It is possible to regenerate a tooth with new paradigm based on tissue engineering and regenerative medicine. However, a regenerative tooth can not survive in vivo or be applied in clinic, since periodontal diseases widely decrease the potential of regenerative teeth. Up to date, the treatment for periodontal diseases in clinic could not recover the regeneration capacity of periodontium successfully, probably because the function ofthe key cellsperiodontal ligament stem cells (PDLSCs) are not fully understood. The PDLSCs are similar as bone marrowderived mesenchymal stem cells (BMMSCs), but more easily attracted by inflammation. Therefore, how to protect the cells against the inflammatory cytokines become a key problem for periodontal regeneration. On one hand, tissue engineering and cell aggregate system can realize the periodontium regeneration under inflammatory microenvironment successfully. On the other hand, BMMSCs canbe recruited into defect part of periodontium and take part in the regeneration process. Therefore, both endogenous and exogenous therapies for periodontium are important for not only clinical treatment but also scientific research.

Objective To explore the effect of porphyromonas gingivalis lipopolysaccharides (P.gLPS) on the expression of CD36 and LOX1 macrophages derived from THP1.Methods THP1 cells were cultured in the presence of 160 nmol/L phorbol 12myristate 13acetate (PMA) for 48 h.An cocultured in vitro model of P.gLPS and THP1 macrophage cells was constructed.In the presence of LDL (50 μg/ml),macrophage cells were incubated with P.gLPS (0.1,1,10 μg /ml) for 48 h or with 1μg/ml P.gLPS for 24,48,72h.The expression of CD36,LOX1 at mRNA and protein levels was determined by real time PCR and Western blot.Results THP1 cells were differentiated into macrophages after the addition of PMA for 48h.P.gLPS downregulated the mRNA and protein expression of CD36 as concentration increased and time extended in the presence of LDL (P<0.05).However,P.gLPS had no effect on the expression of LOX1 at mRNA and protein levels compared with control group.Conclusions P.gLPS downregulated CD36,but had no effect on the expression of LOX1,which may contribute to the excessive accumulation of cholesteryl esters and conversion to foam cells in macrophages.

Objective To evaluate the effects of MTA on the expression of receptor activator of NFκB ligand (RANKL) and osteoprotegerin (OPG) in human periodontal ligament stem cells (PDLSCs).Methods First,PDLSCs were cultured separately by enzyme digestion.Then,PDLSCs were cultured in αMEM medium supplemented with different concentrations of MTA conditioned medium and the optimal concentration of MTA conditioned medium was determined by alkaline phosphatase (ALP) activity.PDLSCs cultured in αMEM (control group),MTA conditioned medium containing 2 mg/mL MTA for 3 days and 7 days were respectively collected to evaluate the expression of RANKL and OPG at protein level by Western blot.Results For PDLSCs cultured in MTA conditioned medium for 3 days and 7 days,expression of OPG was all higher than that in control group,while expression of RANKL was all lower than that in control group.Conclusions MTA can regulate the odonto/osteogenic and odonto/osteoclastic potential of PDLSCs through RANKL/OPG system.

Objective To explore the changes of porphyromonasgingivalis and its virulence factor gingipain K during orthodontic treatment.Methods Totally 45 orthodontic healthy teenagers were randomly chosen from the orthodontics department.Givgival crevicular fluid before orthodontic treatment,in the first, second, third and sixth month after treatment were collected simultaneouslyat each time point.16S rDNA PCR technique was used to detect porphyromonasgingivalis and its virulence factor gingipain K.SPSS 17.0 software package was used to analyze the data.The detection rates of porphyromonasgingivalis and gingipain K between groups were compared by χ2. The correlation of the detection rates and gingival inflammation was analyzed by Spearman.Results Porphyromonasgingivalis before treament was significantly different form that in the first month after treatment (P<0.05), and demonstrated extremely significant difference from that in the second and third month(P<0.01). Difference was also found between the first month after treatment and the second month after treatment.As for gingipain K,there was no difference before treatment,the first month after treatment and the sixth month after treatment，while statistical difference was found between the second month after treatment and the third month after treatment（P＜0.05）.Since the third month after treatment,the rate of porphyromonasgingivalis and gingipain K had decreased，and in the sixth month after treatment,it approached the level before treatment.Conclusions During the early process of orthodontic treatment,porphyromonasgingivalis and gingipain K may increase and can lead to inflammatory reaction.Started from the second month after treatment,it began to decline and it basically approached the level before treatment in the sixth month.

