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Biomedical subjects

G Schillai

Publications and source records attributed to G Schillai.

3 recordsLinked to original sources
PubMed1990

[The enamel surface quality after interproximal stripping--a scanning electron microscopic assessment of different polishing procedures].

The surface features of stripped human enamel were studied with the scanning electron microscope. The efficiency of rotating diamond and polishing discs was compared with that of diamond and polishing strips in a newly developed handpiece. Interproximal stripping with fine and superfine grit diamond coated discs and strips created furrows which were 10 microns in width. At the interface between treated and untreated enamel no hard tissue damage could be observed. Under in vitro conditions the furrows resulting from stripping were almost totally eliminated by using aluminum oxide coated strips or discs in automatically driven handpieces. After 60 s of polishing with each polishing strip/disc the treated enamel surfaces were nearly smooth. Only a few isolated furrows of 1 to maximum 3 microns were detected. As a result, we can state that it is possible to produce surfaces which are smoother than untreated natural enamel with the rotating or the oscillating polishing procedure.

Dental Enamel↗
PubMed1989

[Relation of the activation force and deflection in various orthodontic springs (closing-loops)].

For ten different forms of orthodontic springs, comprising three commercially available preformed types, the relationship between load (force) and the resulting deflection was determined experimentally. The experimental set-up consisted of a micrometric microscope containing a scale which could be calibrated and an optical bench so the springs could be fixed and activated by means of a force gauge in increments of 12.5 p up to 200 p. Ten springs of each of the ten forms were measured once. The results can be summarized as follows: The load-deflection rate of orthodontic springs depends on the modules of elasticity of the utilized alloy and the geometric configuration of the spring. For a given loop configuration the load-deflection rate is proportional to the modulus of elasticity. The more wire length used for shaping the spring elements (loops), the lower the load-deflection rate. With the exception of the Ladanyi retractor and the Bull loop all the springs examined showed a linear relationship between load and deflection. Because of the higher accuracy of force application and the relative force constancy during tooth movement, it is usually preferable to choose springs with a low load-deflection rate of about 50 p/mm.

Activator Appliances↗