Chemical constituents from Incarvillea sinensis var. przewalskii / 中草药

Objective: To investigate the chemical constituents from the whole plant of Incarvillea sinensis var. przewalskii, and a systematically phytochemical investigation was carried out. Methods: The chemical constituents were isolated by column chromatographies, such as silica gel and Sephadex LH-20 columns as well as semi-preparative HPLC, and their structures were determined on the basis of MS, NMR spectroscopic analyses, and/or comparison with literature data. Results: Thirteen compounds, including alkaloids and phenylethanoid glycosides, were isolated from the 80% ethanol extract of the whole plants. Their structures were elucidated as p-butoxyl-salidroside (1), incasine C (2), incarvillateine (3), 7-hydroxyskytanthine (4), incarvilline (5), phenethylalcohol glucoside (6), martynoside (7), acteoside (8), deacylisomartynoside (9), decaffeoy1acteoside (10), carceorioside B (11), salidroside (12), and deacylacteoside dimethyl ether (13). Conclusion: Compound 1 is a new one, and the other compounds are isolated from this species for the first time.

Detorque force and surface change of coated abutment screw after repeated closing and opening / 대한치과보철학회지

STATEMENT OF PROBLEM: Recently researches about WC/C (Tungsten Carbide/Carbon) or TiN (Titanium Nitride) coating on abutment screws are going on. It decreases friction coefficient, resistance against corrosion and withdrawal of physical fragility when the coating is applied to the metal surfaces. It is reported that coated abutment screws improved abrasion, adaptability and detorque force. PURPOSE: This study is about the effects of coated abutment screws on loosening of screw and for the purpose of solving the loosening phenomenon of abutment screws which is clinical problem. MATERIAL AND METHODS: Detorque force and surface changes are compared when 10 times of repeated closing and opening are applied to both uncoated titanium abutment screws (Group A) and coated abutment screws with WC/C (Group B) and TiN (Group C). Each group was made up of 10 abutment screws. RESULTS: 1. Before repeated closing and opening, Somewhat rough surface with regular direction was observed in Group A. Coated granules were observed in group B and group C and overall coated layer appeared in regular and smooth form. 2. Before repeated closing and opening, The coated surface showed bigger and thicker size of coated granules in Group C than Group B. 3. After repeated closing and opening, abrasion and deformation of abutment screw surface was observed in Group A and Group B. Exfoliation phenomenon was observed in Group B. 4. Group A showed biggest range of decrease when the weight changes of abutment screws were measured before and after repeated closing and opening. Group C showed less weight changes than Group B but there was no statistical difference between two groups. 5. Group B and Group C showed higher average detorque force than Group A and there was statistical difference. 6. Group A showed more prominent decrease tendency of average detorque force than Group B and Group C. CONCLUSION: Coated abutment screws with WC/C or TiN did not show prominent surface changes than uncoated titanium abutment screws even though they were repeatedly used. And they showed excellent resistance against friction and high detorque force. Thus it is considered that adaptation of WC/C or TiN coating on abutment screws will improve the screw loosening problem.

Influence of tungsten carbide/carbon coating of implant-abutment screw on screw loosening / 대한치과보철학회지

STATEMENT OF PROBLEM: Dental implant procedure has been recognized as a very effective treatment to rehabilitate fully or partially edentulous patients. However, mechanical failures such as screw loosening, screw fracture have been still reported frequently. PURPOSE: The purpose of this study was to evaluate the influence of tungsten carbide/carbon coating, which has superior hardness and frictional wear resistance, on implant-abutment screw loosening of three different joint connections after one million cyclic loading. MATERIAL AND METHODS: The values of detorque before and after loading were measured in three different joint connections (Osstem Implant, Korea), one external butt joint, US II implant system and two internal cones, SS II and GS II system. The values of detorque before loading was analyzed by one-way ANOVA, and two-way ANOVA and Scheffe'test were performed for the value of detorque after loading. RESULTS: 1. The values of initial detorque of tungsten carbide/carbon coated Ti alloy screw were smaller those of Ti alloy screw (P.05). 2. In comparison of loss rate of detorque value after cyclic loading, US II system was greater than SS II and GS II system but there was no difference between SS II and GS II system (P.05). CONCLUSION: Tungsten carbide/carbon coating to increase preload with reduction of friction resistance was a effective way to decrease screw loosening by functional loading.