Biofilm Control Strategies in Dental Health - Antibiofilm Agents: From Diagnosis to Treatment and Prevention - page 293

capabilities (Reynolds 1997 ), proved to be a successful treatment approach in
removing the cariogenic bacteria and arresting root surface caries in vivo (Vlacic
et al. 2007 ).
Organisms associated with periodontal disease have also been targeted by
photodynamic therapy strategies, especially to reduce their number after scaling
and root planing. Methylene blue has been extensively used as a photosensitizer,
being applied directly to the dental pockets and exposed to red light via a fiber optic.
Other photosensitizers have also been used in experimental settings on planktonic
organisms, biofilms, and model animals. Although, in general there is a decrease in
the number of bacteria, the elimination of periodontal pathogens is not complete
and the reduction of total biofilm load is limited.
Finally, an exciting line of research in phototherapy is based on the observation
that some organisms in the mouth already have “natural” photosensitizers in their
cells; hence, phototherapy can be applied without the addition of any chemicals.
Thus, oral black-pigmented bacteria (species of Porphyromonas and Prevotella ),
which are important organisms associated with periodontal disease, have endoge-
nous porphyrins that when exposed to blue light release oxygen radicals that kill
them. These kinds of approaches are advantageous because they are less aggressive
and specifically target the group of bacteria associated with disease, while leaving
the rest of the biofilm intact and thus shifting the composition from a disease-
associated biofilm to a health-associated one. Moreover, the wavelengths used in
phototherapy are not harmful to host cells (Soukos and Goodson 2011 ).
5.3 Nanoparticles and the Control of Oral Biofilms
In recent years bio-nanotechnology has increasingly been in the spotlight as a new
way of treating medical conditions, either as a more specific delivery system for
drugs or as a technology that allows for the creation of better biomaterials to be used
in medicine. Nanotechnology refers broadly to a field of applied science and
technology whose unifying theme is the control of matter on the atomic and
molecular scale, between approximately 1 and 100 nm. One key element in
designing nanoparticles is that the materials used for their synthesis must be safe
to use in the human body, which limits the number of compounds available.
In photodynamic therapy, nanoparticles made of the biodegradable polymer
poly( D , L -lactide-co-glycolide) (PLGA) have been used to encapsulate different
photosensitizers and deliver them to the pocket before shining it with light (Allaker
2010 ). The use of nanoparticles solves one of the major problems of using photo-
sensitizers in a clinical setting, which is their poor penetration in to the biofilm, thus
reducing the effectiveness of the treatment. Encapsulating these photosensitizers in