Objective To study the color stability of prosthesis silicone elastomer covered by different concentrations of silica alumina coated nanoTiO2 membrane cap,and to improve the effectiveness of facial prostheses silicone rubber color stability with this method so as to provide a theoretical basis.Methods MDX44210 silicone elastomer as substrate,nanoTiO2 coated with Si and Al as masking agent,and cadmium red oil paint as coloring agent,L* a* b* values of specimen were observed when stamped with 1mm thickness,different concentrations (0,0.05%,0.10%,0.15%) of silica alumina nanoTiO2 coated silicone rubber membrane before and after aging.Results As the concentration of silica alumina coated nanoTiO2 decreased,ΔE,ΔL*,Δa*,Δb* values of 0.10% group were the lowest,but the those of 0.15% group increased,and there was a significant difference between groups (P<0.05).Conclusions Coating nanoTiO2 membrane cap with different concentrations of silica alumina has a certain role in delaying fade prosthesis silicone elastomer,which provides a new idea for improving color silicone elastomer prosthesis stability.

Objective To evaluate the remineralization of initial enamel caries on primary teeth by three children′s nonfluoride toothpastes.Methods 50 artificial caries models were created from primary teeth,which were then randomly distributed into 5 groups,namely bioactive glass group,Shuanghuanglian group,xylitol group,NaF group,and deionized water group.The specimens were subjected to a PHcycling regime for 7 days.Surface enamel microhardness was measured by microhardness tester,and morphologic changes of enamel carious lesions were detected by polarized light microscopy.Results Surface microhardness of bioactive glass group was significantly higher after remineralization (P<0.05),but not as much as that of NaF group (P<0.05).Meanwhile,microhardness didn′t improve in xylitol group,Shuanghuanglian group or deionized water group (P<0.05).Polarized light microscopy showed the depth of demineralization lesion obviously reduced in both bioactive glass group and NaF group.Conclusions Bioactive glass children′s toothpastes can obviously promote the remineralization of initial enamel caries on primary teeth,but the remineralization ability is inferior to that of NaF toothpastes.Besides,Shuanghuanglian children′s toothpastes and xylitol children′s toothpastes demonstrate no ability of remineralization in this research.

Objective To study the variation of the surface color of a new type of titanium alloy in simulated oral environment surface,and to provide clinical guidance for patients who have received titanium implant therapy or wear denture.Methods Titanium chips were prepared and divided into eight groups randomly.CIE L*a*b* of each specimen was examined by SPSS software before and after treatment.Results The surface color of the brushing group was more evident than that of the nonbrushing group (P＜0.01).The surface color change of Fluoridecontaining toothpaste group was more than that of nonfluoridecontaining toothpaste group,but the change was not statistically significant（P＞0.05）.pH value had a significant interactive effect with fluoride ionic concentration（P＜0.05）.Conclusions pH,fluoride ionic concentration,and tooth brushing all have an effect on the degree of corrosion.

Objective To study the effect of four different solutions:5.25% NaOCl,0.9% NaCl,17% EDTA,3% H2O2 and the blood on the accuracy of ProPex apex locator.Methods Fortyfive extracted teeth with single straight canals and completed foramina were selected to record the ideal actual measurements and then were taken on a normal saline agar model to mimic the situation in vivo.Fortyfive single canals teeth filled with 5.25% NaOCl,0.9% NaCl,17% EDTA,3% H2O2 and blood were used to record the experimental measurements with the ProPex apex locator.Results The accuracy of ProPex apex locator was not affected by different canal contents and the measurements of each group were not statistically different(F=1.959,P=0.090,P>0.05).Conclusions Canal length measuring accuracy of ProPex is not affected by the contents of the root canal.

Objective To observe anterior and overall Bolton Indexes of different Angle classifications.Methods 1 276 adolescent models were collected.After measurements,anterior and overall Bolton Indexes were calculated,and comparisons among different Angle classifications were made.Results Both anterior and overall Bolton Indexes of male and female Angle Class Ⅲ were significantly higher than that of male and female Angle Class I.Anterior Bolton Index of male Angle Class Ⅱ Division 1 was significantly lower than that of male Angle Class I.And anterior Bolton Indexes of female Angle Class Ⅱ Division 1 and Division 2 were both significantly lower than those of female Angle Class I.Conclusions Differences existed among Bolton Indexes of different Angle classifications.

