1
AU - Ducheyne P
AU - Ellis LY
AU - Pollack SR
AU - Pienkowski D
AU - Cuckler JM
TI - Field distributions in the rat tibia with and without a
porous implant during electrical stimulation: a parametric
modeling.
AB - Expeditious post-operative ingrowth of bone is necessary
for clinically successful fixation of porous joint prostheses.
Electrical or electromagnetic fields to stimulate bone
growth into porous implants have been used; however, they
produced nonconvincing data. This was partially attributable
to the lack of quantification of the localized electric
fields produced in the pores of the implants. Therefore,
this study set out: i) to quantify the local electric field
values induced into the surface pores of nonconducting
implants by "capacitive" coupling and to determine the
magnitude of the macroscopically applied capacitively coupled
electrical currents to induce specific electric field amplitudes
in the pores, ii) to identify the important dielectric
properties of the implant-tissue interface, and iii) to
create the basis for successfully applying electrical fields
in an animal model to stimulate bone ingrowth. A finite
element method was used to calculate the electric field
gradients and current densities present in a rat tibia
modeled with a porous intramedullary implant when capacitively
stimulated. Results indicated that while the current density
in the pores are reduced in comparison to the region just
outside the pore by about one order of magnitude, a significant
current density still exists in the pore region. Furthermore,
the presence of the implant increases the current densities
in the trabecular bone while decreasing these values in
the cortical bone. Replacing the trabecular bone in the
pore by saline increases the current density in the pore
by three-fold, but decreases the voltage gradient by a
similar factor.
MH - Electromagnetic Fields|*
MH - Models, Biological|*
MH - Prostheses and Implants|*
MH - Tibia|*PP
SO - IEEE Trans Biomed Eng 1992 Nov; 39(11):1168-78
DP - 1992 Nov
TA - IEEE Trans Biomed Eng
PG - 1168-78
IP - 11
VI - 39
UI - 93138663
2
AU - Takeshita F
AU - Murai K
AU - Iyama S
AU - Ayukawa Y
AU - Suetsugu T
TI - Uncontrolled diabetes hinders bone formation around titanium
implants in rat tibiae. A light and fluorescence microscopy,
and image processing study.
AB - This study examined the influence of diabetes mellitus
on bone formation around cylindrical titanium (Ti) implants
(1.0 mm in diameter and 1.5 mm in length) inserted transcortically
and extending into the medullary canal of rat tibiae using
light and fluorescence microscopies and image processing.
Forty-eight male Wistar King A rats (age 5 weeks) were
used in this experiment. Streptozotocin was injected intraperitoneally
to induce diabetes and the serum glucose concentration
was checked to ensure the induction of diabetes prior to
implant placement and at the time of sacrifice. The animals
were sacrificed 7, 28, 56, or 84 days after placement.
Toluidine blue-stained undecalcified sections were prepared
for histological observation and image analysis. The Ti
implants in the control group became increasingly encapsulated
with a bone layer. The implants in the diabetes-induced
(DI) group were also surrounded with a thin bone layer.
Abundant adipocytes were observed in the DI group as compared
with the control group. Quantitative evaluation indicated
that the control group showed a significantly higher percent
of bone contact, and thickness of surrounding bone and
area than the DI group. Consequently, the present study
suggests that uncontrolled diabetes would hinder bone formation
around Ti implants in rats.
MH - Diabetes Mellitus, Experimental|BL/PA/*PP
MH - Osteogenesis|*PH
MH - Prostheses and Implants|*
MH - Tibia|PA/PP/*SU
MH - Titanium|*
SO - J Periodontol 1998 Mar; 69(3):314-20
DP - 1998 Mar
TA - J Periodontol
PG - 314-20
IP - 3
VI - 69
UI - 98239220
3
AU - Ohrnell LO
AU - Brﾁnemark R
AU - Nyman J
AU - Nilsson P
AU - Thomsen P
TI - Effects of irradiation on the biomechanics of osseointegration.
An experimental in vivo study in rats.
