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| 2. |
- Ellingsen, Jan Eirik, et al.
(author)
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Improved Retention and Bone-to-Implant Contact with Fluoride-Modified Titanium Implants
- 2004
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In: International Journal of Oral & Maxillofacial Implants. - Chicago, Ill.] : Quintessence Pub. Co.. - 0882-2786 .- 1942-4434. ; 19:5, s. 659-666
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Journal article (peer-reviewed)abstract
- Purpose: The purpose of the present study was to investigate whether a fluoride modification of the titanium surface would have an effect on bone response after implantation. Materials and Methods: Titanium-oxide–blasted titanium implants with and without fluoride modification were investigated in a rabbit tibia model. Quantitative analysis of surface roughness, biomechanical interlocking, and in vivo tissue reactions in rabbit bone at 1 and 3 months after placement were compared. Results: The fluoride-modified test implants had a slightly smoother surface (Sa: 0.91 ± 0.14 µm) than the unmodified control implants (Sa: 1.12 ± 0.24 µm). Significantly higher removal torque values (85 ± 16 Ncm vs 54 ± 12 Ncm) and shear strength between bone and implants (23 ± 9 N/mm2 vs 15 ± 5 N/mm2) were measured for the fluoride-modified implants after 3 months. The histomorphometric evaluations demonstrated higher bone-to-implant contact for test implants at 1 month (35% ± 14% vs 26% ± 8%) and 3 months (39% ± 11% vs 31% ± 6%) after placement. Discussion: Implant surface modification with fluoride may result in morphologic and physiochemical phenomena that are of significance for the bone response. Another possible explanation for the findings in the present study is that a surface modification changes the surface chemical structures to be more suitable for bone bonding. Conclusion: Based on the biomechanical and histomorphometric data, the fluoride-modified titanium implants demonstrated a firmer bone anchorage than the unmodified titanium implants. These implants achieved greater bone integration than unmodified titanium implants after a shorter healing time. (More than 50 references.)
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| 3. |
- Franke Stenport, Victoria, et al.
(author)
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Enamel matrix derivative and titanium implants : An experimental pilot study in the rabbit
- 2003
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In: Journal of Clinical Periodontology. - : Blackwell. - 0303-6979 .- 1600-051X. ; 30:4, s. 359-363
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Journal article (peer-reviewed)abstract
- Aim: The aim of present study was to evaluate if an enamel matrix derivative (Emdogain®) may enhance bone formation and osseointegration of titanium implants, using a well-documented rabbit model. Material and methods: Thirty-six threaded commercially pure titanium (cp.ti.) implants were inserted in six New Zealand white rabbits. One implant was placed in each femur and two in each tibia. Prior to implant insertion approximately 0.5 mL of Emdogain (EMD) (test) or the vehicle gel (PGA: propylene glycol alginate) (control) was injected into the surgically prepared implant site. The follow-up time was 6 weeks. Biomechanical evaluations by resonance frequency analysis (RFA) and removal torque measurements (RTQ) were performed. Histomorphometrical quantifications were made on ground sections by measurements of the percentage of bone-to-metal contact, bone area inside the threads as well as outside the threads (mirror image). Bone lengths along the implant surface were also measured and used for shear strength calculations. Results: The results demonstrated no beneficial effects from the EMD treatment on bone formation around titanium implants in any of the tested parameters. Significant differences were demonstrated with removal torque test and shear force calculations for the control implants. No other parameter demonstrated a statistically significant difference. Conclusion: The results of the present study may indicate that EMD does not contribute to bone formation around titanium implants. This observation may indicate that the bone formation that occurs after EMD treatment in periodontal defects is the result of functional adaptation. However, further research is required to evaluate the effect of EMD treatment on bone formation.
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| 4. |
- Franke Stenport, Victoria, 1970, et al.
(author)
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FGF-4 and titanium implants: a pilot study in rabbit bone.