Objective To study the influence of Eysenck personality factors on anxiety and pains in patients with orthodontic microimplant anchorages by questionnaires,and to analyze the psychological reactions of these patients.Methods 117 patients,before treated with orthodontic microimplant anchorages,were investigated by the Eysenck personality questionnaire (EPQ) and modified dental anxiety scale (MDAS).Pains were measured by the visual analogue scale (VAS) during early,intermediate and late periods of the implantation.Data was statistically analyzed after the questionnaire investigation.Results N score of Eysenck personality factors of patients with orthodontic microimplant anchorages was positively correlated with dental anxiety but negatively correlated with E score（P=0.000）,and shared no correlation with P and L standard score（P=0.524,P=0.293）.E standard score was negatively correlated with pain,positively correlated with P and N standard score（P=0.000）,and shared no correlation with L standard score（P=0.501）.There was a significant difference in VAS between patients with dental anxiety (MDAS≥11) and patients without dental anxiety(MDAS<11)(P=0.000).Conclusions Different personalities will affect the state of anxiety and pain sensitivity in different periods of the implantation.To improve the curative effects,proper psychological counseling is needed.

Objective The objective of this study was to evaluate adult′s satisfaction after orthodontic treatment,and to identify factors that may affect patients′ satisfaction.Methods Dental impact on daily living(DIDL) questionnaire and Eysenck Personality Questionnaire(EPQ) were used to evaluate the satisfaction of patients after orthodontic and their psychological characteristics respectively.Results 27.0% subjects were totally satisfied with their teeth,while 11.5% subjects were dissatisfied.The extraversion score was positively related to overall satisfaction.The neuroticism score was negatively related to overall satisfaction,general performance satisfaction and oral comfort satisfaction.Conclusions Age,gender,treatment time and extraction therapy were unrelated to satisfaction after orthodontic treatment,while personality and satisfaction were correlated to each other.Patients with high neuroticism scores were likely to be dissatisfied with the orthodontic effects,while patients with high extraversion scores were easy to get satisfied.

Objective To explore risk factors of the relapse of post orthodontic treatment so as to help prevent relapse.Methods A total of 128 patients,who finished orthodontic treatment in 2006,were retrospectively examined.A single factor analysis was used for 10 possible risk factors including gender,patient compliance,cheek or tongue position of root,age of finishing treatment,alveolar bone height and periodontal membrane inflammation,patient management after the treatment,retainer type,occlusion,parallel of root,and treatment time.Based on single factor analysis,the multifactor unconditioned logistic regression analysis was made.Results The results of logistic regression analysis revealed 3 statistically significant risk factors:the management for patient after the treatment (OR=7.77),the occlusion at the end of treatment (OR=4.54),and the compliance of patient (OR=3.53).Conclusions Reasonable management after the treatment,stable occlusion,and good compliance contributed to reducing the risks of the orthodontic posttreatment relapse.

Objective To investigate the clinical effect of Disc Anchorage for anterior disc displacement without reduction according to MRI.Methods Disc Anchorages were applied on 15 patients (20 sides) of Anterior disc displacement without reduction according to clinical symptoms and MRI.Results Postoperative MRI showed that among the 15 cases(20 sides) of Disc Anchorage,12 cases(16 sides) achieved excellent result,2 cases(3 sides) achieved good result,and the effective rate was 95%.Only 1 side was “poor pressing”,accounting for 5 %,which had longer course,serious deformation of TMJ disc morphology,and shortened length of disc.A clinical followup of all patients was carried out 3 months,6 months and 12 months after surgery,to compare the pain,mouth opening,degree of lateral movement changes before and after surgery.Conclusions Disc Anchorage has a significant effect on anterior disc displacement without reduction.

