Objective To compare the clinical effects between two methods for preventing the fracture of central cusp deformity on immature premolars.They were enamoplasty preventive resin restoration（or composite resin strengthening） technique and resin restoration after oneoff grinding and indirect or direct pulp capping respectively. Methods 20 child patients who had central cusp deformity on the premolars bilaterally were enrolled.Teeth whose central cusp had erupted but not reached the occlusal plane were divided into two groups randomly,enamoplasty preventive resin restoration group（namely resin strengthening group） and resin restoration after oneoff grinding and indirect or direct pulp capping group.Each group had 31 teeth.All the patients were followed up for one year. Results No tooth was found failed in the group of enamoplasty preventive resin restoration.Among the 31 teeth treated by oneoff grinding method,4 failed,and the success rate was 87.10%.There was no statistical difference between the two methods（P>0.05）. Conclusions Noticing abnormal central cusp early and applying enamoplasty preventive resin restoration to strengthen abnormal central cusp before the teeth reached the occlusal plane can effectively prevent the fracture of abnormal central cusp,and ensure normal development of tooth.

Objective To assess the effect of resin EMBRACE WetBond and glass ionomer GC Fuji Ⅶ as pit and fissure sealant on teeth of children under conditions of limited moisture isolation for 6 months,using QLF. Methods 114 children aged 3 to 5 years old who meet the inclusion criteria were recruited from Chengdu.The subjects were randomized into two groups.Using EMBRACE WetBond and GC Fuji Ⅶ as pit and fissure sealant between two groups.QLF images were taken of each tooth 3 months and 6 months after seal． Results 105 chldren completed the 6 months′ clinical trial,and the number of sealed teeth was 201.The results showed statistically significant differences between sealed teeth of children in two treatment groups in total fluorescence loss of green fluorescence（ΔQ） after seal,3 months and 6 months after seal（P<0.05）,and in total red fluorescence（R）（P<0.01） except in 3 months and 6 months after seal（P=0.191）. Conclusions QLF can effectively evaluate pit and fissure sealant on primary molar teeth,and it can be a monitoring means to prevent tooth decay..

Abstract: Objective To evaluate the apoptosis of osteocytes to determine whether the C/CSiC composites can be used as implant materials. Methods 8 Japanese bigeared rabbits were selected and randomly divided into group A and group B（n=4）.Implant respecitvely 8 pieces of experimental material（C/CSiC composites） and control material（Ti） into femur of the rabbits.Three months later,decalcify the femur specimens with experimental material and control material and immunohistochemical stain them to observe the combination of interface growth and apoptosis of bone tissue.Use Imagepro Plus 6.0 image analysis software to analyse the gray values of brownstained cells,and use SPSS 17.0 statistical software to make ttest analysis of independent samples. Results The experimental animals were anesthetized well and the effect of surgery was good.Implant materials and bone combined tightly.No loosening happened.New bone grew on most of the surfaces of implant materials.Under the light microscopy,cytoplasm of osteocytes was product of immunohistochemistrical positive reaction of caspase3,Bcl2 and Bax,and brown staining of some cell membrane was observed.There was no significant difference in mean grey value between the pure titanium control group and C/CSiC composite experimental group. Conclusions C/CSiC composites and titanium material were implanted in rabbit femurs.3 months later,the apoptosis of the osteoblasts around materials had no significant difference.

Objective To evaluate the effects of fluoride varnish on enamel demineralization adjacent to bonded brackets of orthodontic teeth. Methods Patients who needed to extract at least 2 premolars for orthodontic reasons were selected.For each patient,premolars were randomly divided into 2 groups.Brackets were bonded,and only the test teeth were treated with fluoride varnish.After 85 to 95 days,the occurrence of enamel demineralization was investigated; at the same time, surface enamel microhardness were measured by the microhardness test and the enamel lesions because of demineralization were observed with polarized light microscope after the premolars were extracted.The surface morphology of each tooth was observed by scanning electron microscopy. Results The rate of enamel demineralization in the test group was 11.11%; and that in the control group was 44.44 %（P<0.05）; besides,the microhardness of enamel in the test group was significantly greater than that in control group（P<0.05）.The samples in the control group showed obvious demineralization lesions.The mean lesion depths were（40.24±2.76） μm in the test group and（80.35±5.42） μm in the control group,and therer was statistical difference between them（P<0.05）.Many micropores and cellular structures appeared on the enamel surfaces in the control group,however,smooth and intact surfaces were observed on the enamel surfaces treated with fluoride varnish. Conclusions Fluoride varnish can be a kind of effective preventive adjunct in reducing demineralization adjacent to brackets.

