Abstract: Objective To test microhardness of artificial caries which was treated by different extracts of Geranium Strictipes R.Kunth,to observe its surface morphology by SEM,and to study the effects of different solvent extracts on remineralization of artificial demineralized enamel.Methods 5 groups of artificial demineralized enamel caries models were established by chemical methods:the group of ethyl acetate extract,the group of butanol extract,the group of water layer extract,20 mg/mL NaF positive control group,and deionized water negative control group.After in vitro pH cycling,microhardness was tested and the surface morphology was observed by SEM.Results Microhardness results showed that after the remineralization treatment by three different extracts and NaF,the enamel hardness in each group significantly increased than that before remineralization （P＜0.05）,while the deionized water group showed no significant remineralization difference （P>0.05）,and comparison between groups was statistically significant （P＜0.05）,denoting the remineralization effects of different extracts of Geranium Strictipes R.Kunth and NaF on demineralized bovine incisors.SEM results showed there was uniform and close precipitation zone in NaF group,loose surface structure in deionized water group,close mineral deposits and a small gap in the group of butanol extract,less mineral deposits and a larger gap in the group of ethyl acetate extract,and regular particle deposits in the group of water layer extract.Conclusions The different extracts of Geranium Strictipes R.Kunth have remineralization effects on artificial demineralized enamel.The best effect was obtained by water layer extract,then butanol extract,and lastly ethyl acetate extract.

Abstract： Objective To observe the effect of TNF-α on the proliferative activity of the tongue cancer cell after the treatment of rhBMP2and on the relevant signal path Smad4 as well as the receptor proteins.Methods To resuscitate the tongue cancer cells,and MTT was adopted to detect the effect of TNF-α on the proliferative activity of tongue cancer cell with or without first treatment of rhBMP2,and meanwhile RTPCR and Western blot were used to observe its impact onthe relevant signal path Smad4 and receptor mRNA and receptor proteins.Results Cell proliferation activity decreased obviously when TNF-α acted on the tongue cancer cell and its effect was more obvious when the cells were first treated by rhBMP2.RTPCR and Western blot indicated that TNF-α can induce the expression of Smad4,BMP2 receptor mRNA and receptor proteins.Conclusions TNF-α can inhibit the proliferation of the tongue cancer cell,and when TNF-α and rhBMP2 act on tongue cancer cell together,the proliferation inhibition is more significant.TNF-α can enhance the expression of Smad4,BMP2 receptor mRNA and receptor proteins.

Abstact：Objective: To investigate the expression of Wnt10b and β-catenin in periodontal tissue during experimental tooth movement in rats. Materials and Methods: 30 Sprague-Dawley (SD) rats’ left maxillary molars movement models were established. The right maxillary molars without force application served as control. At 1, 3, 5, 7, 10, and 14 days after force application, the rats were sacrificed. Immunohistochemical staining was used to investigate the expression of Wnt10b and β-catenin in rats periodontal tissue. Results: The expression of Wnt10b and β-catenin was weak in the periodontal tissue of the control group. In the experimental group, β-catenin expression was significantly higher on both sides at every time point, and Wnt10b expression was significantly higher on both sides at 5, 7, and 10 days. Conclusions: These results indicate that Wnt10b and β-catenin play an important role during periodontal tissue remodeling of orthodontic tooth movement.

Abstract: Objective To investigate the effects of Puerarin with different concentrations on inducing osteogenic differentiation of bone marrowmesenchymal stem cells （BMSCs）,and to explore the relationship between the mechanism of Puerarins osteoinductivity and the Notch signaling pathway in vitro.Methods There divided 6 groups according to the concentration of Puerarin.After segregated and cultivated for 3 weeks,marrow stromal cells of SD rats in induction group were induced by osteogenesis medium containing different concentrations of Puerarin.In noninduction group,BMSCs were still cultured with DMEM medium.After further cultivation for 2-4 weeks,alkaline phosphatase （ALP）and osteocalcin （OC）were measured to evaluate the in vitro osteoinductivity of Puerarin; Delta like ligand 4 （DLL4）was measured by Elisa kit to determine the relationship between the osteoinductivity and Notch signaling pathway.Results Cells of different concentrations showed morphological and biological characteristics similar to those of osteoblasts.The content of ALP,OC,and DLL4 increased.The increase in the 10-5 mol/L group was more than that of the control group with significant difference and that of other groups of different concentrations with no statistical significance.Conclusions Puerarin can induce BMSCs to differentiate into osteoblasts,and the effect is the best with the concentration of 10-5 mol/L.Meanwhile,its mechanism may be related with Notch signaling pathway.

