Biomedical Engineering Reference
In-Depth Information
It was interesting to note that the cement without gentamycin showed a de-
crease in ultimate compressive strength during setting from 24 to 48 hours in
phosphate buffered saline at 37 °C. The ultimate compressive strength dropped
from 5.5 MPa, to 3.87 MPa, indicating that the cement had probably dissolved.
When the gentamycin was present, the cement showed an increase in both the
strength and modulus when the set time was extended from 24 to 48 hours. It ap-
peared that the addition of gentamycin may have delayed the dissolution of the
cement, while allowing it to continue to set, to further increase the mechanical
properties.
Owing to its unique preparation method and bioresorbability, the bioactive
cement employed in this study may be effective as both a bone graft substitute
and as a carrier for the local delivery of antibiotics to prevent or treat infections.
An ideal bioactive cement can release a clinically effective amount of antibiotics
initially, maintain a steady release of a safe dose over an extended period, and
retain no residual amount of antibiotics after the desired treatment time is over.
As demonstrated in this study, the MCPC™ bioactive cement released over 50%
of the loaded gentamycin per cylinder, that is, 7.5 mg, in the fi rst 24 hours. A steady
release of a therapeutically signifi cant amount of gentamycin, that is, about 60 to
90
g of gentamycin per day, was maintained up to 28 days. As the MCPC™ is
engineered to bioresorb and quickly develop a macroporous structure, the re-
maining amount of two-to-four mg of gentamycin per set-time sample is expected
to discharge completely as the bioactive cement resorbs. The MCPC™ resorb-
able bone substitute has demonstrated its potential to be used as a carrier for the
local delivery system for gentamycin. Future studies will expand the investigation
to evaluate the release profi le and mechanical properties of this bioactive cement
when loaded with other antibiotics such as tobramycin and vancomycin.
μ
4.5 CLINICAL APPLICATIONS
BCP bioceramics of various sizes and shapes are widely used all over the world in
maxillofacial surgery, dentistry, ENT surgery, and orthopedics. Here, the authors
report some examples of clinical applications for MBCP.
4.5.1 Applications in Dentistry
Dental applications for BCP include prevention of bone loss after tooth extrac-
tion, repair of periodontal defects, and sinus lift augmentation [114-116].
4.5.1.1 Prevention of Bone Resorption.
Bone loss occurs after tooth
extraction, causing reduction of alveolar ridge height and width resulting in
diffi culty in fi tting dentures or placing dental implants. BCP granules with an
HA/TCP ratio of 60/40 or 20/80 (MBCP® and Tribone 80®, respectively) were
placed in the alveolar cavity immediately after tooth extraction and followed up
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