Development of an illustrated index of tooth appearance–perception-based quantification of tooth discolouration and surface defects

Background.  Existing indices to quantify tooth discolouration are mostly aetiology-specific. An index of tooth appearance (IOTA), derived from all types of tooth discolouration and surface defects, would allow the quantification of attractiveness for psychological assessment and treatment planning Objective.  To develop a perception based IOTA for quantification of all forms of tooth discolouration and surface defects. Methods.  One hundred images of discoloured teeth were twice ranked by a panel of judges according to perceived attractiveness. Mean image score was then used to arrange the images into a continuum of attractiveness and from these, ten images were selected, to constitute the illustrated IOTA. A second panel of judges assessed 35 clinical pictures using the IOTA, on two occasions. Results.  The first 100 images were assessed with a correlation of 0.79–0.81 between the two ranking sessions and with intra-group reproducibility of 0.8–0.94. The second panel of judges used the developed IOTA quickly, with an intra-judge correlation of 0.87 and inter-judge reliability of 0.72 and 0.74 for two sessions. Conclusions.  The IOTA could be used by clinicians as a tool for quantifying disfigurement in teeth, irrespective of aetiology or histology.