AB - The present study reports on the late effects of increasing
doses of radiation on the biomechanics of commercially
pure titanium implants (fixtures) installed in the proximal
tibia in 26 rats. Twelve weeks after various doses (10,
20, 30, and 35 Gy) of irradiation, the fixtures were inserted
into rat tibiae, and after another eight weeks these were
tested mechanically in vivo. Acute dose dependent skin
reactions developed after all doses except 10 Gy, but most
subsided within two to three weeks. There was a statistically
significant reduction in torsion but the pull-out load
was not significantly reduced for single doses up to 30
Gy. Histological analysis showed that bone remodelling
was impaired. Shear stresses and shear moduli were estimated
for the bone-implant interface and in the surrounding bone
tissue. These estimated stresses and moduli were not found
to be correlated to the dose of radiation.
MH - Osseointegration|PH/*RE
SO - Scand J Plast Reconstr Surg Hand Surg 1997 Dec; 31(4):281-93
DP - 1997 Dec
TA - Scand J Plast Reconstr Surg Hand Surg
PG - 281-93
IP - 4
VI - 31
UI - 98107109
4
AU - Schwartz Z
AU - Swain LD
AU - Marshall T
AU - Sela J
AU - Gross U
AU - Amir D
AU - Muller Mai C
AU - Boyan BD
TI - Modulation of matrix vesicle enzyme activity and phosphatidylserine
content by ceramic implant materials during endosteal bone
healing.
AB - This study examined effects of bone bonding and nonbonding
implants on parameters associated with matrix vesicle-mediated
primary bone formation, matrix vesicle alkaline phosphatase
and phospholipase A2 specific activities, and phosphatidylserine
content. Tibia marrow ablation followed by implantation
of KG-Cera, Mina 13 (bonding), KGy-213, or M 8/1 (nonbonding)
was used as the experimental model. Postsurgery, matrix
vesicle-enriched microsomes (MVEM) were isolated from implanted
and contralateral limbs. MVEM alkaline phosphatase and
phospholipase A2 were stimulated adjacent to bonding implants
with similar, though reduced, effects contralaterally.
Alkaline phosphatase exhibited slight stimulation in nonbonding
tissue; phospholipase A2 was inhibited or unchanged in
treated and contralateral limbs. Phosphatidylserine content
of MVEM was differentially affected by the implant materials.
Thus, MVEM are modulated by implant materials locally and
systemically. The data demonstrate that the model is a
biologically relevant diagnostic for assessing the tissue/
implant interface, primary calcification is affected by
implant materials, and implant-specific effects are detected
in the contralateral unimplanted limb.
MH - Alkaline Phosphatase|*ME
MH - Bone Matrix|EN/*ME
MH - Osseointegration|*
MH - Phosphatidylserines|*ME
MH - Phospholipases A|*ME
MH - Prostheses and Implants|*
SO - Calcif Tissue Int 1992 Dec; 51(6):429-37
DP - 1992 Dec
TA - Calcif Tissue Int
PG - 429-37
IP - 6
VI - 51
UI - 93082562
5
AU - Yamazaki M
AU - Shirota T
AU - Tokugawa Y
AU - Motohashi M
AU - Ohno K
AU - Michi K
AU - Yamaguchi A
TI - Bone reactions to titanium screw implants in ovariectomized
animals.
AB - OBJECTIVE: The purpose of this study was to investigate
the reactions of bone tissue after the placement of implants
into the tibiae of osteopenic model rats. STUDY DESIGN:
Commercially pure titanium screw implants were placed in
the bilateral proximal tibial metaphyses 168 days after
ovariectomy had been performed on 12-week-old female Wistar
rats. For control purposes, implants were similarly placed
in sham-ovariectomy rats. The healing process was examined
histologically by means of undecalcified sections at various
intervals from 7 to 168 days after implantation. Through
use of an automated imaging analytic system, changes in
relative bone mass and implant-bone contact were histomorphometrically
evaluated. RESULTS: In the cortical bone area, only a slight
difference in bone contact was noted with the implant until
28 days after implantation. However, ovariectomy significantly
affected bone contact at 56 days after implantation. The
rate of bone contact in the cancellous bone area and the
relative bone mass around the implant were significantly
lower in the test group than in the control group. CONCLUSIONS:
It is considered that a decrease in bone mass causes a
reduction in the contact area between implant and bone
and may also cause a reduction in the supporting ability
of the implant because of thinning of the surrounding bone
tissue.
