Fiber Optic Displacement Sensor Using Multimode Plastic Fiber Probe and Tooth Surface

The principle of operation, experimentation, and performance of a fiber optic displacement sensor on a tooth surface is presented. The performances of this sensor are investigated by correlating the detector output with different probe configurations and various teeth samples with different surface reflectivity properties. With a multimode plastic bundled fiber probe, the sensitivities for the molar, canine, hybrid composite resin, and acrylic surfaces are obtained at 0.9667, 0.775, 0.5109, and 0.25 mV/mm, respectively, with a good linearity of more than 99% based on the analysis of the front slope. With a multimode plastic coupler, the sensitivities for the molar, canine, hybrid composite resin, and acrylic surfaces are obtained at 0.3538, 0.2951, 0.2069, and 0.1579 mV/mm, respectively. This proves that the sensor is capable of discriminating between different teeth surfaces. Such results are useful as guidelines for tooth surface related research, such as tooth surface profiling and measurement of tooth surface roughness.