Abstract: Along with the improvement of operating microscopes and instruments,the technique of microscopic root canal treatment has been widely used.The operating microscope can offer a favorable illumination and magnification of vision,so that dentists could observe the tiny morphological structure inside pulp chamber and root canal systems clearly.A good vision can greatly improve the accuracy and quality of root canal therapy.This article introduced the clinical application of microscopic root canal treatment.

Abstract: Objective To investigate the absorption and release kinetics of BMP2 by hydroxyapatite nanoparticles (HANPs),and to analyze the potential of HANPs as a carrier for drug delivery systems.Methods BMP2 was radiolabeled with 125I according to the Iodogen method.HANPs were dispersed in BMP2 solutions with different concentrations.The absorption of BMP2 onto HANPs was detected using ITLCSG and γcounter.A suspension of HANPs/125IBMP2 was prepared in normal saline and incubated at 37 ℃ for 15 days.On each day,the release kinetics of BMP2 from HANPs was detected using ITLCSG and γcounter too.Results When the concentrations of BMP2 solutions ranged from 31.251 000 μg/mL,the absorption rate and the concentration of 125IBMP2 were positively correlated,and the amount of 125IBMP2 absorbed onto HANPs could be as high as 70 μg/mg.The release profile showed sustained release of BMP2 during the period of the investigation and the release ratio could increase moderately to about 43%.Conclusions These results suggest that HANPs has the potential function as a carrier for drug delivery systems and a scaffold material for bone tissue engineering.

Abstract: Objective To establish an in vitro culture model of genioglossus myoblast of rat,and to observe the biological character of myoblasts.Methods Genioglossus muscle was from SD neonatal rat no older than 3 days.Twostep enzymatic digestion using collagenase II and trypsine was applied to obtain genioglossus myoblast.The preplate technique was used to purify myoblast.Cytometry was used to draw the cell growth curve.αsarcomeric actin immunocytochemistry was adopted to identify the myogenic origin of the myoblast.Results Genioglossus myoblast was successfully obtained,and more than 90% of the cells were αsarcomeric actin positive.The cells were active in proliferation and differentiation.The doubling time of cell numbers was about 45 days.The monocyte myoblasts were fused to myotube when cell density was high.Conclusions Sufficient and purified genioglossus myoblast could be obtained by enzymatic digestion and preplate technique.The cells can be proved as myoblast by morphological and immunocytochemistry detection.

Abstract: Objective To observe the effects of different fimA genotypes of Porphyromonas gingivalis(P.gingivalis) on the production of endothelin1 (ET 1) and nitric oxide (NO) by co-cultured human umbilical vein endothelial cells (HUVECs) with human umbilical artery smooth muscle cells (HUASMCs).Methods P.gingivalis ATCC33277 (typeⅠfimA gene) and W83 (type ⅣfimA gene) were cultured anaerobically in standard condition,and a novel co-culture system of HUVECs and HUASMCs was treated with different fimA genotypes of P.gingivalis for 2,8,24 and 48h.At different time points,the supernatant was collected,the levels of ET 1 were determined by ELISA,and the levels of NO were determined by nitrate reductase.A negative control group (blank control) and a positive control group (1ug/mL E.coli LPS) were set in each experimental group.Results The co-culture system of HUVECs and HUASMCs produced ET 1 and NO with Ⅰand ⅣfimA genotypes of P.gingivalis stimulation.Compared with the negative and positive control groups,differences were observed concerning the ET 1 and NO production and ET 1/NO level in the experimental group.In terms of overall trend of the production of ET 1 and NO,the group ofⅠfimA genotype of P.gingivalis was similar to the negative control group,while the group of ⅣfimA genotype of P.gingivalis was similar to the positive control group.ⅣfimA genotype of P.gingivalis demonstrated more secretion of ET 1 and a lower amount of NO compared toⅠfimA genotype of P.gingivalis.At 48h,co-cultured HUVECs and HUASMCs infected by ⅣfimA genotype of P.gingivalis showed a significant imbalance of ET 1/NO.Conclusions Stimulated by different fimA genotypes of P.gingivalis,the production of ET 1 and NO by co-cultured HUVECs and HUASMCs,and the ET 1/NO level were significantly different between two fimA genotype of P.gingivalis,which may be related to the native virulence of the bacteria.ⅣfimA genotype of P.gingivalis could stimulate and influence co-cultured HUVECs and HUASMCs,and is more likely to cause endothelial dysfunction thanⅠfimA genotype P.gingivalis.