MH - Implants, Experimental|*
MH - Osseointegration|*PH
MH - Osteoporosis, Postmenopausal|*PP
MH - Ovary|*PH
SO - Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999 Apr; 87(4):411-8
DP - 1999 Apr
TA - Oral Surg Oral Med Oral Pathol Oral Radiol Endod
PG - 411-8
IP - 4
VI - 87
UI - 99240152
6
AU - Iyama S
AU - Takeshita F
AU - Ayukawa Y
AU - Kido MA
AU - Suetsugu T
AU - Tanaka T
TI - A study of the regional distribution of bone formed around
hydroxyapatite implants in the tibiae of streptozotocin-
induced diabetic rats using multiple fluorescent labeling
and confocal laser scanning microscopy.
AB - The present study was designed to compare the amount and
regional distribution of bone formation around hydroxyapatite
(HA) implants in normal (control) rats with that of animals
with diabetes mellitus (DM), induced by streptozotocin
2 weeks prior to implant placement. Calcein (CAL), alizarin
complexone (AL), and tetracycline (TC) were injected on
the 7th, 14th, and 21st days after implantation, respectively,
and the rats were sacrificed on the 28th day after implantation.
Seventy-microns undecalcified sections of the HA-bone interface
in both groups were then prepared for confocal laser scanning
microscopy (CLSM) observation. In both groups, bone formation
developed from the HA surface to the endosteum, periosteum,
or bone marrow. In the control group, around the HA close
to the endosteum and periosteum, the new bone showed an
extensive lamination pattern of three color layers (CAL,
AL, and TC), but in the DM group the labeling density of
TC on the 21st day was low. In contrast, on the lateral
part of the HA surface (away from the endosteum and periosteum)
, there was considerably less bone formation in the control
group, and in the DM group it was almost completely suppressed.
These findings indicate that bone formation around the
HA was initiated from the HA surface in the control group,
while in the DM group, bone formation along the lateral
part of the HA away from the endosteum and periosteum was
almost completely suppressed. Furthermore, it is also suggested
that in the new bone along the HA close to the endosteum
and periosteum, only calcification on the 21st day was
depressed.
MH - Biocompatible Materials|*
MH - Diabetes Mellitus, Experimental|PA/*PP
MH - Durapatite|*
MH - Implants, Experimental|*
MH - Osteogenesis|*
MH - Tibia|PA/*PP/SU
SO - J Periodontol 1997 Dec; 68(12):1169-75
DP - 1997 Dec
TA - J Periodontol
PG - 1169-75
IP - 12
VI - 68
UI - 98106996
7
AU - Guglielmotti MB
AU - Renou S
AU - Cabrini RL
TI - A histomorphometric study of tissue interface by laminar
implant test in rats.
AB - Study of the implant-tissue interface is one of the fundamental
issues in implantology, both odontologic and orthopedic.
The characteristics of this interface will influence the
success or failure of an implant. The aim of the present
study was to evaluate histomorphometrically the capacity
of different metals to osseointegrate employing laminar
implants of zirconium, titanium, aluminum, and zirconium
coated with diamond-like carbon. The experimental model
herein allowed for the quantitative evaluation of the tissue-
implant interface for different metals. The implants were
placed in the tibiae of Wistar rats under anesthesia and
allowed to remain in situ for a 30-day period. The interfaces
of the zirconium and diamond-like coated zirconium implants
exhibited better responses than the interface of titanium
implants. Aluminum produced a local toxic effect, evidenced
by osteoid formation.
