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The aim of the present study was to conduct a histopathological analysis of an animal model in rats, which simulates the characteristics observable in bones of patients with osteoporosis. To this end, 10 female rats (Rattus norvegicus) Sprague Dawley of 12 weeks of development and approximately 200-250 g were used. Of these, 5 underwent bilateral ovariectomy (OVX), whereas the remaining 5 were used as control. After 12 weeks of ovariectomy in the experimental group, the animals were euthanized and the two femurs were collected, which were then sectioned to process their distal portion. All the animals survived at the end of the study without any signs of postoperative complications. In the experimental group (OVX), the histological images showed a decrease in the thickness of the cortical bone, a greater amount of cancellous bone, loss of the continuity of the periosteum and endostium around the bone matrix in addition to a greater amount of adipose tissue in the bone marrow, when compared with the control group. It can therefore be inferred that a histopathological phenotype can be found at 12 weeks postovariectomy that would be consistent with osteoporotic characteristics in adult rats. [ABSTRACT FROM AUTHOR]

Introducción: La reconstrucción ósea, previo o durante la instalación de implantes dentales, es una técnica rutinaria en la rehabilitación dentoalveolar moderna; clásicamente, la reconstrucción con hueso autógeno ha sido utilizado con altos porcentajes de éxito. Esto requiere de un sitio donante para la extracción del injerto. Dentro de los sitios donantes intraorales, la rama mandibular ha sido utilizada con bajos índices de alteraciones neurosensoriales; esta zona anatómica generalmente no presenta consecuencias morfológicas importantes y no se asocia con alteraciones dentarias cuando se realiza el retiro de hueso; las pocas alteraciones neurosensoriales que presenta pueden limitarse conociendo de forma precisa la posición del nervio alveolar inferior; las tomografías computarizadas de haz cónico han permitido avances importantes en este análisis, sin embargo existen limitados estudios en esta área. Objetivo: Conocer la distancia que existe desde el canal mandibular a la zona lateral y a la zona superior de la rama mandibular a fin de identificar márgenes de seguridad que minimicen el riesgo de lesiones nerviosas en el proceso de retiro de un injerto óseo en bloque para ser utilizado en reconstrucciones óseas. Material y método: Se realizó un estudio descriptivo, analizando bilateralmente 20 exámenes CBCT de pacientes distintos, realizando mediciones en 4 puntos de la zona central, lateral y medial de la rama mandibular correspondiente, los cuales fueron ubicados con distancia de 5 mm entre cada línea, hasta completar los 20 mm. Las mediciones fueron realizadas con el software EZ3D2009 (E-WOO Technology Co, Ltd. Korea) La recolección de los datos fue registrada en una planilla Microsoft Office Excel. Para el análisis de los datos se usó el programa estadístico SPSS Statistics for Windows (versión 23.0, IBM) y se realizó un análisis descriptivo de los datos. Resultados: Cuarenta hemimandíbulas fueron incluidas en esta investigación, estimando una distancia vertical, para los 4 puntos de análisis, de entre 16 y 17 mm, una distancia hacia lateral de 5 mm aproximadamente y hacia medial aproximadamente de 3 a 3,9 mm. Conclusiones: Se estima, que la obtención máxima de un bloque óseo desde la zona posterior al segundo molar debe ser con 13 mm de profundidad y 3 mm desde lateral; considerando una extensión antero-posterior de 20 mm. [ABSTRACT FROM AUTHOR]

Orthognathic surgery is performed in subjects with some type of skeletal alteration. Maxillomandibular movements have an impact on the airway (AW) and this aspect must be included into surgical planning. The aim of this research is to determine the changes in the AW after orthognathic surgery. A pilot study was conducted including 51 subjects with class II and class III facial deformity; they were included using the ANB angle and the type of dental occlusion. Cone beam computed tomography were performed showing the maximum volume in the airway and the minimum and maximum areas; in addition, the position of the hyoid bone and the angle of the mandibular plane were included to relate it to the morphology of the AW; to define statistical significance, a value of p<0.05 was established, including the student's t-test and the t-test. The results showed that class II subjects significantly increased the volume and maximum and minimum areas of the AW; skeletal class III subjects did not presented significant differences between the pre- and post-surgical stage; the hyoid bone was in an anterior position in both class II and class III cases. It is possible to conclude that AW improves substantially in subjects with facial class II and remains unchanged in subjects with facial class III. [ABSTRACT FROM AUTHOR]

The objective of this research was to determine the preferred movements in the maxilla and mandible to obtain normality in facial morphology using superimposition techniques in 3D analysis. A descriptive study was carried out to evaluate bimaxillary bone displacement and hyoid bone in subjects facial class II and facial class III undergoing orthognathic surgery. were used as fixed points for superimposition: Nasion (N) - Silla (S) - Porion (Po) and the zygomatic-maxillary suture (Z). These points were superimposed in pre-surgical and postsurgical CBCT and was evaluated to displacement of the anterior nasal spine, Point A, Point B, Chin and the hyoid bone. For the evaluation and comparison of continuous variables before and after orthognathic surgery, was used the Student's t test. For the correlation between the variables, the Spearman test is used, considering a p value <0.05 as a significant difference. 44 subjects between 18 and 40 years old of both sexes were included in this research. A 90% of subjects a was performed a maxillay sagittal movement. The sagittal movement of mandibular advancement was performed in 100% with facial class type II, while 100 % of the subjects with with facial class type III had a mandibular recession. The hyoid bone advanced in 26 of the 27 subjects with facial class type II. It is possible to conclude that there is a tendency for maxillary advancement, independent of facial deformity. [ABSTRACT FROM AUTHOR]