To establish the animal model of drinking water type fluorosis and observe the morphological changes of its sclerous tissues. Methods 48 Wistar rats were randomly divided into four groups.The fluoride exposed groups respectively drank water containing 50,100 and 150 mg/L NaF,and the control group drank ordinary tap water.8 weeks later,incisors and femur of rats were taken and HematoxylinEosin(HE) staining method was used to observe the changes in rat incisor ameloblasts and the morphological change of bone tissues.The concentrations of fluoride in serum,teeth and bone were determined by fluorine ion selective electrode. Results The rat incisors in the experimental groups showed different performances of dental fluorosis.The contents of fluoride in serum（F=11.234，P<0.05），teeth(F=275.148，P<0.05 ) and bone(F=217.337，P<0.05) in the fluoride exposed groups were much higher than those of the control group.It increased with the increase of concentration,and it showed significant differences among four groups.According to HE staining,in experimental groups,the irregular arrangement of the rat incisor ameloblasts was multilayered.The columnar cells were getting shorter or disappeared,and a few cells were distorted.With the increase of fluoride concentration,the pathological changes got more serious.HE staining showed that the bone trabecula increased and closely arranged together in rat bone tissues in experimental group,which indicated bone sclerosis.Also,epiphyseal plate was getting thicker and the hypertrophic chondrocytes accumulated and arranged disorderedly in fluoridetreated rats.Conclusions Drinking water containing high concentration of fluoride for long time may cause chronic fluorine poisoning and pathological changes of sclerous tissues such as dental fluorosis and skeletal fluorosis.

Abstract: Objective To observe and evaluate the curative effects of Superbond adhesive system as the periodontal splint on loose anterior teeth of patients in treating advanced periodontitis. Methods 64 patients with advanced periodontitis of anterior teeth were selected and randomly divided into two groups,experimental group (superbond fixation group) and control group (wire ligation and resin fixation group),with 32 patients for each group.Fullmouth periodontal treatment and oral hygiene instruction were performed to maintain good oral hygiene,control periodontal disease and eliminate occlusal trauma.After one month,two fixation methods were used in experimental group or control group respectively.The review and maintenance were suggested every three months,and continuous observation was done for 12 months.The treatment response was evaluated as effective and ineffective.The change of alveolar bone density was compared before and after treatment according to the gray scale on panorama radiography.A questionnaire survey was conducted to evaluate the aesthetics and the degree of comfort of two treatment methods. Results In experimental group,29 cases were evaluated as effective while 4 cases were considered as ineffective in control group.Compared with that before treatment,periodontal depth (PD) decreased and the alveolar bone density increased after 12 months in experimental group,and there was statistically significant difference (P<0.05).According to the survey,aesthetics and the degree of comfort was higher in experimental group. Conclusions For appropriate cases,Superbond bonding system can be used as periodontal splint to fix loose teeth in order to improve chewing ability and the quality of life.

Abstract：Objective To evaluate the biocompatibility of titanium alloy before and after casting by cell culture and MTT test. Methods Three kinds of titanium alloys before and after casting were processed into wafers whose diameter was 13.5 mm and thickness was 1 mm.Extracts were prepared for cell culture after cleaning and disinfection.Observe cell morphology and test the cells′ absorbance value in each group after culturing for 1,3 and 5 days. Results ①Cell absorbance value of C group which contained aluminum and vanadium was slightly lower than those of the other two groups no matter before or after casting（P>0.05）.②Cell absorbance values of three groups after casting were slightly lower than those before casting (P>0.05). Conclusions Casting has no effect on the biocompatibility of titanium alloys.It doesn′t affect clinical application.

Objective To investigate the effect of Headgearactivator appliance treating Class Ⅱ division 1 malocclusion on the coordination between nose,lip and the chin. Methods 38 patients with skeletal Angle ClassⅡmalocclusion were divided into two groups (Headgearactivator group and control group）,19 patients in each group.The Xray lateral cephalograms of two groups of patients were photographed before and after treatment and the angle and line spacing was measured.SPSS 11.0 software package was used to calculate the mean and the standard deviation.The paired ttest was performed to compare the changes of the measurements. Results LsE，LiE，U1Stm and the angle of NsLsFH，LsNsLi，LsNsPg′ decreased,SnStms，StmiMe′ and the angle of NsPg′FH，A′LsFH，B′LiFH，CmSnLs，LiB′Pg′， NsPg′FH， Z，GSnPg′ increased,and there was statistically significant difference（P<0.05). Conclusions Headgearactivator can reduce upper and lower lip protrusion,improve incompetent lips,recover the coordination between nose，lips and chin to a certain extend.Soft tissue profile tends to be nature and straightstyled.