Objective To evaluate the clinical effect of closed internal sinus floor elevation on the dental implantation and restoration of patients who suffer from bone dificiency in the maxillary posterior area.Methods 20 patients lack of alveolar bone height underwent closed maxillary sinus floor lifting and 27 implants were implanted in the same period.The followup period was at least 12 months.Another 20 patients who were under the similar condition were chosen as control group,receiving open maxillary sinus floor lifting and simultaneously implants placement.Results During the followup period,all the 26 implants showed good osseointegration and implant prosthesis achieved good clinical effect;1 implant became loose during the secondstage surgery.The success rate of implants was 96.30%.The amount of bone absorption in the experimental group was smaller than that in the control group(P＜0.05).Conclusions Closed maxillary sinus floor lifting with simultaneous implant placement can shorten clinical treatment time,achieving high success rate and better clinical effect.

Objective To evaluate the clinical outcomes and prosthetic complications of mandibular twoimplant overdentures retained with ball attachments over 3 years.Methods 10 patients with severely reabsorbed mandibular edentulous jaws were treated with delayloaded mandibular twoimplant overdentures retained with ball attachments 3 months after the implants were placed in the mandibular anterior region with good consistency in the horizontal level,angulation,and distance from the midline.The implant survival rate,periimplant tissue status,prosthetic complications and patients′ satisfaction were evaluated 1 week,1 year,2 years and 3 years after overdenture rehabilitation.Results Over 3 years′ rehabilitation of mandibular twoimplant overdentures retained with ball attachments,no implants failed,the overall marginal bone loss was lower than 1mm,the mucosal conditions were healthy,and the patients′ satisfaction was significantly improved and remained high over time.The most common prosthetic complications were replacement or reactivation of an attachment matrix,and the frequency of prosthetic maintenance per patient per year was 0.67 during the 3year observation period.Conclusions Mandibular twoimplant overdentures retained with ball attachments are a viable treatment modality with good longterm clinical outcomes,on condition that the placement of implants is well designed.

Objective To evaluate the clinical effects of molars root canal preparation using Waveone.Methods The single file Waveone with crowndown technique was used to prepare 67 teeth and the stainless steel K files were used to prepare 54 teeth with the stepback technique.The lateral condensed technique was employed to fill the root.The root canal preparation time,instrument separation and root canal filling were compared.Results The successful rate of root canal filling in Waveone group was 91.1% and that of the control group was 66.7%.So the rate of Waveone was better than that of the control group(P＜0.01).The root canal preparation time of the group using Waveone was (17.76±1.96) mins and that of the control group was (33.82±2.37) mins.The time of Waveone group was shorter than that of the control group(P＜0.01).Conclusions Root canal preparation with Waveone shortens the time and has good shaping and obturating effects.

Objective To investigate whether the risk of diabetic foot is correlated with periodontal disease (PD).Methods 110 patients with diabetic foot and periodontal disease were investigated and another 102 nondiabetic patients with periodontal disease from the project within the hospital dental clinic of similar condition were randomly selected as the control group.Logistic regression model was used to adjust potential confounding factors.As for the PD risk factors involved in this study such as age,duration of diabetes,patients with oral health and education level,etc,Windows SPSS 12.0 was employed for statistical analysis.Results Age,diabetes duration,oral health care and education level were of statistical significance.After the adjustment of gender,age,duration of diabetes,oral health care and education,PD and dentition defect were independently related with diabetic foot.Conclusions The risk of diabetic foot is strongly associated with periodontal disease.

Objective To study the pathogenesis mechanism of oral candida in patients with head and neck cancer undergoing radiotherapy from the perspective of virulence change.Methods In vitro phospholipase activity, hemolytic activity and adhesion to buccal epithelial cells of oral candida isolated from oral cavities of subjects with head and neck cancer undergoing radiotherapy were measured.Results Oral candida in the candida infection group and the candida colonization group after radiotherapy were detected.The phospholipase activity and adhesion ability to BEC showed no significant difference (P>0.05) in the candida infection,colonization group and the control group after radiotherapy. Secreted hemolysin in the candida infection group after radiotherapy was significantly higher than that of the other two groups (P<0.05) ; secreted hemolysin in the candida colonization group after radiotherapy and the control group showed no significant difference (P>0.05).Conclusions The change of hemolytic activity of oral candidia may be one of the pathogenic factors in head and neck cancer patients who had received radiotherapy.