MH - Bone and Bones|*PA/SU
MH - Prostheses and Implants|*
MH - Prosthesis Implantation|*
SO - Int J Oral Maxillofac Implants 1999 Jul; 14(4):565-70
DP - 1999 Jul
TA - Int J Oral Maxillofac Implants
PG - 565-70
IP - 4
VI - 14
UI - 99383049
8
AU - Werner SB
AU - Tessler J
AU - Guglielmotti MB
AU - Cabrini RL
TI - Effect of dexamethasone on osseointegration: a preliminary
experimental study.
AB - The peri-implant reparative process is one of the factors
involved in osseointegration. Local and systemic factors
may contribute to the peri-implant micro-environment. The
aim of this study was to assess the effect of dexamethasone
(DXM) on the first stages of the post-implantation reparative
process using a quantitative osseointegration experimental
model previously developed at our laboratory. A titanium
laminar implant was inserted into the right tibiae of nine
male Wistar rats under ether anesthesia, following a technique
we previously described. Six rats received 120 micrograms/
kg/day i.p. doses of DXM (Decadron Sidus, Argentina) for
14 days pre-implantation and 14 days post-implantation.
The remaining three (controls) were injected with an equivalent
volume of saline. On day 14 post-implantation, all animals
were killed, and their tibiae were resected, radiographed,
and processed before being embedded in methylmethacrylate.
Microscopic observation and histomorphometric studies were
performed. Results show that, in this experimental model,
the extension of osteogenic peri-implant response was greater
in DXM-treated animals than in controls. Thus, our laminar
implant test may prove useful to study the effects of corticosteroids
on the osseointegration process.
MH - Anti-Inflammatory Agents, Steroidal|*PD
MH - Dexamethasone|*PD
MH - Glucocorticoids, Synthetic|*PD
MH - Implants, Experimental|*
MH - Osseointegration|*DE
SO - J Oral Implantol 1996; 22(3-4):216-9
DP - 1996
TA - J Oral Implantol
PG - 216-9
IP - 3-4
VI - 22
UI - 98185184
9
AU - Allen M
AU - Brett F
AU - Millett P
AU - Rushton N
TI - The effects of particulate polyethylene at a weight-bearing
bone-implant interface. A study in rats [see comments]
AB - In ten male rats we inserted ceramic 'drawing-pin' implants
in weight-bearing positions within the right proximal tibia.
Two animals were killed 6 weeks after surgery and two more
14 weeks after surgery. The remaining six received intra-
articular injections of either high-density polyethylene
(4 rats) or saline (2 rats) at 8, 10 and 12 weeks after
surgery. These animals were killed two weeks after the
last injection. Histological examination of the bone-implant
interface in the control animals showed appositional bone
growth around the implant at both 6 and 14 weeks. Polyethylene,
but not saline, caused a chronic inflammatory response
with numerous foreign-body giant cells in periprosthetic
tissues. Our model of a stable, weight-bearing bone-implant
interface provides a simple and reliable system in which
to study in vivo the effects of particulate materials used
in orthopaedic surgery.
MH - Polyethylenes|*AD
MH - Prostheses and Implants|*
MH - Tibia|PA/RA/*SU
SO - J Bone Joint Surg Br 1996 Jan; 78(1):32-7
DP - 1996 Jan
TA - J Bone Joint Surg Br
PG - 32-7
IP - 1
VI - 78
UI - 97053709
10
AU - Masuda T
AU - Salvi GE
AU - Offenbacher S
AU - Felton DA
AU - Cooper LF
TI - Cell and matrix reactions at titanium implants in surgically
prepared rat tibiae.
AB - The tissue response of rat tibiae to the surgical placement
of commercially pure titanium implants was examined at
2, 6, 10, and 28 days. The transcortical placement of 1.
5-mm x 2-mm implants resulted in the apposition of threaded
implant surfaces within cortical and cancellous regions
of the tibia. In all regions, evidence of bone formation
was obtained through pre-embedding fracture of the implant
from the bone tissue interface. Scanning electron microscopy
examination of early responses revealed a fibrin clot and
rapid formation of a loosely organized collagenous matrix.