Abstract： Objective To assess the effectiveness of a ACPCPP containing new product in reducing enamel demineralizationon post orthodontic patients.Methods The study design was doubleblind,randomized clinical trial .63 subjects with enamel decalcification（not cavitated）on their upper teeth（14～24，or 15～25）were selected and randomly divided into two groups:the experimental group （31 cases）and the control group （32 cases）.The experimental group used GC Mousse while control group used placebo mousse （without CCPACP）once a day at night after brushing with fluoride dentifrice.The Enamel Decalcification Index（EDI）was used to determine the extent/severity of white enamel demineralizationat baseline,1 month and 3 months after treatment.A oneway analysis of variance （ANOVA）was done with STATA 12.0 software packagefor the average enamel decalcification index scores.Results 58 subjects completed the trial,with 28 in the experimental group and 30 in the control group.Baseline,1 month,3 months EDI of the experimental group were（0.5903±0.2585）,（0.4514±0.2077）,（0.2396±0.1499）,respectively; and those for the control group were （0.5291±0.2494）,（0.4397±0.2068）,（0.3287±0.1757）,respectively.The difference between the experimental group and control group was statistically significant 3 months after treatment.〖WTHZ〗Conclusions The application of CPPACP can help reducing the number/extent of white spot lesions already present after fixed orthodontic treatment.

Abstracts: Objective To evaluate dentin bond strength and nanoleakage of 2single bottle universal adhesives used in selfetch modes.Methods 40 flat dentin surfaces were prepared.Composite resin was lutinged on the dentin surface using 2 different adhesives （Singlebond Universal,AllBond Universal）in selfetch mode.Half bonding specimens were stored in water for 24 h （not aging）,and half were subjected to 10,000 times thermocycling （aging）.Then all the specimens were sectioned into composite/dentin beams to submit to microtensile bond strength （μTBS）testing.Data were statistically analyzed by Oneway ANOVA and Tukeys test （α=0.01）.Respective adhesive interfaces and nanoleakage were evaluated by SEM.Results Both groups showed a μTBS more than 30 MPa.No significant difference existed between the 2 adhesives.10,000 times thermocycling decreased μTBS of both adhesives.SEM showed nanoleakage in both groups.Conclusions The 2 adhesives provide high bond strength to dentin in selfetch mode.However,nanoleakage still exists.

Abstract: Objective To compare the effect of different kinds of lasers on microtensile bond strength of noncarious sclerotic dentin.Methods Thirty human molars with occlusal wear were randomly divided into group E,group N and the control group.Group E were treated with Er,Cr:YSGG laser,while group N were treated with Nd:YAG laser.Then all three groups were treated with Adper Prompt LPop,filled with Z350 resin,and preserved in normal saline （37 ℃）for 24 h.Then fatigue test pieces were made and the microtensile bond strength was evaluated.Results were subject to statistical analysis using oneway analysis of variance （ANOVA）.Results The bonding strength was （24.71±3.13）MPa in group E,（21.72±2.36）MPa in group N,and （18.61±2.01）MPa in the control group.The differences among all groups were statistically significant （P＜0.05）.The breakage mostly happened in adhesive dentine surface.Conclusions The bonding strength of molars to Z350 resin can be increased by Er,Cr:YSGG laser and Nd:YAG laser,and the former is more effective.