Objective To establish the experimental animal model of orthodontic tooth movement with alveolar corticotomy surgery and observe the speed of tooth movement and the influence on the remodeling of the periodontal tissue of rats. Methods 75 SpragueDawley rats were selected. Bilateral maxillary central incisor corticotomy was performed on 35 rats (experimental group) and after 1 week conventional orthodontic appliance was used on them to move the teeth like other 35 rats in the control group. Another 5 rats served as baseline control group. Tooth movement distance was measured and the histological changes were observed. Results After 2 weeks,the tooth movement distance of the corticotomy group was (3.471±0.359) mm,compared with (1.247±0.198) mm in the control group. There was significant difference between two groups. HE staining results showed that the forming range of the periodontal ligament hyalinized tissue was smaller in the experimental group than that in the control group,and the time was shorter as well. Conclusions Alveolar corticotomy surgery can accelerate the orthodontic movement.

Objective To evaluate the effects,especially the esthetic effect of applying modified GBR and immediate restoration in the immediate implant in maxillary anterior teeth as well as the technique skills and influence factors. Methods 15 cases of hopeless anterior single tooth were included in this study. Replace,Straumann or Ankylos implantswere implanted after atraumatic tooth removal. Provisional restoration was completed with modified GBR and immediate restoration technique in 2 hours. The final restorations were made after 46 months. The followup period is 624 months. The survival rate,the coordination of soft tissue with neighboring tissue and the satisfactory level of patients were evaluated. Results In the 6 and 12 months followup period,all 15 implants have successful ossteointegration without any failure. The survival rate is 100%. 12 implants had perfect soft tissue compared with neighboring tooth,while 3 had slight difference in terms of margin position. 14 implants had perfect soft tissue compared with neighboring tooth,while 1 had slight difference in terms of color and texture. The mean satisfactory level of patients in terms of VAS was 92. Conclusions The modified GBR and immediate restoration technique in immediate implant is helpful to get ideal esthetic result and to reduce the treatment span.

Objective To investigate the effectiveness of the combination of plateletrich plasma (PRP),bovine porous bone mineral (BPBM) in treating mandibula bicortical bony defects in rabbit. Methods Fiftyfour healthy rabbit participated in the study and they were divided into 3 groups.The 11 millimeter diameter rotundity bicortical bone defects were made surgically on mandible and treated with either the combination of PRP+BPBM+GBR (group 1) or the combination of BPBM+GBR(group 2) or glutin sponge (control group).Changes of the bone defects were observed by Xray,optical microscopy,electron microscopy 4,8 and 12 weeks after operation.The alkaline phosphatase (ALP) and calcium and phosphorus contents in blood were measured and analyzed. Results The platelet concentration of PRP was 4.19 to 4.43 times that of the whole blood.The Xray demonstrated that the bone density in group 1 and 2 was obviously higher than that of the control group during the treatment.HE staining showed that in group 1,the new bone formed at the 4th week and the transplants partly degraded while there was less new bone formation in group 2.At the 8th week,the new bones in group 1 were obviously more than group 2.After 12 weeks,the fillings of group 1 were absorbed and replaced by new bones and the trabecular bones and bone lacuna increased while in group 2,the gegenbaur cells and the newlyformed bones were significantly less than group 1 and the new bones in the control group were even less.According to the transmission electron microscopic study,the osteoblasts were found active during the treatment.The number of mitochondrium and rough endoplasmic reticulum in osteoblasts of group 1 was larger than group 2 and control group and the infiltration capacity was better.The control group proved to be the worst.Both group 1 and 2 modalities resulted in significant enhancement of ALP and calcium and phosphorus in blood at week 4,8 and 12 compared with control group. Conclusions The results suggest that the combination of PRP,BPBM and GBR provides a significant regenerative effect on repairing the bicortical bony defects in rabbit.The effects are associated with the high concentration of platelet and abundant growth factors in PRP,and the porous scaffold bone structure.