Objective To sum up the clinical application of diagnostic waxup in the esthetic anterior teeth restorations with CAD/CAM all ceramic restorations. Methods 110 patients with 137 allceramic crowns were clinically enrolled in this study.First,dianostic waxup used in the esthetic anterior teeth restorations to help dentists communicate with patients; secondly,the shapes of wax frameworks and abutment teeth were captured and digitized by Sirona inEos system,and each individually shaped framework to grant a precise zirconia coping was created based on the reduced program of inLab V3.80 software.All restorations were veneered with VITA VM9. Results During the 18 months′ followup visit,none of the allceramic zirconia restorations had to be replaced due to framework fracture or unrestorable delamination of the ceramic veneer,the marginal fitness of restoration was quite well,and the shape and colour of all restorations satisfied the patients. Conclusions Based on the results of this study,it can be concluded that,diagnostic waxup is useful in helping dentists communicate with patients; allceramic crowns made by CAD/CAM reduced program can make proper room for veneering ceramic,which is helpful to improve the quality of allceramic zirconia restorations.

Objective To design a dental prosthesis retention pin and post system with better biomechanical function. Methods According to the actual biological stress of retention pin and post system in oral cavity,design a new pin and post structure,and carry on experiment on teeth in vitro. Results The designed twoway bone threaded retention pins with Φ 0.75 could improve the retention force by 30~140 N,and the steps could further improve resistance to chewing force by 20~50 N. Conclusions The pin and post system can increase the value of resistance to chewing force,reduce the harm to tooth dentin caused by metal with high modulus of elasticity,improve the repair and retention effect,and extend the life of retention.

Objective The research selected totaletching and selfetching adhesives to compare their bond strength with the remineralized dentin in different etching time periods, which could provide certain theoretical instructions for a better controlling of etching time under clinical situations. Methods Collect 40 human molars of which chronic caries had reached the middle level of dentin. Get rid of decalcified dentin caused by caries lesion, and keep remineralized dentin. Section all teeth into three parts by paralleling the long axis, and then etch them with 35% Gluma etching reagent (or reagent) for 20, 40 and 60 seconds. Use totaletching and selfetching dentin adhesives respectively on dentin, and then build up the crown with resin. Cut the teeth into rectangular shape samples with a cross section of about 1 mm2 with a lowspeed saw, and observe them under a stereoscope microscope to distinguish normal dentin and remineralized dentin. Besides, bond strength was inspected with microtensile testing instrument. Results As to remineralized dentin, the microtensile bond strength in 40 s group was higher than that in the 20 s group and that in the 60 s group (P>0.05); but there was no significant difference between the 20 s group and 60 s group(P>0.05). Conclusions Etching time exerts an influence on the bond strength of remineralized dentin. There should be expanded etching time spans for remineralized dentin.

Abstract： Objective To analyze the application effect of Sofreliner.MS soft lining materials in maxillary unilateral distal-extension removable partial denture. Methods 68 cases of maxillary unilateral free deletion in our hospital were selected and randomly divided into the test group and the control group, with 34 cases in each group. Conventional thermoplastic resin material was used for fabrication of removable partial denture in control group, while Sofreliner.MS self-curing silicone soft material was used for denture in observation group. The treatment effects of denture in two groups were compared. Results The absorbance value of patients in test group was 0.51 ±0.02, while the absorbance value in control group was 0.29±0.03. The absorbance values in two groups were compared, and the difference was statistically significant (P<0.05); The treatment effect and satisfaction of denture in test group were both higher than those in control group (P<0.05). Conclusion Sofreliner.MS soft lining material can improve the repair effect of maxillary unilateral distal-extension removable partial denture. Clinical promotion is recommended.

