| Popis: |
To compare the center of resistance (Cres) of the maxillary central incisor in models with and without the pulp cavity and to evaluate the association of pulp cavity/tooth volume ratio and difference in Cres position between the two models.CBCT images of the right maxillary central incisor were collected from 18 subjects. Pulp cavity/tooth volume ratio was measured, and finite element models of teeth and periodontal structures were generated. Cres location was presented as a percentage of root length measured from the root apex. Differences in Cres positions between models were compared using the paired t-test, while the correlation between pulp cavity/tooth volume ratio and a difference in Cres was evaluated by Pearson's correlation coefficient.For the pulp cavity model, the average location of the Cres measured from the apex of the root was 58.8% ± 3.0%, which resulted in a difference of 4.1% ± 1.1% (0.5 mm) apically, when compared with the model without pulp cavity. Differences in Cres between the models were statistically significant (P 0.01), while the correlation between pulp cavity/tooth volume ratio and a difference in Cres between models was significantly positive (r = 0.709, P = 0.001).In the pulp cavity model, the Cres was located in a more apical position. The difference in Cres between models increased as the pulp cavity/tooth volume ratio increased.The line of force must be applied more apically in the pulp cavity model to achieve the desired orthodontic tooth movement. |
Full text from SpringerLink