Eduardo Borie

The influence of FDBA and autogenous bone particles on regeneration of calvaria defects in the rabbit: A pilot study

The histological behavior of bone formation using three biomaterials was examined including whether an 8mm rabbit calvarial defect would behave as a critical size defect. Four trephine defects of 8mm diameter in were created six rabbit parietal bones. A control defect was maintained only with coagulum and others were filled with autologous bone, FDBA (freeze dried bone allograft) and a mixture of autologous bone with FDBA, respectively. The animals were sacrificed after between 15 and 90 days at intervals of two weeks and the extracted samples were processed for histological evaluation. All control defects showed incomplete bone formation during 90 days of observation. The defects filled with FDBA and mixture of FDBA-autologous bone exhibited a higher regeneration degree than autologous bone after 60 days; however, the only biomaterial revealing complete mineralization of the original defect at 90 days was FDBA. In conclusion, 8mm defects can be considered as critical size defects and only FDBA showed mature lamellar bone at 90 days.

The influence of the connection, length and diameter of an implant on bone biomechanics

Abstract Background. Regardless of the multiple options of connections, diameters and heights for dental implants, the clinician should know the biomechanical behavior of the bone to plan the treatment according to the biological and anatomical conditions of each patient, without risk to the long-term treatment success. Review. The following review attempts to summarize the relevant literature to establish guidelines for clinicians based on the scientific evidence regarding the influence by the implant’s connection, diameter and length on the bone biomechanics. Conclusions. The length, diameter and connection of each implant have a degree of influence in bone biomechanics. Despite the influence of different implant connections, diameters and lengths on peri-implant bone stress and strain, these characteristics should remain within the physiological limits to avoid a pathological overload, bone resorption and consequent risk to the long-term success of implant-prosthetic treatment.

Reliability of Two Techniques for Measuring Condylar Asymmetry with X-Rays

Dentro de las alteraciones estructurales que pueden ser un factor de riesgo de desarrollo de un trastorno temporomandibular (TTM) se menciona a la asimetria condilar. Para realizar la medicion cuantitativa del indice de asimetria condilar en radiografias panoramicas se han propuesto dos metodos, Habets y Kjellberg. El objetivo de este estudio fue determinar si el metodo radiografico de medicion de asimetrias condilares en ortopantomografias que presenta menor tendencia al error por leves desplazamientos de la cabeza en el plano horizontal. Se evaluaron 30 pacientes entre 18 y 25 anos de edad. Cada uno de ellos se sometio a tres radiografias panoramicas en tres posiciones distintas: posicion ortoradia, 5 y 10 de angulacion horizontal. Posteriormente, se realizaron las mediciones de Habets y Kjellberg. La tecnica de Habets no mostro diferencias estadisticamente significativas en las radiografias con 5° y 10° de angulacion horizontal con respecto al angulo de 0. Sin embargo, la tecnica de Kjellberg mostro diferencias estadisticamente significativas solo al angulo de 10° con respecto al angulo de 0. Las alteraciones de 10° produjeron variaciones lineales y de razones, sin embargo no variaron los indices. Se concluye que ambos metodos entregan informacion clinica aceptable con las limitaciones que estas tecnicas tienen para obtener informacion sobre simetrias o asimetrias condilares de cuerpo o de rama.

Glutaraldehyde release from heat-polymerized acrylic resins after disinfection and chemical and mechanical polishing

This study evaluated the release of glutaraldehyde from heat-polymerized acrylic resins subjected to disinfection followed by chemical and mechanical polishing. Ninety disc-shaped specimens (15 x 4 mm), 30 per resin (Lucitone 550, QC-20 and Classico), were made and assigned to 2 groups according to the type of polishing. One side of each specimen was not polished and the other was either mechanically (n = 45) or chemically (n = 45) polished, and immersed in water at 50 °C for 1 h to allow the release of intrinsic substances and then kept in distilled water for 7 days. The specimens were disinfected by immersion in 2% glutaraldehyde for 10 min. After this period, 3 specimens from each group were immersed in water for 15, 30, 60, 120 and 240 min. For the 15-, 30-, 60-min immersions, 4 water exchanges were done at the end of period. High performance liquid chromatography (HPLC) was used to detect and quantify the glutaraldehyde released after each period. Data were analyzed statistically by two-way ANOVA and multiple comparisons were done by Tukeys and Scheffés tests (α = 0.05). No glutaraldehyde release was observed from the specimens with chemical polishing at any of the immersion periods, while the mechanically polished specimens released glutaraldehyde. In the groups with water exchanges, Lucitone released more disinfectant in the 15-min period (0.040 μg/mL), Classico in the 30-min (0.021 μg/mL) and 60-min (0.018 μg/mL) periods, and QC-20 the same amount (-1.760 μg/mL) in all periods. In the groups without water exchanges, Lucitone released the highest amount of disinfectant (-1.370 μg/mL), differing significantly from QC-20 (0022 g/mL) and Classico (0019 g/mL), which were similar. The findings of this showed that chemically polished specimens from the 3 resin brands did not release glutaraldehyde after different periods of immersion, while glutaraldehyde release was observed from the mechanically polished specimens, especially from those made of Lucitone resin.

