups: periodontal treatment group (20 patients) and non-periodontal treatment group (20 patients), then the two groups were given periodontal therapy combined with drug therapy and drug treatment only, respectively. Probing depth (PD), attachment loss (AL), bleeding indices (bleeding index,BI) and levels of IL-10 and TGF-β were detected at the baseline and one month after treatment. Results After treatment, PD and BI except AL were lower than before treatment (P<0.05) in periodontal treatment group. There were no significant differences in PD and AL in non-periodontal treatment group before and after treatment (P>0.05); in contrast, BI after treatment was higher than before treatment (P<0.05). In periodontal treatment group, the expression level of TGF-β in serum decreased after treatment and the difference was statistically significant (P<0.05); however, the level of IL-10 had no significant difference before and after periodontal treatment (P>0.05). The levels of IL-10 and TGF-β had no statistically significant differences before and after treatment in non-periodontal treatment group (P>0.05).Conclusion The periodontal basic therapy can affect the level of TGF-β in the serum of patients with both OLP and periodontitis. Periodontal basic treatment can be used as one of the auxiliary treatment to control the disease development, but the long-term effect is worth further observation. Conclusion: The periodontal basic therapy can affect the serum level of TGF-β in patients with both OLP and periodontitis, periodontal basic treatment can be used as one of the auxiliary treatment to control the disease development, but the long-term effect is worth further observation.

Objective To compare the clinical effect of minimal invasive and general tooth extraction in pulling out residual roots, residual crowns and fractured tooth. Methods Six hundred and thirty patients who have to extract tooth were randomly divided into minimal invasive group (315 persons) and traditional technique group (315 persons). The time of operation, dental fear rate, alveolus intact rate, incidence rate of root broken, gingival lacerated rate, and postoperative effects were compared and analyzed. Results The operation time in minimal invasive group was shorter than that in traditional technique group (p<0.05), the intraoperative and postoperative complications incidence rate of the minimal invasive group were markedly lower than the traditional technique group (p<0.05). Conclusion Minimal invasive tooth extraction applied in extraction of residual roots, residual crowns and fractured tooth can efficiently reduce complications of intraoperative and postoperation, and make the operation more comfortable. Therefore, minimally invasive tooth extraction is recommendable.

Abstract： Objective This study aims to determine the effects of application of berberine gelatin on the treatment of minor RAU (MiRAU).Methods A randomized, double-blind, placebo-controlled, clinical trial was performed. The gelatin containing berberine(5 mg/g) or placebo only was applied 4 times per day for 5 days. Clinical evaluation included pain level, size, erythema, and exudation of certain ulcers on 1st, 2nd, 4th and 6th days. Results A total of 47 subjects including 24 subjects in treatment group and 23 subjects in the control group fulfilled the study without obvious side effects. On 2nd, 4th and 6th days, the ulcer pain score of the treatment group decreased by 15.8%, 41.27% and 80.58%, respectively, while the control group decreased by 5.56%, 19.60% and 51.25%. Berberine gelatin treatment reduced the ulcer pain score compared with control group and there was significant difference between the two groups(P＜0.05) .The ulcer size of treatment group decreased by28.36%, 48.63% and 72.72%,respectively, while the control group decreased by 11.41%, 25.77% and 50.92%, The ulcer size was significantly reduced in treatment group (P＜0.05) .On the 2nd day, there was no difference in congestion and exudation between two groups (P＞0.05).On 4th and 6th days, the erythema and exudation of the treatment group significantly reduced (P＜0.05) (P＜0.05)compared with control group. No obvious adverse reaction was found. Conclusion Berberine gelatin can promote the healing of MiRAU and relieve the pain . It has good clinical effects and may be a safe and effective local administration for MiRAU.

Objective　To analyze the prognosis of mucoepidermoid carcinoma (MEC) of salivary gland and to explore the clinicopahtological influencing factors. Methods　78 patients with MEC of salivary gland treated with operation in our hospital from January 2001 to February 2016 were retrospectively selected. Related clinicopahtological materials were collected. Postoperative survival rates of 3, 5 and 10 years were calculated by Kaplan-Meier method and prognostic factors were analyzed by Log rank tests and Cox regression model. Results　(1). The overall survival rates of 3, 5, and 10 years were 98.6%, 89.6% and 73.5% among patients with salivary gland MEC respectively after surgical therapy. (2). Univariate analysis: The overall survival rates of patients with high differentiation and no lymphatic metastasis were statistically significantly higher than those of patients with low differentiation (Log-rank=10.03,P<0.01) and lymphatic metastasis (Log-rank=8.57, P=0.01) respectively. (3). Multivariate analysis: Pathological differentiation (HR=12.71; P=0.02) and lymphatic metastasis (HR=6.84; P=0.01) were the independent clinicopahtological influencing factors among patients with salivary gland MEC after operation. Conclusion　Pathological differentiation and lymphatic metastasis are the independent prognostic clinicopathological factors of salivary gland MEC. Comprehensive measures should be taken for patients with poorly differentiation or lymphatic metastasis to improve the postoperative prognosis.

