Uso de membrana de colágeno y placa de protección mecánica como instrumento de conservación alveolar / Use of collagen membrane and mechanical protective plate as an instrument for alveolar preservation

Luego de una extracción dental ocurren inevitablemente procesos de reabsorción y remodelación ósea, donde la dimensión y morfología de la cresta alveolar se ve modificada, representando un problema para la rehabilitación de la zona. Estudios clínicos han documentado un promedio de 4,0 a 4,5 mm de reabsorción ósea horizontal luego de una exodoncia, como así también cambios dimensionales significativos en los alrededores del hueso alveolar. El propósito fue evaluar y comparar clínica y tomográficamente los procesos de reparación y conservación del reborde alveolar post-extracción de paredes intactas, con y sin la utilización de esponjas de colágeno intraalveolar como relleno y placa termoformada como barrera física, durante el proceso de cicatrización. Se seleccionaron pacientes con indicación de exodoncia de elementos dentarios normalmente implantados y clínicamente aceptables, aplicando los criterios de exclusión, se realiza toma de impresión del terreno para la confección de una placa de protección rígida 0,8 termoformada para ser colocada posterior a la extracción durante la masticación por un período de 30 días. Se indica tomografía cone-beam post operatoria inmediata y a los tres meses para analizar, medir y comparar alto y ancho de crestas alveolares residuales. En la evaluación clínica y tomográfica de los casos estudiados, el grupo control donde se usó únicamente placa de protección alveolar arrojó mejores resultados que el grupo donde se colocaron esponja de colágeno en el interior del alvéolo. Palabras clave: Regeneración ósea, esponja de colágeno, cicatrización ósea, alvéolo postextracción, placa de protección alveolar (AU)

After a tooth extraction, bone resorption and remodeling processes inevitably occurs, where size and morphology of the alveolar crest is modified, representing a problem for the rehabilitation of the area. Clinical studies have documented an average of 4.0 to 4.5 mm of horizontal bone resorption after an extraction, us well us substantial dimensional changes around the alveolar bone. The purpose was to evaluate and compare clinical and tomographically both repair and preservation of post extraction alveolar ridge of intact walls processes, with and without the use of intraalveolar collagen sponges as filler and a thermoformed protective plaque, us physica? barrier, during healing process. Patients with normally implanted and clinically acceptable tooth with extraction indication were selected, applying the exclusion criteria, impression of the field is taken to build a 0.8 rigid thermoformed protective plaque in order to be placed after extraction and used during chewing for a period of 30 days. Immediate and three months post-operative cone beam tomography are indicated to analyze, measure and compare height and width of residual alveolar crests. In the clinical and tomographic evaluation of the cases treated, control group where only alveolar protective plaque was used, showed better results than the group with intraalveolar collagen sponge (AU)

* Bone Regeneration Mediated by a Bioactive and Biodegradable Extracellular Matrix-Like Hydrogel Based on Elastin-Like Recombinamers.

The morbidity of bone fractures and defects is steadily increasing due to changes in the age pyramid. As such, novel biomaterials that are able to promote the healing and regeneration of injured bones are needed to overcome the limitations of auto-, allo-, and xenografts, while providing a ready-to-use product that may help to minimize surgical invasiveness and duration. In this regard, recombinant biomaterials, such as elastin-like recombinamers (ELRs), are very promising as their design can be tailored by genetic engineering, thus allowing scalable production and batch-to-batch consistency, among others. Furthermore, they can self-assemble into physically crosslinked hydrogels above a certain transition temperature, in this case body temperature, but are injectable below this temperature, thereby markedly reducing surgical invasiveness. In this study, we have developed two bioactive hydrogel-forming ELRs, one including the osteogenic and osteoinductive bone morphogenetic protein-2 (BMP-2) and the other the Arg-Gly-Asp (RGD) cell adhesion motif. The combination of these two novel ELRs results in a BMP-2-loaded extracellular matrix-like hydrogel. Moreover, elastase-sensitive domains were included in both ELR molecules, thereby conferring biodegradation as a result of enzymatic cleavage and avoiding the need for scaffold removal after bone regeneration. Both ELRs and their combination showed excellent cytocompatibility, and the culture of cells on RGD-containing ELRs resulted in optimal cell adhesion. In addition, hydrogels based on a mixture of both ELRs were implanted in a pilot study involving a femoral bone injury model in New Zealand white rabbits, showing complete regeneration in six out of seven cases, with the other showing partial closure of the defect. Moreover, bone neoformation was confirmed using different techniques, such as radiography, computed tomography, and histology. This hydrogel system therefore displays significant potential in the regeneration of bone defects, promoting self-regeneration by the surrounding tissue with no involvement of stem cells or osteogenic factors other than BMP-2, which is released in a controlled manner by elastase-mediated cleavage from the ELR backbone.