Many extravasated blood cells contacted the implant surface.
At day 6, a more organized matrix containing many blood
vessels opposed the implant surfaces, and few extravasated
blood cells remained in contact with the implant surface.
By day 10, the surgical wound was filled with woven bone
that approximated the contours of the threaded implant.
Later, few cells were attached to the retrieved implants.
The consolidation of the forming matrix was clearly evident
at 28 days. The tissue interface was an amorphous matrix
that revealed the surface characteristics of the machined
implant. Light microscopic analysis of ground sections
indicated that, from day 6 onward, cells morphologically
consistent with the osteoblastic phenotype were predominant
within the gap between the surgical margin and implant
surface. Osteoblastic cells had achieved the formation
of an osteoid seam upon which bone formation progressed.
The matrix that had formed represented woven bone containing
many osteocytes. At day 6, evidence of remodeling was observed
at sites distant from the surgical site, and by day 28
osteoclastic activity was observed at trabecular sites
adjacent to the implant surface. The rat tibia model provides
evidence of rapid formation of bone at implant surfaces.
MH - Bone Matrix|BS/PH/*UL
MH - Osseointegration|*
MH - Osteoblasts|PH/*UL
MH - Prostheses and Implants|*
MH - Tibia|BS/PH/*UL
MH - Titanium|*
SO - Int J Oral Maxillofac Implants 1997 Jul; 12(4):472-85
DP - 1997 Jul
TA - Int J Oral Maxillofac Implants
PG - 472-85
IP - 4
VI - 12
UI - 97419569
11
AU - Takeshita F
AU - Iyama S
AU - Ayukawa Y
AU - Kido MA
AU - Murai K
AU - Suetsugu T
TI - The effects of diabetes on the interface between hydroxyapatite
implants and bone in rat tibia.
AB - We examined the influence of diabetes on the implant-bone
interface of hydroxyapatite (HA) implants inserted transcortically
and extending into the medullary canal of rat tibiae, and
quantitatively assessed the differences in bone reaction
using an image processing system. Forty male Wistar King
A rats (aged 5 weeks) were used in this experiment; they
were sacrificed 84 days after implant placement. Toluidine
blue-stained undecalcified sections were prepared for histological
observation and image analysis, and the labeled sections
were observed by confocal laser scanning microscopy. The
HA implants in the bone marrow area in the control group
were completely encapsulated with a bone layer, and there
were some osteoblast-like cells in the bone lacunae apposing
the implant surface. The HA implants in the diabetes-induced
(DI) group were partially surrounded with a thin bone layer,
and there were some fibroblasts running parallel to the
implant surface at areas of no bone contact. Quantitative
evaluation indicated that the control group showed significantly
higher bone contact rate, bone contact thickness, and bone
contact area than the DI group. The DI group showed approximately
30% reduction in the percentage of bone contact and 50%
reduction in the thickness and the area of surrounding
bone tissue.
MH - Diabetes Mellitus, Experimental|*PP
MH - Durapatite|*
MH - Osseointegration|*
MH - Prostheses and Implants|*
SO - J Periodontol 1997 Feb; 68(2):180-5
DP - 1997 Feb
TA - J Periodontol
PG - 180-5
IP - 2
VI - 68
UI - 97211339
12
AU - Takeshita F
AU - Takata H
AU - Ayukawa Y
AU - Suetsugu T
TI - Histomorphometric analysis of the response of rat tibiae
to shape memory alloy (nitinol).
