Page 28 - 00. Complete Version - Progress Report IPEN 2014-2016

28 Lasers Technology | Progress Report

Although a remarkable decline in the incidence ed increased temperature up to 300 oC. The
of dental caries worldwide has been document- compositional analysis revealed that laser ir-
ed, it is still the most prevalent disease during radiation promotes changes in the carbonate
childhood and adolescence. On account of the content and affects the intermolecular inter-
widespread use of fluoride, lasers have been action from (within the) mineral part of bone.
tested to improve dental enamel properties in Moreover, the proportion of organic compo-
order to enhance its resistance to demineral- nents (amides) in the bone samples signifi-
ization. We evaluated the effect of combining cantly decreased with the increase in ener-
laser irradiation (Nd:YAG and Er,Cr:YSGG) with gy density, which points out the importance
fluoride on an enamel microstructure and de- of using the proper energy density in clinical
mineralization by FTRaman spectroscopy. De- procedures to avoid thermal or chemical dam-
mineralization promoted reduction in organic age to the tissue caused by laser irradiation.
contents; Nd:YAG laser irradiation promoted
loss of carbonate and organic content, while Other Laser Health activities (activities) in-
Er,Cr:YSGG did not produce significant chang- clude Development of therapeutic processes
es in the relative band intensities of organic of photobiomodulation and photodynamic in-
and inorganic contents of the enamel. In lased activation which aims to explore innovative
samples, no effects caused by pH-cycling on light-based therapeutic processes through low
enamel were observed. Our group showed that power lasers and light-emitting diodes (LEDs)
laser treatment and its association with fluo- to provide scientific background for clinicians.
ride can interfere with the demineralization Our major interests are to investigate the ef-
dynamics, reducing its effects over the enamel. fects of photobiomodulation (PBM) and pho-
todynamic inactivation (PDI) therapies. Other
Infrared lasers can be useful in several appli- activities encompass tissue optics, nanomate-
cations, since they are strongly absorbed by rials, and tissue engineering.
water and hydroxyapatite, two of the main
components of the body mineralized tissues, Photobiomodulation
like enamel, dentine and bone. The Er,Cr:YS-
GG laser (2780 nm) cuts bone by thermal ab- Photobiomodulation (PBM) is a non-invasive
lation. In this process, the water molecules of therapeutic modality used in Health Scienc-
tissue absorb the laser energy, increasing its es for pain relief, wound healing, bone repair,
temperature and the pressure inside the tis- although mechanisms behind its effects are
sue, causing a micro-explosion that removes still not completely known. Our group devel-
the material. However, for an efficient and ops researches about the physical, chemical
safe application(,) it is necessary to know the and biological mechanisms of the non-thermal
exact effects that the laser irradiation pro- effects of light on biological tissues. Studies
motes in tissue. Infrared Thermography and are carried out in vitro and in vivo to investi-
Attenuated Total Reflectance-Fourier Trans- gate the influence of PBM on cell cultures, tu-
form Infrared spectroscopy (ATR-FTIR) tech- mor cells, pain relief, bone repair, and chron-
niques were used to characterize natural and ic inflammation in obesity. Our results show
irradiated bone tissue showing that irradia- that PBM is able to trigger senescence in tu-
tion at 3 J/cm2 promotes an increased tem- mor cells(,) but proliferation in fibroblasts fol-
perature of approximately 100 oC, while 6 J/ lowing gamma-radiation (,) reduces abdomi-
cm2 up to 215 oC; 8, 12, and 15 J/cm2 promot- nal adipose tissue inflammatory infiltrate of

Instituto de Pesquisas Energéticas e Nucleares