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ABSTRACT: Titanium oxide (TiO(2)) scaffolds have previously been reported to exhibit very low mechanical strength. However, we have been able to produce a scaffold that features a high interconnectivity, a porosity of 91% and a compressive strength above 1.2MPa. This study analyzed the in vivo performance of the porous TiO(2) scaffolds in a peri-implant cortical defect model in the rabbit. After 8weeks of healing, morphological microcomputed tomography analyses of the defects treated with the TiO(2) scaffolds had significantly higher bone volume, bone surface and bone surface-to-volume ratio when compared to sham, both in the cortical and bone marrow compartment. No adverse effects, i.e. tissue necrosis or inflammation as measured by lactate dehydrogenase activity and real-time reverse transcription polymerase chain reaction analysis, were observed. Moreover, the scaffold did not hinder bone growth onto the adjacent cortical titanium implant. Histology clearly demonstrated new bone formation in the cortical sections of the defects and the presence of newly formed bone in close proximity to the scaffold surface and the surface of the adjacent Ti implant. Bone-to-material contact between the newly formed bone and the scaffold was observed in the histological sections. Islets of new bone were also present in the marrow compartment albeit in small amounts. In conclusion, the present investigation demonstrates that TiO(2) scaffolds osseointegrate well and are a suitable scaffold for peri-implant bone healing and growth.
Acta biomaterialia 09/2012; · 3.98 Impact Factor
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ABSTRACT: Colonization of implant surfaces with bacteria should ideally be prevented right from implantation, as bacteria attaching to the surface will form a biofilm, being then well protected against antibiotic treatment. Therefore, implant coatings should combine antibacterial properties with biocompatibility towards their host tissue. We tested a UV-induced covalent coating procedure with eicosapentaenoic acid (EPA) for smooth titanium (Ti) surfaces for its ability to prevent attachment and proliferation of Staphylococcus epidermidis and to allow mineralization of MC3T3-E1 osteoblasts. Bacterial initial attachment was highest for EPA-coated surfaces, but was reduced by vigorous washing, possibly due to low adhesive strength on those surfaces. We found an increase in the ratio of dead bacteria and in overall biofilm after 16 h on Ti surfaces with covalently bound EPA compared to Ti. The UV-induced EPA coating did not impair the ability of MC3T3-E1 preosteoblasts to mineralize, while a reduction in mineralization could be found for UV-irradiated Ti surfaces and UV-irradiated surfaces washed with ethanol compared to Ti. Although in vivo studies are needed to evaluate the clinical significance, our results indicate that covalent coating of Ti surfaces with EPA by UV irradiation decreases the survival of S. epidermidis and maintains the mineralization ability of osteoblasts.
Journal of Orthopaedic Research 02/2012; 30(9):1384-90. · 2.81 Impact Factor
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ABSTRACT: The osteoconductive potential of titanium is interesting from the perspective of periodontal surgery and reconstitution of osseous defects. The aim of the present consecutive case series is to evaluate a surgical strategy based on the use of porous titanium granules (PTG) in the treatment of Class II buccal furcation defects in mandibular molars in humans.
Surgical intervention with PTG used as a bone graft substitute was performed in 10 patients with 10 mandibular Class II buccal furcation defects. Clinical parameters (probing depth (PD), clinical attachment level (CAL), gingival recession (GR), gingival index (GI), bleeding on probing (BOP), and horizontal and vertical bone sounding) and radiographic measurements of vertical furcation height were compared among baseline (presurgery), 6, and 12 months (post-surgery). The significance level (α) was set at 0.05.
With respect to vertical and horizontal bone sounding measurements, CAL, and GR, no significant improvements between baseline and the 12-month examination were seen. Both PD and radiographic vertical furcation height were significantly reduced between baseline and 12 months. When comparing the baseline to 12-month data, a significantly lower GI score was seen but the BOP score was unchanged. None of the treated teeth showed radiographic signs of root resorption.
This study suggests that PTG is safe to use in close proximity to root surfaces, but no significant improvements in clinical endpoints of defect resolution were observed.
