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- Title
On the Interaction between Incisor Crown-Root Morphology and Third-Order Angulation.
- Authors
Knösel, Michael; Jung, Klaus; Attin, Thomas; Engelke, Wilfried; Kubein-Meesenburg, Dietmar; Gripp-Rudolph, Liliam; Attin, Rengin
- Abstract
Objective: To evaluate the significance of crown-root angles (CRAs) by testing the null hypothesis that there are no significant differences in deviations of third-order angles to axial inclination values between Angle Class II division 2 incisors and a neutral occlusion control sample. Materials and Methods: The study group comprised ntotal = 130 whites with either Angle Class II division 2 (n1 = 62; group A) or neutral (n2 = 68; control group B) occlusal relationships. Upper central incisor inclination (U1) was assessed with reference to the cephalometric lines NA and palatal plane (U1NA/deg, U1PP/deg). Craniofacial sagittal and vertical relations were classified using angles SNA, SNB, ANB, and NSL-PP. Third-order angles were derived from corresponding dental cast pairs using an incisor inclination gauge. Welch's two-sample t-tests (α-level: .05) were used to test the null hypothesis. Single linear regression was applied to determine third-order angle values as a function of axial inclination values (U1NA, U1PP) or sagittal craniofacial structures (ANB angle), separately for group A and B. Results: The discrepancy between axial inclination (U1NA, U1PP) and third-order angles is significantly different (P < .001) between groups A and B. Regression analysis revealed a simply moderate correlation between third-order measurements and axial inclinations or sagittal craniofacial structures. Conclusion: The hypothesis is rejected. The results of this study warn against the use of identical third-order angles irrespective of diminished CRAs typical for Angle Class II division 2 subjects. Routine CRA assessment may be considered in orthodontic treatment planning of Angle Class II division 2 cases.
- Subjects
TEETH; CEPHALOMETRY; DENTAL arch; DENTAL therapeutics; DENTAL care; REGRESSION analysis
- Publication
Angle Orthodontist, 2009, Vol 79, Issue 3, p454
- ISSN
0003-3219
- Publication type
Article
- DOI
10.2319/0003-3219(2009)079[0454:OTIBIC]2.0.CO;2