| Autor: |
Dankmar Ihlow, Michael Cronau, Dietmar Kubein-Meesenburg, Gernot Heine, Henning Dathe, Claudia Hansen, Hans Nägerl |
| Zdroj: |
Journal of Orofacial Orthopedics/Fortschritte der Kieferorthopadie; May2003, Vol. 64 Issue 5, p321-329, 10p |
| Abstrakt: |
For analysis of the initial tooth movement in vivo, an optical measuring apparatus with a resolution of 0,001 degrees for rotation or 0.5 µm for translation respectively has been developed. Its design is described in detail. Because of its high sensitivity it is experimentally feasible to investigate the biomechanical properties of the periodontium under force application and to determine if it makes any difference whether a tooth is rotated mesially or distally out of its neutral position. For that purpose moments with defined time responses are buccally applied to premolars by means of a cardan shaft and the corresponding rotational angle-time characteristics are recorded. As expected, first measurements show sign symmetry for widely spaced teeth. In the case of pronounced anterior crowding, however, asymmetry seems to occur in such a manner that the force system has to overcome a threshold in order to rotate the tooth distally. Additionally, the periodontium may be subject to a sign-dependent rigidity. In all cases, the movement is limited to some degree. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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