Objective To evaluate the sealing ability of Cshaped root canal system of mandibular second molars filled with GuttaFlow. Methods 63 mandibular second molars with Cshaped root canals were collected and then prepared with Hero shaper system.Then the teeth were randomly divided into 3 groups and the root canals were respectively filled with GuttaFlow,EQ plus thermoplasticized gutta percha and by cold lateral compaction technique.Then roots were sectioned at 2,4,6,8 mm from apical foramen.All sections were observed through stereomicroscope and the images were acquired.The percentage of guttaperchafilled area (PGP) was calculated with Image Analysis Software and the sealing ability was evaluated. Results At the 2 mm,4 mm levels from apex,sealing ability of GuttaFlow was better than thermoplasticized gutta percha and cold lateral compaction.At the 6 mm,8 mm levels,there was no significant difference between GuttaFlow and thermoplasticized gutta percha,but both were better than cold lateral compaction group . Conclusions GuttaFlow has good sealing ability in filling C shaped root canals of mandibular second molars.

Objective To explore the application value of CBCT and digital orthopantomography in dental implant in the posterior area of maxillary and mandible. Methods 50 patients received 58 implants,adopting CBCT and digital orthopantomography method at the same time.The preoperative radiographic results and the postoperative images of the osseointegrated implants were compared and the differences were analyzed. Results The detected positive rate of bone deficiency in the mandible posterior area was 28.57% by CBCT and 7.14% by digital pantomogram,showing statistical significance by Chisquare test(P<0.05).The detected positive rate of bone deficiency in the maxillary posterior area was 36.36% by CBCT and 9.09% by digital pantomogram,also showing statistical significance by Chisquare test (P<0.05).The detected positive rate of osseointegration failure after 3 months was 3.45% (2/58) by CBCT and 8.62% (5/58) by digital pantomogram,showing no statistical significance by Chisquare test (P>0.05).In clinic test,there was just 1(1.72%) case of osseointegration failure. Conclusions CBCT is considered as the relatively reliable method for measurement of jaw bone volume nowadays.Digital pantomograms,however,display distortion and have greater measurements of the alveolar bone when compared with CBCT.In postoperative examination,CBCT images can more clearly exhibit the periimplant sclerotin,so that CBCT plays an important role in evaluating the success of the planting operation and in restoration of upper structure.

Objective To investigate the differences of the upper airway morphology and the hyoid position among nonsnorig youths with different sagittal skeletal patterns． Methods 90 nonsnoing youths with malocclusion were divided into three groups based on their ANB angles:class Ⅰ group,class Ⅱ group and class Ⅲ group. CBCT scans were performed on all patients in natural head posture. Dolphin Imaging 11.0 was used for threedimensional reconstruction.The anteroposterior (AP) and lateral (LAT)dimensions,crosssectional areas(CSA) of retropalatal region and retroglossal region,airway volume(AV),minimum axial area(MAA),and length of airway were measured.Cephalometric radiographs and the position of the hyoid bone were analyzed with Winceph 7.0. All data were statistically analyzed and evaluated. Results RPCSA、RGCSA were smaller in classⅠand class Ⅱ group than in class Ⅲ group. RGL AT,RGAP,AV and the position of the hyoid were statistically different between Class Ⅱand ClassⅢ group(P<0.05). Correlations among upper airway morphology,hyoid position,and head posture were confirmed. Conclusions Differences in the upper airway morphology and hyoid position are statistically significant among the three groups. The upper airway morphology and the hyoid position of nonsnoring youths with malocclusion can be affected by the sagittal skeletal patterns.

Objective To investigate whether toothpaste containing bletilla and borneol could inhibit dental plaque formation and reduce gingival inflammation. Methods 200 volunteers were divided into two groups receiving a 3month randomized，doubleblind and controlled clinical trials.Objects in the treatment group would use toothpaste containing traditional Chinese medicine,while the control group objects would use toothpaste having definite efficacy. All the subjects should use the unified toothbrushes and brushing method twice a day respectively in the morning and in the evening.An experienced dentist examined plaque index(PLI)，gingival index(GI)，bleeding index(BI) of each subject at baseline，1.5th and 3rd month in this trial. Results GI and BI in two groups as well as PLI in the treatment group at 1.5th and 3rd month significantly decreased compared with that in baseline (P＜0.01); however,there was no statistical difference in PLI in the control group before and after treatment(P＞0.05).In addition,PLI of treatment group was lower than that of control group at 1.5th and 3rd month,and there was significant difference(P＜0.01). Conclusions Toothpaste containing bletilla and borneol can obviously inhibit dental plaque formation and reduce gingival inflammation.

