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Title: Assessment of Tooth Colour using Digital Imaging
Author: Luo, Wen
ISNI:       0000 0004 2667 9939
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2008
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As tooth whitening has become a popular and routine dental procedure, the measurement of tooth colour, especially for the evaluation of the efficacy of the tooth-whitening products, has become important. One of the instrumental methods of assessing tooth whiteness is digital photography. The aim of this study was to develop a digital imaging method in colorimetry of human teeth which could be used for evaluating the efficacy of tooth-whitening products. The successful use .of a tooth-imaging system for assessing tooth whiteness relies upon two things: precise and preferably accurate colour-rendering for teeth, and an appropriate whiteness scale or index for quantifying the tooth whiteness according to human perception. These two things are the main objectives needed to be achieved in this study. The development of the tooth-imaging system consists of two essential procedures: calibration and characterisation. The imaging system was firstly calibrated according to the requirements of clinical tooth-colour measurement, including accurate control of the intensity of the light source with the aid of software. For camera characterisation, besides the traditional methods, efforts were made by choosing training samples that are physically similar to real human teeth for the characterisation model to improve the accuracy of the system. Two cameras were evaluated and several characterisation models were compared. Moreover, uncertainties involved in the clinical tooth-colour measurement were investigated as a complementarity to the performance of the tooth-imaging system. In order to find the relationship between the objective measurements and visual assessments of tooth whiteness, psychophysical experiments were conducted in a controlled viewing condition as well as a typical clinical viewing condition. A whiteness index for quantifying tooth whiteness was proposed and its performance was compared with some existing whiteness/yellowness indices. Finally, the validation of the tooth-imaging system and the tooth-whiteness index were assessed under the conditions of clinical whitening trials. In addition to the tooth-whiteness study, the gloss of tooth, as one part of the tooth appearance, was investigated on a gonio-imaging system which was verified by results from the repeatability test and the tooth-etching experiments.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available