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

0.05,group 1 or group 2 vs group 3 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.

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 investigate the effects of cerium oxide content on the color of alumina glass composite. Methods: Infiltration glass powder with different content of cerium oxide (1%～4%) were fabricated. Alumina glass composite was prepared by infiltrating molten glass into presintered alumina block at 1 250 ℃ for 2 h, and the color of the alumina glass composite were measured with Minolta chromatic instrument(CR 321) . For comparison, the color of VITA In Ceram alumina technical shade guide was recorded too. Results: After infiltration, the b * range of the alumina glass composite was in accord with that of the shade guide. With the increasing content of the cerium oxide, a *, b * and chroma increased, L * decreased, the hue of the alumina glass composite shifted from yellow green to yellow red. Conclusion: Cerium oxide may effectively enhance b * of the alumina glass composite, but its ability of reducing L * and enhancing a * is weak.

objective: To study the metal ceramic bond of reused surplus alloy of a precious metal ceramic alloy. Methods: The samples in control group for reused surplus alloy were treated by only remelting without adding any fresh alloy up to four generations, those in the test group by adding one third fresh alloy in each generation and up to four generations. Metal ceramic bond strength of the samples was surveied by pull shear test. Results: In control group, the pull shear bond strength (MPa) from generation Ⅰto Ⅳcastings was 47.53?2.02, 33.23?2.03, 25.08?1.88 and 14.61?1.56 respectively( P

A 61-year-old patient with type I diabetes, diabetic nephropathy, thyroid hypofunction, chronic renal insufficiency anemia period, class IV heart function. During kidney dialysis, a little bleeding when puncture needle punctured the right common carotid artery, bleeding stopped after compression hemostasis. One week later, the patient complained of swollen neck, pain and difficult breathing. Ultrasonic examination suggested that local eminence beside the right common carotid artery, echoless and vascular interlinked; CDFI blood flow signal appeared the artery frequency spectrum, eddy current. Enhanced CT prompted right common carotid artery pseudoaneurysm, the contrast medium extravasated. The patient was diagnosed right common carotid artery pseudoaneurysm.
Aneurysm, False ; surgery ; Carotid Artery, Common ; Humans ; Iatrogenic Disease ; Male ; Middle Aged