Considering several clinical situations, low intensity laser therapy has been widely applied in pain relief or analgesia mechanism. With the advent of new LED-based (light emitting diode) light sources, the need of further clinical experiments aiming to compare the effectiveness among them is paramount. The LED system therapeutic use can be denominated as LEDT - Light Emitting Diode Therapy. This study proposed two clinical evaluations of pain relief effect: to dentin hypersensitivity and to cervicogenic headache using different sources of lasers (low and high intensity) and light emitting diodes (LEDs), one emitting at the spectral band of red (630+/- 5nm) and the other one at infrared band (880+/- 5nm). Two different clinical studies were performed and presented interesting results. Considering dentin hypersensitivity, red and infrared led were so effective than the control group (high intensity laser system); by the other side, considering cervicogenic headache, control group (infrared laser) was the best treatment in comparison to red and infrared led system.
Skin hydration is important to prevent aging and dysfunction of orofacial system. Nowadays, it is known that cutaneous system is linked to muscle system, then every dentist need to treat healthy facial skin, as lips, keeping orofacial functions healthy. Thirty-two patients were treated using laser and led therapy single or associated to biomaterials (dermo-cosmetics) searching for the best protocol to promote skin hydration. Using a peace of equipment to measure electric impedance, percentage of water and oil from skin, before and after different treatments were analyzed. Statistic tests using 5% and 0.1% of significance were applied and results showed that light could improve hydration of epidermis layer of facial skin. Considering just light effect, using infrared laser followed by blue led system is more effective to hydration than just blue led system application. Considering dermo-cosmetic and light, the association between both presented the best result.
The concern with the hydrogen penetration towards the pulp can be observed on the literature by the great number of papers published on this topic; Those measurements often uses chemical agents to quantify the concentration of the bleaching agent that cross the enamel and dentin. The objective of this work was the quantification of oxygen free radicals by fluorescence that are located in the interface between enamel and dentin. It was used to accomplish our objectives a Ruthenium probe (FOXY R - Ocean Optics) a 405nm LED, a bovine tooth and a portable diagnostic system (Science and support LAB - LAT - IFSC/USP). The fluorescence of the probe is suppressed in presence of oxygen free radicals in function of time. The obtained results
clearly shows that the hydrogen peroxide when not catalyzed should be kept in contact with the tooth for longer periods of time.
Nowadays the real contribution of light on the acceleration of the chemical reaction for
the dental bleaching is under incredulity, mostly because the real mechanisms of its
contribution still are obscure. Objectives: Determine the influence of pigment of three
colored bleaching gels in the light distribution and absorption in the teeth, to accomplish
that, we have used in this experiment bovine teeth and three colored bleaching gels. It is
well Known that the dark molecules absorb light and increase the local temperature
upraising the bleaching rate, these molecules are located in the interface between the
enamel and dentin. Methods: This study was realized using an argon laser with 455nm
with 150mW of intensity and a LED with the same characteristics, three colored gels
(green, blue and red) and to realize the capture of the digital images it was used a CCD
camera connected to a PC. The images were processed in a mathematical environment
(MATHLAB, R12 ®). Results: The obtained results show that the color of the
bleaching gel influences significantly the absorption of light in the specific sites of the
teeth. Conclusions: This poor absorption can be one of the major factors involved with
the incredulity of the light contribution on the process that can be observed in the
literature nowadays.
In this work a technique was proposed and evaluated for detection of metallic posts of parallel sides through a test body
of Z100 dental resin. The technique presented involves the acquisition and the image processing by trans-illumination of
the resin to detect the edges of the posts. LASER and LED systems in different colors were used as a source of
irradiation for the image formation. The qualitative analysis of the results showed that just by using LED in the red and
green colors it was possible to detect the edges of the posts. The results also showed that the use of LASER in this
experiment was not successful mainly due to the LASER light optical interference phenomenon inside the resin, which
resulted in low definition images. Lastly the discussion of the work was directed to the optical effects of absorption and
scattering of light throughout the resin, light diffraction through the posts and interference of the coherent light
evaluating the influence of each effect in the experiment.