Objective To observe the effects of emodin in combination with baicalin on inflammatory factor of gingival tissue in rats with periodontitis. Methods Periodontitis models in SD rats were prepared with ligation method and highcarbonhydrate diet.They were randomly divided into blank control group,model group,tinidazole group,baicalin group,emodin group,and emodin together with baicalin group.Rats were sacrificed in the 4th week and 8th week separately.Homogenate of gingival tissues was collected from each group to determine contents of TNFα、IL6 with ELISA method. Results After building models in rats,their periodontitis symptoms were obvious.Contents of TNFα、IL6 in tissues rose to different degrees,which was most obvious in the model group.Levels of TNFα、IL6 in gingival tissues in combination group were significantly lower than those in emodin group（P<0.05） in the 4th week and 8th week.In the 4th week,the levels of TNFα、IL6 in combination group were significantly lower than those in baicalin group（P<0.05）,while there was no difference between the two groups in the 8th week. Conclusions Combined application of emodin and baicalin can remarkably reduce the contents of TNFα、IL6 in gingival tissue in rats with periodontitis,which is better than single application of emodin or baicalin.

Objective 　To observe the clinical effects of nylon wire resin splint on dental traumatic loose tooth fixation. Methods A total of 100 cases of dental traumatic loose teeth were randomly divided into the experimental group and the control group.Nylon wire resin splints were used in the experimental group,while arch bar splints were used in the control group.The outcomes were observed. Results The effective rate（96.00%）of the experimental group was significantly higher than that（80.00%）of the control group（P<0.05）. Conclusions Nylon wire resin splint is a reliable and effective tool for dental traumatic loose tooth fixation.It is pleasing and easy to clean.Besides,it has low irritation with high performance.

Regional odontodysplasia is an unusual developmental anomaly in which ectodermal and mesodermal tooth components are affected.We present a rare case of regional odontodysplasia or hamely“ghost teeth”.The anomaly affected teeth are right maxillary permanent teeth，but the mandibular teeth are unaffected.The clinical and radiographic features are reviewed.The therapeutic method of affected patients is discussed.

Electrical burn in oral and maxillofacial region can produce serious disfunction to patients.We reported an unusual case of electrical injuries that involves the right orbital,zygomaticofacial and left submandibular regions.The patient lost his sight of the right eye,and the right eyeball was enucleated in the debridement.The medial upper arm free flaps were used to repair the defect of the right orbital region.After the flap was transplanted,the wound in the supply region and the left submandibular region was covered with skin graft in middle thickness.In his followup examination 1 month after surgery,the defect was satisfactorily reconstructed in appearence in the right orbital region,and the evidences of wound infection were not observed in his left submandibular region.

Objective To investigate the dentition defect and prosthesis conditions of Tibetans. Methods Tibetan patients who visited our department from 2007 to 2010 completed questionnaire and were clinically examined. Results The rate of patients with dentition defect was 78.8%.The older the patients were,the higher the rate went.The rate of patients with removable partial denture repaired was 28.4%，while the rate of patients with fixed partial denture repaired was 18.7%. Conclusions The dentition defect conditions of Tibetans were serious.Their repair rate of dentition defect was low.They had inadequate understanding of dental prosthesis.We should strengthen oral health education and standard prosthodontic treatment.

【Abstract】 Objective To investigate the situation of dental heath and oral disease of the pregnant women in the second trimester. Objective To investigate the situation of dental heath and oral disease of the pregnant women in the second trimester. Methods 845 pregnant women who visited our hospital for prenetal examination from Apr.2009 to Aug.2010 were inquired with questionairs and examinated clinically. Results The incidence of tooth decay,gingivitis and periodontis was 43.67%,84.38% and 8.28% respectively.The incidence of prepregnancy oral health care was only 22.2%.Food debris and dental tartar were the main causes of gingivitis and periodontis. Conclusions It is important to strengthen oral health education for prepregnant and pregnant women.

Objective To investigate the prevalence of caries in native children and nonnative children located in Changning District of Shanghai. Methods A survey of caries was performed in 645 native children and 614 nonnative children in Shanghai according to the Criteria for National Oral Epidemiologic Survey. Results Caries prevalence rate in deciduous teeth of native children was 26.98%,dmft was 0.87 and dmfs was 1.51. Caries prevalence rate in deciduous teeth of nonnative children was 47.07%,dmft was 1.76 and dmfs was 3.08.There was significant difference between two groups(P<0.01). Conclusions Prevalence of deciduous tooth caries in 3yearold nonnative children in Changning District of Shanghai is obviously higher than that in native children in this district.More attention should be addressed to caries prevention and treatment in nonnative children.