Ex vivo microleakage comparison between glass ionomers used as pit and fissure sealants.

The aim of this study was to evaluate in vitro the marginal microleakage of two glass ionomer materials used as pit and fissure sealants. Thirty healthy premolars extracted for orthodontic treatment were randomly assigned to two groups (n=15) and respectively sealed with two glass ionomers (Group I, Fuji VII and Group II, Fuji IX). All teeth were preserved in artificial saliva (NAF) for 10 days, thermocycled (250 cycles; 5 °C, 37 °C and 60 °C), isolated, and immersed in 2% alcohol gentian violet blue solution for 24 h. After washing, teeth were included in acrylic resin and sectioned longitudinally in a bucco-lingual direction with a Struers-Minitom cutting device. Samples were analyzed for leakage using an optical microscope (Olympus BX- 60M). TheWilliams and Winter semi-quantitative ranked scale was used to score dye penetration. In Group I the grades were distributed as follows: Grade 1, 1 sample and Grade 3, 14 samples (Mean 2.87 Median 3, SD 0.52). In Group II: Grade 0: 4 samples, Grade 1, 3 samples, Grade 2, 2 samples and Grade 3, 6 samples (Mean 1.67, Median 2, SD 1.29). Fisher's exact test showed statistically significant differences between materials (p=0.006). From these results, we conclude that Fuji IX had better marginal sealing than Fuji VII when used as a pit and fissure sealant.

Ex vivo microleakage comparison between glass ionomers used as pit and fissure sealants / Comparación in vitro de filtración marginal entre ionómeros vítreos selladores

El objetivo del trabajo fue comparar la eficacia como sellador de dos ionómeros vítreos. Se emplearon 30 premolares sanos extraídos por razones ortodóncicas. Se dividieron en dos grupos iguales (n=15) .Grupo I: Fuji VII y Grupo II: Fuji IX. Los dientes, fueron conservados en saliva artificial (NAF) durante 10 días. Luego, fueron termociclados (250 ciclos) a 5ºC, 37ºC y60ºC. Posteriormente se sumergieron en violeta de genciana durante 24 hs. Una vez lavadas las muestras se seccionaron y evaluaron con el criterio de Williams y Winter, utilizando un microscopio óptico (Olympus BX-60M) para valorar la penetración del colorante. Los grados obtenidos para cada grupo fueron: en Grupo I (Fuji VII), Grado 1, 1 muestra y Grado3, 14 muestras (Media 2,87, Mediana 3 y SD 0.52). En el Grupo II (Fuji IX) los grados se distribuyeron así: Grado 0, 4 muestras, Grado 1, 3 muestras, Grado 2, 2 muestras y Grado 3, 6 muestras.(Media 1.67, Mediana 2 y SD 1.29). La Prueba exacta de Fisher (p=0,006) demostró diferencias estadísticamente significativa entre materiales. Se concluyó que el mejor sellado marginal fue obtenido utilizando el material Fuji IX comparado con Fuji VII cuando es utilizado como sellador.

