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Changes in incisor third-order inclination resulting from vertical variation in lingual bracket placement
Michael Knösel1, Klaus Jung, Liliam Gripp-Rudolph
1Departmento of Orthodontics and Dentofacial Orthopedics, Center of Dentistry, Georg-August-University, Göttingen, Germany. mknoesel@yahoo.de
The Angle Orthodontist
|June 23, 2009
Summary
Third-order measurements correlate with lingual incisor features, allowing prediction of bracket placement variations from radiographs. This study rejects the null hypothesis, confirming a link between incisor anatomy and orthodontic treatment outcomes.
Area of Science:
- Orthodontics
- Dental Radiology
- Biometrics
Background:
- Understanding lingual incisor morphology is crucial for precise orthodontic bracket placement.
- Third-order angulation, a critical parameter in bracket positioning, is influenced by incisor features.
- Radiographic assessment offers a non-invasive method to evaluate incisor anatomy.
Purpose of the Study:
- To investigate the correlation between third-order measurements and lingual incisor features on radiographs.
- To test the null hypothesis that these measurements are not correlated.
Main Methods:
- Lateral headfilms of 38 subjects were analyzed for third-order measurements of central incisors.
- Inclination of four lingual bracket placement sites (S1-S4) was assessed relative to the occlusal plane.
- Regression analysis correlated radiographic measurements with incisor inclination gauge data from dental casts.
Main Results:
- The null hypothesis was rejected, indicating a significant correlation.
- A 0.4-0.7 degree change in third-order inclination is expected per degree of lingual surface inclination change at common bracket sites (S1, S2).
- Bracket placement error impact on third-order angulation is comparable across S1, S2, and S4; S3 showed the least variation.
Conclusions:
- Third-order measurements are indeed correlated with lingual incisor features.
- Radiographic assessments can predict individual variations in third-order changes due to lingual bracket placement.
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