AB - The bone reaction to nitinol (Ni-Ti), a metal with shape
memory, and other materials inserted transcortically and
extending into the medullary canal of rat tibiae was quantitatively
assessed using an image processing system. The materials
examined were implants, all of the same shape and size,
composed of nitinol, pure titanium (Ti), anodic oxidized
Ti (AO-Ti), a titanium alloy (Ti-6Al-4V) and pure nickel
(Ni). While the other four implant materials were progressively
encapsulated with bone tissues, Ni was encapsulated with
connective tissues through the 168-day experimental period,
and the Ni implants showed no bone contact at any time
during the experimental period. Histometric analysis revealed
no significant difference among the tissue reactions to
Ti, AO-Ti and Ti-6Al-4V, but Ni-Ti implants showed significantly
(P < 0.01) lower percentage bone contact and bone contact
area than any of the other titanium or titanium alloy materials.
MH - Alloys|*
MH - Bone and Bones|AH/*CY
MH - Bone Substitutes|*
MH - Osseointegration|*
MH - Prostheses and Implants|*
SO - Biomaterials 1997 Jan; 18(1):21-5
DP - 1997 Jan
TA - Biomaterials
PG - 21-5
IP - 1
VI - 18
UI - 97157613
13
AU - Clokie CM
AU - Warshawsky H
TI - Development of a rat tibia model for morphological studies
of the interface between bone and a titanium implant.
AB - Over the last decade, osseointegrated dental implants have
become an integral part of the restorative dental armamentarium.
Reproducible success rates approaching 100% further emphasize
the importance and value of this treatment modality. Still,
a significant waiting period is required between implant
placement and prosthesis delivery, which necessitates a
two-surgery approach for implant protection during healing.
This article discusses the development of an animal model
that is being used to investigate methods of manipulating
the healing process of bone next to dental implants. Osseointegration
has been shown to occur at 6 weeks in the rat tibia model,
demonstrating many of the same characteristics seen in
humans. The successful manipulation of bone next to the
implant surface may ultimately lead to a surgical protocol
for the placement of dental implants requiring only one
surgery, significantly reducing the overall healing time.
MH - Disease Models, Animal|*
MH - Osseointegration|*
MH - Prostheses and Implants|*
MH - Titanium|*
MH - Wound Healing|*PH
SO - Compendium 1995 Jan; 16(1):56, 58, 60 passim; quiz 68
DP - 1995 Jan
TA - Compendium
PG - 56, 58, 60 passim; quiz 68
IP - 1
VI - 16
UI - 95277769
14
AU - Brﾁnemark R
AU - Ohrnell LO
AU - Nilsson P
AU - Thomsen P
TI - Biomechanical characterization of osseointegration during
healing: an experimental in vivo study in the rat.
AB - This study reports torsion tests and pull-out tests on
osseointegrated commercially pure titanium fixtures. The
tests were performed in vivo on a total of 26 rats. Three
fixtures with a diameter of 2.0 mm were installed bilaterally
in the proximal tibia in each animal. The mechanical testing
was performed immediately after installation, after 2,
4, 8 and 16 weeks of unloaded healing. The torsional strength
started to increase after 4 weeks of unloaded healing and
there was a significant increase with time during the initial
16 weeks. The pull-out load increased rapidly during the
first 4 weeks; thereafter, a moderate increase occurred
during the following 12 weeks. A histological evaluation
was performed after 0, 4, 8 and 16 weeks. There were significant
(P < 0.01) correlations between torque and percentage of
bone in contact with the fixture, and between pull-out
load and the bone thickness around the fixture (P < 0.001)
. Estimations of shear stresses and shear moduli in the
bone tissue (pull-out test) and at the interface (torque
test) indicated that the increase in bone volume around
the implant substantially improved the mechanical capacity.
MH - Calcification, Physiologic|*PH
MH - Prostheses and Implants|*ST
MH - Tibia|ME/*PH
MH - Titanium|*ME
SO - Biomaterials 1997 Jul; 18(14):969-78
DP - 1997 Jul
TA - Biomaterials
PG - 969-78
IP - 14
VI - 18
UI - 97355711
15
AU - Clokie CM
AU - Warshawsky H
TI - Morphologic and radioautographic studies of bone formation
in relation to titanium implants using the rat tibia as
a model.
AB - A rat tibia model was developed to analyze bone formation
leading to osseointegration with threaded titanium implants.