Evaluation of therapeutic effects on cracked teeth preserving SUN ShuWen , BAILian. (Fifth Clinic, Peking University School andHospital of Stomatology, Beijing 100020, China) Abstract: Objective To investigate the clinical methods of preserving cracked teeth that need to have a root canal therapy . Methods 75 cracked teeth that need to have a root canal therapy were included.These cases were treated with occlusal adjustment, root canal therapy, resin restoration，temporary crown restoration，full crown restoration. And then follow- up results were evaluated. Results The results were satisfactory in 57 teeth (>=2 years) and failure in 18 teethafter treatment . Conclusions Indicationsshould be restricted according tocrack range，periodontal condition and the relevance between the former two, and full crown restoration. The use of rubber dam, occlusal adjustment, temporary crown repair and complete coronal restoration after root canal therapy can be effective in preventing teeth fracture.Strict indications and teeth fracture prevention are the key of successful therapy. Key words: cracked tooth; root canal therapy;temporary crown restoration; full crown restoration

[Abstract] Objects: To analyse the skeletal structure of temporomandibular joint in skeletal class Ⅲ with high-angle in mixed dentition by using CBCT. Methods: Twenty normal occlusion children in mixed dentition and twenty skeletal class Ⅲ children with high-angle in mixed dentition were included in this study. CBCT was performed in the intereuspal position. Relevant parameter from reconstructed images of TMJ were calculated with invivo 5 software. Results: compared with normal occlusion group，the condylar mediolateral diameter, fossa width and condylar length were larger while condylar anteroposterior diameter, fossa depth, Tuberculum articulare angle and condylar height were smaller in the skeletal class Ⅲ group in mixed dentition. Conclusion: There are statistical differences of skeletal structure between normal occlusion group and the skeletal classⅢ group in mixed dentition.

Mophological changes of the condyle in adult patients with open bite by CBCT observation Abstract Objective To investigate the relationship between the condylar morphology and malocclusions with different overbite depths. Methods The samples were divided into two groups:G1,malocclusion with normal amount of overbite;G2,openbite malocclusion.To ascertain the morphology of the different condyles, 80 mandibular condyles of 40 adult cases, ranging from 18 to 36 years of age, were assessed using CBCT. Measureing and calculating the upper condylar height to the ramus height ratio(UCH/RH)and the condy height to the width ratio(CW /TCH).The condylar morphology was classified into four types:Type A,straight;Type B, anteriorlyinclined; TypeC, posteriorly inclined,and Type D,spiky or finger-shaped.The symmertry of the condyle and ramus in vertiacl dimension between the right and left side was calculated with the asymmetric index formula. Results ①The open bite group has a significantly smaller amount of TCH/RH and CW /TCH than normal overbite group（P<0.05）;②Type A and C have normal condylar shapes that comprised 73% while Type B and D have abnormally condylar shapes that comprised 26.7% of the open bite group. ③the openbite group showed condylar height asymmetry（P<0.05）.Conclusions openbite group has a shorter condyle relative to the ramus than normal bite group, and showed condylar height asymmetry, abnormally condylar shapes higher than normal bite groups.

[摘要]目的：调查上海市替牙期小学生错牙合畸形患病率及类型，为早期矫治提供科学依据。方法：在7-11岁小学生随机抽样调查，按Angle错牙合分类法进行统计。结果：受检小学生中错牙合畸形患病率为48.67%，男女有统计学差异。错牙合类型以AngleⅡ类最多，占50.23%。在各种错牙合畸形类型中，较为明显的是深覆盖、深覆牙合、轻度拥挤和反牙合，患病率分别是63.93％、58.90％、38.36％和18.69％。结论：上海市替牙期小学生错牙合畸形患病率仍较高，错牙合类型构成比及主要类型表现发生变化，应加大力度普及错牙合畸形早期防治知识，有针对性地进行早期矫治。

The resistance of bacterial strains to current antibiotics has become a serious public health problem which needs us to develop new bactericidal materials. As photocatalyst, nano-TiO2 materials have a safe and efficient antibacterial activity, which makes them more and more widely used in the field of antibacterial. This paper reviews the antibacterial mechanism and influencing factors of photocatalytic nano-titanium dioxide materials.

TiO2 nanomaterial is one of the most used nanomaterials in the world, which has big specific surface area and outstanding performance in photocatalysis. Recently the application of nano-sized dioxide titanium in the field of biomedicine has raised much attention because of the advanced development of nanomaterial technology. This review summarizes the applications of nano-sized dioxide titanium in tumor therapy, surface modification on implant and antibacterial aspects.

Orthodontic tooth movement depends on the remodeling of periodontal tissues, and the alveolar bone remodeling depends mainly on osteoclast and osteoblast activity. Osteoclast derived from hematopoietic stem cells, a kind of multinucleated giant and highly differentiated cells， which is the main functional cell of bone resorption in the pressure side during orthodontic tooth movement. The number and function of osteoclasts is one of the main factors determining the efficiency of orthodontic tooth movement. The differentiation of osteoclast is influenced via a variety of systemic factors or local factors directly or indirectly, thus affecting the absorption of bone remodeling, such as hormones, drugs, orthodontic force local loading, periodontal status and various cytokines. Research about these factors has certain guiding significance for the clinical accelerating tooth movement or increasing anchorage and reducing unnecessary tooth movement.

Abstract: With the laser in oral medicine having increasingly wider range of application, attention to various types of laser in endodontic treatment has been higher. Root canal therapy is the first choice of treatment method of pulpitis and periapical disease, while the root canal cleaning is the key link to the success of root canal therapy. Er,Cr:YSGG laser, due to its disinfection, removal of smear layer on the root canal wall, and cleaning of root canal dentin debris and other infectious substances , becomes one of the most advantageous and promising lasers in the root canal cleaning-up. This article then reviewed the application of Er,Cr:YSGG laser in the root canal cleaning-up of root canal therapy, expecting to provide some help for the clinical application of this laser.