The aim of this study was to evaluate in vitro the marginalmicroleakage of two glass ionomer materials used as pit andfissure sealants. Thirty healthy premolars extracted fororthodontic treatment were randomly assigned to two groups(n=15) and respectively sealed with two glass ionomers (Group I,Fuji VII and Group II, Fuji IX). All teeth were preserved inartificial saliva (NAF) for 10 days, thermocycled (250 cycles; 5ºC,37ºC and 60ºC), isolated, and immersed in 2% alcohol gentianviolet blue solution for 24 h. After washing, teeth were included inacrylic resin and sectioned longitudinally in a bucco-lingualdirection with a Struers-Minitom cutting device. Samples wereanalyzed for leakage using an optical microscope (Olympus BX-60M). TheWilliams and Winter semi-quantitative ranked scale wasused to score dye penetration. In Group I the grades weredistributed as follows: Grade 1, 1 sample and Grade 3, 14 samples(Mean 2.87 Median 3, SD 0.52). In Group II: Grade 0: 4 samples,Grade 1, 3 samples, Grade 2, 2 samples and Grade 3, 6 samples(Mean 1.67, Median 2, SD 1.29). Fisher’s exact test showedstatistically significant differences between materials (p=0.006).From these results, we conclude that Fuji IX had better marginalsealing than Fuji VII when used as a pit and fissure sealant.

Critical size defect regeneration by rhPTH-collagen membrane as a new tissue engineering tool.

Recombinant Human Parathyroid Hormone (rhPTH 1-34) administration is an effective treatment to improve bone mass in osteoporosis. The aim of this study was to develop a Tissue Engeenering Tool for bone regeneration. We evaluated the efficacy of a freeze dried rhPTH membrane in calvarial critical size defect (CSD). Forty-four Wistar female rats (body weight 150 ± 50 g) with CSD (5 mm) were divided into four groups: group 1: rhPTH membrane (rhPTHm); group 2: atelocollagen membrane (Cm); group 3: rhPTH and atelocollagen I (CrhPTHm); group 4: without any treatment (CG). All samples were evaluated on the 1st, 3rd, and 6th weeks (weeks) post-surgery by soft X-ray, histological and histometric studies. Soft X-ray results showed a radiolucent image with many irregular radiopaque areas. Histologically, rhPTHm was replaced by reticular bone (7%) since 3rd week, and lamellar bone ossicles (30%) at 6th week. Cm showed bone formation like composite bone type on week 1st, 3rd, and 6th (2%, 44%, and 41%, respectively). With CrhPTHm, bone formation was observed in all periods (2.4%, 48%, and 53%), showing statistical difference with CG in the 3rd and 6th wks (p = 0.03 and 0.01). Our results demonstrated the effectiveness of a new biomaterial called CrhPTHm because its ability to regenerate calvarial CSD. Moreover, the membrane represents a new local intermittent delivery system allowing rhPTH slow release.

Clinical evaluation of glass ionomer for pit and fissure sealing of fully erupted molars.

The aim of this study was to evaluate the clinical behavior of two conventional glass ionomers used for pit and fissure sealing in terms of retention, marginal adaptation, caries recurrence and cracking. Eighty-three fully erupted first permanent molars were sealed, in a group of children aged 5 to 8 years. A double-blind, single operator, paired design was used. Materials applied were Fuji IX and VII. Retention (R), presence of caries (PC), marginal discoloration (MD), marginal adaptation (MA) and cracking (C) were evaluated at 6 and 12 months using Ryge's criteria. Data registered 6 months after treatment were: Fuji IX: R: Alpha 37, Bravo 2, Charlie: 4; PC: Alpha 43, Bravo: 0; MA: Alpha 38, Bravo: 1; MD: Alpha 39, Bravo: 0, Charlie: 0; C: Alpha 39, Bravo: 0. Fuji VII: R: Alpha 29, Bravo 4, Charlie: 7; PC: Alpha 40, Bravo: 0; MA: Alpha: 34, Bravo: 0; MD: Alpha: 34, Bravo: 0, Charlie: 0; C: Alpha 33, Bravo: 0. Results after one year were: Fuji IX: R: Alpha 33, Bravo: 3, Charlie: 9; PC: Alpha 44, Bravo: 1; MA: Alpha 33, Bravo: 1; MD: Alpha: 34, Bravo: 0, Charlie: 0; C: Alpha: 34, Bravo: 0. Fuji VII: R: Alpha 22, Bravo 4, Charlie: 13, PC: Alpha 40, Bravo: 0; MA: Alpha 23, Bravo: 1; MD: Alpha 23, Bravo: 1, Charlie: 0; C: Alpha 23, Bravo: 1. Statistical analysis using Fisher test showed no significant difference (p > 0.05) for R, and MA. For PC, MD and C, values are not reported because both materials showed the same results. The second control showed no significant difference (p > 0.05) for R, MA, PC, MD and C. Results suggest no difference between Fuji IX and Fuji VII as sealants in fully erupted permanent molars.

