RESUMEN
INTRODUCTION: In orthodontic treatment, an increased bone mineral density of the alveolar bone is considered as a risk factor for apical root resorption (ARR), whereas the mineral density of cementum has been associated with root protection against resorption. METHODS: This study aimed at evaluating the grey values (GVs) of the apical third of the root and of the alveolar bone adjacent to maxillary incisors with and without ARR in orthodontic patients. Twenty-one patients under treatment who presented one incisor with ARR and its corresponding contralateral without ARR were selected and submitted to cone-beam computed tomography. GVs were evaluated on the images obtained of four areas of the apical third of the root and of four areas of the adjacent alveolar bone. RESULTS AND CONCLUSIONS: The radicular tissue of the apical third of the incisors with ARR showed greater root GV (p < .05) than that of the incisors without ARR. Supra-apical alveolar bone exhibited greater GV in the incisors without ARR than incisors with ARR (p < .05). Root GV was not associated with root protection, but rather seemed to have facilitated the process of resorption. The GV of the lingual bone was associated with a higher progression of ARR in the incisors.
Asunto(s)
Incisivo , Resorción Radicular , Proceso Alveolar , Tomografía Computarizada de Haz Cónico , Humanos , Maxilar , Raíz del DienteRESUMEN
Objective:To assess the long-term stability of leveling the curve of Spee after at least 8 years post-treatment in patients with mesocephalic pattern. Material and Methods:Measuring the depth of the curve of Spee in 10 mesocephalic patients at the following times: T0 (before the beginning of orthodontic treatment), T1 (at the end of orthodontic treatment) and T2 (at least 8 years after orthodontic treatment). These measures were compared using paired t-test (significance level of 5%). The curve depths were calculated from the measures of the distances between the lower buccal cusp of the posterior teeth of each side to a reference surface, which was supported by 3 points of the lower cast. Results:The mean curve of Spee depth at T0 was 1.86 mm, 0.50 mm at T1 and 0.53 mm at T2. The mean correction of the curve of Spee depth was 1.36 mm (73.11%) and the average relapse was 0.03 mm (2.2%). No statistically significant differencebetween T1 and T2 values in left or right sides was found. On the other hand, significant differences among T0 and T1 and T0 and T2 values were found. Conclusion:The results suggest that there was no significant depth relapse of the curve of Spee and also that leveling the curve is a stable procedure after 8 years after treatment in mesocephalic patients still using mandibular fixed retainer. The values found when comparing the depth in T0 and T1 showed that the curve of Spee was leveled during orthodontic treatment