Objective:To evaluate the masking ability of the Rely XTM Veneer try-in pastes. Methods: 100 discolored teeth, including 50 nonvital ones and 50 vital ones, has been collected and restored respectively with all-ceramic crowns and veneers. Five try-in pastes including A1, A3, Translucent (Trt), White opaque(WOT) and B0.5 Opaque(B0.5),which were different in shade, were used to try in before adhesion. The color was measured by a digital colorimeter, and expressed in terms of 3 coordinate values(L*、a*、b*) of the CIE1976- L*a*b* system.Then the color differences of crowns and veneers ?E=[(?L*)2+(?a*)2+(?b*)2]1/2 as well as the value of Light (L= L*)、Chroma[C=〔(a*)2+(b*)2〕1/2] and Hue [H=arctan(b*/a*)] were calculated. The thickness of the measurement point was also measured and recorded. A one-way ANOVA was used to analyze ?E as well as L, C and H. Results:The chromatism of the veneers after try-in was higher than that of the crowns(P

Objective To investigate the effects of the thickness of the adhesives(3 M ESPE RelyX ARC)on the internal stress distribution of the IPS Empress Ⅱ full-ceramic crowns by using Finite Element Analysis(FEA).Method A dummy Empress Ⅱ ceramic crown restoration of the mandible right first molar was prepared according to standard dental process.Followed by micro-CT scanning,four 3D numerical models with cement thickness 60,90,120 and 150 μm were established respectively.The models were subjected to four loading conditions and stresses in veneer and core layers were presented.Result Numerical results indicate that when adhesive thickness increases from 60 μm to 90 μm,the maximum principal stress either in veneer or core decreases.However,when thickness increases to 150 μm,stress variation trends differ from adhesives.Conclusions The normal stresses in adhesives remain a low level when the thickness varies from 90 μm to 120 μm,while the shear stress is less sensitive to the thickness when it exceeds 90 μm.There is an optimal thickness which can reduce the tensile stress in the core and veneer.Attention should be paid to the shear strength of the adhesives since the shear stress could cause failure in the adhesive layer.

Objective To explore new method to improve the teaching effects of complete denture prosthetics.Methods Totally 49 students were divided into 6 groups randomly.Lecture-based learning (LBL) combined with problem-based learning (PBL) methods were tried in complete denture prosthetics teaching.LBL teaching was made up of 18 class hours,in which teachers' teaching in the form of lecture was given priority to and introduction to basic theory of complete denture was focused on.PBL teaching was made up of 6 class hours in the form of small class ； the teaching plan ' new dentures of uncle Wang' compiled by the teaching and research section was taken as the blueprint；students searched for the references and discussed on the upcoming problems,relevant reasons and processing methods for wearing new dentures ； students made the final report.The effects were estimated by denture prosthodontics examination and PBL teaching feedback form.Data were described by percentage.Results 93.88％ students passed the exam,67.35％ students got good results.Feedback showed that 77.55％ students hold a positive attitude to PBL teaching.Conclusion Combining LBL with PBL in complete denture prosthetics teaching can achieve satisfactory results.

OBJECTIVEThis study was about the influence of porcelain thickness on crack at interface.

METHODSThe effect of porcelain thickness on the flaw at the interface between porcelain and metal was studied in three groups with porcelain thickness of 0.5 mm, 1.5 mm and 2.5 mm (metal thickness of 0.5 mm) by means of moire interferometre and interfacial fracture mechanics. The parameter Jc was compared among the three groups and the growing of the flaw was observed.

RESULTSJc and the extreme strength of group with porcelain thickness of 0.5 mm (2.813 N/m and 9.979 N) were lower than those of the groups with porcelain thickness of 1.5 mm and 2.5 mm (5.395 N/m, 19.134 N and 5.429 N/m, 19.256 N). Flaws extend along the interface in the groups with porcelain thickness of 1.5 mm and 0.5 mm.

CONCLUSIONS(1) Fracture resistance of the interface in the groups with porcelain thickness of 1.5 mm and 2.5 mm is similar and it decreases in the group with 0.5 mm thick porcelain. (2) When porcelain is 1.5 mm or 0.5 mm thick, flaws will extend along the interface. When porcelain is 2.5 mm thick, flaws will extend into the porcelain layer.

Objective To develop the technique to detect total core antigen of HCV(Total HCV-cAg) by Enzyme-Linked Immu-nosorbent Assay (ELISA) and apply it for clinical diagnosis. Methods 201 serum samples with anti-HCV antibody were detected total HCV-cAg after pre - treating the samples, then the sensitivity of results were compared with HCV RNA tests. Among them, 176 cases was determined by FQ-PCR, and 25 cases by RT-PCR for HCV-RNA. Results HCV RNA was found in sera from 88 of 201 samples (43.8%). Total HCV-cAg was positive in 71 (35.3%) of 201 samples . There was no significant difference between the detection rate of HCV RNA by PCR and total HCV-cAg by ELISA. Conclusion Detection of total core antigen of HCV is suitable to be used as to diagnose HCV in clinic.

Objective: To investigate the effects of the related factors on the aesthetic implant restoration of anterior maxilla with a typical case report. Methods : A patient, who was failed with metal-ceramic bridge half year, required an implant restoration. Before treatment, a thorough clinical and radiological examination and a SAC classification were done. The teeth were extracted in mininal truama without flap reflection, and implants were inserted with delayed restoration. A provisional restoration supported by temporary abutment was placed to guide the development of the soft tissues. Then the final impression with the custom-made transcopings was made. And a screwretention metal-resin bridge was made with CAD/CAM titanium framework. Results: During follow-up the dental implants and provisional restoration provided the patient with good esthetics, pronunciation and chewing function. Conclusion Many factors may affect the success rates and asethetic effect of anterior implant restorations. Indications, pre-surgical assessments, treatments are keys to aesthetic implant restoration.

Objective: To investigate the acceptance status of internet+health management among hypertensive patients in Xuzhou city and the related influencing factors. Methods: An interviewing questionnaire survey on the acceptance of internet+health management was conducted among 1,200 hypertensive patients from Xuzhou community health service centers selected by randomized cluster sampling and stratified sampling methods from February tp August 2018, 1 116 valid questionnaires were finally obtained with a response rate of 93.0%. The respondents were divided into two groups according to whether they would accept the internet+health management, and the general conditions and health management status of the two groups were compared. Results: The acceptance rate of internet+health management was 71.9% (802/1 116). The univariate analysis showed that age, education level, occupation, and monthly income of hypertensive patients were associated with the acceptance of internet+health management (P<0.05); patients with family history of hypertension, cardiovascular and cerebrovascular complications and high health literacy had higher acceptance rate of internet+health management (P<0.05). Multivariate analysis showed that educational levels of junior high school and above (OR=0.426, 0.318, 0.089), good sleep (OR=0.453) were protective factors for acceptance of internet+health management; while not knowing the diagnostic criteria for hypertension (OR=1.494), not knowing the blood pressure monitoring (OR=2.668), not knowing ECG monitoring (OR=2.247), quitting smoking (OR=2.444), no complications (OR=2.247), and not participating in community health management (OR=1.758) were the risk factors of acceptance of internet+health management for patients with hypertension. Conclusion The acceptance rate of internet+health management among hypertensive patients in Xuzhou city is relatively high. A variety of factors have impact on the acceptance of internet + health management.