High resolution films for bone regeneration evaluation.

Diagnostic imaging techniques (DIxT) seem to be a useful tool for evaluating bone formation in both human and animal models. There is little evidence on the use of Soft X-Rays (sXR) with high-resolution films for studying the healing process in critical bone size defects (CSD). The aim of this study was to evaluate the ability of soft X-Ray - High Resolution Films (sXR) to distinguish bone regeneration in CSDs. A CSD was created in each of 16 Wistar rat calvariae. The animals were euthanized at 1, 3 and 6 weeks after surgery. The samples were submitted to cXR (conventional X-rays), sXR techniques and histological procedures (HP). Bone formation was observed at CSD edges at all periods of time. At 6 week there was also new bone in the central area. The CSD was not fully regenerated after any period of time. Histometric results were 0.16%; 0.75% and 0.89% new bone formed at weeks 1, 3 and 6 respectively; radiometric results at cXR were 0% in all samples. Evaluation of sXR shows 0.4%; 0.50% and 3.64% bone at weeks 1, 3 and 6. Mean and Standard Deviation were calculated. The data were submitted to statistical analysis using the Pearson product-moment correlation coefficient test. The r value was 0.581. Under these experimental conditions, sXR was found to be a suitable method for detecting new bone formation, based on the positive correlation between sXR and HP during the bone healing process of CSDs in rat calvaria. Furthermore, the sXR technique allowed us to obtain samples with appropriate spatial orientation.

Clinical evaluation of glass ionomer for pit and fissure sealing of fully erupted molars

The aim of this study was to evaluate the clinical behavior of two conventional glass ionomers used for pit and fissure sealing in terms of retention, marginal adaptation, caries recurrence and cracking. Eighty-three fully erupted first permanent molars were sealed, in a group of children aged 5 to 8 years. A doubleblind, single operator, paired design was used. Materials applied were Fuji IX and VII. Retention (R), presence of caries (PC), marginal discoloration (MD), marginal adaptation (MA) and cracking (C) were evaluated at 6 and 12 months using Ryge's criteria. Data registered 6 months after treatment were: Fuji IX: R: Alpha 37, Bravo 2, Charlie: 4; PC: Alpha 43, Bravo: 0; MA: Alpha 38, Bravo: 1; MD: Alpha 39, Bravo: 0, Charlie: 0; C: Alpha 39, Bravo: 0. Fuji VII: R: Alpha 29, Bravo 4, Charlie: 7; PC: Alpha 40, Bravo: 0; MA: Alpha: 34, Bravo: 0; MD: Alpha: 34, Bravo: 0; Charlie: 0; C: Alpha 33, Bravo: 0. Results after one year were: Fuji IX: R: Alpha 33, Bravo: 3, Charlie: 9; PC: Alpha 44, Bravo: 1; MA: Alpha 33, Bravo: 1; MD: Alpha: 34, Bravo: 0, Charlie: 0; C: Alpha: 34, Bravo: 0. Fuji VII: R: Alpha 22, Bravo 4, Charlie: 13, PC: Alpha 40, Bravo: 0; MA: Alpha 23, Bravo: 1; MD: Alpha 23, Bravo: 1, Charlie: 0; C: Alpha 23, Bravo: 1. Statistical analysis using Fisher test showed no significant difference (p>0.05) for R, and MA. For PC, MD and C, values are not reported because both materials showed the same results. The second control showed no significant difference (p>0.05) for R, MA, PC, MD and C. Results suggest no difference between Fuji IX and Fuji VII as sealants in fully erupted permanent molars.