Abstract: Objective To explore a safe and efficient method for isolation and identification of the rabbit bone marrow mesenchymal stem cells (BMSCs) in vitro,and to provide an experimental basis for the clinical application of BMSCs.Methods Bone marrow was aspirated from rabbit tibias,and the BMSCs were isolated and cultivated by total adherence method.The cells were observed by inverted phase contrast microscopes.The P5 cells were also induced to differentiate towards osteoblasts and chondroblasts,which were identified by corresponding histochemistry staining and FCM (flow cytometry).Results The primary and passage cells were spindleshaped and grew in colonies.ALP (alkaline phosphatase) activity increased continuously and the calcium nodule which was positive by Alizarin red staining was formed.The surface molecules including CD90,CD44 and CD105 were positive,and the cell surface markers including CD45,CD34 and Ckit were negative.Conclusions The adherence method is a simple and reliable method for rabbit BMSCs cultivation.BMSCs may be ideal seed cells for tissue engineering,which possess power of multidirectional differentiation.

Abstract: Objective To discuss the effect of root canal instrumentation on mechanical characters of Chinese tooth root.Methods A total of 40 mandibular premolars with single canal extracted from Chinese adults were randomly divided into 4 groups (A,B,C,D),which were all prepared by rotary instruments up to #25 0.04 taper,#25 0.06 taper,#30 0.04 taper and #30 0.06 taper.All specimens were filled with gutta percha and AHPlus sealer with lateral condensation filling technology.The specimens were then submitted to compressive strength testing by a universal testing machine.The highest compressive strength value was recorded when each root exhibited vertical fracture.Results No significant differences were obtained either between Group A (182.17±49.22) N and Group B (146.28±56.54) N or between Group C (98.14±12.25) N and Group D (86.10±29.44) N (P >0.05).However,there were significant differences between Group A and Group C as well as Group B and Group D (P <0.05).Conclusions Increased taper and size of file tip of root canal instrumentation could lead to decreased root strength,and the size of file tip exhibited more influences.

Abstract: Objective To investigate the effect of growth hormone (GH) on periodontal ligament,alveolar bone and orthodontic tooth movement in rats.Methods 40 Wistar rats (gender:male; age:7weeks) were randomly divided into control and experimental groups,each having 20 rats.The experimental group received subcutaneous injections of growth hormone at a dose of 0.15 IU/kg·d,and the control group received equivalent volumes of saline.A nickel titanium spring was fixed to maxillary incisors and the left upper first molar,with a force of 0.49N,so as to move the molar mesially.The rats were sacrificed on day 3,7,10 and 14.The distance of tooth movement was determined by using a vernier caliper.The sections of the maxillae were prepared for hematoxylineosin staining.Results On day 10 and 14,there was a significant difference of total tooth movement between the experimental group and the control group (P <0.05).Compared with the control group,the experimental group showed more osteoclasts on day 7 and more blood vessels on day 7 and 10.Conclusions Shortterm GH administration can affect bone remodeling and accelerate orthodontic tooth movement,shortening treatment time.

Abstract: Objective To observe the therapeutic effects of marsupialization and orthodontic traction on the treatment of dentigerous cyst in mixed dentition stage．Methods Twelve cases of dentigerous cysts in mixed dentition stage were treated at the Affiliated Hospital of Stomatology,Nanjing Medical University from 2007 to 2012 with marsupialization of the cysts to preserve permanent tooth buds,then obturators were used to guarantee the effective draining and maintain the teeth space,and further orthodontic treatment was carried out to ensure the normal eruption of the involved teeth.The patients were followed up for 2~3 years after marsupialization,and the bone tissue healing and permanent teeth eruption were observed.Results After the therapy of marsupialization and further treatment of orthodontic traction for 12~15 months,permanent teeth which were involved in the cysts of all the 12 patients erupted totally and dental arrangement was kept in alignment.Patients′ facial morphology returned to normal,and the lowdensity shadow of cyst cavity disappeared according to imageological examination.No cyst recurrence was observed during the following up for more than 2 years postoperatively.Conclusions Marsupialization and further orthodontic treatment is an effective treatment of dentigerous cysts in mixed dentition stage,which could retain the involved teeth and bone tissue to the maximum degree.