Miniaturized titanium implants were placed in the anterior
aspect of the upper tibia of rats weighing 350 g. Twenty-
four rats were involved; 12 rats were sacrificed at 6 weeks,
and another two rats were sacrificed weekly for 6 weeks
following implantation. Four days prior to sacrifice, the
animals were injected intraperitoneally with 3H-proline
(10 microCi/g body weight). The rats were fixed by perfusion
with 5% glutaraldehyde, and the tibia were decalcified
and embedded in Epon. The implants were removed from the
embedded bone by fracturing, and the specimens re-embedded.
Sections were prepared for light and electron microscopy
and radioautography. Morphologic observations indicated
that implant placement resulted in bone necrosis and resorption.
This was followed by bone growth from the old bone surfaces
filling the threads with vascular channels and new lamellar
bone. Osseointegration was complete at 6 weeks in all animals
examined. Electron microscopy at various places along the
bone-titanium interface showed an amorphous layer, a granular
electron-dense layer, or a layer of uncalcified collagen
fibrils. At each week after surgery, radioautography showed
the position and thickness of new bone labeled with 3H-
proline during the last 4 days. Radiolabeled new bone was
deposited only on previously existing bone and extended
toward the available space. Since there was no apparent
relationship between the implant and the new bone, it was
suggested that titanium is biocompatible, but not necessarily
osteoinductive.
MH - Bone and Bones|*AH/BS/ME
MH - Osseointegration|*
MH - Osteogenesis|*
MH - Prostheses and Implants|*
MH - Titanium|*/CH
SO - Int J Oral Maxillofac Implants 1995 Mar; 10(2):155-65
DP - 1995 Mar
TA - Int J Oral Maxillofac Implants
PG - 155-65
IP - 2
VI - 10
UI - 95263095
16
AU - Boyan BD
AU - Schwartz Z
AU - Hambleton JC
TI - Response of bone and cartilage cells to biomaterials in
vivo and in vitro.
AB - In vivo and in vitro models have been developed to study
the bone/material interface. The in vivo model exploits
the osteogenesis that accompanies marrow ablation of the
rat tibia and uses morphological and biochemical changes
in extracellular organelles, called matrix vesicles, as
markers of the healing process. Matrix vesicles, which
are associated with primary bone formation and calcification,
are produced by osteoblasts and are sensitive to cellular
and environmental regulation. In bone adjacent to bone-
bonding implants, matrix vesicle number increases, as does
its alkaline phosphatase activity. In bone adjacent to
nonbonding materials, matrix vesicle activity is inhibited.
The materials exert systemic effects which can also be
studied by use of matrix vesicles. Cell models are needed
in order for the specificity of the cellular response to
the material to be understood. By the use of culture plates
sputter-coated with implant materials, the response of
cells can be studied under controlled conditions. Comparison
of the response of costochondral chondrocytes at two stages
of endochondral development demonstrates that the effects
of various materials are surface- and cell-maturation-dependent.
Cells cultured on Ti exhibited increased alkaline-phosphatase-
specific activity, whereas those cultured on Al2O3 have
decreased enzyme activity.
MH - Biocompatible Materials|*PD
MH - Cartilage|*CY/DE/EN
MH - Extracellular Matrix|*EN
MH - Osseointegration|DE/*PH
MH - Osteogenesis|*DE/PH
SO - J Oral Implantol 1993; 19(2):116-22; discussion 136-7
DP - 1993
TA - J Oral Implantol
PG - 116-22; discussion 136-7
IP - 2
VI - 19
UI - 94066188
17
AU - Skripitz R
AU - Aspenberg P
TI - Tensile bond between bone and titanium: a reappraisal of
osseointegration.
AB - When Branemark in the 1970s established the term osseointegration,
this implied a direct chemical bond between a titanium
implant and bone. However, ultrastructural studies seemed
not to support this idea, and osseointegration came to
be defined as the absence of interfering fibrous tissue.