Objective To assess the clinical efficacy of a new instrument in lateral window maxillary sinus lifting.Methods 34 patients with 51 posterior teeth lost were augmented with lateral window maxillary sinus lifting,22 patients using Dentium Advanced Sinus Kit as the experiment group and 12 patients using common ball drill as the control group.Then the sinus floor was elevated,filled with artificial bone,and the implant was inserted simultaneously,covered with biological membrane.The time of lateral window,the membrane perforation rate,patients′ subjective feeling during operation and the postoperative reaction three days after operation,as well as the situation of sinus and osseointegration of implant while finishing restoration in two groups were compared.Results ①The time of lateral window in the experiment group（(7.34±0.72) minutes) was less than that in the control group ((17.84±1.29) minutes).②The membrane perforation rate of the experiment group was 0,which was less than the control group (16.7%).③The painful and swelling feeling in the experiment group was slighter than that in the control group.4.All cases had no sinusitis and the bone resorption was less than 1mm.Conclusions The application of DSAK in lateral window maxillary sinus lifting could shorten the surgery time obviously with low membrane perforation rate and slighter postoperative reaction.It is safe ,quick and effective.

Objective To explore the influence of root canal retreatment procedures on the appearance of defects on the root canal walls.Methods One hundred and sixty premolars extracted for orthodontics were randomly divided into two groups with 80 in each group.They were treated and retreated a month（A group） and half a year(B group) after extraction.Forty teeth （A1 group）in A group were treated and the other 40 (A2 group) were retreated at random,and B group was divided into B1 group and B2 group in the same way.Among retreated teeth,twenty teeth filling materials were removed by ProTaper retreatment files only(A21 group，B21 group) and the other twenty teeth were removed by ProTaper retreatment files with chloroform（A22 group，B22 group）.Roots were then sectioned and inspected under a microscope.Results Retreatment groups showed significantly more defects than the initial treatment group.There was difference in the appearance of defects after retreatment between ProTaper retreatment files only group and chloroformsupplied group.Conclusions Retreatment procedures result in more defects than initial treatment.When assessing the outcomes of endodontic retreatment,the substantial damage to the root canal walls should be considered.

Epithelioid hemangioenodthelioma(EH) is a rare malignant or borderline vascular tumor.In this paper,the clinical symptoms,physical signs,pathological features,immunohistochemical staining findings,imaging features as well as the outcome of the patient with epithelioid hemangioendothelioma were reported,and with review of the literature,the differential diagnosis and therapy of EH were summarized.

Plateletrich fibrin(PRF) is a concentrated source similar to a natural blood clot that contains rich cytokines and growth factors.Due to its function in helping repair tissue defects,PRF has been widely accepted in experimental and clinical studies.This article reviewed the research progress of the preparation of the PRF,its physiological characteristics,and its application in tissue repair.

With the development of web technology and the electronic information,medical education has entered the era of electronic information.Medical education is advancing，and ELearning is not a new concept for most in the medical profession.However,it is rarely mentioned in teaching of oral and maxillofacial surgery.ELearning with its powerful update speed and the diversity of learning materials,can cater to the development of oral and maxillofacial surgery teaching.This article introduced the development,characteristics,application and investigation of ELearning teaching in oral and maxillofacial surgery teaching,providing a reference for ELearning teaching in medical colleges and universities.

Alveolar bone is an important component of periodontal tissues,and plays a significant role in oral physiological functions.Alveolar bone has high plasticity,which can change as the tooth grows and falls off,and the chewing pressure changes.By now,a large number of studies have demonstrated that many cytokines have important influences on the remodeling of the alveolar bone,including bone resorption and bone regeneration.Cytokines such as BMP2 and PTH can help mesenchymal stem cells differentiate into osteocytes,which promotes the new bone formation.And cytokines like IL1 and TGFβ can accelerate the differentiation of monocytes and increase osteoclasts,leading to bone resorption.This article summarizes the research progress on the effects of various cytokines on alveolar bones so as to improve the process of bone remodeling.

Root resorption is a large side effect which occurrs in the course of orthodontic treatment,and early diagnosis of root resorption is important for the prognosis.The purpose of this article was to give an overview of the application of CBCT in the diagnosis of root resorption.The article reviewed three aspects:the cause of root resorption,the technology of the existing research and the application of CBCT in the diagnosis of root resorption,which could afford the reference for the use of CBCT.