			Home About us Contact

HA Coatings (ha + coating)

Distribution by Scientific Domains

Polymers and Materials Science	50%
Medical Sciences	50%

Selected Abstracts

Partial generation of periodontal ligament on endosseous dental implants in dogs

CLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2005
Leila Jahangiri
Abstract Objectives: The objective of this pilot study was to investigate the feasibility of periodontal ligament (PDL) generation on an implant surface by approximating a tooth-to-implant contact using orthodontics. Methods: Maxillary second premolars of six beagle dogs were extracted bilaterally. After 2 weeks of healing, hydroxyapatite (HA) coated titanium implants, 5 mm in length and 3.3 mm in diameter, were placed in the extraction sites. One side of the arch was used as control. Orthodontic tooth movement was initiated following implant placement to tip the first premolar roots into contact with the implant. This was achieved in 4,6 weeks as confirmed radiographically. Tooth-to-implant contact was maintained for further 6 weeks after which time, teeth were separated from implant contact orthodontically. After further 2 weeks of stabilization, the animals were sacrificed. Samples were analyzed by Faxitron radiographs before histology. Histology samples were prepared with Stevenel's Blue and Van Gieson stain and were subjected to polarized light microscopy. Results: Histologic analysis revealed transfer and formation of PDL-like structure with formation of cellular cementum on the implant surfaces, in four out of six animals, where tooth-to-implant contact had been achieved. Direct bone-to-implant contact was noted in the areas coronal to the PDL-like tissue, an important sign to distinguish between PDL-like tissue and connective tissue that could originate from the coronal portion of a failing implant. Additionally, at the site of contact, the implant surface revealed some resorption of the HA coating. Conclusion: An animal model was established in which the proximity of tooth-to-implant contact lead to partial generation of PDL on a bioactive implant surface in four out of six animals. Résumé L'objectif de cette étude pilote a été d'analyser la possibilité d'obtenir une régénération du ligament parodontal (PDL) sur une surface implantaire en rapprochant le contact implant-dent par l'orthodontie. Les deuxièmes prémolaires maxillaires de six chiens beagle ont été avulsées bilatéralement. Après deux semaines de guérison, des implants en titane recouverts d'hydroxyapatite de 5 mm de long et de 3,3 mm de diamètre ont été insérés dans les sites d'avulsion. Un site de chaque arche était utilisé comme contrôle. Le mouvement orthodontique de la dent était initialisé après le placement de l'implant pour mettre en contact les raçines des premières prémolaires avec l'implant. Ceci a été réalisé en quatre à huit semaines comme l'a confirmé la radiographie. Le contact dent-implant a été maintenu pour une durée supplémentaire de six semaines après lesquelles les dents ont été séparées du contact des implants de manière orthodontique. Après deux semaines de stabilisation, les animaux ont été euthanasiés. Les échantillons ont été analysés par radiographie Faxitron avant l'histologie. Les échantillons histologiques ont été préparés par les colorations du Bleu de Stevenel et de Van Gieson et ont été analysés au microscope optique à polarisation. L'histologiea révélé un transfert et une formation d'une structure ressemblant à PDL avec la formation d'un cément cellulaire à la surface des implants chez quatre des six animaux chez lesquels le contact dent-implant avaient été réalisés. Le contact direct os-implant a été noté dans les zones coronaires au tissu qui ressemblait à PDL, un signe important pour distinguer le tissu ressemblant à PDL et le tissu conjonctif qui pouvait provenir de la portion coronaire de l'implant qui échoue. De plus, au site de contact, la surface implantaire révélait quelques résorptions du recouvrement d'hydroxyapatite. Un modèle animal a donc étéétabli dans lequel la proximité du contact dent-implant était suivie d'une génération partielle