Civil Engineering Reference
In-Depth Information
Recently, in 2004, Macedo
et al.
[126] also compared microbial cellulose and polytet-
ral uoroethylene (PTFE) as physical barriers to treat bone defects in adult rabbits. In
the study, two osseous defects of 8 mm in diameter were performed in each hindfoot of
the animal. h e let hindfeet were protected with Gengil ex, while the wounds created
at the right hindfeet were covered with PTFE barriers. h e histological evaluation of
the treatments at er 3 months revealed that defects covered with PTFE barriers were
completely repaired with bone tissue, whereas incomplete lamellar bone formation
was observed in defects treated with Gengil ex membranes. h e study hence demon-
strated that compared to microbial cellulose membrane, nonporous PTFE barrier is
more ef ective to treat osseous.
In 2009, Silva [127] evaluated the biological behavior of synthetic hydroxyapa-
tite (HAP-91) when implanted in dental cavities and covered with nanocellulose.
Membranes were shaped into triangles fully covering the cavities, avoiding contact
between hydroxyapatite and the oral cavity (a source of contaminants). Silva found that
compared with the control group, nanocellulose associated to the HAP promoted faster
bone regeneration. Immediate implant placement is a relatively recent procedure and
has advantages, such as reduced number of surgical procedures, preservation of alveo-
lar bone, reduction of cost and period of edentulism, and increased patient acceptance.
However, there are some specii c contraindications for the technique, such as the pres-
ence of an infection caused by periodontal disease and periapical lesions. A two-phase
histomorphometric study of Gengil ex on mongerel dogs showed negligible improve-
ments compared to the control group [128].
16.13
Conclusions
h e aim of this chapter was to demonstrate a comprehensive as well as state-of-art
review of cellulosic materials together with their medical applications. Down through
the centuries, humans have used one form of cellulose or another in medical applica-
tions and wound care products. Now, through the serendipity of better understanding
a novel form of cellulose assembled by microbes, called microbial cellulose, scientists
are positioned to exploit the unique properties and biocompatibility of these remark-
ably versatile biomaterial materials for a wide variety of biomedical and biotechno-
logical applications. h e extraordinary supramolecular nanoi ber 3D network structure
and the resulting valuable properties have been exploited for various medical applica-
tions, such as tissue engineering, drug delivery, wound dressings, medical implants,
etc., and clinical studies have been performed showing its ef ectiveness and uniqueness
in these areas. However, much interdisciplinary research and development is required
in order to bring microbial cellulose products to successful commercialization. From
the scientii c and economic perspective, cellulosic materials are on the threshold of a
breakthrough that is also being driven by recent extraordinary activities in the i eld
of nanosized materials. In keeping with a vision for the future of novel products from
renewable resources, certainly cellulose is a material that has the capacity to be greatly
improved with prolonged benei ts to mankind.
