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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Maxillary central incisor crown-root relationships in Class I normal occlusions and Class II division 2 malocclusions

Bauer, Thomas J. 01 May 2014 (has links)
Introduction: The purposes of this study were several. The first was to establish a mean value for the crown-to-root angle, or collum angle (CA), for maxillary central incisors in Class I normal occlusions. The second was to create a new crown-to-root angle based on anatomic points, the labial crown-root angle (LCRA), and correlate it with the CA for Class I normal occlusions and Class II division 2 malocclusions. Third, torque values were measured for maxillary central incisors using these anatomic points, and mean values were calculated for Class I normal occlusions and Class II division 2 malocclusions. Finally, mean values for CA and LCRA were analyzed for Class I normal occlusions and Class II division 2 malocclusions to detect differences between the two groups. Methods: 51 Class I normal samples and 42 Class II division 2 samples who met the inclusion criteria were studied cephalometrically. Relevant landmarks were placed, analyzed for reliability, and recorded for the measurements of interest. Results: The mean CA for Class I normal occlusions was not statistically different from zero (p= .0657). A strong increasing correlation between CA and LCRA was found for all samples (Pearson's correlation coefficient = 0.88, p < .0001). Mean torque values for Class I normal occlusions and Class II division 2 malocclusions were statistically different (3.95±10.85 degrees vs. 12.54±5.82 degrees, p < .0001). The mean CA for Class I normal occlusions and Class II division 2 malocclusions were statistically different (4.29±5.77 degrees vs. 1.78±3.94 degrees, p = .0178). The mean LCRA for Class I normal occlusions and Class II division 2 malocclusions were statistically different (31.60±4.24 degrees vs. 34.84±5.95 degrees, p = .00037). Conclusions: The mean CA in Class I normal occlusions is not statistically different from zero degrees. The LCRA is strongly correlated with the CA in both Class I normal occlusions and Class II division 2 malocclusions. The mean maxillary central incisor torque values for Class I normal occlusions is similar to that found in bracket prescriptions currently offered. Patients with Class II division 2 malocclusion exhibit statistically higher mean CA and LCRA values than patients with Class I ideal occlusion.

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