Titanium was therefore described as bioinert rather than
bioactive. We now demonstrate mechanically a chemical bond
between bone and titanium, using unloaded cp titanium plates,
similar to those used in previous studies on prosthetic
loosening. Tensile force can be transmitted only by chemical
bonds. Bone-bonding was therefore evaluated by a detachment
test. The plates were developed so that a flat titanium
surface touched traumatized bone and the rest of the detachable
part had no contact with surrounding tissue. The titanium
plates were either polished and sterilized in an autoclave
or treated in 4 M NaOH and then heated to 600 degrees C
according to Yan et al. (1996). After 4 weeks, the plates
were separated from the bone by a perpendicular traction
force. The detaching load of the untreated titanium plates
never exceeded 0.03 MPa, whereas with treatment it increased
to median 0.8 MPa, with bone remaining attached to parts
of the plates after detachment. Our findings confirm that
a chemical bond can be obtained within 4 weeks with the
described pretreatment. It may occur also without treatment,
after a longer implantation time.
MH - Biocompatible Materials|*
MH - Implants, Experimental|*
MH - Materials Testing|*
MH - Osseointegration|*
MH - Titanium|*
SO - Acta Orthop Scand 1998 Jun; 69(3):315-9
DP - 1998 Jun
TA - Acta Orthop Scand
PG - 315-9
IP - 3
VI - 69
UI - 98366971
18
AU - Cabrini RL
AU - Guglielmotti MB
AU - Almagro JC
TI - Histomorphometry of initial bone healing around zirconium
implants in rats.
AB - Histometric evaluations as a function of time were performed
with zirconium implants during the healing period in 10
Wistar rats. The implants (7 mm x 1 mm x 0.1 mm) were placed
in the right tibia of the animals. Five rats were killed
after 14 days and the remainder were sacrificed 30 days
after implantation. The tibiae were resected, radiographed,
and embedded in poly(methyl methacrylate). Three cross-
sections were obtained transverse to the major axis of
each tibia. Osseointegrated tissue thickness, percentage
of direct bone-to-implant contact, and osseointegrated
tissue volume were evaluated for each specimen. Bone formation
was observed on the surface of the implanted strip that
was in contact with tibia marrow. This method is proposed
for the evaluation of the first stage of healing of bone
in contact with different implant materials subjected to
various surface treatment.
MH - Osseointegration|*
MH - Prostheses and Implants|*
MH - Wound Healing|*
MH - Zirconium|*
SO - Implant Dent 1993 Win; 2(4):264-7
DP - 1993 Win
TA - Implant Dent
PG - 264-7
IP - 4
VI - 2
UI - 94272421
19
AU - Shirota T
AU - Donath K
AU - Matsui Y
AU - Ohno K
AU - Michi K
TI - Reactions of bone tissue in old rats to three different
implant materials.
AB - This study compares the bone responses of old rats when
implanted with hydroxyapatite ceramic (HAC)-coated titanium,
high-density HAC, and uncoated titanium. Twelve two-year-
old Wistar rats were used in this study. Cylindrical implants
were placed into each tibia, and the animals were killed
seven, 14, 28, or 56 days after implantation. Undecalcified
sections were prepared and were then stained with toluidine
blue. The healing process was examined histologically,
and histomorphometric measurements were made with a computer-
based image analyzer to quantify the percentage of implant-
bone contact. The results indicated that the HAC-coated
implants were superior to the uncoated titanium implants
in relation to bone contact. In the cases where the bone-
free surface of HAC coating was dissolved, macrophages
were often seen on the surface of the implant. Although
further longitudinal data are needed to evaluate the decrease
of HAC coating, in this animal model, HAC-coated implants
may be useful for osseous response in bones of poor quality.
MH - Bone Regeneration|*PH
MH - Durapatite|*
MH - Osseointegration|*
MH - Prostheses and Implants|*
SO - J Oral Implantol 1994; 20(4):307-14
DP - 1994
TA - J Oral Implantol
PG - 307-14
IP - 4
VI - 20
UI - 95371166