			Home About us Contact

Mature Bone (mature + bone)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Behavior of dense and porous hydroxyapatite implants and tissue response in rat femoral defects

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2002
J.C.T. Andrade
Abstract Porous and dense hydroxyapatite cylinders (PHA and DHA) were implanted into cavities produced in rat femora and the sites of implantation were examined at different times over a period of 24 weeks by microradiologic and histological techniques. Microradiographs showed the presence of a layer of trabecular bone around the implants, which became more radiopaque and thinner along the experimental time. The microradiologic methodology used was suitable for the evaluation of the interface between hydroxyapatite and newly formed bone in nondecalcified materials. Microscopic observations showed that young bone grew over the surface of both types of implants after 1 and 2 weeks of surgery and that bone also grew inside PHA implants. Progressive bone absorption was observed in both types of implants after the fourth week. A layer of fibrous tissue was formed in the interface between new bone and DHA. Mature bone with haversian systems surrounded DHA implants and filled the pores of PHA implants throughout the experimental period. The pores of PHA implants were smaller than those commonly reported, which should have been a disadvantage, although it was observed that the extra cellular fluid induced disintegration of the ceramic granules, allowing the gradual growth of bone tissue into the spaces among them, without the interposition of fibrous tissue. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 30,36, 2002 [source]

Application of Histomorphometric Methods to the Study of Bone Repair,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2005
Louis C Gerstenfeld
Abstract ABSTRACT: Standardized methods for the histomorphometric assessment of bone are essential features of most studies of metabolic bone diseases and their treatments. These methodologies were developed to assess coupled remodeling, focusing primarily on osteoblasts and osteoclasts, the anabolic and catabolic rates of these cells, and structural features of mature bone. Research studies on bone healing and the development of new therapeutic approaches for the enhancement of bone repair also require a comprehensive understanding of the basic cellular and tissue level mechanisms that underlie these processes. However, the histological methods developed for metabolic bone disease studies are not completely suitable for studies of bone repair because they are based on assumptions that there is little variation in tissue composition within a sample of bone and not generally designed to quantify other types of tissues, such as cartilage, that contribute to bone healing. These techniques also do not provide tissue-based structural measurements that are relatable to the specific types of biomechanical and radiographic structural assessments that are used to determine rates of bone healing. These deficiencies in current histological approaches therefore point to the need to establish standardized criteria for the histomorphometric assessments that are specifically adapted for the study of bone repair in models of fracture healing and bone regeneration. In this Perspective, we outline what we believe to be the specific structural, tissue. and cellular aspects that need to be addressed to establish these standardized criteria for the histomorphometric assessment of bone repair. We present the specific technical considerations that need to be addressed to appropriately sample repair tissues to obtain statistically meaningful results and suggest specific procedures and definitions of nomenclatures for the application of this technology to bone repair. Finally, we present how aspects of histomorphometric measurements of bone repair can be related to biomechanical and radiographic imaging properties that functionally define rates of bone healing, and thus, how these tools can be used to provide corroborating data. [source]

Combining Scaffolds and Osteogenic Cells in Regenerative Bone Surgery: A Preliminary Histological Report in Human Maxillary Sinus Augmentation

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2009
Carlo Mangano DDS
ABSTRACT Purpose: The following case series evaluated the maxillary sinus augmentation responses to tissue-engineered bone graft obtained by a culture of autogenous osteoblasts seeded on polyglycolic,polylactic scaffolds and calcium phosphate. Materials and Methods: Sinus floor augmentation was performed bilaterally in five patients (mean age 58.4 years) with tissue-engineered bone (test site , Oral Bone®, BioTissue, Freiburg, Germany) or calcium phosphate (control site , Biocoral, Novaxa Spa, Milan, Italy). Biopsies were harvested 6 months after sinus augmentation for histometric evaluation. Volumetric measurements were taken at baseline and 6 months after the surgical procedure. Results: The mean of vertical bone gain was 6.47 ± 1.39 mm and 9.14 ± 1.19 mm to test and control sites, respectively. The histological sections depicted mature bone with compact and cancellous areas. All biopsies contained varying percentages of newly formed bone and marrow spaces. The mean of bone tissue in the grafted area was 37.32 ± 19.59% and 54.65 ± 21.17% for tissue-engineered bone and calcium phosphate, respectively. Conclusion: Within the limits of the present report, the histological data in humans confirmed that tissue-engineered bone and calcium phosphate allowed newly formed bone after maxillary sinus augmentation. [source]

