Objective To investigate the influence of CpG 2006 on tooth movement and alveolar bone remodeling in rats. Methods Male Wistar rats were chosen. Orthodontic tooth movement devices were installed at both maxillary of each rat, and the left side was chosen to be the treatment lateral, while the right side the control lateral. CpG 2006 or PBS was injected under the buccal mucosa of the maxillary first molar. Injection repeated every 72 h to all the animals sacrificed 14 days later. The migration distance of the molar was measured depending on specimen and Xray. The expression levels of osteoclast and inflammatory related factors were detected by Realtime PCR. HE staining was used for detecting the effects of CpG 2006 on the organ. Results The migration distance of the molar in treatment lateral was smaller and the expression levels of IL1,IL6,TNFɑ mRNA were lower than the control lateral, while the expression levels of Runx2,SP7,OCN mRNA were higher than the control lateral, and there were no differences among the expression levels of Nfatc,CTSK, MMP9 mRNA between the two laterals. No pathological changes were found in their organs. Conclusion CpG 2006 can regulate the distance of tooth movement by promoting the osteogenic activation of periodontal tissue, and reduce the expression of inflammatory factors during tooth movement.

Objective To compare the effects of different instruments of interproximal enamel reduction(IER) on enamel surface roughness before and after polishing. Methods Sixty healthy premolars were used after removal for orthodontic reasons and divided into six groups. Each group underwent IER with different IER instruments:Ⅰ:diamond burs(medium);Ⅱ:diamond burs(fine);Ⅲ: handheld diamond strips(medium);Ⅳ: handheld diamond strips(fine);Ⅴ:diamond discs; Ⅵ:control group(no IER). One proximal surface of sample after IER was polished with SofLex polishing discs.Striped and polished surface roughness was assessed and morphology was observed respectively using laser scaning confocal microscopy(LSCM). Results ①After IER but before polishing, groupⅠand groupⅢ had the roughest surfaces (no statistically significant,P= 0.632),followed by groupⅡ, Ⅳ, Ⅴ,and these surfaces were significantly rougher than the control surfaces; ②The enamel surface roughness of the groupⅠ,Ⅱ, Ⅲ, Ⅳ,Ⅴdecreased significantly after polishing(no significant difference between groups), and these surfaces are smoother than the control surfaces. ③LSCM image: After IER,groupⅠ,Ⅱ, Ⅲ, Ⅳ,Ⅴ all produced enamel furrows and scratches, groupⅠ,Ⅱcreated deeper furrows and scratches than group Ⅲ, Ⅳ,Ⅴ, and group Ⅴproduced the shallowest scratches. Polishing with SofLex polishing discs after IER basically eliminated the scratches that were created by IER(no significant difference between groups Ⅰ, Ⅱ, Ⅲ, Ⅳ and Ⅴ). Conclusions ①Different IER instruments will increase enamel surfaces roughness to different extents. Enamel surfaces treated with diamond burs (medium)and diamond strips(medium) were the roughest, followed by diamond burs (fine), diamond strips(fine) strips,and treated with diamond discs are the smoothest. ②Polishing with SofLex polishing discs after IER with different instruments reduced the enamel surface roughness(no significant difference between groups), and these surfaces are smoother than untreated enamel. 

Objective To study the effect of different point mutations in exon 3 on the structure of PAX9 protein. Methods The DNA and amino acid sequence information of exon 3 mutations of human PAX9 gene were retrieved by Pubmed and ClinVar databases, and the amino acid sequences affected by exon 3 mutations were compared in different species and different PAX genes. Phyre2 and RaptorX were used to predict and analyze the threedimensional structure of the amino acid sequence. Results The amino acid sites of the PAX9 gene affected by exon 3 mutation were highly conserved. 25, 26, 28, 43, 51, 56, 59, 87, 91 and 143 amino acids participated in the composition of Alpha helix secondary structure. 6, 73, 80, 136, 143, 145, 168 and 172 amino acid sites had strong pathogenicity. Gly6Arg and Pro20Leu would alter the alpha helix secondary structure of the DNA binding region in the PAX9 protein. Other amino acid changes could also alter the space folding and structure of PAX9 protein in different degrees. Conclusion The change of amino acid caused by mutations in exon 3 may cause different changes in the structure of PAX9 protein, which may also be the reason that the phenotype of oligodontia or hypodontia caused by different PAX9 mutations are not exactly the same.