Histological Evaluation of Bone Regeneration Means Freeze Dried Bone Allograft (FDBA) in Post Exodontia Sockets

Dentro de la rehabilitacion oral, es importante preservar el reborde alveolar post exodoncia. Se expone un analisis histologico, histoquimico e histomorfometrico de dos casos clinicos de terapias de regeneracion osea de alveolos post extraccion mediante FDBA. En dos pacientes se extrajeron piezas dentarias destruidas y se indujo regeneracion osea mediante FDBA. Seis meses despues, se obtuvo una biopsia del injerto y mediante un implante de titanio fue rehabilitado. Para el analisis Histologico e Histomorfometrico, las muestras fueron tratadas con las tecnicas Hematoxilina-Eosina, Azul de Alcian, Masson, Von Kossa y colorante Picrosirius de Junqueira.Se midio el area total de tejido, asi como el area de tejido oseo. Las superficies de hueso de las muestras se observaron inactivas, no fueron encontrados osteoblastos ni osteoclastos, solo osteocitos y celulas osteogenas, lo que no significa que el hueso este en estado quiescente, sino mas bien a que su genesis ocurre a partir de la matriz de tejido donde se encuentran celulas con potencialidad de formar osteocitos indiferenciados y un microambiente con proteinas de la familia de factor de crecimiento transformante beta. No fueron encontradas particulas de biomaterial inactivo. En las muestras se cuantifico 0% y 30% de hueso mineralizado. Dadas las diferencias histologicas encontradas con otros estudios, es necesario profundizar el conocimiento en los procesos involucrados en la regeneracion osea dependiendo del biomaterial utilizado, y la calidad osea resultante en cada procedimiento en particular sin perder de vista la variabilidad que puede presentarse dependiendo de cada caso clinico.

Caracterización de Estructuras Anatómicas Mediante Radiografías Panorámicas: El Foramen Mental

El foramen mental (FM) es un referente anatomico importante durante procedimientos quirurgicos y colocacion de implantes. Con el proposito de conocer la detectabilidad y posicion del FM, caracterizandolo respecto a sus relaciones anatomicas, fueron analizadas 215 radiografias panoramicas convencionales. Ademas, se determino la presencia y extension del bucle del canal mandibular. El FM se detecto en el 87,9% de los casos, en mayor porcentaje en hombres y a menor edad. La posicion anteroposterior mas frecuente del FM fue en relacion al eje longitudinal del segundo premolar en el lado derecho y en el izquierdo entre los ejes longitudinales del primer y segundo premolar. La posicion supero-inferior mas frecuentemente observada en ambos sexos y todos los grupos etarios fue bajo el apice de los dientes. La distancia promedio desde el centro del FM a la linea mediana fue de 35,3 mm y 35,6 mm en el lado derecho e izquierdo, respectivamente. La distancia promedio desde el centro del FM al margen mandibular fue de 16,6 mm a la derecha y 17,1 mm a la izquierda. En relacion al bucle del canal mandibular, se detecto en un 33,9% de los casos y su extension fue de 5,3 mm y 4,8 mm en el lado derecho e izquierdo, respectivamente. Es fundamental conocer la anatomia, ubicacion de estructuras y evaluar esta zona previo a cualquier procedimiento quirurgico o colocacion de implantes dentales, para asi evitar lesiones del FM y nervio mental o el bucle del canal mandibular anterior o posterior y nervio alveolar inferior.

