The validation of a novel index assessing canine impactions

The aims of this study are to determine the level of agreement of orthodontists in the management of impacted maxillary canines and test this agreement against a novel three-dimensional (3D) classification system (KPG index).

A total of 55 clinicians evaluated 18 impacted maxillary canines of variable complexity. For each case, they used a panoramic and maxillary standard occlusal radiographs derived from cone beam computed tomography. Clinicians were asked to rate each canine in one of four categories: Easy, moderate, difficult and extremely difficult. The obtained scores were tabulated and compared with a novel index rating the difficulty of canine impactions. Statistical package for the social science 17.0 was used to analyze the datasets and the kappa score was used to determine levels of agreement.

The kappa score was 0.437. The levels of agreement in the novel index and the clinician scoring were as follows; easy (62.73%), moderate (60.59%), difficult (61.80%) and extremely difficult (72.72%).

THE FOLLOWING CONCLUSIONS CAN BE DRAWN FROM THIS STUDY: (1) Clinicians are variable in rating the complexity of canine impactions using traditional radiographic techniques. (2) The novel index shows a good level of agreement with the clinician's perception of difficulty in orthodontic cases especially at the extremes of the spectrum. (3) This index based on the 3D coordinates of the spatial arrangement of the canine may be incorporated into clinical practice.