Efecto en la regeneración ósea guiada de una membrana de PLGA modificada a nivel microtopográfico con plasma de oxígeno y funcionalizada con una capa inorgánica de óxido de silicio

Este propósito de Tesis Doctoral tiene como fin la valoración de un nuevo tipo de membrana de ácido poliláctico-co-poliglicólico (PLGA) modificada con un tratamiento físico de plasma de oxígeno (P-O2) para favorecer su degradación en el tejido receptor y variar su topografía a escala nanométrica y, con óxido de silicio (SiO2) con el fin de promover la osteogénesis. Las membranas de PLGA se saben que son biocompatibles, reabsorbibles, y ejercen un efecto barrera para evitar la colonización del espacio óseo a regenerar por el tejido conjuntivo adyacente. Hemos realizado una introducción donde se ha hecho una revisión del uso del SiO2 tanto a nivel general como en odontología, así como de los diferentes materiales utilizados en ingeniería tisular, sus composiciones químicas moleculares, técnicas de fabricación, perspectivas y aplicaciones actuales en biomedicina. Como hipótesis se establecieron que las membranas reabsorbibles estudiados (SiO2/PLGA + P-O2) son estables y biocompatibles, y que los defectos óseos regenerados con ellas generan una mayor proporción de hueso neoformado en comparación con las membranas control (PLGA). Para ello utilizamos cuatro conejos de la raza New Zeland a los que a cada uno se les realizó dos defectos críticos de 11mm de diámetro no auto-regenerables. Tras un mes de cicatrización se sacrificaron y se les realizó la biopsia. El objetivo principal de este proyecto es testar in vivo una membrana artificial, reabsorbible y modificada para evaluar su viabilidad y posible utilización en humanos para llevar a cabo tratamientos de regeneración ósea guiada (ROG) Para poder comparar el efecto potencial osteoinductor y osteoconductor de estas membranas y estructurar una valoración con mayor significancia estadística, hicimos un análisis histomorfométrico cuantitativo del porcentaje óseo neoformado mediante Von Kossa (nitrato de plata), una comparación cualitativa de la estructura integral y densidad ósea regenerada (osteoide, médula, adipocitos y presencia o no de inflamación anormal) mediante azul de toluidina, un estudio cuantitativo nivel de resorción ósea (osteoclastos por milímetro) mediante TRAP, una comparación cualitativa de la presencia normal de aposición osteoblástica mediante ALP, y un análisis cuantitativo de los milímetros de hueso neoformado por día mediante calceína, respecto a los controles, tras un mes de regeneración. Los resultados arrojaron valores significativos de un rendimiento mucho mayor de las membranas de estudio frente a los controles, con p<0,05 para todas las diferencias entre los valores de estudio cuantitativos, y obteniendo por todo ello una valoración positiva de la influencia de estas membranas en la regeneración ósea. Podemos concluir que el óxido de silicio favorece la formación ósea.This project of doctoral thesis aims at evaluating a new type of polylactic acid-co-polyglycolic membrane (PLGA) physically modified with treatment of oxygen plasma (P-O2) to promote their degradation in the receptor tissue and vary nanoscale topography and silicon oxide (SiO2) to promote osteogenesis. PLGA membranes are known to be biocompatible, absorbable, and have an effect barrier to prevent colonization of bone regenerate space by the adjacent connective tissue. We have made an introduction where it has made a review of the use of SiO2 both generally and in dentistry, the different materials used in tissue engineering, their molecular chemistries, manufacturing techniques, perspectives and current applications in biomedicine. Our established hypothesis was that resorbable membranes of the study (SiO2 / PLGA + P-O2) are stable, biocompatible, and bone defects regenerated with this kind of membrane have a greater proportion of newly formed bone compared to control membranes (PLGA). We use four New Zealand rabbits to study bone regeneration in two critical defects of 11 mm diameter (no self-regenerated). After a month of healing they were sacrificed and underwent biopsy. The main objective of this project is to test a modified membrane in vivo and to evaluate its feasibility and possible use in humans to perform treatments GBR (GBR) To compare the osteoinductive and osteoconductive potential effect of these membranes, we made a quantitative histomorphometric analysis of the percentage of bone newly formed by Von Kossa (silver nitrate), a qualitative comparison of the integral structure and bone density generated (osteoid bone, adipocytes and presence or absence of abnormal inflammation) using toluidine blue, a quantitative study of level of bone resorption (osteoclasts per mm) by TRAP, a qualitative comparison of the normal presence of osteoblastic apposition by ALP, and a quantitative analysis of newly formed bone millimeters per day by calcein, relative to controls, after a month of regeneration. The results showing a much higher performance between the study membranes vs controls, with p <0.05 for all the values of quantitative study and obtaining all this a positive assessment of the influence of these membranes on bone regeneration

Prospective double-blind clinical trial evaluating the effectiveness of Bromelain in the third molar extraction postoperative period

