Nanoparticles improve strength of 'invisible' dental brackets
8 November 2012
A polymer used for dental braces has improved mechanical
properties and abrasion resistance when alumina nanoparticles are added
to the ingredients, and so can better withstand the wear and tear of
Brackets made from clear plastic polymer used in dental correction
orthodontics have produced very good results in recent years,
especially in relation to the improved esthetics when compared to
metal brackets, but they do present certain problems of wear and
tear within the mouth.
The solution is to use very hard alumina nanoparticles and spread
them evenly in the polysulfone, the polymer mould that is used in
the industrial production of dental brackets.
This new process, patented by the Composite Group and Universidad
Carlos III de Madrid (UC3M) researchers, has produced a new material
which increases mechanical as well as friction resistance, thereby
maintaining the brackets’ transparency. “We have been able to
develop a more rigid material with this technology which has a
clearly improved friction resistance, thus helping to withstand the
wear and tear produced by the teeth or by chewing, explained
Professor Juan Baselga, head of the UC3M Polymers and Composite
Group. In addition, it is biocompatible, which is essential for
something that is going to be used in the mouth, and complies with
European requirements for products which are in contact with food.
These new types of materials- nano-reinforced plastics- have
applications in diverse areas of industry, according to the
researchers. In particular, polysulfone is of interest in the
bio-health field because of its bio-compatibility in the development
of medical- surgical equipment, where it is of the essence to
improve rigidity and friction resistance. Furthermore, it has
potential applications in the auto industry and in the area of
safety such as, for example, the development of a new visor for
Dental brackets made of the new polymer material
This innovation allows nanoparticles to be incorporated and
evenly dispersed in a polymer mould in a very low proportion.
After this process that is based on green chemical techniques is
carried out by UC3M researchers, the particles, which are now
dispersed in the polymer through micro-extrusion and micro-injection
techniques, are then mixed to produce the final piece in the CEOSA-Euroortodoncia.
“ We measure out the plastic since the minimum that a normal
machine can inject is 15 grams, whereas our pieces weigh .06
grams…it would be akin to injecting insulin with a horse syringe”,
explained the company director, Alberto Cervera. “And with the
technology we are using, micro-extrusion and the micro-injection, we
are capable of controlling these minuscule quantities of material
with the utmost precision,” he added.
The relationship between UC3M and CEOSA/Euroortodoncia takes
advantage of the synergy between the public and private sector.
“We are a small to medium-sized enterprise and we get support from
the University to produce a first rate product, which is then
advantageous in the agreements which we have had for a decade
in the form of end-of-degree-projects, doctorial theses and joint
research programs within the European Union and in the Madrid
Autonomous Community, for example,” Alberto Cervera ellaborated. “We
learn a lot from this collaboration,” continued Juan Baselga,
“because this company presented us with real problems that they face
in their industrial area and they open up their laboratories to our