Cone-beam computed tomography for evaluating root length of maxillary and mandibular anterior teeth in open bite patients.

Objectives: To compare the root length of maxillary and mandibular anterior teeth between open bite patients and normal overbite patients via cone-beam computed tomography (CBCT) as well as the root length of anterior teeth in different degree of open bite patients, and to analyze the correlation between the degree of open bite and root length.

Methods: A total of 106 untreated patients were enrolled retrospectively (53 anterior open bite patients and 53 normal overbite patients).Three-dimensional position of the CBCT image for the patient's teeth was performed using Dolphin software. The median sagittal plane of the tooth was used as the measurement plane, and the line connecting the apical point and the midpoint between the labial and lingual cementoenamel junctions was defined as the root length. Independent -test was used to compare the difference of anterior root length between the open bite group and normal overbite group, mild open bite group and moderate-severe open bite group. Pearson correlation analysis was used to explore the correlation between the degree of open bite and the root length of anterior teeth.

Results: Significant differences were found in the root length of maxillary and mandibular anterior teeth between the open bite group and the normal overbite group (<0.001), and there was significant difference in root length of mandibular central incisor between mild open bite group and moderate-severe open bite group (=0.039). Pearson correlation analysis showed that maxillary anterior teeth were correlated with root length of anterior teeth (all <0.05).

Conclusions: The root length of maxillary and mandibular anterior teeth in the open bite patients is shorter than that in the normal overbite patients, and the severer the degree of open bite, the shorter the root length of the mandibular central incisor tends to be. There is a certain relationship between maxillary anterior teeth and the root length of anterior teeth.