El objetivo de este trabajo fue evaluar el comportamiento clinico de dos ionomeros vitreos convencionales aplicados como selladores de fosas y fisuras. Se evaluo la retencion, decoloracion y adaptacion marginal, incidencia de caries y agrietamiento. Se sellaron ochenta y tres primeros molares totalmente erupcionados en un grupo de ninos de 5 a 8 anos. Se llevo a cabo un diseno de doble ciego, unico operador y apareado. Los materiales aplicados fueron Fuji IX y VII. Luego de 6 y 12 meses se recitaron los ninos y se evaluo: Retencion (R), presencia de caries (PC), decoloracion marginal (MD) y agrietamiento (C). La evaluacion se realizo utilizando los criterios de Ryge. Los datos registrados al cabo de 6 meses fueron: Fuji IX: R: Alpha 37, Bravo 2, Charlie: 4; PC: Alpha 43, Bravo: 0; MA: Alpha 38, Bravo: 1; MD: Alpha 39, Bravo: 0, Charlie: 0; C: Alpha 39, Bravo: 0. Fuji VII: R: Alpha 29, Bravo 4, Charlie: 7; PC: Alpha 40, Bravo: 0; MA: Alpha: 34, Bravo: 0; MD: Alpha: 34, Bravo: 0; Charlie: 0; C: Alpha 33, Bravo: 0. A los 12 meses: Fuji IX: R: Alpha 33, Bravo: 3, Charlie: 9; PC: Alpha 44, Bravo: 1; MA: Alpha 33, Bravo: 1; MD: Alpha: 34, Bravo: 0, Charlie: 0; C: Alpha: 34, Bravo: 0. Fuji VII: R: Alpha 22, Bravo 4, Charlie: 13, PC: Alpha 40, Bravo: 0; MA: Alpha 23, Bravo: 1; MD: Alpha 23, Bravo: 1, Charlie: 0; C: Alpha 23, Bravo: 1. La evaluacion estadistica por medio de la prueba de Fisher no mostro diferencias significativas entre los materiales (p>0.05) para R y MA. En PC, MD y C, el valor de p no se indica ya que los resultados fueron identicos. El segundo control no mostro diferencias significativas (p>0.05) para R, MA, PC, MD y C. Los resultados sugieren que no existiria diferencia en la aplicacion de Fuji IX y Fuji VII como selladores de fosas y fisuras en molares totalmente erupcionados.

High resolution films for bone regeneration evaluation

Diagnostic imaging techniques (DIxT) seem to be a useful tool for evaluating bone formation in both human and animal models. There is little evidence on the use of Soft X-Rays (sXR) with high-resolution films for studying the healing process in critical bone size defects (CSD). The aim of this study was to evaluate the ability of soft X-Ray - High Resolution Films (sXR) to distinguish bone regeneration in CSDs. A CSD was created in each of 16 Wistar rat calvariae. The animals were euthanized at 1, 3 and 6 weeks after surgery. The samples were submitted to cXR (conventional X-rays), sXR techniques and histological procedures (HP). Bone formation was observed at CSD edges at all periods of time. At 6 week, there was also new bone in the central area. The CSD was not fully regenerated after any period of time. Histometric results were 0.16%; 0.75% and 0.89% new bone formed at weeks 1, 3 and 6 respectively; radiometric results at cXR were 0% in all samples. Evaluation of sXR shows 0.4%; 0.50% and 3.64% bone at weeks 1, 3 and 6. Mean and Standard Deviation were calculated. The data were submitted to statistical analysis using the Pearson product-moment correlation coefficient test. The r value was 0.581. Under these experimental conditions, sXR was found to be a suitable method for detecting new bone formation, based on the positive correlation between sXR and HP during the bone healing process of CSDs in rat calvaria. Furthermore, the sXR technique allowed us to obtain samples with appropriate spatial orientation.

