Application of Sphenoid Sinus Morphological Characteristics in Sex Estimation Based on Magnetic Resonance Imaging Images / Aplicación de las Características Morfológicas del Seno Esfenoidal en la Estimación del Sexo Basada en Imágenes de Resonancia Magnética

SUMMARY: Sex determination of unknown persons plays an important role in forensic science. As most bones used for sex determination are recovered in incomplete state, it is often necessary to use bones that are recovered intact e.g., the sphenoid sinus. This study aimed to evaluate the diagnostic value of sphenoid sinuses dimensions for sex determination using Magnetic Resonance Imaging (MRI) images in Chinese adults. MRI images of 79 sphenoid sinuses (from 44 men and 35 women) were retrospectively selected. The height, anterior-posterior diameter, area, and perimeter were measured in the midsagittal view of the sphenoid sinuses. All data were subjected to descriptive and discriminative functional analysis with unpaired t-test and canonical discriminant. Comparison between male and female groups showed significant statistical differences regarding the height, anterior-posterior diameter, area, and perimeter of sphenoid sinuses. The predictive accuracy rate of the sphenoid sinus to identify sex was 63.6 % in males and 62.9 % in females with an overall accuracy of 63.3 %. This study proposed the importance of sexual dimorphism of sphenoid sinus dimensions, especially if other methods are not available. It suggested using MRI in forensics science thus obviating the complete dependence on the usage of conventional computed tomography (CT) and facilitating the study of forensic anatomy at the level of soft tissue.

La determinación del sexo de personas desconocidas juega un papel importante en la ciencia forense. Como la mayoría de los huesos utilizados para la determinación del sexo se recuperan en un estado incompleto, a menudo es necesario utilizar huesos recuperados intactos, por ejemplo, el seno esfenoidal. Este estudio tuvo como objetivo evaluar el valor diagnóstico de las dimensiones de los senos esfenoidales para la determinación del sexo utilizando imágenes de resonancia magnética en individuos adultos chinos. Se seleccionaron retrospectivamente imágenes de resonancia magnética de 79 senos esfenoidales (de 44 hombres y 35 mujeres). La altura, el diámetro anteroposterior, el área y el perímetro de los senos esfenoidales, se midieron en vista mediana sagital. Todos los datos se sometieron a análisis funcional descriptivo y discriminativo con prueba t no pareada y discriminante canónico. La comparación entre los grupos de hombres y mujeres mostró diferencias estadísticas significativas en cuanto a la altura, el diámetro anteroposterior, el área y el perímetro de los senos esfenoidales. La tasa de precisión predictiva del seno esfenoidal para identificar el sexo fue del 63,6 % en hombres y del 62,9 % en mujeres, con una precisión general del 63,3 %. Este estudio propuso la importancia del dimorfismo sexual de las dimensiones del seno esfenoidal, especialmente si no se dispone de otros métodos. Se sugiere utilizar la resonancia magnética en la ciencia forense, obviando así la dependencia total del uso de la tomografía computarizada convencional y facilitando con esto el estudio de la anatomía forense a nivel de los tejidos blandos.

Study on the morphology of micro-implant-bone interface cells and bone histomorphology under different implantation / Estudio sobre la morfología de las células de la interfaz microscópica implante-hueso y la histomorfología ósea bajo diferentes implantaciones

SUMMARY: Micro-implant stability has always been the focus of orthodontic clinical research.In the experiment, the morphological changes of bone tissue around the micro-implants in self-tapping and assisting implantation were investigated to explore the effect of different implantation on the osseointegration of micro-implants in order to provide some theoretical basis for clinical practice. Six adult male Beagle dogs were selected,three implants were implanted into the left and right maxillary bone of Beagle dogs at the 0th, 4th and 6th week, respectively. One side to self-tapping implantation, the opposite side to assisting implantation. At the 8th week of the experiment, the animals were sacrificed and the micro-implant-bone tissue specimens with the healing time of 8w, 4w and 2w were obtained.The specimens were stained with Toluidine Blue (TB) and photographed under 100X, 200X microscope. Morphology of microimplant- bone interface cells was observed under light microscope. In self-tapping group, there were some fibrous tissues surrounding the micro-implants at the 2th week, the formation of osteoblasts and osteoid was observed at the 4th week, the wavy and lamellar bone tissues were seen at the 8th week.In assisting group,more collagen fibers were deposited around the micro-implant at the 2th week, there were a large number of osteoid-like cells, and the collagen was gradually replaced by the bone tissue at the 4th week, the osteoblasts were active and the osteoblasts were linear arrange and form a laminate bone at the 8th week.Whether implanted self-tapping or assisted implantation, micro-implant-bone interface reconstruction can occur. If the clinical need for early loading force, micro-implant try to choose selftapping implantation. By appropriately prolonging the healing time, the initial stability of the micro-implant under assistive implantation can be improved.

