RESUMEN
The purpose of this study was to determine the amount of root resorption during orthodontic treatment, and to examine the relationship between tooth movement and apical root resorption. Twenty-seven Class I and 27 Class II patients treated with edgewise mechanics following first premolar extractions were selected. The following measurements were made on the pre- and post-treatment cephalograms: upper central incisor to palatal plane distance, the inclination of upper central incisor to the FH and AP planes, the perpendicular distances from the incisor tip to the AP and PTV planes, and incisor apex to PTV. The amount of apical root resorption of the maxillary central incisors was determined for each patient by subtracting the post-treatment tooth length from the pre-treatment tooth length measured directly on cephalograms. Intra-group differences were evaluated by the Student's t-test and inter-group differences by the Mann-Whitney U-test. For correlations the Pearson correlation coefficient was used. The results show that there was a mean of approximately 1 mm (P < 0.01) of apical root shortening in Class I patients, but in Class II division I subjects the mean root resorption was more than 2 mm (P < 0.001). The inter-group differences were statistically significant. No significant correlations were found between the amount of apical root resorption and tooth inclination, or the duration of active treatment.
Asunto(s)
Incisivo/patología , Maloclusión Clase II de Angle/terapia , Maloclusión Clase I de Angle/terapia , Resorción Radicular/etiología , Extracción Seriada/efectos adversos , Ápice del Diente/patología , Técnicas de Movimiento Dental/efectos adversos , Adolescente , Diente Premolar/cirugía , Cefalometría , Niño , Estudios de Evaluación como Asunto , Femenino , Estudios de Seguimiento , Humanos , Masculino , Maloclusión Clase I de Angle/patología , Maloclusión Clase II de Angle/patología , Odontometría , Hueso Paladar/patología , Hueso Esfenoides/patología , Factores de TiempoRESUMEN
This study was aimed at measuring the changes in the hyoid bone position, tongue position, and hypopharyngeal airway space in subjects with mandibular setback osteotomies. Lateral cephalometric radiographs of 15 patients were taken preoperatively, 6 weeks postoperatively, and at the follow-up with a mean of 1.5 +/- 0.4 years. A significant decrease in the hypopharyngeal airway space following mandibular setback surgery was found (P < .01). This change sustained during the follow-up period. The hyoid bone moved down (P < .001), and the lower tongue point also moved down (P < .05) postoperatively. Results of the study suggest that narrowing of the hypopharyngeal airway space due to the posterior and inferior movement of the tongue can be permanent.