- 2003
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In: Clinical oral implants research. - : Wiley. - 0905-7161 .- 1600-0501. ; 14:3, s. 363-8
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Journal article (peer-reviewed)abstract
- AIM: To evaluate the effect of a local single injection of amino-terminally truncated recombinant human fibroblast growth factor-4 (rhFGF-4s) on titanium implant incorporation in a rabbit bone. MATERIAL AND METHODS: Thirty-six threaded titanium implants were inserted into the femur and tibia of six rabbits. Three weeks prior to implant insertion 10 microg of FGF-4 in an altelocollagen carrier or the carrier alone was injected into the intended implant sites. Biomechanical evaluation by (i) resonance frequency analysis and (ii) peak removal torque measurements was performed after 6 weeks. The implants with surrounding tissue were processed to undecalcified ground sections followed by light-microscopic quantifications of the bone in threaded area and the apical parts of the implants. RESULTS: A general trend, however not statistically significant, with higher mean values obtained in the above-mentioned tests was found. The FGF-4-treated implants revealed a significantly increased bone area in the apical part of the implants compared to the corresponding control implants. CONCLUSION: A local single injection of rhFGF-4 may stimulate bone formation around titanium implants in bone. However, further research is required to confirm these results, understand the mechanisms of FGF, and establish optimal dose and delivery methods.
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| 5. |
- Franke-Stenport, Victoria, et al.
(author)
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Titanium implants and BMP-7 in bone : an experimental model in the rabbit
- 2003
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In: Journal of materials science. Materials in medicine. - 0957-4530 .- 1573-4838. ; 14:3, s. 247-254
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Journal article (peer-reviewed)abstract
- This study evaluates the effect of rhBMP-7/OP-1 on the osseointegration of commercially pure titanium implants in an experimental implant model in rabbits. Threaded titanium implants with two transverse parallel canals were inserted in the femur and tibia of rabbits. The canals were filled with, 10 microg of BMP-7/collagen carrier, pure collagen carrier or were left empty as a control. The stiffness of the implant fixation was evaluated by Resonance Frequency Analysis (RFA) at baseline and four weeks postoperatively. Percentage of bone ingrowth in the canals was measured on microradiographs. Histomorphometry along the threaded part of the implants was performed on 15 microm thin sections. The results from the RFA demonstrated a higher mean value for the BMP-7 treated implants in the tibia than the carrier treated implants but not compared to the control implants. The control implants in the tibia demonstrated more bone ingrowth in the upper canal than to the carrier or the BMP-7 treated implants. Apart from these differences there were no significant effects of BMP. In this study BMP-7 did not contribute to any substantially improved bone anchorage of titanium implants.
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| 6. |
- Ivanoff, Carl-Johan, et al.
(author)
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Histologic evaluation of bone response to oxidized and turned titanium micro-implants in human jawbone
- 2003
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In: International Journal of Oral & Maxillofacial Implants. - 0882-2786 .- 1942-4434. ; 18:3, s. 341-348
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Journal article (peer-reviewed)abstract
- PURPOSE: To evaluate the human bone tissue response to 2 surfaces (oxidized or turned) on commercially available titanium implants. MATERIALS AND METHODS: Screw-type turned (control) and oxidized (test) micro-implants were manufactured in the same manner as commercially available turned and oxidized (TiUnite, Brånemark System) implants. The thickness of the oxide layer of the test implants was on average 10 microm, corresponding to the oxide thickness of the apical part of the TiUnite implant. Twenty patients received 1 test and 1 control micro-implant each during implant surgery. Before placement, the surface topography of the implants was characterized with an optical confocal laser profilometer. After a mean healing period of 6.6 months in the maxilla and 3.5 months in the mandible, the micro-implants and surrounding tissue were removed with a trephine bur. Histologic sections were produced, and the specimens were analyzed histomorphometrically. RESULTS: Surface roughness and enlargement were greater for the oxidized implants than for the turned implants. All micro-implants, except for 2 controls, were found to be clinically stable at the time of retrieval. Histomorphometric evaluation demonstrated significantly higher bone-to-implant contact for the oxidized implants, whether placed in the maxilla or in the mandible. Significantly more bone was found inside the threaded area for the oxidized implants placed in the mandible and maxilla, but there was no difference between implants with regard to position (maxilla or mandible). DISCUSSION: The stronger bone response to the oxidized implants may have contributed to the fact that 2 control implants but no test implants were lost. The reason for these findings may depend on one or multiple differences of the surfaces between test and control implants: (1) the thicker oxide layer itself, (2) increased surface roughness, (3) different surface morphology in terms of porosity, or (4) change in crystal structure. CONCLUSION: The present histologic study in human jawbone demonstrated a significantly higher bone response for anodic oxidized titanium implants than for implants with a turned surface.
