Objective: To measure the convergence angles of teeth in different teeth positions and different denture designs.Methods:Mesio-distal widths and labio-lingual widths were measured on 226 teeth according to three points in a line on three surfaces (gingival, middle and incise) of each tooth.The distance between every point and the counterpart point in the adjacent surface was measured.Then convergence angles were calculated. Results:The means of the angles were 4.13°±0.77°,4.14°±0.76°, 4.46°±0.95°, 4.76°±0.84° on the first and second premolar, the first and second molar,respectively . There were significant differences between the premolars and molars(P<0.05).On the dentures with the designs of monocrown, triunit-bridge and long bridge the means of the angles were 3.78°±0.74°,4.69°±0.75° and 5.08°±0.85° respectively,the angle on the denture with the design of monocrown was smaller than that of bridge (P<0.05).Conclusion:The convergence angles are different according to different teeth positions and different denture designs, so they should be adjusted according to the clinical requirements.

0.01). There was a significant difference in TIMP-1,-2 expressions between saccule injury group and control group (P

s〕 Objective:To investigate the influence of repeated firings on the color of porcelain fused to metal crown(PFM) . Methods: 5 PFM samples were prepared and fired for 9 times.The color of the samples was measured following firing with CIE1976 L*a*b* color system . The color difference ?E ab *,hue angle h ab * and chroma C ab * were calculated according to the following calculations:?E ab * ={(?L*) 2 +(?a*) 2 +(?b*) 2} 1/2 , C ab * ={(a*) 2+(b*) 2} 1/2 , h ab *=tg 1 b*/ a*, L* presented brightness. Results: After repeated firing, L* value of PFM , C ab * and L* value of dentin layer and h ab * value of opaque layer increased. Conclusion: The color of PFM after repeated firing may become brighter. The color change is resulted from the increase of L* and C ab * of dentin layer.

Objective: To study the influence of repeated firings on the PFM bond strength. Methods: 25 specimens of PFM in the diameter of 13.0 mm and thickness of (1.0?0.02) mm were prepared and fired at 920 ℃ for 1, 3, 5, 7 or 9 times(5 samples for each time). The remained porcelain rate(RPR) was measured by Mackert method and used to evaluate the bond strength.Results: After 3 firings, the RPR of PFM decreased obviously, and additional firings had no obvious effect on the RPR. Conclusion: 3 times firing or more may decrease the bond strength of PFM.

0.05,group 1 or group 2 vs group 3 P

AIM: To synthesize a number of novel heterocyclic compounds and screen for their biological activities. Sixteen title compounds were prepared. METHODS: These novel compounds were prepared by the reaction of 3-aryl/aryloxymethyl-4-amino-5-mercapto-1,2,4-triazoles with aryl carboxylic acids in the presence of phosphorus oxychloride. The structures of these compounds were confirmed by elemental analysis, IR, 1HNMR and MS. The reaction conditions for the synthesis had been investigated. All the compounds were screened for antimicrobial activity against bacteria S.aureus, E.coli and B.subilis. The concentration of the test compounds was 0.002%. The antibacterial activities of the test compounds were compared with those of penicillin and gentamicin. RESULTS: The results display that some of them possess strong biological activities.CONCLUSION: Syntheses of these novel heterocyclic compounds and study on their biological activities are very important and valuable in medicine.

Objective To study the effect of glutamine on hypermetabolism reaction and hormone secretion after severe burn injury. Methods Eighty-eight Wistar rats were inflicted with 30% total body surface area full thickness burns and randomly divided into two groups: namely burned control (B) and glutamine treatment(GLN) group. There was isonitrogenous and isocaloric intake in both groups, and rats of GLN and B groups were given glutamine and glycine at 1 0g/kg d, respectively. The following indices including the resting energy expenditure (REE), the levels of plasma cortisol, insulin and glucagon were determined. Results After burn injury, the REE, plasma cortisol,insulin and glucagons levels were significant increased in both groups. Compared with B group, the level of REE decreased and the ratio of insulin/glucagons increased in GLN group. Correlation analyses showed that REE had a negative correlation with insulin/glucagons ratio (r=-0 78,P

Objective:To study the sensitization of two newly developed titanium alloys, TLE and TLM.Methods:According to ISO 10993-10:1995 standard,maximization test was conducted in guinea pig.The skin sensitization reactions,including erythema and oedema, induced by TLE, TLM, normal saline and 2,4-dinitrochlorobenzene were observed and scored respectively at 24,48 and 72 h exposure of the infusion of the materials. The allergenic rates and mean response score were calculated.Results:The allergenic rates and score of skin reaction of TLE and TLM were 0/15 and 0,those of normal saline 0/15 and 0,those of 2,4-dinitrochlo-robenzene 15/15 and 5,respectively.Conclusion: TLE and TLM both are not of sensitization.

Objetive:To detect the gene mutation of a patient with anhidrotic ectodermal dysplasia. Methods: Genomic DNA was extracted from the peripheral blood of the patient and all the exon fragments were obtained by PCR. These fragments were sequenced directly. Results: In EDA gene a novel base transition was detected: -48A→G. Conclusion: There is a new base transition in EDA gene in this patient