Journal of Periodontology 05/2011; 83(1):61-9. · 2.60 Impact Factor
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ABSTRACT: The question of specific immunomodulating qualities of hypertonic saline (HTS) has not been settled. It has proven difficult to distinguish between immunomodulation directly attributable to HTS and influence because of favorable circulatory effects. The nature of immune activator may also play a role. In a whole-blood model, we have investigated these relations further, with special emphasize on osmolalities usually found after recommended dosing. Blood from 10 healthy donors was exposed to osmolalities ranging from 295 to 480 mOsm/kg and stimulated with the two clinically relevant stimulators peptidoglycan (1 µg/mL) or LPS (10 ng/mL) for 6 h at 37°C. Leukocyte response was evaluated by measuring selected cytokines in the supernatant. Moderate hyperosmolality alone boosted the release of CXCL8/IL-8. The peptidoglycan-stimulated synthesis of pivotal proinflammatory cytokines was inhibited in an osmolality-dependent way, but statistically significant only at osmolalities above those attained after routine use of HTS, i.e., 310 mOsm/kg or greater: IL-6 (P < 0.05 at 315 mOsm/kg), IL-1ß, and TNF-α (P < 0.05 at 335 mOsm/kg). Similar effects were seen for the chemokine CCL3 and the anti-inflammatory cytokine IL-10. In contrast, the effects in cells stimulated with LPS were either lower or absent. Thus, osmolalities usually found after clinical use of HTS only modestly influenced the selected immune parameters, regardless of stimulator.
Shock (Augusta, Ga.) 05/2010; 34(5):450-4. · 2.87 Impact Factor
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ABSTRACT: Previous studies have shown that bone-to-implant attachment of titanium implants to cortical bone is improved when the surface is modified with hydrofluoric acid. The aim of this study was to investigate if biological factors are involved in the improved retention of these implants. Fluoride was implemented in implant surfaces by cathodic reduction with increasing concentrations of HF in the electrolyte. The modified implants were placed in the cortical bone in the tibias of New Zealand white rabbits. After 4 weeks of healing, wound fluid collected from the implant site showed lower lactate dehydrogenase activity and less bleeding in fluoride-modified implants compared to control. A significant increase in gene expression levels of osteocalcin and tartrate-resistant acid phosphatase (TRAP) was found in the cortical bone attached to Ti implants modified with 0.001 and 0.01 vol.% HF, while Ti implants modified with 0.1% HF showed only induced TRAP mRNA levels. These results were supported by the performed micro-CT analyses. The volumetric bone mineral density of the cortical bone hosting Ti implants modified with 0.001% and 0.01% HF was higher both in the newly woven bone (<100 microm from the interface) and in the older Haversian bone (>100 microm). In conclusion, the modulation of these biological factors by surface modification of titanium implants with low concentrations of HF using cathodic reduction may explain their improved osseointegration properties.
Acta biomaterialia 09/2009; 6(3):1025-32. · 3.98 Impact Factor
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ABSTRACT: The adipose tissue is the site of expression and secretion of a range of biologically active proteins, called adipokines, for example, leptin, adiponectin, and resistin. Leptin has previously been shown to be expressed in osteoblasts and to promote bone mineralization, whereas adiponectin expression is enhanced during osteoblast differentiation. In the present study we explored the possible role of resistin in bone metabolism. We found that resistin is expressed in murine preosteoclasts and preosteoblasts (RAW 264.7, MC3T3-E1), in primary human bone marrow stem cells and in mature human osteoblasts. The expression of resistin mRNA in RAW 264.7 was increased during differentiation and seemed to be regulated through PKC- and PKA-dependent mechanisms. Recombinant resistin increased the number of differentiated osteoclasts and stimulated NFkappaB promoter activity, indicating a role in osteoclastogenesis. Resistin also enhanced the proliferation of MC3T3-E1 cells in a PKA and PKC-dependent manner, but only weakly interfered with genes known to be upregulated during differentiation of MC3T3-E1 into osteoblasts. All together, our results indicate that resistin may play a role in bone remodeling.
Journal of Cellular Biochemistry 11/2006; 99(3):824-34. · 2.87 Impact Factor
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ABSTRACT: The aim of the study was to investigate the effect of low-level laser therapy (LLLT) on attachment and proliferation of human gingival fibroblasts (HGF) cultured on titanium implant material. HGF were exposed to gallium-aluminum-arsenide diode laser at dosages of 1.5 or 3 J/cm(2) and then cultured on commercially pure titanium discs. Cell profile areas were measured after 1, 3 and 24 h, using scanning electron microscopy and an automatic image analyzer. The results were expressed as percentage of attachment. In order to investigate the effect of LLLT on cellular growth after 8 and 10 days, HGF were cultured on titanium discs for 24 h and then exposed to laser irradiation on 3 consecutive days. Colony-forming efficiency (CFE) and clonal growth rates (CGR) were measured. Cell viability was determined by Hoechst and prodidium iodide staining. Non-lased cultures served as controls. Morphologically, the cells spread well on all titanium surfaces, indicating good attachment by both irradiated and non-irradiated cells. Fibroblasts exposed to laser irradiation had significantly higher percentages of cell attachment than the non-exposed cells (P<0.05). CFE and CGR were also enhanced for the irradiated cells (P<0.05). Cell viability was high (>90%) in the irradiated and control groups, without significant differences. It is concluded that in vitro LLLT enhances the attachment and proliferation of HGF on titanium implant material.