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| 8. |
- Ramires, P. A., et al.
(author)
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Biological behavior of sol-gel coated dental implants
- 2003
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In: Journal of materials science. Materials in medicine. - 0957-4530 .- 1573-4838. ; 14:6, s. 539-545
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Journal article (peer-reviewed)abstract
- The biocompatibility of dental implants coated with titania/hydroxyapatite (HA) and titania/bioactive glass (BG) composites obtained via sol-gel process was investigated using an in vitro and in vivo model. A device for the in vitro testing of screw-shaped dental implants was developed, in order to well compare the two experimental models studying the behavior of human MG63 osteoblast-like cells seeded onto a particular geometry. The expression of some biochemical parameters of osteoblastic phenotype (alkaline phosphatase specific activity, collagen and osteocalcin production) and some indications on cells morphology obtained by scanning electron microscopy were evaluated. The in vitro and in vivo models were compared after implants insertion in rabbit tibia and femur. The removal torque and histomorphometric parameters (percentage of bone in contact with implant surface and the amount of bone inside the threaded area) were examined. A good agreement was found between the in vitro and in vivo models. These experiments showed better performances of HA and BG sol-gel coated dental implants with respect to uncoated titanium; in particular, it was found that in vitro the HA coating stimulates osteoblastic cells in producing higher level of ALP and collagen, whereas in vivo this surface modification resulted in a higher removal torque and a larger bone-implant contact area. This behavior could be ascribed to the morphology and the chemical composition of the implants with rough and bioactive surfaces.
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| 9. |
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| 10. |
- Reikeras, O., et al.
(author)
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Hydroxyapatite and carbon coatings for fixation of unloaded titanium implants
- 2004
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In: Journal of Long-Term Effects of Medical Implants. - 1050-6934 .- 1940-4379. ; 14:6, s. 443-454
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Journal article (peer-reviewed)abstract
- The aim of this study was to investigate the interaction between bone and pure titanium, titanium coated with hydroxyapatite (HA), and titanium coated with carbon in a rat femur model. In 25 rats, the medullary cavity of both femurs was entered by an awl from the trochanteric area. With steel burrs it was successively reamed to a diameter of 2.0 mm. Nails with a diameter of 2.0 mm and with a length of 34 mm were inserted in a random manner; either a pure titanium nail, a titanium nail entirely plasma-sprayed with a 75-100-microm layer of HA or a titanium nail coated with 2-10-microm carbon. The surface roughness of the pure titanium was characterized by Ra 2.6 microm and Rt 22 microm. Ra of HA was 7.5 microm and Rt 52 microm, and of carbon Ra was 0.4 microm and Rt 4.0 microm. Twelve rats were randomized to a follow up of 8 weeks, and the remaining 13 rats were followed for 16 weeks. At sacrifice both femora were dissected free from soft tissues and then immersed in fixative. A specimen slice of about 5 mm thickness was prepared from the subtrochanteric region with a water-cooled band-saw. Sample preparation for un-decalcified tissue followed the internal guidelines at the laboratories of Biomaterials/Handicap Research. At 8 weeks the median bone bonding contact of the implants was 43% (range 0-74) in the titanium group, 39% (0-75) in the HA group, and 3% (0-59) in the carbon group. At 16 weeks the corresponding figures were 58% (0-78) in the titanium group, 51% (15-75) in the HA group, and 8% (0-79) in the carbon group. In conclusion, we found great variability in bone bonding contact. In general, carbon-coated nails had reduced bone bonding contact both at 8 and at 16 weeks as compared to pure titanium or titanium coated with hydroxyapatite.
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