Assessing Gloss of Tooth using Digital Imaging

The aim of this study was to assess gloss of tooth by digital photography. A gonio-imaging system (gonio being Greek for angle) was developed to measure the gloss of human teeth in a laboratorial stage. Polarised and non -polarised images were acquired around the specular angle. The gloss component was extracted and normalised to a theoretical standard; a BRDF curve was built to describe the gloss profile of the subject. Porcelain teeth were used to test the repeatability of the system and several human lateral teeth were etched to check the system’s capability to detect gloss changes. In addition to the BRDF, the area under the curve was calculated to give a quantitative value of gloss. The comparison result between the original and etched teeth can prove the validation of the gonio¬imaging system for measuring tooth-gloss changes.