Korean J Orthod.  2022 Nov;52(6):432-438. 10.4041/kjod22.126.

Crown-root angulations of the maxillary anterior teeth according to malocclusions: A cone-beam computed tomography study in Korean population

• Lee KH
• Choi DS
• Jang I
• Cha BK

• KMID: 2536336
• DOI: http://doi.org/10.4041/kjod22.126

Abstract

Objective
To compare crown-root angulations of the permanent maxillary anterior teeth in skeletal Class I, Class II, and Class III Korean malocclusion patients using cone-bean computed tomography (CBCT) images.
Methods
Sixty CBCT images were collected from orthodontic patients archive based on skeletal Class I (0˚< A point-nasion-B point angle [ANB] < 4˚), Class II (ANB ≥ 4˚), and Class III (ANB ≤ 0˚) to have 20 samples in each group. Mesiodistal crown-root angulation (MDCRA) and labiolingual crown-root angulation (LLCRA) were evaluated after orientation of images. Crown-root angulations were compared among Class I, Class II, and Class III groups and among the maxillary anterior teeth in each group.
Results
LLCRAs of the maxillary central incisor and the lateral incisor were significantly lower in Class III group than those in Class I group. However, those of the canine showed no significant differences among groups. MDCRAs of the maxillary anterior teeth did not significantly differ among groups either.
Conclusions
Our results suggest that skeletal Class III malocclusion might affect LLCRA of the maxillary incisors, especially the central incisor.

Keyword

Computed tomography; Tooth shape; Class III; Malocclusion

Figure

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  Figure 1 Four reference points: apex, mesial cementoenamel junction (M-CEJ), distal cementoenamle junction (D-CEJ), and cingulum. A, Coronal view. B, Proximal view.

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  Figure 2 Three-dimensional orientation of tooth. A, X-axis is the line passing through mesial cementoenamel junction (M-CEJ) and distal cementoenamle junction (D-CEJ). Y-axis is the line passing through the projected distal CEJ (D-CEJ’) and cingulum point (Cingulum’) on the sagittal reference plane. B, Z-axis is the cross product of the X-axis and Y-axis.

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  Figure 3 Measurement of the crown-root angulation (CRA). A, Mesiodistal CRA (MDCRA) in the coronal plane. B, Labiolingual CRA (LLCRA) in the sagittal plane.

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