Alveolar Ridge Regeneration with Equine Spongy Bone: A Clinical, Histological, and Immunohistochemical Case Series

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2 2009
Danilo Alessio Di Stefano DDS
ABSTRACT Background: In the case of localized ridge atrophy, a ridge augmentation procedure, with the use of bone substitutes and barrier membranes, may then be necessary. Purpose: The aim of the present study was a clinical, histological, and immunohistochemical evaluation of an equine spongy bone in alveolar ridge augmentation procedures. Materials and Methods: Five patients showing horizontal mandibular ridge defects participated in this study. A ridge augmentation was performed through an onlay apposition of equine bone covered by a titanium-reinforced membrane. After 6 months of healing, five bone cores from nonaugmented sites (control) and five from augmented sites (test) were retrieved. Results: In test sites, no postoperative complications occurred. Horizontal bone width increased from ,4 to ,7 mm. In control sites, the newly formed bone represented 33%, and in test sites, 35% of the total area. The mean value of the microvessel density was 25.6 +/, 3.425 per mm2 in controls, while 33.3 +/, 2.5 vessels per mm2 in the test sites were found (p < .05). Both groups showed a high intensity (++) of vascular endothelial growth factor expression in the newly formed bone, while a low intensity (+) was found in the mature bone. Conclusion: Equine bone appeared to be biocompatible and to be associated with new vessel ingrowth. Within the limits of the small sample size, the present study indicated that equine bone could be used in mandibular ridge augmentations. [source]

Tissue-engineered injectable bone regeneration for osseointegrated dental implants

