By Shannon Collins
DoD News, Defense Media Activity
WASHINGTON, May 18, 2015 – Within the laboratories of Naval
Medical Research Unit-San Antonio, or NAMRU-SA, interdisciplinary teams of
biomedical engineers, environmental microbiologists, dentists, chemists and
other researchers work to research technology that will help wound treatment
for the Defense Department warfighter.
NAMRU-SA’s mission is to conduct medical, craniofacial and
biomedical research, which focuses on ways to enhance the health, safety,
performance and operational readiness of Navy and Marine Corps personnel and
addresses their emergent medical and dental problems in routine and combat
operations. They share their findings with the other service branches.
Within NAMRU-SA, the Craniofacial Health and Restorative
Medicine Directorate team focuses on research to re-engineer wound healing,
infection control and dental treatments.
It also advances DoD’s environmental stewardship and assists
wounded warriors.
“The research here encompasses everything above the
shoulders,” said Navy Capt. Rita Simmons, NAMRU-SA’s commanding officer. “And
the most common injuries now -- with the body armor being so effective -- we’re
looking at wounds in the head and face area. That area of research has really
moved to the forefront of our wounded warrior issues.
“Groups of scientists are spending a lot of time looking at
ways to fight infection caused by injuries of various forms to the head, face
and neck areas, and we are working to improve outcomes,” Simmons said.
Cranial Implants
The researchers at NAMRU-SA do not create the cranial
implants, but they are working on redesigning the surface of titanium implants
and developing nano delivery systems for antimicrobials and local anesthetics
for controlling pain and infection after a burn or head injury, said Mauris
DeSilva, a principle investigator with the directorate.
DeSilva said a patient who has a traumatic head injury may
suffer the loss of portions of their skull bone or could have an elevation of
intracranial pressure requiring the removal of a portion of the skull by
surgeons to relieve pressure from excess fluid build-up. Replacing the skull
bone often requires an implant. These implants are typically made of durable
polymers or titanium. Patients who go through this surgery have a high rate of
post-surgical infections, which may necessitate removal and replacement of the
implant. Warfighters going through these surgeries could get post-surgical
infections, which is what DeSilva’s team is trying to reduce.
“Obviously, through any type of force, whether it’s some
sort of blunt force trauma or blast injury to the head, quite often, the skull
will be damaged during that process,” Simmons said. “But there are ways to
improve the cranial implants that are used as part of the recovery process and
ways that we can help fight infection. We don’t make the implants here but we
investigate new surface materials to improve the implant’s function and reduce
the rates of infection that can directly improve quality of life outcomes after
the injury.”
Simmons added, “Infections beget surgery and if there are
more infections, there’s more surgery, lost tissue, lost recovery time,
psychological impact.”
DeSilva said his team is working on optimizing the surface
roughness of the implants. His team is also developing a nano coating that has
nano materials with antimicrobials so they will have a controlled release over
a specific duration of time.
“What we hope is, after recommending the roughness scale
that’s optimized for this implant, we want to take it a step further and have
the implant produce an acute antimicrobial release for at least 30 days,” he
said. “This is the time period that they’re seeing is therapeutically effective
to kill most infections.”
Wound Dressing
Currently, wound dressings used on the battlefield are
traditional bandages, officials said. They help control hemorrhage but do not
actively help in the healing process. Researchers are looking into creating
bandages with bioactive factors such as growth factors, antibiotics and other
agents that may speed up healing and reduce scar formation, said Navy Capt.
Jonathan Stahl, a research dentist.
The engineers and scientists at NAMRU-SA have built an
electrospinning device that researchers can use to make dressings using
nanofiber technology. Biologically compatible natural and synthetic polymers
are dissolved into a solvent along with bioactive agents and spun into a wound
dressing using electrical forces. The resulting wound dressing will release the
growth factors and other drugs over time and can be tested to determine if they
improve and possibly accelerate the wound healing process. If successful, the
new dressing may speed up healing and reduce scars for those injured on the
battlefield.
Cracked Teeth
“Fractured teeth and restorations are the most commonly
reported dental emergencies among military personnel,” said Navy Cmdr. David
Leal, acting director for the Craniofacial and Restorative Medicine Department
directorate. “This can be a showstopper for them, and it can affect their work
schedules. If they’re deployed, they may have to get sent back home so somebody
can take care of the problem.”