Las tecnicas de diagnostico por Imagenes (DxI) han demostrado su utilidad para evaluar formacion osea en situaciones de salud y enfermedad. Son utilizadas tanto en humanos como en modelos animales; aunque la tecnica de rayos X blandos en placas de alta resolucion (rXb) ha sido escasamente aplicada. El objetivo de este trabajo fue evaluar la capacidad tecnica de los rayos X blandos en placas de alta resolucion (rXb) para distinguir la neoformacion osea en defectos oseos criticos (DOC) en calotas de ratas, durante el proceso de regeneracion osea. En 16 ratas Wistar hembras (150 ± 50 g), se realizaron DOC circulares en calota. Los animales fueron eutanasiados a la 1o, 3o y 6o semana post-quirurgica. Las muestras experimentales (MEx) recibieron rayos X convencionales (rXc), rayos X blandos (rXb) y luego fueron procesadas histologicamente (TH). Se realizaron estudios histometricos y radiometricos; utilizando soft Image J (NIH). Los resultados histologicos demostraron presencia de tejido de granulacion en el area del DOC a la 1° semana y se observo tejido fibroso desde la 3° semana. En todos los periodos de tiempo, se observo formacion osea en los bordes del DOC, mientras que a la 6° semana, fue evidente en el area central del mismo. No se evidencio regeneracion osea en ningun periodo estudiado. Los resultados histometricos fueron 0,16%; 0,75% y 0,89% a la 1o, 3o y 6o semana respectivamente. Los resultados radiometricos obtenidos utilizando placas radiograficas convencionales (rXc) fueron de 0% en todos los casos; mientras que en placas de alta resolucion con rayos X blandos (rXb) fueron 0,4%; 0,50% y 3,64% a las 1o, 3o y 6o semanas respectivamente. Se calcularon la media y Desvio Estandar a la 1°, 3° y 6° semana. Ademas se utilizo el coeficiente rho de Pearson, para estimar la correlacion existente entre rXb y TH; obteniendo un valor r de 0,581. En las condiciones experimentales utilizadas, podemos concluir que la tecnica de rXb fue un metodo apropiado para la deteccion de neoformacion osea, ya que demostro una correlacion positiva con la TH, durante los periodos de tiempo estudiados; ademas de facilitar la orientacion de las MEx durante su procesamiento histologico.

Matrix vesicles are carriers of bone morphogenetic proteins (BMPs), vascular endothelial growth factor (VEGF), and noncollagenous matrix proteins.

Matrix vesicles (MVs) are well positioned in the growth plate to serve as a carrier of morphogenetic information to nearby chondrocytes and osteoblasts. Bone morphogenetic proteins (BMPs) carried in MVs could promote differentiation of these skeletal cells. Vascular endothelial growth factor (VEGF) in MVs could stimulate angiogenesis. Therefore, a study was undertaken to confirm the presence of bone morphogenetic protein (BMP)-1 through-7, VEGF, and the noncollagenous matrix proteins, bone sialoprotein (BSP), osteopontin (OPN), osteocalcin (OC), and osteonectin (ON) in isolated rat growth plate MVs. MVs were isolated from collagenase-digested rachitic rat tibial and femoral growth plates. The presence of BMP-1 through BMP-7, VEGF, BSP, ON, OPN, and OC was evaluated by Western blot, plus ELISA analyses for BMP-2 and-4 content. The alkaline phosphatase-raising ability of MV extracts on cultured rat growth plate chondrocytes was measured as a reflection of MV ability to promote chondroosseous differentiation. BMP-1 through-7, VEGF, BSP, ON, OPN, and OC were all detected by Western blot analyses. Chondrocytes treated with MV extracts showed a two-to threefold increase in alkaline phosphatase activity over control, indicating increased differentiation. Significant amounts of BMP-2 and BMP-4 were detected in MVs by ELISA. Combined, these data suggest that MVs could play an important morphogenetic role in growth plate and endochondral bone formation.

Sequential expressions of Notch1, Jagged2 and Math1 in molar tooth germ of mouse.