MAXIMUM BITE FORCE IN ELDERLY INDIGENOUS AND NON-INDIGENOUS DENTURE WEARERS

The aim of this study was to compare the measures of maximum bite force (MBF) in elderly edentulous indigenous (Mapuche) and non-indigenous individuals with new complete dentures at two different measuring times. A sample of 100 elderly subjects was divided into two groups: 50 indigenous and 50 non-indigenous, each including 25 females and 25 males. All individuals were totally edentulous, with new maxillary and mandibular removable complete dentures. Measurements were taken at the time of new prosthesis placement and after 1 month of use. Subjects were asked to perform with maximum effort three bites per side at maximum intercuspidation, with a rest time of 2 minutes in between. Statistics were analyzed with Student s t-test. The MBF values were significantly higher in indigenous than non-indigenous subjects. Force after 1 month of wearing the new prosthesis was significantly higher than at the time of new prosthesis placement. No significant difference was found between sides. Elderly indigenous complete denture wearers had the greatest MBF values. Denture wearers were observed to undergo an adaptation process to the new prosthesis, with MBF increasing considerably after one month of use.

Bone Healing in Transverse Maxillary Defects with Different Surgical Procedures Using Anorganic Bovine Bone in Humans

La reabsorcion centripeta del maxilar es un proceso continuo despues de la perdida dentaria. Para el tratamiento de sitios oseos deficientes, se pueden utilizar injertos de hueso autologo; como alternativa, se puede aplicar biomateriales, que no requieren sitios donantes intra o extraorales. Se describe el uso de hueso inorganico bovino (HIB) base en tres casos en diferentes modos: membrana, barrera rigida e injerto de tejido conectivo. Los resultados clinicos muestran que en todas las condiciones se formo suficiente tejido duro para permitir la rehabilitacion de implantes en los sitios de hueso insuficiente. La evaluacion histologica revelo hueso trabecular en una matriz casi madura con particulas en reposo de HIB. Dependiendo de la situacion del sitio original, se puede aplicar el concepto de barrera oclusiva rigida en dos pasos, si el hueso en reposo no proporciona la estabilidad del implante, mientras que el aumento cubierto con membrana en combinacion con tejido conectivo se recomienda si es posible la insercion simultanea de implantes.

Three-Dimensional Finite Element Analysis of the Biomechanical Behaviors of Implants with Different Connections, Lengths, and Diameters Placed in the Maxillary Anterior Region.

PURPOSE To evaluate the biomechanical behaviors of multiple implant-supported prostheses with different implant lengths, connections, locations, and restoration materials in the maxillary anterior region using three-dimensional finite element analysis. MATERIALS AND METHODS A finite element model of a maxillary image was created from a tomography data bank. The simulations were executed in two types of models based on the treatment plan: (1) two implants with 4.0-mm diameters placed in the maxillary central incisors to simulate an implant-supported fixed prosthesis with four elements with a cantilever of both maxillary lateral incisors; (2) two implants with 3.75-mm diameters placed in the maxillary lateral incisors to simulate a conventional fixed prosthesis with four elements with pontics for maxillary central incisors. Subsequently, the models created were subdivided into eight subgroups according to implant length, connection type, and restoration material. A total static oblique load of 150 N was applied to the cingulum area of the palatal surfaces of the four incisors at an angle of 45 degrees to the long axis of the implant in the palatal-labial direction. Bone stresses were analyzed through maximum and minimum principal stresses and ductile material as implant, framework, and abutments were analyzed using von Mises stress criterion. RESULTS Regardless of implant diameter and type of treatment, the 8.5-mm-long implants exhibited the lowest tensile and compressive stresses. Maximum and minimum principal stresses were identified in the cortical bone. The lowest von Mises equivalent stress values were identified in the metal-ceramic prostheses, with the exception of the cantilever prosthesis model with flat top connection. Conical cone implant models exhibited maximum von Mises equivalent stress in contact with the abutment. CONCLUSION The lowest principal stresses in the peri-implant bone were observed in implants with conical cone connection and 8.5 mm in length. Also, in most cases, the models with metal-ceramic restorations exhibited better stress distributions.

Bilateral Two-rooted Mandibular Canines in the Same Individual: a Case Report

La anatomia normal de los dientes caninos comprende una raiz y un gran canal centrado a traves de su eje, sin embargo algunos dientes canino pueden presentar dos raices y dos canales. Asi, el conocimiento de la anatomia normal de canal de la raiz y sus variaciones son esenciales para minimizar la posibilidad de accidentes durante el desarrollo de tratamientos dentales. En este informe se describe el caso de dientes caninos mandibulares con dos raices y dos canales bilateralmente hallados radiograficamente en el mismo individuo.