Current methods for detection of enamel cracks provide
limited information, Leal said. For example, he said, trans-lumination uses a
bright visible light, which scatters when reflected on enamel. The dentist can
see the fracture but is unable to determine the depth or extent of it. X-rays are
not very diagnostic unless the fracture is grossly displaced.
The researchers at NAMUR-SA designed the Optical Coherence
Tomography, or OCT. It uses non-ionizing laser light for obtaining sub-surface
images of translucent or opaque materials.
“Our team’s goal is to use OCT as a new tool to develop a
predictive model that dentists can use chairside to quickly scan a tooth and
help them to evaluate the severity of tooth cracks,” Leal said.
With OCT, the dentists will be able to obtain live 3-D
images instantly, Leal said, that will aid them in making diagnostic decisions
to assist them with appropriate treatment plans to prevent or reduce dental
emergencies.
Nano Technology in Fillings
Navy researcher Dr. Amber Nagy, an environmental
microbiologist and biomedical scientist, said one of the projects they are
working on is improving resin formulations used to treat cavities. When a
patient has a cavity cleaned out, he or she may receive an amalgam filling or a
filling with resin that is tooth colored so that it is more aesthetically
pleasing.
Nagy said the resin fillings will be modified to have
nanoparticles in it, which can use visible light to activate antibacterial
activity. The goal is to eventually issue each patient a toothbrush that has a
light emitting diode in the toothbrush head so that every time he or she
brushes his or her teeth, the resin antibacterial process will be activated by
the toothbrush.
“We want to prevent bacteria from attaching to the tooth
because bacteria are what cause the decomposition of the tooth or the decay of
the tooth in the first place,” Nagy said. “By adding nano particles to the
resin and hitting it with a light, it will prevent the bacteria from binding
which will help to reduce cavity formation.”
Environmental Stewards
“All military installations want to be good stewards in the
towns and cities in the states in which they live,” Simmons said. “Our goal and
mission is to make sure our military dental treatment facilities properly
handle and dispose of dental amalgam waste from fillings.”
A large number of cavities are filled with dental amalgam
each year by Navy dentists to ensure sailors are ready for deployment, said Nagy,
who’s the principal investigator for NAMRU-SA’s mercury abatement project.
Dental amalgam is a safe, cost-effective, and durable metallic mixture
consisting of about 50 percent liquid mercury and a powdered alloy that
contains silver, tin, and copper. When mixed, the two components harden and
become a solid material, commonly referred to as silver fillings, which is used
to fill cavities in teeth.
“After dentists go in and drill to take out a filling, we
don’t want the amalgam filling waste, which contains mercury, to go into the
public wastewater stream,” Nagy said. “To combat this issue, we use a dental
chair filter that was designed, developed, prototyped and patented by NAMRU-SA
researchers for Navy dental chairs throughout the Navy and Marine Corps dental
clinics. This novel filter can capture 96.7 percent of amalgam from dental
wastewater before it enters the public wastewater stream, and it is
inexpensive, easy to install, and available for use across all services.”
NAMRU-SA, the lead agent for mercury abatement, has patented
and developed this chairside dental wastewater filtering system with a special
focus on the accumulation of inorganic chemical contaminants such as mercury.
The Navy is ahead of the Environmental Protection Agency proposed nationwide
requirement that will mandate amalgam separators to reduce mercury and other
chemical contaminants from dental wastewater in all dental facilities in the
country, Nagy said.
“We’re ahead of the curve there, and we want to stay ahead
of the curve and be the gold standard for environmental surveillance for all of
the DoD,” Simmons said. She said this is a collaborative effort, and the Air
Force is working with the Navy to help develop filter systems that also remove
organic contaminants from dental wastewater.
Teamwork
Nagy said the success of the research could not happen
without teamwork.
“This research isn’t possible without our interdisciplinary
team,” she said. “We have an excellent, dedicated and diverse team working
together to solve these problems to save lives out there in the field.”
Simmons said those interdisciplinary teams seek to address
the problem by bringing together people with varying expertise to answer
questions from many different approaches.
“This way, they can downscale to a more workable solution to
tackle that problem from the onset, rather than taking that very serial
approach of, ‘Well, we tried that and it didn’t work, now what am I going to
do?’” Simmons explained.
She said the teams have been successful at developing
synergistic cross-talk between departments and directorates with research.
“Teams come together to come up with the best solution in
the fastest means possible,” Simmons said. “Whether it’s a device, a capability
or a scientific innovation that can be pushed forward, NAMRU-SA continues to
make great progress in research that optimizes warfighter readiness and saves
lives.”
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