The Notch signaling pathway is an evolutionary conserved mechanism that plays an important role in cell-cell communication and cell fate in a wide range of tissues. The mammalian family of Notch receptors consists of 4 members: Notch1/2/3/4. The Notch ligand family consists of 5 members: Delta1/3/4 and Jagged1/2. Math1 encodes a murine basic helix-loop-helix (bHLH) transcription factor that acts as positive regulator of cell differentiation. Recently, links between Notch and Math1 pathways were demonstrated in various tissues. Expression of Notch1, Jagged2 and Math1 were analyzed in the mouse molar tooth germ during embryonic stage (E) 13 and E15 and during postnatal stage (PN) 1, PN3, PN5, PN10 and PN14 by using in situ hybridization. Positive Notch1 expression was found at the tooth bud during embryonic stages, but its expression was absent from the basal cells in contact with the dental mesenchyme. Jagged2 and Math1 were strongly expressed in differentiated ameloblasts and odontoblasts and Math1 strong expression was even maintained until PN14 stage. Math1 showed the strongest expression. Our results suggest that the Notch1 signaling pathway through Jagged2 could be importantly related to Math1, directing the process of odontogenesis toward cell differentiation.

Efficacy of atelocollagen honeycomb scaffold in bone formation using KUSA/A1 cells.

To induce new bone formation, mesenchymal stem cells were seeded onto atelocollagen honeycomb scaffold. We evaluated the efficacy of this scaffold combined with KUSA/A1 cells in vivo. KUSA/A1 cells alone and with atelocollagen were implanted in the subcutaneous pockets of 4-week-old male SCID mice. The transplants were subjected to radiographical, histological, and immunohistochemical examinations after 2 and 4 weeks of implantation. Radiographically, both KUSA/A1 cells alone and KUSA/A1-atelocollagen showed some radiopaque areas formation but the latter disclosed a larger amount. Histologically, KUSA/A1 cells alone showed few small islands of new bone formation surrounded by a thin layer of cellular proliferation. On the other hand, KUSA/A1-atelocollagen revealed abundant new bone formation as well as cellular proliferation. We also determined the immunolocalization of type I collagen, CD34, osteocalcin, osteopontin, and PCNA in this newly formed bone. Our results indicated that collagen scaffold plays an important role allowing vessel formation and cell anchorage, especially through the proliferation and differentiation process in a confined space. This study supports tissue engineering as an alternative for treating different target diseases, such as trauma or congenital defects, and enhances existing therapeutic applications.

An experimental model in calvaria to evaluate bone therapies.

The clinical therapeutic application of experimental strategies requires extensive preclinical experimentation in appropriate animal models. Thus, a valid model must be established. The aim of the present study was to determine the critical size defect (CSD) of rat calvaria that is unable to undergo spontaneous bone regeneration. Forty Sprague Dawley female rats (body weight (bw): 250 +/- 20 g) were distributed in two groups. Circular surgical defects, 3 mm (Group A) and 5 mm (Group B) in diameter, were produced in the parietal bones. The animals were left untreated and sacrificed 1, 2, 3 and 6 weeks after surgery. Group A showed bone formation at the experimental site, increasing from 1 week (4.5%) to 6 weeks (46%). However, Group B showed scarce bone formation (less than 10%) throughout the experimental period. We may conclude that a defect 5 mm in diameter is a critical size defect (CSD) because it is the minimum bone defect size that requires treatment to heal. Thus, a circular defect 5 mm in diameter in rat calvaria would be an appropriate experimental model to study bone therapies.