Abstract: Objective To study the influence of two low noble metal alloys for dental restorations on MRI.Methods Anhydrite model for full crown preparation of low right second premolar was prepared.Porcelainfusedtometal （PFM）crown and ceramic crown were made from silverpalladium （AgPd）,goldpalladium （AuPd）,cobaltchrome （CoCr）and zirconia,with 8 samples for each type.The samples were subjected to magnetic resonance imaging （MRI）examination.The areas of MRI artifacts were measured and then analyzed with SPSS16.0 Statistic Software.Results Conspicuous artifacts were found in all the materials in GRE sequence,and crown structures could hardly be discriminated.In SE and TSE sequences,the artifact area in CoCr PFM crown was larger than that in AgPd and AuPd PFM crowns,and the difference was statistically significant.Besides,the difference of artifact areas between AgPd and AuPd PFM crowns demonstrated no statistical significance.Conclusions There are no conspicuous MRI artifacts of AgPd and AuPd PFM crowns in SE and TSE sequences,which is preferable in clinic.

Abstract: Objective To investigate the impacts of ceramic restoration splinting on severe periodontitis and oral healthrelated quality of life in Chinese patients.Methods 104 Chinese patients with severe chronic periodontitis were selected to complete a questionnaire of 14item Oral Health Impact Profile （OHIP14,Chinese version）and an inventory on self evaluation of periodontal health at the following four time points:pretherapy （T0）,1 month （T1）6 months （T2）,and 12 months （T3）after the placement of the ceramic restoration splinting.The patients gingival index （GI）and plaque index （PLI）were also measured during the four time points.Results Significant differences of average OHIP14 scores were found between T1 （15.63.0）and T0 （33.73.1）（P 0.01）,T2 （10.32.8）and T1 （P<0.01）,but not between T3 （7.92.5）and T2 （P>0.05）.Compared to T0,the score of each item and the percentage of positive response of the patients in OHIP14,and the ratio of oral healthrelated symptoms significantly decreased after therapy （T1,T2,T3）.Meanwhile,there were significant differences in GI and PLI between posttherapy （T1,T2,T3）and T0 （P<0.01）.Conclusions Ceramic restoration splinting has significant therapeutic effects on severe periodontitis and can reduce periodontal healthrelated symptoms and the degree of their impacts on oral health,thus improving oral health related quality of life.

Abstract: Objective To evaluate the incidence of pain and inflammation after treating acute apical periodontitis of deciduous teeth using pulp open or cover treatment at the first time.Methods 100 patients with acute apical periodontitis were randomly allocated to two groups. One was pulp open group, and the other was cover treatment group, 50 cases in each group. In the pulp open group, the dental cavity was conventionally opened, the dental pulp was extracted using H file, the pulp chamber and infected sloughs in the root canal were cleaned, then the root canal was douched, the occlusion was lowered, and the dental cavity was open with cotton ball in. In the cover treatment group, the dental cavity was conventionally opened, inflected sloughs were eliminated, K file was used for root canal preparation to No.35, then the root canal was douched, and was covered with CP (camphor phenol) cotton ball after the exudation became low. The relief of pain at 24th h and of inflammation on 7th d were observed. Results There were obviously difference between two groups about pain and on the changes of inflammation.Conclusions The treatment by opened can reduce the pain in a short time, but the cover treatment can effectively prevent to develope into chronic periodontitis during root canal therapy on acute apical periodo ntitis.

Abstract: Objective To assess the diagnostic accuracy of cone beam computed tomography in comparison with radiography in detecting periapical lesions. Methods 35 patients (41 teeth) diagnosed with periapical lesions were selected. Digital radiographs and CBCT images were used to scan the teeth, and the diagnostic accuracy was judged afterwards. Results The overall accuracy for detecting periapical lesions was higher for CBCT compared with the digital radiographs. According to the CBCT images, 37 teeth showed periapical shadows, while only 27 teeth showed periapical shadows by digital radiographs. Conclusions The CBCT technique has higher accuracy than digital radiographs, which can help diagnose intractable cases in clinic.