Abstract: Objective To explore the application of different margin designs (edge to edge margin/concave shoulder margin) to chairside computeraided design/computeraided manufacturing (CAD/CAM).Methods 144 teeth with root canal therapy were randomized into group A that used CAD/CAM with an edge to edge margin design or group B that used CAD/CAM with a concave shoulder margin design.The marginal adaptation,and the fracture and falling off rates of teeth and allceramic onlay restorations were evaluated.Results With no statistical significance (P >0.05),the vertical marginal gap of group A was (80.90±15.99) μm,and that of group B was (82.21±15.39) μm.Followed up within 6 to 12 months,the fracture rate of restorations in group A and B was 0% and 4.17%,respectively.The falling off rate in both groups was 0%.Meanwhile,no teeth fell off or fractured in either group.Conclusions s Both the edge to edge margin and the concave shoulder margin are acceptable for CAD/CAM generated allceramic onlays,and the former is good for teeth and more convenient in clinic.

Abstract: Objective To compare the pretreatment and posttreatment changes of arch widths and buccal corridor widths between premolar extraction and nonextraction treatment,and to analyze the correlation between arch width changes and buccal corridor width changes.Methods Pretreatment and posttreatment casts,frontal smiling photographs of 50 extraction and 50 nonextraction patients were collected to obtain their corresponding pretreatment and posttreatment changes of arch widths and buccal corridor widths.The amount of changes between pretreatment and posttreatment archwidths and buccal corridor widths were measured in order to explore the extraction effects on them，and the correlations between the changing amounts of arch widths and that of buccal corridor widths were measured as to compare the extraction effects on arch widths and buccal corridor widths.Results ①There was a significant increase inthe posttreatment maxillary intercanine width in the extraction group but not in the nonextraction group.②Pretreatment and posttreatment arch widths between the maxillary premolars in both groups increased,and the amounts were greater in the extraction group than in the nonextraction group.③Pretreatment and posttreatment arch widths between the maxillary first molars in both groups increased,and the amount was greater in the nonextraction group than in the extraction group.④There were no significant differencesin any buccal corridor widths measured in both groups.⑤There were correlations between the pretreatment first molar and posttreatment canine arch widths and the buccal corridor widths.Conclusions The pretreatment and posttreatment changes of arch widths are related to extraction，while the buccal corridor widths are not.Besides,these arch width differences are not directly related to changes of buccal corridor widths in most cases.

Abstract: Objective To investigate the selection of cooling water in minimally invasive exodontia using high speed handpiece by evaluating the effect of sodium hypochlorite disinfection method which is a common approach to sterilize dental unit waterlines (DUWLs).Methods Ten dental units were randomly selected．Water samples were taken from their water outlets of highspeed handpiece at three different time points:8∶00 (the time after sterilization with 700 mg/L sodium hypochlorite and before receiving patients),11∶30 (the time right after semi day′s therapy) and 17∶30 (the time right before the end of the daily clinical work),respectively.Then,Colony Forming Units (CFU) were counted.The data were analyzed by generalized estimating equation with SPSS 19.0 software.Results The CFUs of water samples at different time points were significantly (P <0.05).No microorganisms were detected in samples of 8∶00.Microorganisms were detected in samples of 11∶30 and 17∶30,and the CFUs observed in samples of the latter were more than those of the former.Conclusions Sodium hypochlorite has a good effect on DUWLs infection control.However,during the use of the dental unit,the waterlines can be contaminated,which does not cater for the requirements of exodontia which should be an aseptic operation.Therefore,it is necessary to apply other cooling water system for high speed handpieces to cooling water systems in minimally invasive exodontia.

Abstract: Objective To explore effects of the orthognathic surgery treating class Ⅲ osseous maxillofacial deformities on the patients′ voice function.Methods A total of 26 consecutive cases,who were diagnosed as class Ⅲ osseous maxillofacial deformities by orthodonticorthognathic associated therapy center of the affiliated stomatological hospital of Nanjing Medical University,were enrolled in this study.Those cases were divided into two groups according to the medical history and specialized examination.The cleft lip and palate group (Group A)included 10 cases.They were all congenital cleft lip and palate patients with secondary maxillary dysplasia.The other 16 cases diagnosed as developmental malformation alone were named none cleft lip and palate group (Group B).The voice information was collected before and one month after the surgery respectively.The statistic differences in voice intelligibility and first three formant frequencies of 6 vowels (/a/,/o/,/e/,/i/,/u/,/ü/) were analyzed.Results Group A,the voice intelligibility,the first and second formants of vowel /i/,and the second formant of /o/ and /u/ changed significantly(P ＜0.05);the decline degree of voice intelligibility was positively correlated with antedisplacement distance(r=0.8125).In Group B,the changes of voice intelligibility and every vowel′s formant were not significant after operation.Conclusions Orthognathic surgery treating class Ⅲ osseous maxillofacial deformities may exacerbate the degree of velopharyngeal incompetence for patients with secondary maxillary dysplasia,worsening their voice function.However,the surgery could be a compensation for the developmental malformation patients,delivering no significant impact.

