CBCT Analysis of Impacted Incisors: Bone and Root Parameter Differences

Objectives: To assess differences in alveolar bone and root parameters in subjects with unilateral impacted maxillary central incisors by cone-beam computed tomography in comparison with the contralateral, normally erupted maxillary central incisor.
Methods: A total of 22 subjects were included in the study; 14 with an impacted left central incisor and 8 with an impacted right central incisor. Alveolar bone width was measured at 2mm, 6mm, and 10mm apical to the alveolar crest to assess potential differences in bone width due to lack of eruption of the incisor. Also measured was the distance from the bony palate to the incisal edge of the impacted incisor, and incisal edge to the incisal edge of the normally impacted incisor to determine the severity of impaction of the sample group from a vertical perspective.
Results: There was a significant difference between the alveolar bone width at 6mm (p < 0.001) and 10mm (p = 0.002) apical to the alveolar crest of the impacted side [6mm: 11.61mm ± 2.67, 10mm: 12.44mm ± 3.23] and the non-impacted side [6mm: 9.09mm ± 1.77, 10mm: 10.31mm ± 2.68]. Length and morphology of the root was also evaluated. There was a significant reduction in root length (p < 0.00) of the impacted incisor compared to the normal incisor. Seven of the 22 impacted incisors were also found to have root dilaceration.The average distance from the palate to incisal edge was 15.77mm ± 6.96 and from incisal edge to occlusal edge was 14.25mm ± 5.42.
Conclusions: Alveolar bone width at 6mm and 10mm apical to the alveolar crest on the side of the impacted maxillary central incisor was found to be greater than the normally erupted side. Root length of the impacted incisors was less than the normally erupted incisor, but there was no association with root resorption of adjacent teeth.