In this work the color dependence of resin composites with the background color was evaluated. The objective was to
measure since what thickness the color of the sample stops being influenced by the color of the background over which
the resin is placed and the methodology used in experiment was based in analyzing the contrast of digital images of the
sample over a black background. The results shown that since 0.8 mm the images contrast becomes almost constant; it
prove that since this thickness the color of resin composite depends on the optical resin properties only. The experiment
was repeated under three conditions of luminosity to evaluate the influence of it on the image contrast and the results
obtained were identical.
The dental bleaching is known for many years. Recently a technique employing light has
open up new and exciting possibilities. Besides its vast application there are still many
important points to be understood about teeth photon bleaching. In this work we present an
"in vitro" experiment to explore the main mechanisms involved during the photon action in
tooth whitening. Our results indicated that light at same wavelengths are great absorbed by
pigments creating a local heating which considerably increase the bleaching rate. This
results in a fast reaction without heating the whole dental structure. We discuss details of
our experiment. Work supported by Fapesp and CNPq.
Selection of the proper shade and color matching of restorations to natural dentition continues to be one of the most frustrating problems in dentistry and currently available shade guide presents a limited selection of colors compared to those found in natural dentition.
This investigation evaluation if the composites resins shade B2 are equivalent to the Vita shade guide B2.
Twelve composite resins (Renamel Microfill Super Brite- Cosmedent USA, Renamel Universal Brite- Cosmedent USA, Renamel Microfill Body- Cosmedent USA, Renamel Universal Body- Cosmedent USA, Opallis EB2-FGM, Opallis DB2-FGM, Filtek Supreme XT-3M/ESPE, Filtek Z250-3M/ESPE, Filtek Z350-3M/ESPE, Z100-3M/ESPE, 4 Seasons Dentin-Ivoclar/Vivadent, Tetric Ceram-Ivoclar/Vivadent) shade B2 were used. From each composite, two specimens were made in a steel matrix with 8.0 mm diameter and 10.0 mm different predetermined thickness (0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0 mm). The specimens were 40 seconds light polymerized by LED Ultrablue (DMC). The specimens were measured 10 times each to determine the shade using a reflectance spectrophotometer (Pocket Spec).
According to results was verified that not any of composites resins shade B2 evaluated in this study presented values of color difference (ΔE) equivalent to the Vita shade guide B2 and the 2 mm thickness showed the closer match to the Vita shade guide B2.
This work presents a study to understand the interaction between Er:YAG laser and composite resin. The main purpose is the development of a new ultra-conservative clinical technique: differential ablation for composite resin restorations using Er:YAG laser. A hybrid composite resin (Z100, 3M, USA) formatted as tablets recently cured was used and after artificial aging method the teeth were irradiated with a Er:YAG laser and two different conditions were considered, energy level per pulse (100, 300 and 500mJ), frequencies (5, 10 and 15Hz) and different water fluxes. Diameter and depth of each resulted microcavity was measured and the material removed volumes were calculated. The resulted values were plotted and feted to allow a comparative observation of the material removed as a function of energy level per pulse. Frequencies of 5 and 10Hz were similar between them and seemed to allow the highest material ablated volume, however considering the energy per pulse parameter, 300mJ was more efficient than the others, mainly when water flux was around 0.1ml/s. The highest water flux showed lower ablation rate with the lowest fluency. Water fluxes presented an important factor considering composite ablation, even because it could modulate depth and surface regularity of the irradiated material.
KEYWORDS: Light sources, Light emitting diodes, Chemical reactions, Dental bleaching, Blue light emitting diodes, Absorption, RGB color model, 3D modeling, Hydrogen, Chemical elements
The bleaching process is been objective of many studies since the beginning of the XX century. Heat has been used to activate the hydrogen peroxide; the aesthetic results were satisfactory, but associated with this process high incidence of hypersensitivity as well as radical endodontic treatment was observed making this technique clinically hard to implemented.
Nowadays the dental bleaching is one of the most wanted aesthetic procedures by the population at the dental office. With the utilization of new light sources as LASER and LED a technique to evaluate the efficiency of photo-bleaching of many pigments is necessary.
This work demonstrates a new method to quantify the breakage of pigments on a cellulose matrix using a blue LED system with 1W/cm2. We employed a computational analysis and digital spectroscopy. These matrixes were used because of its inert physical-chemical properties.
The obtained results are within the expectative, where the groups irradiated with light presents more broken pigments that the group with no light, it was also possible to observe on this experiment that light acts decreasing the free energy of the reaction and that way speeding up the rate of bleaching.
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