Development and Application of Fiber Optic Curvature Sensor
Date Issued
2008
Date
2008
Author(s)
Lin, Min-Wei
Abstract
Due to the curved geometry of the root canal, the Ni-Ti rotary instruments are under rotating bending condition during the root canal treatment, which incurs alternating tensile and compressive stresses in the instruments. Such an alternating loading will lead to fatigue fracture. To predict the remaining life of a Ni-Ti rotary instrument, it is important to know curvature of the root canal. The purpose of this study was to develop fiber optic curvature sensors for measuring curvature in the root canal and deduced the curvature of a Ni-TI rotary instrument. The sensitive element of the curvature sensor was by fabricating one necked segment disposed within the distal section of the optical fiber and a metallic film was deposited on the distal end for reflecting light signal. The reduced diameters 30%, 50% and 70% of the original optical fiber were employed. The calibration results show that different reduced diameters displayed different sensitivities in curvature. The sensing mechanism of the curvature sensor was that when the distal section of the curvature sensor was bent so that attenuation of light signal occurred. Thereby the curvature could be evaluated in accordance with the amount of energy attenuation in the reflected light signal. The experimental results also show that the deduced bending curvature agreed well with the instrument curvature inside the canal.
Subjects
fiber optic curvature sensor
Ni-Ti rotary instrument
curvature measuring
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-97-R95522531-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):6357c645ac08668cc196150ff02e3cd5