de PDL sur une surface implantaire bioactive chez quatre des six animaux. Zusammenfassung Ziele: Das Ziel dieser Pilotstudie war, zu untersuchen, ob es möglich sei, ein parodontales Ligament (PDL) auf einer Implantatoberfläche durch Herstellung eines Zahn-Implantat-Kontakts mittels Orthodontie zu generieren. Methoden: Bei sechs Beagle-Hunden wurden bilateral die zweiten Prämolaren extrahiert. Nach einer Abheilzeit von zwei Wochen wurden Hydroxyapatit beschichtete Titanimplantate mit einer Länge von 5 mm und einem Durchmesser von 3.3 mm in die Extraktionsstellen eingesetzt. Eine Seite des Zahnbogens diente als Kontrolle. Nach der Implantatplatzierung wurde mit der orthodontischen Zahnbewegung begonnen, um die Wurzeln der ersten Prämolaren in Kontakt mit den Implantaten zu bringen. Es wurde radiologisch bestätigt, dass dies nach 4,6 Wochen erreicht wurde. Der Zahn-Implantat-Kontakt wurde für weitere sechs Wochen belassen, danach wurden die Zähne wieder orthodontisch vom Kontakt mit den Implantaten separiert. Nach weiteren zwei Wochen zur Stabilisierung wurden die Tiere geopfert. Die Proben wurden vor der Histologie mittels Faxitron Röntgen analysiert. Die histologischen Proben wurden mit Stevenel`s Blau und van Gieson Färbungen bearbeitet und durch Lichtmikroskopie mit polarisiertem Licht untersucht. Resultate: Die histologische Analyse zeigte einen Transfer und eine Formation von Parodontalligament ähnlichen Strukturen mit der Bildung von zellulärem Zement auf der Implantatoberfläche bei 4 von 6 Tieren, bei welchen ein Zahn-Implantat-Kontakt erreicht worden war. Koronal des PDL-ähnlichen Gewebes bestand ein direkter Knochen-Implantat-Kontakt. Dies war ein wichtiges Merkmal, um zwischen PDL-ähnlichem Gewebe und Bindegewebe, welches vom koronalen Anteil eines fehlgeschlagenen Implantats stammen könnte, zu unterscheiden. Zusätzlich zeigten die Implantatoberflächen im Bereich der Berührungsfläche etwas Resorption der Hydroxyapatit Beschichtung. Schlussfolgerung: Es wurde ein Tiermodell etabliert, in welchem ein Zahn-Implantat-Kontakt bei 4 von 6 Tieren zu einer partiellen Generation eines PDL auf einer bioaktiven Implantatoberfläche führte. Resumen Objetivos: El objetivo de este estudio piloto fue investigar la viabilidad de generación de ligamento periodontal (PDL) en la superficie de un implante por aproximación de un contacto diente a implante usando ortodoncia. Métodos: Se extrajeron los segundos premolares de seis perros beagle bilateralmente. Tras dos semanas de cicatrización, se colocaron en los lugares de extracción implantes de titanio cubiertos de hidroxiapatita, de 5 mm de longitud y 3.3 mm de diámetro. Un lado del arco se usó como control. El movimiento dental ortodóntico se inició tras la colocación del implante para apuntar las raíces del primer premolar hacia el contacto con el implante. Esto se logró en 4-6 semanas tal como se confirmó radiograficamente. El contacto diente a implante se mantuvo durante seis semanas mas tras lo cual, los dientes se separaron del contacto con el implante ortodonticamente. Tras dos semanas más de estabilización, los animales se sacrificaron. Las muestras se analizaron por medio de radiografías Faxitron antes de la histología. Las muestras histológicas se prepararon con azul de Stevenel y tinción de Van Gieson y se sometieron a microscopio de luz polarizada. Resultados: El análisis histológico reveló transferencia y formación de estructuras tipo ligamento periodontal con formación de cemento celular en las superficies del implante, en 4 de 6 animales, en los que se logró el contacto diente a implante. Se notó contacto en las áreas coronales al tejido tipo PDL, un signo importante para distinguir tejido tipo PDL y tejido conectivo que se podría originar de la parte coronal de un implante en vías de fracaso. Además, en el lugar del contacto, la superficie del implante reveló algo de reabsorción de la cubierta de hidroxiapatita. Conclusión: Se estableció un modelo animal en el que la proximidad del contacto diente a implante llevó a la generación parcial de PDL en una superficie de implante bioactiva en 4 de 6 animales. [source]

