Zahn-, Mund-, und Kieferheilkunde mit Zentralblatt最新文献

The tensile strength of adhesive metal bonds of the alloys Gisadent KCM degrees, KCM 83 degrees and NCA degrees with the adhesive materials Evicrol degrees, Spofacryl degrees and ABC-Cement degrees has been determined in dependence on the conditioning methods sandblasting, electrolytic etching and Silicoater degrees treatment. The Silicoater degrees treatment was found to be the most successful conditioning method independent on the alloy and the used adhesives. After electrolytic etching increased bond strength values are to be expected particularly with Gisadent NCA degrees. Independent on the used alloy and the conditioning method Spofacryl degrees shows the best adhesive properties of the tested adhesive materials.

The concentration of lead in four layers of dental hard tissues was analysed in 108 deciduous teeth of children from nine places of the G.D.R.. The result was a typical gradient from enamel to dentine. The average concentration of lead corresponds with that of other industrial countries. Although regional differences were found equal exposition of lead for both urban and rural areas can be assumed.

Selected material properties of hot and cold polymerized denture basic materials (polymethylmethacrylate) were investigated after different methods of isolation: alginate, tin foil and silicone. Both tin foil and silicone isolation the handling of which is much easier result in a decreased portion of porosities and an increased microhardness in the PMMA.

Sagittal split osteotomy by Obwegeser and Dal Pont with lag screw osteosynthesis by Spiessl is a promising method of treatment for the surgical correction of progenia. Functional and aesthetic results of this method are well. Lesions of the mandibular nerve require subtle technique of operation.

Model impact tests on 3-dimensional PMMA eye models with a swing type impact tester (Dynstat) were performed. There are three kinds of impact tests; the impact to the eyeball alone, the impact to the eyeball and infraorbital margin, and the impact to the isolated infraorbital margin. All impact tests of eye models were recorded by high speed camera with 3,000 pictures per second. Analysis of impact tests showed, that the primary factor of blow-out fractures was deformation of the eyeball by kinetic energy of impact. Transmission of impact force by deformed eyeball to orbital walls is causing blow-out fractures on the weakest areas of the orbit without fracturing the orbital rim. Against the present accepted theories of "hydraulic force" und "buckling force" this is a new theory for pathomechanism of blow-out fractures. Our experimental results support the clinical investigations on treated patients.

In two studies with a total of 16 test persons, gingival temperature being a measure of blood flow was taken in the region of the front teeth, canines and molars in defined intervals. Gingival temperature has got--like other biological criteria--a circadian rhythmic that may be both of therapeutical and methodical value.

As a base for single crowns and bridge anchors the individual casted construction combined with the manufactured root post offers undisputed advantages. At casting silver-palladium alloys, the root posts possibly may change the characteristic properties of their material. The casting reactions of sipal with cylindrical pins made of pure titanium (EMO Ti110) and root posts with adhesion head made of implant steel (URX2CrNiMoN18.12(0] was investigated. Interstice-free castings of sipal to pin from implant steel and titanium can be demonstrated by means of pictures of metallographic (grinding) specimens investigated by light- and electron-beam microscopy. The casting quality is identified mainly by selection of the embedding mass, the rise of the preheating temperature and period of preheating.

For further elucidation of the connection between tumor differentiation, intensity of stroma reaction and the capacity of prostacyclin biosynthesis comparable investigations were performed on the PGI2 formation and the microscopic pattern of 10 tissue samples from naevus cell tumors, skin basalioma, oral pavement epithelium carcinoma and their direct adjoining region. The effects were compared with 10 tissues from healthy oral mucosa and facial skin. The results indicate that the PGI2 activity depends on the quantity of cells within the tissue. The various cells were stimulated in a different manner. The highest values of the PGI2 biosynthesis were found in cells of an inflammatory proliferation direct adjoining the oral pavement epithelium carcinoma. This shows a connection between tumor differentiation, intensity of stroma reaction and the activity of prostacyclin biosynthesis, possibly indicating a criterion of malignity for the prognosis of the tumor disease.