Schematic illustration showing the criteria used to define the position of the impacted maxillary canine: Angle α = the angle formed between the long axis of the impacted canine and the inter-incisor median line; Distance d = the distance between the peak of the impacted cuspid and the occlusal plane; Sectors = the area in which the impacted cuspid is located, divided in sector 1 between the inter-incisor median line and the long axis of the central incisor, sector 2 between the long axes of the lateral and central incisors, sector 3 between the long axes of the lateral incisor and the first premolar.