Objectives: To evaluate the anti-inflammatory and analgesic effect of Bromelain (pineapple extract) administered orally in the postoperative after extraction of impacted lower molars. Study Design: This is a prospective, placebo-controlled, unicentric, double-blind study; the sample size was 34 patients. The pre and postoperative outcomes, evaluated on the third (D3) and eighth day (D8), included inflam - tion, pain and oral aperture, as well as the need for analgesics. One group received bromelain 150mg per day for three days and 100mg on days 4 to 7. The other group received placebo in the same dosage. All outcomes wer - recorded quantitatively and analyzed with the Mann-Whitney U test for independent samples. Results: Although there were no statistically significant differences between the treatment groups, a trend towards less inflammation and improved oral aperture was observed in the group that received bromelain, compared to the group that received placebo. This trend can be attributed completely to random reasons, since there is no statistical difference in the results. Conclusions: Further studies are necessary to analyze different administration patterns and doses of bromelain for the use in the postoperative of impacted third molars

Kissing molars extraction: case series and review of the literature

Kissing molars are a very rare form of inclusion defined as molars included in the same quadrant, with occlusal surfaces contacting each other within a single dental follicle. We present four cases of this pathology: a 35 year-old male, referred to the Oral and Maxillofacial Surgery Department of the Hospital Virgen del Rocio in Seville, and three females of 24, 26, and 31 years, all of which had kissing molars that were treated by tooth extraction. We have found only 10 cases published in the medical literature in which this type of inclusion is briefly described, none of which elaborate on the surgical technique employed. In these cases, the indication for surgery is established when there is a history of recurring infections or cystic lesions associated with dental inclusions. The extraction of kissing molars requires an exhaustive comprehension of the anatomy of the region involved, sufficiently developed surgical abilities, and an extensive planning proces

Cirugía preortodóntica y erupción natural mediante cemento quirúrgico en los caninos maxilares impactados en el paladar

Los caninos incluidos son los dientes más impactados después de los terceros molares. La mayoría se encuentran en el paladar. Cuando se ha completado el recambio de todos los dientes o la corona del canino sobrepasa la raíz del incisivo lateral es necesaria la exposición quirúrgica de los caninos, seguida del tratamiento ortodóncico hacia el arco dental. Al descubrir la corona del canino podemos encontrarnos con dos opciones de tratamiento: erupción autónoma del canino o erupción ortodóncica. En este artículo describimos y seguimos la evolución ortodóncica de un paciente de 25 años al que se le realiza una cirugía preortodóncica bilateral de los caninos incluidos en palatino y erupción autónoma

'Pre-prosthetic use of poly(lactic-co-glycolic acid) membranes treated with oxygen plasma and TiO2 nanocomposite particles for guided bone regeneration processes'

[Objectives] Guided bone regeneration (GBR) processes are frequently necessary to achieve appropriate substrates before the restoration of edentulous areas. This study aimed to evaluate the bone regeneration reliability of a new poly-lactic-co-glycolic acid (PLGA) membrane after treatment with oxygen plasma (PO) and titanium dioxide (TiO) composite nanoparticles.[Methods] Circumferential bone defects (diameter: 10 mm; depth: 3 mm) were created on the parietal bones of eight experimentation rabbits and were randomly covered with control membranes (Group 1: PLGA) or experimental membranes (Group 2: PLGA/PO/TiO). The animals were euthanized two months afterwards, and a morphologic study was then performed under microscope using ROI (region of interest) colour analysis. Percentage of new bone formation, length of mineralised bone formed in the grown defects, concentration of osteoclasts, and intensity of osteosynthetic activity were assessed. Comparisons among the groups and with the original bone tissue were made using the Kruskal-Wallis test. The level of significance was set in advance at a = 0.05.[Results] The experimental group recorded higher values for new bone formation, mineralised bone length, and osteoclast concentration; this group also registered the highest osteosynthetic activity. Bone layers in advanced formation stages and low proportions of immature tissue were observed in the study group.[Conclusions] The functionalised membranes showed the best efficacy for bone regeneration.[Clinical significance] The addition of TiO nanoparticles onto PLGA/PO membranes for GBR processes may be a promising technique to restore bone dimensions and anatomic contours as a prerequisite to well-supported and natural-appearing prosthetic rehabilitations.This study is supported by the research project P09CTS 5189

DNA Methylation and Stress-induced Reversions from Asexual to Sexual Seed Formation in Boechera (Brassicacea)

Apomixis is a form of asexual reproduction that occurs in many plants and animals. Eggs of apomictic plants and animals form by apomeiosis, which means they do not become genetically reduced. Furthermore, these eggs develop into embryos without fertilization. Apomictic plants and animals generally reproduce quickly by making genetic copies of themselves, a trait that would be economically beneficial for perpetuating hybrid vigor if introduced into major seed crops. Metabolic stress induces a reversion from apomixis to sex in many apomicts, and this was recently shown to occur in species of the plant genus Boechera. 1 Transcriptome studies strongly suggest that this switch involves epigenetic reprogramming of the genome. I have drought-stressed cultured buds of apomictic Boechera in vitro to varying levels to determine an optimum treatment for inducing the switch from apomeiosis to meiosis. I have also exposed clusters of very immature floral buds to a DNA analogue that prevents DNA methylation (Fig. 1). This research is designed to allow me to determine the extent to which genome reprogramming, which involves DNA methylation, is involved in the switch from apomeiosis to meiosis