Clinical Oral Implants Research 04/2005; 16(2):168-75. · 2.51 Impact Factor
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ABSTRACT: The aim of the study was to investigate the effect of low-level laser therapy (LLLT) on attachment and proliferation of human gingival fibroblasts (HGF) cultured on titanium implant material. HGF were exposed to gallium–aluminum–arsenide diode laser at dosages of 1.5 or 3 J/cm2 and then cultured on commercially pure titanium discs. Cell profile areas were measured after 1, 3 and 24 h, using scanning electron microscopy and an automatic image analyzer. The results were expressed as percentage of attachment. In order to investigate the effect of LLLT on cellular growth after 8 and 10 days, HGF were cultured on titanium discs for 24 h and then exposed to laser irradiation on 3 consecutive days. Colony-forming efficiency (CFE) and clonal growth rates (CGR) were measured. Cell viability was determined by Hoechst and prodidium iodide staining. Non-lased cultures served as controls. Morphologically, the cells spread well on all titanium surfaces, indicating good attachment by both irradiated and non-irradiated cells. Fibroblasts exposed to laser irradiation had significantly higher percentages of cell attachment than the non-exposed cells (P<0.05). CFE and CGR were also enhanced for the irradiated cells (P<0.05). Cell viability was high (>90%) in the irradiated and control groups, without significant differences. It is concluded that in vitro LLLT enhances the attachment and proliferation of HGF on titanium implant material.RésuméLe but de l'étude présente a été d'analyser l'effet du traitement par laser à bas niveau (LLLT) sur l'attache et la prolifération des fibroblastes gingivaux humains (HGF) mis en culture sur du matériel implantaire en titane. HGF ont été exposés à des lasers d'iode GaA1As à des doses de 1,5 ou 3 J/cm2 et ensuite mis en culture sur des disques de titane commercialement purs. Des aires de profils cellulaires ont été mesurés après une, trois et 24 h en utilisant le MEB et l'analyse d'image automatique. Les résultats ont été exprimés en pourcentage d'attache. Afin d'analyser l'effet du LLLT sur la poussée cellulaire après huit et dix jours, HGF ont été mis en culture sur des disques en titane pour 24 h et ensuite exposés à l'irradiation par laser trois jours consécutifs. L'efficacitéà former des colonies (CFE) et les taux de croissance de clônes (CGR) ont été mesurés. La viabilité cellulaire a été déterminée par la coloration iodure de prodidium et Hoechst. Des cultures sans utilisation du laser ont servi de contrôles. Morphologiquement les cellules s'étalaient bien sur toutes les surfaces en titane indiquant une bonne attache des cellules tant irradiées que non-irradiées. Des fibroblastes exposés à l'irradiation laser avaient significativement des pourcentages plus élevés d'attache cellulaire que les cellules non-exposées (P<0.05). Les taux de CFE et de CGR augmentaient également pour les cellules irradiées (P<0.05). La vitalité cellulaire était importante (>90%) dans les groupes irradiés et contrôles sans aucune différence significative. Le LLLT in vitro augmente l'attache et la prolifération des HGF sur le matériel implantaire en titane.ZusammenfassungDas Ziel dieser Studie war, den Einfluss der Low Level Laser Therapie (LLLT) auf die Anhaftung und Proliferation von humanen gingivalen Fibroblasten (HGF), welche auf Titan Implantatmaterial gezüchtet wurden, zu untersuchen. HGF wurden einem GaAlAs Diodenlaser mit einer Dosis von 1.5 oder 3 J/cm2 ausgesetzt und dann auf im Handel erhältlichen reinen Titanscheiben gezüchtet. Die Zellprofilareale wurden nach 1, 3 und 24 Stunden mit einem Rasterelektronenmikroskop und einer automatischen Bildanalyse ausgemessen. Die Resultate wurden als Prozent der Anhaftung ausgedrückt. Um den Effekt der LLLT auf das Zellwachstum nach 8 und 10 Tagen zu untersuchen, wurden HGF auf Titanscheiben während 24 Stunden gezüchtet und dann an den drei darauf folgenden Tagen der Laserbestrahlung ausgesetzt. Es wurden die Koloniebildungseffizienz (CFE) und die klonalen Wachstumsraten (CGR) gemessen. Die Zelllebensfähigkeit wurde durch die Hoechst und Prodidiumjodid Färbung bestimmt. Als Kontrolle dienten nicht mit Laser bestrahlte Kulturen. Morphologisch breiteten sich die Zellen gut auf den Titanoberflächen aus, was eine gute Anhaftung sowohl für die bestrahlten als auch für die unbestrahlten Zellen bedeutete. Fibroblasten, welche der Laser Bestrahlung ausgesetzt waren, zeigten höhere Prozentwerte bezüglich Zellanhaftung als die nicht bestrahlten Zellen (P<0.05). Die Koloniebildungseffizienz und die klonalen Wachstumsraten waren bei den bestrahlten Zellen gesteigert (P>0.05). Die Zelllebensfähigkeit war bei der bestrahlen Gruppe und bei der Kontrollgruppe