Fibronectin Functionalized Hydroxyapatite Coatings: Improving Dermal Fibroblast Adhesion In Vitro and In Vivo,

ADVANCED ENGINEERING MATERIALS, Issue 8 2010
Catherine J. Pendegrass
Skin-penetrating devices including intraosseous transcutaneous amputation prostheses (ITAP) and external fixator pins rely on a skin-implant seal to prevent infection. In this study, we assess the effectiveness of fibronectin (Fn) functionalized hydroxyapatite (HA) coatings for promoting dermal fibroblast and dermal tissue attachment and ingrowth in vitro and in vivo. By measuring the number of focal adhesions per unit cell area we have demonstrated that HA significantly promotes dermal fibroblast attachment compared with titanium alloy. Dermal fibroblast attachment is promoted further using Fn functionalized HA coatings incorporated into an implant design with 700,µm pores, which significantly increased dermal tissue ingrowth and attachment compared with non-functionalized HA and titanium alloy controls incorporating 500 or 1000,µm pores. We postulate that Fn functionalized HA coatings applied to transdermal implants may promote and sustain the skin-implant interface and assist in preventing infection long term. [source]

Electrolytic Deposition of Hydroxyapatite Coating on CoNiCrMo Substrates

ADVANCED ENGINEERING MATERIALS, Issue 1-2 2010
Dong-Yang Lin
Hydroxyapatite (HA) coating was fabricated on CoNiCrMo alloy by electrolytic deposition (ELD). Different kinds of uncharged substrates were placed close to the cathode separately during the ELD process. Both CoNiCrMo and uncharged substrates were covered with uniform HA coatings composed of hexagonal prism crystals after 60,min deposition. The pH value of the bulk solution changed hardly while the local pH had a sharp increase after ELD. The results demonstrate the local pH plays a crucial role in the ELD process. [source]

Hydrothermal crystallization of carbonate-containing hydroxyapatite coatings prepared by radiofrequency-magnetron sputtering method

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2007
Satoshi Nakamura
Abstract Carbonate-containing hydroxyapatite (HA) films were prepared by low-temperature hydrothermal annealing from carbonate-containing calcium phosphate amorphous coatings on titanium substrates. The biocompatibility of the carbonate-containing HA layers was estimated by in vitro tests using simulated body fluid (SBF). Precursory amorphous coatings were deposited with rf-magnetron sputtering apparatus, using calcium phosphate glass target in Ar/CO2 atmosphere. The carbonate-containing HA coatings were successfully formed by the annealing at above 130°C for 20 h. On the basis of SEM observation, about 2-,m thickness films coated rigidly were durable enough for the hydrothermal treatment. The coating layer was revealed to consist of single phase of PO4, and OH, partially carbonated HA by XRD and IR analyses. Overgrowing of bone-like apatite layers on the carbonate-containing HA surfaces in the SBF implied that the obtained films acquired a sufficient osteoconductivity, while it was still unclear that activity was enhanced, compared to pure HA coatings. The low-temperature hydrothermal annealing method was effective for preparation of rigid HA coatings on titanium as well as modification of their chemical compositions. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007 [source]

Implant Surface Modification Using Laser Guided Coatings: In Vitro Comparison of Mechanical Properties

JOURNAL OF PROSTHODONTICS, Issue 5 2008
Asvin Vasanthan DDS
Abstract Purpose: Plasma-sprayed hydroxyapatite (HA)-coated implants show failures along the coating,substrate interface due to poor bond strength. We analyzed HA coatings obtained by pulsed laser deposition (PLD) and compared them to commercially used plasma-sprayed coatings with respect to their bond strength to titanium alloy (Ti-6Al-4V), as well as surface roughness alterations produced by each of the two deposition methods. Materials and Methods: Twelve titanium alloy disks were plasma-sprayed under commercial implant coating conditions, and 24 titanium alloy disks were coated using PLD. All coatings were characterized by the presence of the different calcium phosphate (CaP) phases. The plasma-sprayed coatings (n = 12) were predominantly HA, and the pulsed laser-deposited coatings were hydroxydyapatite (n = 12) and HA coating with a tetra calcium phosphate (TTCP) phase (n = 12). The surface roughness was analyzed before and after the coating processes to assess roughness changes to the surface by the coatings. The adhesive bond strengths of these coatings to the substrate titanium alloy was tested and compared. Scheffé's test was used to analyze the statistical significance of the data. Results: The surface roughness alteration following PLD was a decrease of 0.2 ,m, whereas following plasma spraying the decrease was 1.0 ,m. Bond strengths were as follows [mean (SD) in MPa]: pulsed laser-deposited HA coatings: 68.3 (17.8); pulsed laser-deposited HA with tetra-CaP: 55.2 (21.1); plasma-sprayed HA 17.0 (2.8). The multivariate Scheffé's test revealed that HA coatings obtained by PLD had significantly increased bond strengths compared with the plasma sprayed ones (p, 0.05). Conclusions: HA coatings obtained by PLD showed greater adherence to titanium alloy. PLD offers an alternative method to produce thinner coatings with better adherence properties, along with precise control over the deposition process. [source]