Objective To study the effects of azithromycin on the micro structure of alveolar bone of rats with periodontitis by MicroCT. Methods Male SD rats were randomly divided into 3 groups:control group, ligation group, azithromycin group. The left maxillary first molars of rats in ligation group and the azithromycin group were ligated by thread to establish the experimental periodontitis model. From the ligation, rats in azithromycin group received intraperitoneal injection of azithromycin 3.5 mg/kg. After two weeks’ injection, the rats were killed and the maxillary bones were removed. By MicroCT the changes of maxillary first molar alveolar bone loss and microstructure were analyzed. Results Compared with the control group, the height of the maxillary first molar surrounding alveolar bone in ligation group decreased obviously, while in drug induced state, alveolar bone resorption of azithromycin group decreased significantly. Azithromycin inhibited the alveolar bone height decrease. After ligation, micro structure of rats’ alveolar bone obviously changed. The values of BV /TV, Tb.N, Tb.Th and BMD significantly decreased, while that of Tb.Sp increased. And the alveolar bone microstructure parameters of azithromycin group could reach a certain level of recovery, and the difference with the control group decreased significantly. Conclusion Azithromycin can prevent alveolar bone of experimental periodontitis rats from continuing to be destroyed, which has a therapeutic effect on experimental periodontitis rats. Key words: azithromycin; experimental periodontitis; alveolar bone; MicroCT； SD rats

Objective To observe and assess the longterm clinical effect of domestic ZDI implant system. Methods 35 patients with totally 46 implants were recruited in this study. The longterm clinical effect of ZDI implant system was analyzed by observing the incidence of biological and mechanical complications, measuring the extent of implant bone loss and scoring the patients degree of satisfaction. Results After six years followup, only two cases occurred periimplantitis, one case of crown loss and none of other mechanical complications. Eventually, the success rate was 95.7%, the survival rate was 100%, and the overall satisfaction index was 9.79±0.29. Conclusion The ZDI implant system can achieve a good longterm clinical outcome as long as the operation is standardly performed, the restoration is accurately performed and the oral hygiene is continuously maintained.

Objective　 To detect the contents of matrix metalloproteinase 9(MMP-9) in gingival groove fluid and serum of patients with chronic periodontitis (CP) and rheumatoid arthritis (RA), and discuss the correlation between MMP-9, CP and RA. Methods According to the inclusion criteria, 23 patients with rheumatoid arthritis (RA), 18 patients with chronic periodontitis (CP), 24 patients with chronic periodontitis and rheumatoid arthritis (CP+RA) and 16 healthy control group (H) were selected. The general conditions of patients were recorded, including the probing depth (PD), clinical attachment loss (CAL), sulcus bleeding index (SBI), simplified dental calculus index (CIS), and simplified debris index (DIS). Gingival crevicular fluid and serum were collected from each group. The expression level of MMP-9 in gingival crevicular fluid (GCF) and serum was detected by ELISA. The correlation between MMP-9 and periodontal index was analyzed. SPSS20.0 software package was used for statistical analysis of the data. Results The values of CAL, SBI and DI-S in RA+CP group were higher than RA group, CP group and H group. The level of MMP-9 in serum in CP+RA group (2671.71±1258.33μg/L) was higher than that in the RA group (1444.54±770.03μg/L), CP group (511.38±539.52μg/L), and H group (67.14±34.95μg/L) (P?0.05). The level of MMP-9 in the gingival crevicular fluid was higher in CP+RA group (26.11±5.25μg/L) than in the CP group (18.83±11.87μg/L) and H group (1.04±0.58μg/L) (P?0.05). There was a positive correlation between CAL and SBI in CP+RA group and MMP-9 expression in serum, CI-S and DI-S in CP group were positively correlated with serum MMP-9 . Conclusion There is a correlation between CP and RA, and the expression of MMP-9 significantly increases in CP and RA. MMP-9 may be related to the occurrence and development of CP and RA.

Objective To compare the clinical effects of single implant crowns in the anterior maxilla following immediate placement with immediate prosthesis or delayed prosthesis. Methods 58 patients within single implant crown in the anterior maxilla were included in the study. Among them, 28 patients received immediate implant placement and immediate prosthesis (II group), and 28 patients were given immediate placement and delayed prosthesis (ID group).The implant survival rate, pink esthetic score(PES), white esthetic score(WES), marginal bone resorption surrounding implants and patients satisfaction were compared between two groups 3 months,6 months and 12 months after final restoration. Results The implant survival rates of the two groups both reached 100%. The vertical bone resorption at distal sites at 3 months in II group was (0.34±0.18)mm, and in ID group was (0.45±0.13)mm, and the difference was statistically significant (P<0.05), but at 6 months and 12 months it showed no statistical difference between two groups. Horizontal bone resorption:At 12 months, the bone resorption at MP1 site in II group was (0.67±0.16) mm, (0.65±0.15) mm in ID group, at MP2 site in II group it was (0.54±0.14) mm, (0.56±0.12) mm in ID group, and there was no significant difference at MP1 and MP2 sites between the two groups. PES:The scores of PES at permanent restoration, 3 months, 6 months and 12 months were (9.69±1.04), (10.00±1.03), (10.59±1.20), (10.79±0.98), which were all significantly higher than those in ID group (P<0.05). WES and patients’ satisfaction at 12 months in II group were both higher than the other group, and there were statistical differences in them between the two groups. Conclusion There is no statistical difference in the marginal bone resorption of implants and implant survival rate between two groups, but in terms of aesthetic effect，immediate prosthesis is superior to delayed prosthesis, and patients satisfaction is also higher.