Abstract: Objective To discuss the treatment effect of using mineral trioxide aggregate (MTA) to fill the crack of incomplete vertical root fracture in periodontal flap surgery.Methods 6 teeth with incomplete vertical root fracture were made to undergo a periodontal flap surgery so as to expose the pattern of the root fracture.After the inflammatory tissues were removed,the root fracture was abraded,and the fracture line was filled with MTA.Periodic review was done during the following 3rd,6th and 12th month.Results One tooth was extracted because of its complete root fracture in the surgery; the other 5 teeth underwent the surgery as planned.In the 3rd,6th and 12th months followup,all the 5 cases showed clinical and radiographic success.Conclusions The present surgical approach for preserving teeth with incomplete vertical root fracture demonstrated satisfactory results regarding the clinical outcome.

Abstract: Objective To investigate changes of the upper airway dimensions before and after using stepwise Twinblock appliances （TB appliance）in young adult patients with mandibular retrognathia malocclusion.Methods 13 Angle class II division I patients with mandibular retrusion in mixed dentition or early permanent dentition were treated with stepwise Twinblock appliances.Cephalometric analysis was made before and after treatment.Results After the treatment,PNSR,SPPSPPW,UMPW,PAS,VLPW,HMP,HC3Me,HCVP,TGI,TGH,SPL,SPT increased significantly （P<0.05）,while PNSAd2 increased with no statistical significance （P＞0.05）.Conclusions Stepwise TB appliances can enlarge the patients upper airway and thus effectively improve the airway ventilation in the treatment of mandibular deficiency.

Abstract: Objective To study the clinical satisfaction and the success rateof a new style improved vacuum formed space maintainer and its influence on periodontal tissue compared with traditional band and loop space maintainer.Methods 40 patients with the need of maintaining space were divided into 2 groups randomly,each wearing one kind of space maintainers.Visual Analogue Scales （VAS）was used to evaluate the degree of comfort wearing different space maintainers after 4 weeks.Plaque indexes,gingival indexes and probe depth of the lower first molar,and the success rate of the space maintainer were recorded after 4 weeks,8 weeks and 12 weeks respectively.All data were subject to ttest and χ2 analysis.Results The degree of comfort when wearing improved vacuum formed space maintainer was obviously higher than that when wearing traditional band and loop space maintainer and the periodontal index was also better （P＜0.05）.The success rates of two groups were not statistically different （P>0.05）.Conclusions Improved vacuum formed space maintainer is more favorable compared with traditional band and loop space maintainer and is more effective in reducing the influence on periodontal health.

Abstract： Objective To assess the effectiveness of a ACPCPP containing new product in reducing enamel demineralizationon post orthodontic patients.Methods The study design was doubleblind,randomized clinical trial .63 subjects with enamel decalcification（not cavitated）on their upper teeth（14～24，or 15～25）were selected and randomly divided into two groups:the experimental group （31 cases）and the control group （32 cases）.The experimental group used GC Mousse while control group used placebo mousse （without CCPACP）once a day at night after brushing with fluoride dentifrice.The Enamel Decalcification Index（EDI）was used to determine the extent/severity of white enamel demineralizationat baseline,1 month and 3 months after treatment.A oneway analysis of variance （ANOVA）was done with STATA 12.0 software packagefor the average enamel decalcification index scores.Results 58 subjects completed the trial,with 28 in the experimental group and 30 in the control group.Baseline,1 month,3 months EDI of the experimental group were（0.5903±0.2585）,（0.4514±0.2077）,（0.2396±0.1499）,respectively; and those for the control group were （0.5291±0.2494）,（0.4397±0.2068）,（0.3287±0.1757）,respectively.The difference between the experimental group and control group was statistically significant 3 months after treatment.Conclusions The application of CPPACP can help reducing the number/extent of white spot lesions already present after fixed orthodontic treatment.