Abstract: Objective To investigate the relationship between vertical dimension and bite force as well as electromyography (EMG) in elderly edentulous people,and to provide references for determining normal vertical dimension in clinic.Methods 10 edentulous subjects who went to the Affiliated Stomatological Hospital,College of Medicine,Zhejiang University were chosen.The normal vertical dimension was measured by conventional method.Based on the normal vertical dimension (M position),other 12 vertical dimensions were settled at every 0.5 mm.Bite force at different vertical dimensions was measured using an occlusometer,while electromyography of bilateral masseter and anterior temporal muscles were recorded by multichannel physiologic collection device.Vertical dimension,bite force and muscle activity were statistically analyzed.Results ①Bite force was positively correlated with vertical dimension (P <0.05).②Normalized masseter muscle activity (NMM) and normalized anterior temporal muscles activity (NATM) were negatively correlated with vertical dimension (P <0.05).③Masseter muscle activity/bite force (MM/BF) and anterior temporal muscles activity/bite force (ATM/BF) were negatively correlated with vertical dimension.Conclusions ①Bite force increased with the increase of vertical dimension.The normal vertical dimension wasn′t where bite force is maximal.②Masseter muscle activity decreased with the increase of occlusal vertical dimension,but the change of anterior temporal muscle activity wasn′t so apparent compared to that of masseter muscle activity.③MM/BF and ATM/BF decreased with the increase of occlusal vertical dimension.④There may be a stable area nearby the normal occlusal vertical dimension.Inside the stable area,changes of bite force,masseter muscle and anterior temporal muscle activity were not significant.

Abstract: Objective To analyze the curative effect of modified pendulum appliance on maxillary molar distalization.Methods 20 cases of odontogenic angle class Ⅱ malocclusion patients were selected using modified pendulum appliance to achieve maxillary molar distalization.Measurement and analysis of model cephalometrics were made before and after treatment.Results For 4-6 months,the average molar distalization on both sides was 5 mm,which guaranteed enough clearance.Conclusions Modified pendulum appliance is an economical and convenient maxillary molar distalization device with reliable curative effects.

Abstract: Objective To explore the clinical efficacy of sterngold attachment denture restoration of dentition defect.Methods 150 cases of patients with dentition defect in Department of Stomatology of our hospital from August 2008 to August 2011 were selected,and were divided into experimental group,control group 1 and control group 2 with 50 cases in each group using the random number table method.Patients of the experimental group were given sterngold attachment dentures,patients of control group 1 were given titanium alloy casting frame removable denture,and patients of control group 2 were given the ball type attachment denture.Before treatment and after 3,6,12,24 months were selected as the time nodes when the masticatory efficiency and the abutment periodontal index (gingival index and plaque index) of 3 groups of patients were tested and compared.Results There was no significant difference among masticatory efficiency,gingival index and plaque index of the 3 groups before treatment (P >0.05).At each time node after the treatment,the masticatory efficiency of 3 groups was significantly higher than that before treatment.There was no significant difference between control groups (P >0.05),while masticatory efficiency in the experimental group was significantly higher than that in both control groups,showing statistically significant difference (P <0.05).With the extension of time,chewing efficiency in two control groups decreased,while the experimental group did not decrease obviously.At each time node after treatment,the gingival index and plaque index in all groups increased significantly.The control groups showed no significant difference (P >0.05).The increase in the experimental group was not as much as that in control groups,and the difference was statistically significant (P <0.05).Conclusions Restoring dentition defect with sterngold attachment denture shows good masticatory function,which affects little the abutment periodontal tissue and has good tissue compatibility,is worthy of clinical application.

Abstract: Objective To compare the root filling quality assessed by conebeam computed tomography (CBCT) and periapical radiographs (PA),and to explore the advantage and application value of CBCT in the root canal treatment.Methods In total,100 teeth (221 canals) were clinically diagnosed and received root canal therapy.After root canal filling,the length and density of root filling were assessed with PA and CBCT simultaneously by two experienced endodontists.Chisquare test was performed with the data from PA or CBCT to evaluate the quality of the root filling.Results In total，214 canals received rootcanal treatment while 7 canals were omitted.In terms of length,density and satisfaction of the root filling,there were about 34.58%,30.48% and 37.58% of canals demonstrated different results based on the evaluation from PA and CBCT respectively.According to the result of statistical test,PA and CBCT had significant differences (P <0.01) in the assessment of the three aspects mentioned above.Conclusions It is more sensible and accurate of CBCT in detecting the quality of the root filling compared with PA,thus it is of great value in the complex or difficult root canal treatment.