Objective To evaluate the efficacy and safety of ornidazole in the treatment of pericoronitis of wisdom teeth by metaanalysis. Methods RCTs of ornidazole in the treatment of pericoronitis of wisdom teeth from the major databases (PubMed, Cochrane Library, CNKI, VIP, Wanfang) were searched from the basebuilding to December 2017. Metaanalysis was performed using Review Manager 5.3 software after data extraction and evaluation. Results A total of 27 RCTs were included, including 3 464 patients. Metaanalysis showed that ornidazole could improve the efficiency, reduce duration time of pain and pericardial swelling, also inhibit oral bacterial density, and had less adverse reactions. Conclusion Olanzanide has a significant effect on the treatment of periapical periodontitis and has less adverse reactions, which is worthy to be popularized in clinic.

Objective To detect and locate mandibular incisive canals (MICs) on 3dimension images scanned from conebeam computerizing tomography (CBCT) in vivo, and to discuss its clinical significance. Methods Based on an inout standard, a sample was screened out of the CBCT databank of radiology department in our hospital, which involved a part of individuals at the age of 18 to 85. Teeth of 44~34 were selected as the sites of our study. Beneath them MICs were distinguished, of which the visibilities were decided, and the diameters and distances to some anatomic landmarks were measured. Results The visibility of lower first premolar and canine obviously excelled incisors. Most MICs stretched their ways slightly nearer to the buccal or labial cortex in the perpendicular middlethird of mandible in the crosssectional images. The diameters of MICs became thinner while running closer to the mental symphyseal region, and mostly invisible below incisors. Conclusions Clinical significance of MICs may not be so important as assumed. It is essential to inform of MICs damage and nerve dysfunction risks before surgical operations, however, which is taken into account grounded on ethicality and forensicality. Customized preoperative 3Dimage examinations and measurements, and avoidance from MIC injury as much as possible, are still basic clinical requests.

Objective To observe and compare the clinical effects of Z350 and sonicfill resin filling in the treatment of maxillary first molar defect. Methods The maxillary first molars were left after the root canal treatment in the outpatient department. Forty samples were randomly divided into group A and group B. Group A was repaired with Z350, while group B was repaired with sonicfill. The two groups of patients were examined and followed up immediately and 12 months after the repair, and the clinical repair effect of the defects was evaluated by referring to the evaluation criteria of the prosthesis of the United States department of public health. Results There was no significant difference between the two groups in the repair effect immediately and 12 months after the treatment of maxillary first molar root canal. Conclusion Both resins are suitable for the repair of dental defects after the treatment of maxillary first molar root canal with sufficient residual tooth volume, in which sonicfill resin filling operation time is obviously superior.

After the loss of the posterior teeth, the absorption of alveolar bone leads to insufficient keratinized mucosa (KM), which is a problem often encountered in the process of dental implantation. The KM acts as the first barrier against external stimuli around the implant. Studies have shown that patients with insufficient KM have an increased risk of periimplant diseases, often requiring soft tissue augmentation procedures to increase the width of the KM to maintain longterm stability of the implant. However, the extent to which softtissue augmentation procedures can reduce the risk of periimplant diseases remains unclear. Therefore, it is a hot debate among scholars whether it is necessary to perform soft tissue augmentation procedures patients with insufficient KM. This article will briefly review the effects of periimplant KM on implant restoration and related methods of soft tissue augmentation.

Presence of adequate keratinized tissue around dental implants helps oral hygiene maintenance and enhances esthetic blending. However, whether mucosa graft is necessary for deficient posterior area (keratinized mucosa width ≤ 2 mm) remains controversy. This paper mainly discusses the effect of keratinized tissue deficiency in the posterior jaw on periimplant indexes, and the pros and cons of keratinized mucosa graft, and implant long stability. It is concluded that mucosa graft is not necessary, while oral hygiene maintenance, regular followup and individual consideration of treatment strategies are necessary.