Objective To explore influences of different membrane materials for oral rehabilitation on bone regeneration in tooth implantation, and to cary out analysis on it.Methods Sixty four patients undergoing tooth implantation and bone regeneration admitted by the outpatient and inpatient department of this hospital from April, 2013 to April, 2014 as research subjects, they were divided into the observation group and the control group according to different membrane materials for oral repair, patients in the observation group were subject to the guidance of bone regeneration by Bio - Gide bio-film, while patients in the control group were subject to the guidance of bone regeneration by titanium membrane, the conditions, thickness of bone implantation, bone thickness upon 1W and the occurrence of adverse reactions of patients with repair of success in two groups, and the analysis and comparison were carried out. Results The success rate of surgical repair of patients in the observation group hit 100%, the comparison in success rate of surgical repair of patients in the control group hit 81.25%, the comparison in success rate of surgical repair of patients in two groups hitχ2=6.5172（p=0.0107）, the comparison in the density of bone grafting of patients in two groups hit t=5.2894（p=0.0000）, the comparison of bone thickness of patients in two groups hit t=6.2960（p=0.0000）, the comparison in total incidence of adverse reactions of patients in two groups hitχ2=6.5172（p=0.0107）, and the difference was statistically significant.Conclusions Bio - Gide bio-film delivers significant guiding effects on the bone regeneration in the application of tooth implantation surgery and high success rate of surgeries, the re-establishment of alveolar bone appearance makes for the growth and development of implanted bone and bone, being of high value of clinical use.

Abstract: Objective evaluation of lateral incisor lingual dislocation lines zirconia all-ceramic restorations long-term efficacy and aesthetic effect. Methods selected 106 cases from April 2012 to May 2014 in our hospital dentistry treatment of (130) lateral incisor lingual errors were randomly divided into experimental group and control group, the experimental group 53 cases (68) take zirconia all-ceramic restorations, the control group 53 cases (62) take the nickel-chromium alloy porcelain repair, follow-up of 2 years, two groups of patients to evaluate the effect of the restoration of the two groups of patients for aesthetic effect repair satisfaction to investigate the situation. Result at 2 years, the experimental group patients prosthesis shape, color matching, gums and tooth sensitivity adaptability pass rates were 97.1% and 100.0%, 94.1% and 94.1%, were higher in patients, the differences were statistically significance (P <0.05); experimental group patients satisfaction aesthetic effect prosthesis was 98.1%, significantly higher than 81.1%, the difference was statistically significant (P <0.05). Conclusion Zirconia applied lateral incisor lingual dislocation repair can effectively improve the long-term efficacy and aesthetic effects in patients, improve patient satisfaction with aesthetic effect.

Objective To explore the application of computer-assisted implant guide in inclined implant surgery. Methods From February 2011 to January 2014, after conventional CT scanning of maxillary and mandible, the software modeling was made with the assistance of computer, and 13 cases with inadequate bone mass in maxillary were selected to undergo an inclined implant surgery. Individualized implant models were made by rapid prototyping for 21 implants in total and were applied in the surgery. Results Inclined implant surgeries were operated by using computer-assisted implant guide. The accurate implantation was accomplished thanks to preoperative designs for the location of implants so that favorable occlusion was formed, which was consistent with the preoperative designing scheme. Conclusion Instead of sinus elevation, inclined implant surgery using computer-assistant implant guide is a relatively safe choice for the location and guiding of surgeries in the area where bone mass is inadequate.

Abstract: Objective To study the effects of MIA （miniimplant anchorage）combined with traction hooks with different heights on the movement of anterior teeth in order to better use the MIA in orthodontic treatment.Methods 24 patients with severe maxillary protrusion were randomly divided into experimental group and control group,each containing 12 patients.The patients were treated with MIA and straight wire appliance by sliding mechanics to retract anterior teeth and narrow the extraction space.2 mm hooks in experiment group and 6 mm hooks in control group were used for retraction.Cephalometric radiographs were collected before and after the anterior teeth retraction and ttest was used to analysis the data.Results 0.31 mm maxillary molar mesial movement was observed in both groups and the anterior teeth were retracted effectively and uprighted.In the experiment group,anterior teeth were intruded about 1.82mm,while anterior teeth were protruded about 1.05 mm in the control group.Conclusions As the height of traction hook increased,the elongation tendency of anterior teeth increased during the retraction process,and the lingual movement of the maxillary anterior teeth decreased.In the clinical treatment,the traction hooks with different heights should be used according to the specific malocclusion.