RESUMEN: La estabilidad del microimplante siempre ha sido el foco de la investigación clínica en ortodoncia. En este trabajo se investigaron los cambios morfológicos del tejido óseo alrededor de los microimplantes autorroscantes y se ayudó a la implantación para explorar el efecto de diferentes implantes en la osteointegración de microimplantes con el fin de proporcionar alguna base teórica para la práctica clínica. Se seleccionaron seis perros Beagle machos adultos, y se colocaron tres implantes en los huesos maxilares izquierdo y derecho en la 0ª, 4ª y 6ª semana, respectivamente. De un lado se colocó el implante autorroscante, y del otro lado el implante asistido. En la octava semana, se sacrificaron los animales y se obtuvieron las muestras de microimplante-hueso con el tiempo de cicatrización de 8, 4 y 2 semanas. Las muestras fueron teñidas con azul de toluidina (TB) y fotografiadas bajo aumento de 100X, y microscopio de 200X. La morfología de las células de la interfaz microimplante-hueso se observó bajo microscopio óptico. En el grupo autorroscante, había tejido fibroso que rodeaba los microimplantes a la 2ª semana, se observó la formación de osteoblastos y osteoide a la 4ª semana y de tejido óseo ondulado y lamelar a la 8ª semana. En el grupo asistido, se depositaron más fibras de colágeno alrededor del microimplante en la 2ª semana, hubo un gran número de células similares a osteoide, y el colágeno fue reemplazado gradualmente por el tejido óseo en la 4ª semana; los osteoblastos estaban activos y se ubicaron linealmente formando un hueso laminado en la 8ª semana. Ya sea que el implante sea con autoasistencia o con implantación asistida, puede ocurrir la reconstrucción de la interfaz microimplante-hueso. Si existe la necesidad clínica de una fuerza de carga temprana, el microimplante de elección sería la implantación autorroscante. Al prolongar apropiadamente el tiempo de curación, se puede mejorar la estabilidad inicial del microimplante bajo implantación asistida.

Maxillary distraction osteogenesis in cleft lip and palate patients with skeletal anchorage.

OBJECTIVE: Maxillary distraction osteogenesis with the rigid external distraction (RED) system has been used to treat cleft lip and palate (CLP) patients with severe maxillary hypoplasia. We introduce maxillary distraction osteogenesis for CLP patients with skeletal anchorage adapted on a stereolithographic model. PATIENTS: Six maxillary deficiency CLP patients treated according to our CLP treatment protocol had undergone maxillary distraction osteogenesis. METHOD: In all patients, computed tomography (CT) images were recorded preoperatively, and the data were transferred to a workstation. Three-dimensional skeletal structures were reconstructed with CT data sets, and a stereolithographic model was produced. On the stereolithographic model, miniplates were adapted to the surface of maxilla beside aperture piriforms. The operation performed involved a high Le Fort I osteotomy with pterygomaxillary disjunction. Miniplates were fixed to the maxillary segment with three or four screws and used for anchorage of the RED system. Retraction of the maxillary segment was initiated after 1 week. RESULTS: The accuracy of the stereolithographic models was enough to adapt the miniplates so that there was no need to readjust the plates during surgery. Postoperative cephalometric analysis showed that the direction of the retraction was almost parallel to the palatal plane, and dental compensation did not occur. CONCLUSIONS: We performed maxillary distraction osteogenesis with skeletal anchorage adapted on the stereolithographic models. Excellent esthetic outcome and skeletal advancement were achieved without dentoalveolar compensations.