Characteristics of Laser Speckle Measurement of Tooth Roughness

Abstract

This study is concerned with the fundamental characteristics of a new nondestructive measuring technique of the tooth roughness with precisely. In the dental clinics, the estimation of roughness of tooth surfaces with a hand explorer is one of the important tests for the finishing the crown re-shaping and resin fillings. If the tooth surface is rough enough to hold dental plaque, it occasio-nally causes dental diseases around it. Therefore, it is important to measure the roughness of the tooth surfaces for the prevention of furthermore distraction of the tooth. Laser speckle measurement is used as an evaluation method for objectively measuring the surface roughness with non-contact. In this study, a laser speckle measurement system for measuring the surface roughness is constructed. Comparison measurement is carried out for the tooth pieces with the various unidirectional roughness and the metallic test pieces with the standard roughness. The experimental results using the actual measuring system show some important points as follows. Firstly, there is a good correla-tion between the laser speckle pattern and the tooth roughness as well as that of the metallic test pieces. Secondly, the reflection from the tooth shows a different tendency in comparison with the reflection from the metallic test pieces.