Objective To discuss and compare the similarities and differences in the curative effects of SUS2 and Jasper Jumperin treating Angle class Ⅱdivision 1 malocclusion. Methods 46 adolescent Angle class Ⅱdivision 1 patients were selected and randomly divided into two groups,respectively using SUS2 and Jasper Jumper orthodontic appliances.Lateral cephalograms were taken and the changes of 18 measurement indexes were observed and used in cephalometric analysis before and after treatment. Results Changes of such indexes as ANB,Yaxis,L1MP and U6OLP were significantly different between two groups. Conclusions There are some differences in the curative effects between SUS2 and Jasper Jumper and we should choose the most appropriate one for treatment.

Objective To investigate the clinical significance of conebeam computed tomography (CBCT) in the diagnosis of maxillofacial cystic diseases. Methods CBCT images from 53 cases who suffered from jaw cystic disease were collected.CBCT threedimensional image reconstruction technique was used and the involvement of roots,information of impacted teeth and anatomic relationship between the lesions and mandibular canal,nasal floor,maxillary sinus were observed and analyzed preoperatively and verified during the operations. Results The involvement of roots,information of impacted teeth and anatomic relationship were clearly displayed in CBCT images. Conclusions CBCT can produce complete image information of jaw cystic diseases,thus its application might be a great support for clinical operation.

Objective To explore the major points and evaluate the clinical effect of applying orthodontic microimplant anchorage in treating maxillary protrusion. Methods A total of 10 patients (8 females,2 males) were selected to be treated with the orthodontic miniimplants.Micro implant titanium screws were used in the maxillary molar buccal position as anchorages to retract the anterior teeth. Results All the patients got satisfying treatment effects and their facial profiles were improved. Conclusions Miniimplant can provide strong anchorage for the orthodontic treatment,thus the application of orthodontic miniimplants is an effective way to treat maxillary protrusion.

Objective 　To explore the clinical effect of applying maxillary sinus floor elevation and dental implantation in repairing maxillary posterior teeth loss and maxilla bone insufficiency. Methods 45 patients with 85 implants undergoing implant prosthesis for maxilla bone insufficiency were given maxillary sinus floor elevation combined with simultaneous dental implantation,and the cases whose residual bone height (RBH) <5 mm were given osteotome and bone meal additionally.Patients were followed up after 1,3,6,and 12 months,the survival rate of implants was checked,and bone trabecula formation and bone resorption were measured. Results All the cases gained good ossteointegration periimplant bone was stable,and no maxillary sinus inflammation was found.There was no significant difference in the survival rate of implants in Group A (100.0%) and Group B (95.6%)(χ2=0.51,P>0.05).There was no significant difference in sinus floor remodeling among different implant elevation heights (χ2=4.49,P>0.05). Conclusions Maxillary sinus floor elevation with simultaneous dental implantation is an effective way for the restoration of maxilla posterior teeth loss and bone insufficiency,and it also can achieve good survival rate of implants in patients with RBH less than 5 mm.

Objective To compare the retention effect of activators and Hawley retainers in retention period of the mandibular retrusion patients after fixed orthodontic treatment. Methods 40 adolescent patients who had finished their fixed orthodontic treatments were randomly divided into two groups,respectively wearing activators or Hawley retainers.Cephalometric analysis and difference in model overjet,overbite proceeded forthwith and one year later.All data were subjected to paired ttest and Wilcoxon rank sum test. Results Patients wearing Hawley retainers indicated more retrusion tendency compared with the activator group. Conclusions Activators serves as a better choice for patients with mandibular retrusion in retention period which can better prevent recurvence of mandibular retrusion.

Objective To investigate the health status of stomatological medical staff,so as to promote preventive health care. Methods 431 cases of the stomatological specialist hospital staff physical examination data in 2012 were analyzed.The cases were divided into groups according to age，gender and occupation,and calculation and the statistical analysis were done. Results There were 431 people being examined,including 122 males and 309 females.30 diseases or abnormalities involving 239 people were detected,with a prevalence of 1.58 per capita. The top three diseases of male were:hyperlipidemia，fatty liver，hypertension and the top three of female were:hyperlipidemia，fatty liver，mammary lobular hyperplasia.Morbidity of diseases like hyperlipidemia，fatty liver,hypertension increased with age,and the difference between age groups was of statistical significance(P<0.01).Prevalence rate of hyperlipidemia,fatty liver,hypertension among oral physicians was higher than other workers.The difference between occupation groups was of statistical significance (P<0.05). Conclusions The health situation of stomatological medical staff is not optimistic.Age，occupation and unhealthy lifestyle may be the main factors influencing health.We should take suitable actions for preventive health care.