Korean J Orthod.
1988 Sep;18(2):289-303.
Experimental study of the center of resistance of a maxillary canine using laser speckle interferometry and holographic interferometry
- Affiliations
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- 1Department of Dental Science, Graduate School, Yonsei University, Korea.
Abstract
- The center of resistance is a important determining factor of tooth movement pattern. Laser speckle interferometry, recently developed for noninvasive measurement of small displacements (microns), was used to detect the center of resistance of a maxillary canine which has normal tooth axis and distal curved root in dry human skull. Laser holographic interferometry was used to verify the results of laser speckle interferometry. The following result were obtained; 1. In measurement of the degree of rotation, center of resistance was localized when the traction line passed 4.4/18.0 level from alveola crest to root apex. 2. In measurement of the degree of tipping, center of resistance was localized when the traction line passed 4.6/18.0 level from alveola crest to root apex. 3. In holographic determination, the center of resistance was observed when the traction line passed between 3mm to 6mm level from alveola crest to root apex, therefore the results using laser speckle interferometry was coincided with holographic results.