An experimental model in calvaria to evaluate bone therapies

El desarrollo de estrategias óseas experimentales para su aplicación en terapéutica clínica, requiere evaluación preclínica extensa en modelos animales adecuados. El objetivo de este trabajo fue determinar el tamaño mínimo del defecto óseo experimental (TMD) en calvaria de ratas hembras que no repare espontáneamente. En 40 ratas Sprague Dawley de 250 +- 20 g de peso se practicaron defectos circulares quirúrgicos de A) 3mm de diámetro y B) 5 mm de diámetro, en los huesos parietales derechos. El grupo A demostró neoformación ósea en aumento desde la primera (4,5 por ciento) a la sexta semana (47 por ciento). Sin embargo, el grupo B desarrolló escasa regeneración ósea (no mayor al 10 por ciento) en los períodos estudiados. Por lo tanto, se estableció en 5 mm de diámetro el tamaño crítico del defecto experimental ósea en calvaria de ratas Sprague Dawley que requiere tratamiento para reparar, constituyendo un buen modelo de evaluación de estrategias óseas terapéuticas

An experimental model in calvaria to evaluate bone therapies

El desarrollo de estrategias óseas experimentales para su aplicación en terapéutica clínica, requiere evaluación preclínica extensa en modelos animales adecuados. El objetivo de este trabajo fue determinar el tamaño mínimo del defecto óseo experimental (TMD) en calvaria de ratas hembras que no repare espontáneamente. En 40 ratas Sprague Dawley de 250 +- 20 g de peso se practicaron defectos circulares quirúrgicos de A) 3mm de diámetro y B) 5 mm de diámetro, en los huesos parietales derechos. El grupo A demostró neoformación ósea en aumento desde la primera (4,5 por ciento) a la sexta semana (47 por ciento). Sin embargo, el grupo B desarrolló escasa regeneración ósea (no mayor al 10 por ciento) en los períodos estudiados. Por lo tanto, se estableció en 5 mm de diámetro el tamaño crítico del defecto experimental ósea en calvaria de ratas Sprague Dawley que requiere tratamiento para reparar, constituyendo un buen modelo de evaluación de estrategias óseas terapéuticas (AU)

An experimental model in calvaria to evaluate bone therapies.

The clinical therapeutic application of experimental strategies requires extensive preclinical experimentation in appropriate animal models. Thus, a valid model must be established. The aim of the present study was to determine the critical size defect (CSD) of rat calvaria that is unable to undergo spontaneous bone regeneration. Forty Sprague Dawley female rats (body weight (bw): 250 +/- 20 g) were distributed in two groups. Circular surgical defects, 3 mm (Group A) and 5 mm (Group B) in diameter, were produced in the parietal bones. The animals were left untreated and sacrificed 1, 2, 3 and 6 weeks after surgery. Group A showed bone formation at the experimental site, increasing from 1 week (4.5

) to 6 weeks (46

). However, Group B showed scarce bone formation (less than 10

) throughout the experimental period. We may conclude that a defect 5 mm in diameter is a critical size defect (CSD) because it is the minimum bone defect size that requires treatment to heal. Thus, a circular defect 5 mm in diameter in rat calvaria would be an appropriate experimental model to study bone therapies.

Quistes de glándulas salivales menores tapizados por epitelio oxífilo / Minor salivary glands cysts lined with oxyphil epithelium

Se describen los quistes oxífilos de glándulas salivales menores, llamados así porque su pared está formada por una o varias capas de células de citoplasma eosinófilo. Su contenido basófilo puede en alguna circunstancia responder a las características histoquímicas de las mucinas epiteliales y es cuando en su pared se diferencian células mucoproductoras que vuelcan su contenido en él. Su incidencia es muy baja (4,06 por ciento) ya que son una variedad de los quistes por retención. Las características clínicas como consistencia firme, color rosa pálido y la edad en que aparecen (18 a 30 años), serían elementos de valor para su diagnóstico

Quistes de glándulas salivales menores tapizados por epitelio oxífilo / Minor salivary glands cysts lined with oxyphil epithelium

Se describen los quistes oxífilos de glándulas salivales menores, llamados así porque su pared está formada por una o varias capas de células de citoplasma eosinófilo. Su contenido basófilo puede en alguna circunstancia responder a las características histoquímicas de las mucinas epiteliales y es cuando en su pared se diferencian células mucoproductoras que vuelcan su contenido en él. Su incidencia es muy baja (4,06 por ciento) ya que son una variedad de los quistes por retención. Las características clínicas como consistencia firme, color rosa pálido y la edad en que aparecen (18 a 30 años), serían elementos de valor para su diagnóstico (AU)