2023 Volume 61 Issue 1 Pages 44-53
The patient was a 10-year-8-month-old boy who had severe root resorption of the adjacent maxillary lateral and central incisors reaching the pulpal chambers caused by ectopic impaction of the maxillary left canine. Those incisors had significant mobility. The dental follicle of the impacted canine was 3.5 mm thick and considered a dentigerous cyst. The canine cusp crossed the lateral incisor, Ericson's analysis of overlap of the root of the permanent incisors and the crown of the impacted canine was assessed as sector 4, and the angle of mesial inclination to the midline was 26.5°. More than 1/2 of the root length of the lateral incisor was resorbed, and the crown-to-root length ratio of the central incisor was 4 : 3, which was 64% of the root length of the contralateral central incisor. Since the ipsilateral mandibular lateral incisor was congenitally missing, we decided to extract the severely root-resorbed lateral incisor and to erupt the impacted canine distally to the central incisor.
Twelve months after the extraction of the deciduous canine and the permanent lateral incisor, the impacted canine spontaneously erupted, and the tooth axis was improved. Furthermore, as the apex of the canine was moved away from the root of the central incisor, root resorption of the central incisor stopped, regeneration of alveolar bone occurred, and tooth mobility disappeared.
The patient's oral findings at 2 years and 8 months after treatment were, including the rotation of the left maxillary canine, that malocclusion was minor. From X-ray images of the preserved maxillary left central incisor, an alveolar hard line was confirmed around the entire root circumference. Moreover, from CBCT images, it was confirmed that the root canal of the central incisor, which had been opened due to root resorption caused by the ectopically impacted canine, was tapered from the palatal to the labial direction due to the promotion of dentin formation in the dentin at the root tip and that an apical foramen had formed at the end.
These results suggest that the long-term prognosis of severely root-resorbed permanent incisors due to impacted canines may be improved by removing the cause. However, since root-resorbed incisors may become more mobile with age, careful oral management is considered necessary.
