ERUPTION OF THE PERMANENT UPPER CANINE - A RADIOLOGIC STUDY

The early detection of eruptive anomalies of the upper canine requires an understanding of its normal eruptive pattern. We studied this patt ern in terms of upper canine inclination and its relation to the later al incisor, on the basis of the panoramic radiographic records of 305 children aged 4 to 12 years. The study sample comprised 554 maxillary canines in the oral pre-emergence phase of eruption. Subject age, sex, inclination of the canine (CI), its relation to the lateral incisor ( RCLI), and development of the lateral incisor (DLI) were evaluated. Th e results show that the canine erupts, increasing its inclination mesi ally until a maximum is reached, at about 9 years of age, after which the tooth begins to progressively upright itself. The individual varia bility of the degree of CI at a given age is considerable. In the init ial stages, the RCLI is most commonly characterized by overlapping, a situation rarely seen in the final stages. The DLI effectively discrim inates both periods, because when DLI is incomplete, more than half of the cases have an overlapping RCLI. In contrast. when the DLI is comp lete, this overlapping is seen in only 7% to 11% of the cases. This va riable therefore increases the capacity to detect a possible eruptive anomaly at an early stage. In patients with complete DLI and overlappi ng RCLI, particularly when associated with other clinical signs such a s the nonpalpation of the cuspid bulge in the alveolar process, the pr esence of dental agenesis, ankylosis, malformations, or ectopic erupti ons, extraction of the primary canine is advised to prevent impaction.