Objective To investigate dental patients’satisfaction for the medical service in the main hospitals of Hangzhou. Methods The patients were divided into four groups as teenagers, youths, middle-ages and old-ages. A self-designed questionnaire survey was conducted among the patients at random, which included patients’satisfaction and opinions towards the service of the doctors and nurses, such as techniques, attitudes, environments, charges and so on. Results This survey’s effective rate was 98%. The courtesy of the reception staff, the nursing service and the doctors’operation techniques got the highest satisfaction from the old patients. 45.4% of the young patients expressed that they had a slight discomfort when treated, which topped the four groups. More than 98% of the patients thought they had got the relevant advice on oral health nursing. As for the waiting time, the four groups agreed that it was fair. Conclusion On the whole, patients in Hangzhou felt satisfied with the main hospitals’dental medical service. It was suggested that dental consulting rooms should be set up and the professional levels be improved.

Abstract： Objective To investigate the prevalence and risk factors of dentine hypersensitivity of rural adults in Ji’ning City, Shandong Province, and to provide the basis for diagnosing, preventing and treating the disease. Methods 1200 adults from the rural areas of Ji’ning were selected by multi-stage, stratified and random sampling. The dentine hypersensitivity of all samples was surveyed with questionnaires and on-the-spot oral examinations. SPSS 13.0 software was used for statistical analysis. Results According to the questionnaires, 43.25% of the rural adults in Ji’ning City suffered from dentine hypersensitivity, while according to on-the-spot oral examinations, 35.68% of all suffered from dentine hypersensitivity. The prevalence rate of females was higher than of males（P＜0.01）. Cold was the most common stimulus for dentine hypersensitivity (63.97%). Females, high frequency of eating pancakes, horizontal tooth-brushing, and acid regurgitation symptoms were probably the risk factors of dentine hypersensitivity. The premolar was the most commonly affected tooth by dentine hypersensitivity, followed by the first molar. The high-incidence age group of dentine hypersensitivity was 50-59 years old. The most common affected tooth surface was collum dentis, and 82.44% sufferers had gingival attachment loss. Conclusion The dentine hypersensitivity of rural adults in Ji’ning City is widespread. Therefore, the prevention and treatment for dentine hypersensitivity should be more promoted by dental professionals.

Abstract: The occurrence of three canals in mandibular premolars is very rare. This article reported and discussed the root canal therapy of a mandibular first premolar with 3 root canals, especially in aspect of root canal-detecting and root canal-shaping.

Abstract: Root resorption is a physiological or pathological phenomenon of dentin and cementum defects. It is common in oral diseases. Root resorption often causes reduction of the tooth crown-root ratio and decreases tooth stability, which leads to the looseness or even falling off of teeth, thus seriously affecting the oral health and appearance. So far, there hasn’t been any effective way to prevent or cure root resorption. In recent years, it has been found that osteoprotegerin (OPG) plays an important role in root resorption. This article reviewed the structure, expression and function of OPG, OPG/RANKL/RANK system and the protective effects of OPG on related tissues around root.

Problem-based learning (PBL) teaching is a problem-based, student-centered, teacher-guided small-group discussion learning mode. Currently, this model has been widely accepted and applied in the medical education field. Plenty of studies have shown that PBL learning can achieve a good result in oral and maxillofacial surgery teaching. We introduce the application of PBL in oral and maxillofacial surgery teaching as well as its problems and prospects by reviewing the relevant literature.

Open reduction and rigid internal fixation surgery is one of the most commonly used methods of surgical treatment for maxillofacial fractures. With the development of polymer material science in recent years, absorbable internal fixation materials have greatly improved in term of mechanical strength, biocompatibility, etc. Showing advantages, absorbable internal fixation materials have been gradually applied in clinic. This paper reviews absorbable internal fixation materials applied in the maxillofacial surgery regarding their cranial classification, degradation of absorption, clinical applications as well as advantages and disadvantages.

Abstract: As an important modality in the treatment of head and neck malignancies,radiation therapy has adverse side effects on regional normal osseous tissue inevitably.Using in vitro cell model,the studies confirmed that ionizing radiation inhibited the proliferation of the osteoblasts.Additionally,it induced DNA damage and cell cycle arrest in osteoblasts.However,the influence of ionizing radiation on cellular differentiation was not consistent.This paper reviewed of the effects of ionizing radiation on osteoblasts in vitro.