Authors: Mitsuru Takemoto, Shunsuke Fujibayashi, Masashi Neo, Kazutaka So, Norihiro Akiyama, Tomiharu Matsushita, Tadashi Kokubo, Takashi Nakamura
Abstract: We have developed a porous titanium implant sintered with spacer particles (porosity =
50 %, average pore size ± standard deviation = 303 ± 152 !m, yield compression strength = 100MPa).
This porous titanium was successfully treated with chemical and thermal treatment that gives a
bioactive micro-porous titania layer on the titanium surface, and it is expected as effective biomaterial
for biological fixation on load bearing condition. In this study, ten adult female beagle dogs
underwent anterior lumbar interbody fusion at L6-7 using either BT-implant or non-treated implant
(NT-implant), then followed by posterior interspinous wiring and facet screw fixation. The
radiographic evaluations were performed 1, 2 and 3 months postoperatively using X-ray fluoroscopy.
Animals were sacrificed after 3 months postoperatively, and fusion status was evaluated by manual
palpation. Histological evaluation was also performed. Both histological and radiological evaluation
revealed that interbody fusion was achieved in 5 of 5 dogs (100%) in BT-group and 3 of 5 dogs (60%)
in NT-group. In BT implants, we could observe a large amount of new bone formation from periphery
to the center of the implant, whereas in NT implants, fibrous tissue formation was still observed even
in the implants with successful fusion. The results of this study indicate that porous bioactive titanium
implant will represent a new osteoconductive biomaterial with improved fusion characteristics.
987
Authors: Jung Hwa Hong, Young Hwan Park, Sang Ok Ko
Abstract: Osseointegration (OI) could be described as the modality for stable fixation of titanium
implant to bone structure. The OI has become a realized phenomenon of importance in the dental and
rehabilitation sciences since recently developed dentures and artificial limbs are directly attached to
human skeleton by using osseointegrated (OI) implants. Previously, a study showed that bone strain
generated potential (SGP) that is an electrical potential and considered to be generated by fluid flow in
bone could be used as a parameter to examine the amount of OI on bone-implant interface. Since no
study was performed to understand effects of loading rate changes on behavior of SGP for the
bone-implant composite, rate dependent behavior of SGP was investigated in this study. Four
different displacement rates, 100, 200, 500, and 1000 mm per minute were applied to the
bone-implant composites. During the compression tests, SGPs were also measured. Magnitude of
SGP was found to be significantly increased as the rate increased for OI bone-implant composite. In
contrast, the time duration of SGP was decreased as the rate increased. These results could imply that
the temporal SGP behavior of bone-implant composite is significantly affected by the loading rate.
1173
Authors: Jung Hwa Hong, Sang Ok Ko, Soon Hyuck Lee
Abstract: "Osseo" refers to bone and "integration" refers to how a prosthesis can be integrated with
the bone in residual limbs both arms and legs. Osseointegration(OI) was originally defined as a
direct structural and functional connection between ordered living bone and the surface of a loadcarrying
implant. OI could be described as the modality for stable fixation of titanium implant to
bone structure. The OI has become a realized phenomenon of importance in the dental and
rehabilitation sciences since recently developed dentures and artificial limbs are directly attached to
human skeleton by using osseointegrated implants. Previously, a study showed that bone strain
generated potential (SGP) that is an electrical potential and considered to be generated by fluid flow
in bone could be used as a parameter to examine the amount of OI on bone-implant interface. Since
no study was performed to understand according to the point on behavior of SGP for the boneimplant
composite. In this study, we used a multi-channel measurement system and investigated
SGP according to the point. Four white New Zealand rabbits underwent pure titanium implant
insertion surgery to tibia after amputation. After checking full OI at the end of the 5 weeks,
experimental animals were euthanized and the amputated tibia-implants were harvested. Holes of
0.5mm in diameter were made on the tissue of the tibia and electrodes of 0.16mm in diameter were
inserted to the holes. Then, the instrumented bone-implant composites were placed to a servo
material testing machine to apply axial compressive displacement loadings. During the compression
tests, SGPs were also measured. Magnitude of SGP was found to be significantly increased near
bone and implant interface for the osseointegrated bone-implant composite.
1569
Authors: Daniel Lin, Qing Li, Wei Li, Michael V. Swain
Abstract: Currently, titanium dominates the dental implant materials due to its strength and bio-inerrability. The
use of titanium implant had demonstrated considerable surgical success. However, researchers are
spontaneously pursuing better materials to achieve better osseointegration in the early stage of
implantation. Recently, dental implants based on functionally graded material (FGM) were
introduced in pursuit for the goal of enhanced bio-compatibility. The concept for FGM dental implant
is that the property would vary in certain pattern to match the biomechanical characteristics required
at different regions in the oral bone. However, mating properties do not necessarily guarantee better
osseointegration and bone remodelling. There is no existing report available on the long-term effect
of FGM dental implant on its hosting bone tissues. This paper aims at exploring this critical problem
by using computational bone remodelling technique. The magnitude of bone remodelling due to use
of FGM implant is identified over a healing period of four years. Comparisons were made between
titanium and various FGM designs, the interesting differences were observed and the optimum FGM
design was suggested based on the remodelling results.
1035
Authors: Ana Cristina P. Machado, Marize Varella de Oliveira, Robson Pacheco Pereira, Yasmin R. Carvalho, Carlos Alberto Alves Cairo
Abstract: The osseointegration of porous titanium implants was evaluated in the present work. Implants were fabricated from ASTM grade 2 titanium by a powder metallurgy method. Part of these implants were submitted to chemical and thermal treatment in order to deposit a biomimetic coating, aiming to evaluate its influence on the osseointegration of the implants. The implants were characterized by Scanning Electron Microscopy (SEM), Electron Dispersive X-Ray Spectroscopy (EDS) and Raman Spectroscopy. Three coated and three control (uncoated) implants were surgically inserted into thirty albino rabbits’ left and right tibiae, respectively. Tibiae samples were submitted to histological and histomorphometric analyses, utilizing SEM, optical microscopy and mechanical tests. EDS results indicated calcium (Ca) and phosphorous (P) at the surface and Raman spectra exhibited an intense peak, characteristic of hydroxyapatite (HA). Bone neoformation was detected at the bone-implant interface and inside the pores, including the central ones. The mean bone neoformation percentage in the coated implants was statistically higher at 15 days, compared to 30 and 45 days. The mechanical tests showed that coated implants presented higher resistance to displacement, especially after 30 and 45 days.
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