Periodontitis is a common oral disease in human. The immune mechanism plays an important role in the development of periodontitis. In recent years, it has been found that programmed death 1 (PD-1) and its ligands are important molecules involved in immunosuppression. It has been demonstrated that the molecules involved in PD-1 signaling can be expressed on peripheral blood lymphocytes, periodontal ligament fibroblasts and gingival epithelial cells in patients with periodontitis. This article is to discuss the correlation between PD1 signaling pathway and periodontitis.

Jaw bone defects are common in oral maxillofacial surgery, which will lead to abnormality in the function and morphology of maxillofacial region. So bone defect repair is necessary. To avoid secondary injury caused by autogenous bone harvesting, seeking an ideal bone substitute material becomes the present research focus. Dentine material has been paid much attention in recent years because of its similar characteristics to bone and merits of easy availability, simple preparation and good ability to form new bone. Researchers found that decalcification makes dentine material a more effective material which can help bone formation. This paper reviewed the characteristics, mechanism of bone formation and clinical application of decalcified dentin matrix.

Patients with cleft lip and palate frequently present with developmental defects in teeth and maxillary bone. They are affected by many factors, which are very complicated. The preoperative and postoperative perioral muscle pressures of patients with cleft lip and palate are different from those of healthy people. Many scholars believe that one of the factors leading to defects in teeth and maxillary bone is the soft tissue tension change after the operation. Now the research status of the oral peripheral force in patients with cleft lip and palate will be reviewed.

Maxillary protraction is often applied into the treatment of skeletal Class Ⅲ malocclusion caused by maxillary deficiency, which can effectively guide maxillary to grow forward and improve maxillary dysplasia of patients. Recently, with the development of technology, maxillary protraction with miniscrew implant applied in the treatment of skeletal Class Ⅲ malocclusions has been more widely accepted. This article made a brief review on the research progress of clinical procedures of maxillary protraction with miniscrew implant, including the placement of implant, protraction force and angle, the time of treatment, and the stability of treatment effect.

Dental caries can not only reduce childrens oral chewing function, but also affect the growth and development of the whole body of children. According to the results of the fourth national oral health epidemiology survey, the caries rate of deciduous teeth in children aged 5 increased by 5.9% compared with ten years ago, and the caries rate of permanent teeth in children aged 12 increased by 9.6%. Therefore, the prevention of caries in children is imperative. With the emergence of new materials and new technologies, the preventive measures for dental caries in children are changing. In this paper, the methods of preventing caries in children with different mechanisms are summarized.

Lowlevel laser therapy (LLLT) is the direct application of photobiomodulation to accelerate wound healing, reduce inflammation, and induce analgesia. A large number of studies have confirmed that it has achieved satisfactory results in the treatment of muscle damage, degenerative diseases and motor dysfunction. So far, its application in maxillofacial tissue is limited. This article briefly reviews the application and treatment prospects of lowlevel laser in oral and maxillofacial surgery.

Saliva is the external environment of teeth. The changes in organic components, inorganic components, buffering capacity, secretion velocity and flow of the saliva have significant effects on the eroding risk. Knowing the saliva factors that affect the risk of tooth erosion can targetedly detect saliva. It can detect susceptible people early, help early diagnosis of erosion, and make preventive measures as early as possible. This paper reviews the research progress in the study of saliva factors that affect the risk of tooth erosion.

Paranasal sinuses are located in the mid of the craniomandibular complex, including maxillary sinus, frontal sinus, sphenoid sinus and ethmoidal sinus. Paranasal sinuses take up most of the craniomandibular complex and exploring the relationship between the sinus and malocclusion is helpful to estimate the stability of craniomandibular structure. And this relationship is gradually clarified with the development of finite element technology and imageology. The maxillary sinus volume is positively correlated with the size of maxillary body, that is, the average volume of maxillary sinus is bigger in Class Ⅱ than Class I and Class Ⅲ. Vertically, the function stimulation to the maxillary sinus bottom is insufficient in the increasedFMPA patients with the weak masticatory muscle strength, resulting in the lower position of the maxillary sinus bottom. The size of frontal sinus is closely related to the occlusion of anterior teeth. The normal overjet and overbite induce a smooth flow to the sinus so it is smaller. The research on the relationship between sphenoid sinus, ethmoid sinus and malocclusion is still lacking. To explore the mechanical relationship between the sinus, craniomandibular complex and the maxillofacial system is helpful to determine whether the relationship between the maxilla and mandible is balanced and stable, which has some guiding values for the occurrence, treatment and prognosis of malocclusion.