hoch (>90%). Es bestanden keine signifikanten Unterschiede. Es wird die Schlussfolgerung gezogen, dass LLLT in vitro die Anhaftung und die Proliferation von HGF auf Titan Implantatmaterial fördert.ResumenLa intención del estudio fue investigar el efecto del tratamiento con láser de bajo nivel (LLLT) en la inserción y la proliferación de fibroblastos humanos (HGF) cultivados en material de implantes de titanio Se expusieron HGF a láser de diodo GaA1As en dosis de 1.5 o 3 J/cm2 y posteriormente cultivados en ciscos de titanio comercialmente puro. Se midieron los perfiles de las áreas de células tras 1, 3 y 24 h, usando microscopía electrónica de barrido y un analizador de imágenes automático. Los resultados se expresaron en porcentajes de inserción. En orden a investigar el efecto de LLLT en el crecimiento celular tras ocho y diez días, se cultivaron HGF en discos de titanio durante 24 h y Lugo se expusieron a irradiación láser durante tres días consecutivos. Se midieron la eficiencia en formar colonias (CFE) y los índices de crecimiento clonal (CGR). Se determinó la viabilidad celular por medio de tinción de Hoechst y Prodidium iodide. Cultivos no expuestos al láser sirvieron de control. Morfológicamente, las células se expendieron bien en todas las superficies de titanio, indicando una buena inserción tanto las células irradiadas como las no irradiadas. Los fibroblastos expuestos a la irradiación láser tuvieron unos mayores porcentajes de inserción celular que las células no expuestas (P<0.05). La eficiencia en la formación de colonias y los índices de crecimiento clonal fueron también realzados en las células irradiadas (P<0.05). La viabilidad celular fue alta (>90%) en los grupos irradiados y de control, sin diferencias significativas. Se concluye que in vitro el LLLT realza la inserción y la proliferación de HGF en material de implante de titanio.
Clinical Oral Implants Research 03/2005; 16(2):168 - 175. · 2.51 Impact Factor
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ABSTRACT: In the present study, the effect of a dual treatment of titanium implants and the subsequent bone response after implantation were investigated. Coin-shaped c.p. titanium implants were placed into the tibias of 12 rabbits. The implant, which was dually blasted with TiO2 particles of two different sizes, was compared with implants that were blasted with only one of these particle sizes. Implants in group 1 were grit blasted with small particles, 22-28 microm in size, and group 2 with coarser particles, 180-220 microm size. These two treatments gave different surface micro textures. To test the effect of a combination of two different treatments, group 3 implants were blasted first with the 180- to 220-microm and subsequently with the 22- to 28-microm particles. The surface topography of the implant specimens was examined by scanning electron microscopy and by a confocal laser scanner and a numeric evaluation of S(a), S(t), and S(dr) was recorded. Group 2 implants, which were blasted with only the coarse particles, showed a significantly better functional attachment (p < 0.001) than the other two groups. Group 1, which was blasted with only small particles, showed the lowest retention in bone. There was a positive correlation between the topographical and mechanical evaluation of the surfaces.
Journal of Biomedical Materials Research Part A 11/2003; 67(2):524-30. · 2.63 Impact Factor
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ABSTRACT: In the present study, the bone response of titanium implants at early bone healing stages, was evaluated using a tensile test. Test surface of coin-shaped cp. titanium implants were standardized by grit blasting with TiO(2), grain size 180-220 microm. The surface topography of the implant specimens was examined by SEM, and by a confocal laser scanner for evaluation of S(a), S(t) and S(dr). The implants were placed onto the leveled site on the tibia of 12 New Zealand White rabbits, 4 implants in each animal. The rabbits were divided into three groups with different observation times i.e. 2, 4 and 6 weeks. The retention of 12 implants were tested by measuring the pull-out force needed to detach the implant from the bone. There was a significant increase in implant retention from 2 to 4 and to 6 weeks healing time (p<0.05). Four implants from each time point were randomly chosen for histological evaluation. The histological appearance of the implant-bone interface at the different healing times showed noticeable differences in the degree of bone healing and maturation, suggesting that, in rabbits, 6 weeks healing time is a suitable observation point for tensile testing of surface optimized osseointegrating implants.
Journal of Materials Science Materials in Medicine 10/2003; 14(10):843-9. · 2.32 Impact Factor