Abstract: Objective To measure palatine cortical bone densities of adolescent and adult patients to provide,and the reference for the clinical application of micro screw implant.Methods 30 cases of adolescent patients (mean age (13.2 ± 1.2) years),and 30 cases of adult patients (mean age (23.2 ± 4.9) years) were selected,among whom there were half men and half women.CBCT was taken respectively.Cortical bone density testing was performed on all patients and palatal bones were divided into 72 test areas.Results The density of the adults group ((736 ± 5)hu)was greater than that of the adolescents group ((613 ± 28)hu; P <0.01).Bone mineral density in male patients was greater than that in female patients in the same group.The lateral bone density in all patients was significantly less than that in the middle side of the bone (P <0.01).Conclusions The palatal bone density of adult group is significantly higher than that in adolescent group,palatal bone density in women is lower than that in men.

Objective To Investigate parents’ attentions on malocclusion`s early prevention in Shandong province. Methods 752 parents were selected to carry out questionnaires randomly .They all took their children treated at Shandong University Stomatology Hospital during March to October ,2014. 307 parents of children with mixed dentition and 445 parents of deciduous Children were included. Results①Parents` attention on hereditary was low and they paid more attention on hereditary when presenting family history. ②In terms to environmental factors, parents paid most attention on diet, then poor oral habits and deciduous diseases, they paid least attention on related respiratory diseases.③Parents thought aesthetics was more important than psychology.④Parents of deciduous children focused on diet while parents of children with mixed dentition thought poor oral habits and the effects on children`s psychology were more important. Conclusions In general, parents` attention on early prevention are low. Disseminating preventive knowledge and strengthing parents` attention are necessary.

Abstract： Objective To describe the caries status in 8yearold children in Jiangsu Province and to provide evidence for health service of caries prevention.Methods A sample of 4416 8yearold children from Jiangsu Province was chosen and their caries status was investigated.Results The caries prevalence of permanent teeth was 17.50% and the mean DMFT was 0.33; The caries prevalence of deciduous teeth was 64.08% and the mean DMFT was 2.35; The filling percentage of permanent teeth was only 4.37% and that of deciduous teeth was only 5.21%.Conclusions The caries prevalence is relatively high,and the filling percentage is at a low level.We should strengthen and promote the oral health education and caries prevention programs.

Abstract: Central cusp deformity is a disease characterized by deformed teeth with non-carious lesion of dental hard tissue,generally located in the central facial fossa with conical projections,and more commonly located in mandibular premolars,especially the second premolars.This paper reported a case whose two premolar teeth were removed due to orthodontic reasons,and the remaining six premolar teeth had central cusp deformity.Besides,relevant literature was reviewed to summarize the etiology,clinical manifestation and treatment of central cusp deformity so as to provide a reference for clinical diagnosis and treatment．

Abstract: With its osseointegration characteristic,titanium is considered to be the most suitable material for oral implants.However,as an inert metal,the biological activity of titanium is inadequate.In order to obtain better and faster osseointegration,titanium surface micro-topography has been changed by a variety of surface modification techniques to improve its biological activity and osteogenic ability.To figure out the internal molecular mechanism of surface modification promoting osseointegration,lots of studies home and abroad have also been undertaken.In this paper,advances in the effect of titanium surface micro-topography on osteoblast behavior and its molecular mechanism were reviewed.

Abstract: With the domestic and overseas growth of dental erosion,this disease is gaining attention of the researchers.Meanwhile,many erosion indices are created and used in clinical examinations,epidemiological investigations and laboratory studies.The aim of this paper is to review several erosion indices mainly used in clinical examinations and epidemiological investigations.

Abstract： Oral treponema is a member of oral bacteria in the healthy periodontal tissue.However,once flora imbalance occurs in the periodontal pocket,oral treponema will reproduce rapidly and becomes the main pathogenic bacteria of periodontal disease.Currently,researchers all focus on how treponema can adapt to oral micro ecological environment and mediate periodontal disease.Studying the gene sequence of treponema and twocomponent regulatory systems may provide the theoretical basis for explaining the above phenomena.Therefore,this review will focus on the characteristics of twocomponent regulatory systems of treponema,so as to provide certain theoretical basis for controlling breeding of treponema denticola and finding new targets or new therapeutic agents in the treatment of periodontal disease.