CLINICAL ORAL IMPLANTS RESEARCH, Issue 5 2004
Yoichi Yamada
Abstract: The present study investigated a correlation between osseointegration in dental implants and an injectable tissue-engineered bone, using mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP). Initially, the teeth in the mandible region were extracted and the healing period was 1 month. Bone defects on both sides of the mandible were prepared with a trephine bar. The defects were implanted with graft materials as follows: PRP, dog MSCs (dMSCs), and PRP, autogenous particulate cancellous bone and marrow (PCBM), and control (defect only). Two months later, the animals were evaluated by histology, and at the same time dental implants were installed. Two months later, the animals were sacrificed and nondecalcified sections were evaluated histologically and histometrically. According to the histological observations, the dMSCs/PRP group had well-formed mature bone and neovascularization, compared with the control (defect only) and PRP groups, as was the same for the PCBM group. A higher marginal bone level was observed around implants with PRP, PCBM, and dMSCs/PRP compared with the control. Furthermore, the values describing the amount of bone,implant contact (BIC) at the bone/implant interface were significantly different between the PRP, PCBM, dMSCs/PRP, and control groups. Significant differences were also found between the dMSCs/PRP and control groups in bone density. The findings of this experimental study indicate that the use of a mixture of dMSCs/PRP results in good results such as the amount of BIC and bone density comparable with that achieved by PCBM. Résumé L'étude présente a analysé une corrélation entre l'ostéïntégration d'implants dentaires et un os injectable traité en utilisant des cellules souches mésenchymateuses (MSC) et du plasma riche en plaquette (PRP). Initialement, les dents de la région mandibulaire ont été avulsées et la période de guérison a été d'un mois. Les lésions osseuses des deux côtés de la mandibule ont été préparées avec un trépan. Les lésions ont été traitées avec les matériaux de greffe suivants : PRP, MSC canin (dMSC) et PRP, moelle l'os spongieux en petites particules autogènes (PCBM) et contrôle (lésion seulement). Deux mois plus tard, les animaux ont étéévalués et en même temps les implants dentaires ont été placés. Deux mois plus tard, les animaux ont été euthanasiés et des coupes non-décalcifiées ont étéévaluées histologiquement et histométriquement. Suivant les observations histologiques, le groupe dMSC/PRP avait de l'os mûr bien formé et une néovascularisation comparé au contrôle et aux groupes PRP, comme pour le groupe PCBM. Un niveau osseux marginal plus important a été observé autour des implants avec PRP, PCBM et dMSC/PRP comparé au contrôle. De plus les valeurs décrivant la quantité de contact os/implant à l'interface os/implant étaient significativement différentes entre les groupes PRP, PCBM, dMSC/PRP et contrôles. Des différences significatives étaient aussi trouvées entre les groupes dMSC/PRP et contrôle en ce qui concernait la densité osseuse. Ces découvertes indiquent que l'utilisation d'un mélange dMSC/PRP résulte en de bons résultats tels que la quantité de contact os-implant et la densité osseuse comparéà ce qui se passe après l'utilisation du PCBM. Zusammenfassung Gewebemanipulierte injizierbare Knochenregenerate für osseointegrierte dentale Implantate Die vorliegende Studie untersuchte eine Korrelation zwischen der Osseointegration bei dentalen Implantaten und einem injizierbaren gewebemanipulierten Knochenregenerat aus mesenchymalen Stammzellen (MSCs) und plättchenreichem Plasma (PRP). Zuerst wurden die Zähne im Unterkiefer extrahiert. Darauf folgte eine Heilungsperiode von 1 Monat. Auf beiden Seiten der Unterkiefer wurden mit einer Hohlfräse Knochendefekte präpariert. Die Defekte wurden mit folgenden Transplantatmaterialien aufgefüllt: PRP, Hunde MSCs (dMSCs) und PRP, autologer zerkleinerter Knochen und Knochenmark (PCBM) und kein Füllmaterial (Kontrolle). Zwei Monate später wurden die Tiere histologisch untersucht und es wurden dentale Implantate eingesetzt. Nach weiteren zwei Monaten wurden die Tiere geopfert und nicht entkalkte Schnitte wurden histologisch und histometrisch ausgewertet. Gemäss der histologischen Beobachtungen zeigten die dMSCs/PRP Gruppe im Vergleich zur Kontrollgruppe und zur PRP Gruppe gut ausgebildeten reifen Knochen und neue Gefässe. Das Selbe galt für die PCBM Gruppe. Bei den Implantaten mit PRP, PCBM und dMSCs/PRP konnte im Vergleich zur Kontrollgruppe ein höheres marginales Knocheniveau beobachtet werden. Zudem waren die Werte, welche das Ausmass an Knochen-Implantat-Kontakt an der Kochen/Implantat Berührungsfläche beschreiben, zwischen den PRP, PCBM, dMSCs/PRP und der Kontrollgruppe signifikant verschieden. Signifikante Unterschiede wurden auch bezüglich Knochendichte zwischen der dMSCs/PRP und der Kontrollgruppe gefunden. Die Ergebnisse dieser experimentellen Studie zeigen, dass die Anwendung eines Gemisches aus dMSCs/PRP zu guten Resultaten bezüglich Ausmass an Knochen-Implantat-Kontakt und Knochendichte führt. Die erzielten Resultate sind mit den mit PCBM erreichten vergleichbar. Resumen El presente estudio investigó la correlación entre osteointegración en implantes dentales y un tejido-elaborado óseo inyectable, usando células madre mesenquimales (MSCs) y plasma rico en plaquetas (PRP). Inicialmente, se extrajeron los dientes de la mandíbula y el periodo de cicatrización fue de un mes. Se prepararon defectos óseos en ambos lados de la mandíbula con una fresa trépano. Los defectos se implantaron con material de injerto de la siguiente manera: PRP, MSCs de perro (dMSCs) y PRP, partículas de hueso esponjoso y médula autógenos (PCBM), y control (defecto solo). Dos meses mas tarde, los animales se evaluaron por histología, al mismo tiempo se instalaron implantes dentales. Dos meses mas tarde se sacrificaron los animales y se evaluaron secciones no descalcificadas histológica e histometricamente. De acuerdo con las observaciones histológicas, el grupo dMSCs/PRP había formado bien un hueso maduro y una neovascularización, comparado con el control (defecto solo) y grupos PRP, también fue igual para el grupo PCBM. Se observó un nivel óseo marginal mas alto alrededor de los implantes con PRP, PCBM, y dMSCs/PRP comparados con el control. Mas aun, los valores que describen la cantidad de contacto hueso-implante en la interfase hueso/implante fueron significativamente diferentes entre los grupos PRP, PCBM, dMSCs/PRP, y de control en la densidad ósea. Estos hallazgos de este estudio experimental indican que el uso de una mezcla de dMSCs/PRP resulta en buenos resultados tales como la cantidad de contacto hueso-implante y densidad ósea comparable a aquella lograda por PCBM. [source]