Biomedical Engineering Reference
In-Depth Information
the implant or implants, a healing period (osseointegration) and implant restora-
tion to replace the missing tooth or teeth. The treatment may be a cooperative
effort between a surgical dentist who actually places the implant and a restorative
dentist who designs, prescribes, and inserts the fi nal replacement teeth. Some den-
tists have advanced training and provide both of these services.
15.3.5 Bioadhesive
There are a number of adhesives and sealants that are suitable for short and/or
long term biomedical applications. Typical adhesives used in medical products
include silicones, epoxies, acrylics, and polyurethanes. But perhaps the most inter-
esting materials are those that are aimed at surgical applications.
Today, most of these are based on cyanoacrylate materials. Two such com-
mercial products are Dermabond—surgical glue that replaces suture and
staples—and Liquid Band-Aid—a protective covering for cuts and scrapes that
acts as a bandage. Both of these products have been developed by “Closure,” a
small start-up company located in Raleigh, North Carolina. Now Johnson &
Johnson, one of the world's largest manufacturers of heath care products, has
agreed to acquire the company. Biomaterials are not only used as adhesives for
the human body, but are also being developed as sealants.
In addition to the two products mentioned above, Closure is developing
several surgical sealants. Omnex, a vascular sealant is about to become available
in Europe. This sealant can be used to glue blood vessels and will be the fi rst surgi-
cal glue to be used inside the body. A sealant for use after lung cancer surgery is
at least two years from commercialization, and an orthopedic sealant for tendon
and muscle repair is at least three years from market. An especially useful fi brin
glue composition comprises a biocompatible, bioabsorbable, hyaluronic acid
derivative material, upon which are applied or chemically bonded fi brinogen and
thrombin, along with other optional constituents, such as additional coagulation
factors, anti - fi brinolytics, stabilizers, and biologically active substances. The fi brin-
ogen, thrombin and other components can take the form of a dry preparation, an
aqueous or nonaqueous preparation, or as a combination thereof. Such a fi brin
glue composition can be placed directly on a wound site and is fully reabsorbed
into the body.
Bioactive materials encourage specifi c reactions between the material and
the surrounding tissue. One example of such a bioactive material is hydroxyapa-
tite. This polymer is used as a porous coating on hip implants. The coating encour-
ages growth of surrounding tissues that interlock into the pores to help stabilize
the stem of the implant in the bone.
15.3.6 Opthalmologic Applications
The different types of eye medical devices such as Ophthalmic Tantalum Clip,
Conformer Artifi cial Eye, Absorbable Implant, Eye Sphere, Extra Ocular Orbital
Implant, Keratoprosthesis, Intraocular Lens, Scleral Shell, and Aqueous Shunt
Search WWH ::




Custom Search