low level laser energy

Weijun Xuan in 2013 experimentally showed effect of low level laser on improvement of various parameters of traumatic brain injury brain and concluded that transcranial laser is a promising treatment for TBI in mice. However, selecting a proper LLLT regimen has shown to be a key factor for optimal therapeutic effect. They also demonstrated that the effect is time dependent application for greater duration does not show significant improvement 33 . Its similar with the dose of the lasers. Our research reported that higher energy dose with same wavelengths were less effective as compared to lower energy doses. Thus the energy medicine must have the optimum time and dose on which it works at maximum efficiency and activate the healing mechanism of cells. Higher doses must dilute this effect. Further studies are needed to explain further.

of both LLLT and LIPUS during tooth movement in which the LLLT stimulates cell metabolic activities through stimulating cell mitochondrial energy cycle [30], and the LIPUS signals induce conformational changes in osteoblast cells membrane that alter ionic permeability and second messenger activity. The changes in the sec- ond messenger activity lead to downstream alterations in gene expression and resulting in an acceleration of the osteoblasts activity by upregulating bone-specific genes [31]. Using both LLLT and LIPUS combined in- creased the beneficial stimulatory effect compared with using each one of them alone. That is because the LLLT by its electromagnetic waves possibly stimulated the cell mitochondria and energy cell cycle, while at the same time the LIPUS physical vibration stimulated a natural functional movement around the cell membrane [32, 33]. To the best of our knowledge, there is a limited number of studies comparing the effect of LLLT, LIPUS, or their combination on orthodontic tooth movement, gene expression, or histological evaluation.

Improving male factor infertility using low-level laser therapy is a discernable area in the field of reproductive medicine. Phototherapy has also been extensively administered in the veterinary medicine practice and livestock breeding. The underlying pathways of photobiomodulation are not well established. However, several studied addressed probable mechanisms regarding interaction of laser light and spermatozoa. Motility is one of the most significant characteristics of sperm, which is associated with fertilizing capability. The mitochondrial apparatus within the midpiece of spermatozoa provides required energy for movement of flagellum or tail [20]. Albuquerque-Pontes et al. [21] indicated that low-level laser irradiation could induce activity of cytochrome C oxidase (COX). The COX complex is part of the mitochondrial respiratory chain and plays a critical role in the electron transport cascade. Modulation of this certain cytochrome oxidase activity leads to enhanced oxidative phosphorylation or adenosine triphosphate (ATP) generation. This process subsequently augments the sperm motility. Likewise, another study evaluating the efficacy of laser on the cryopreserved ram sperm showed an increase in the COX Vmax values as well as the COX affinity for its substrate. These findings were consistent with enhanced ATP levels in the irradiated samples and improved sperm motility [22]. Additionally, Passarella et al. [23] reported that some certain NADH-linked reactions occurring in the mitochondria are stimulated and triggered through laser irradiation.

22. Yamaguchi M, Hayashi M, Fujita S, Yoshida T, Utsunomiya T, Yamamoto H, Kasai K: Low-energy laser irradiation facilitates the velocity of tooth movement and the expressions of matrix metalloproteinase-9, cathepsin K, and alpha(v) beta(3) integrin in rats. Eur J Orthod 2010, 32:131-139. 23. Rabie AB, Xiong H, Hagg U: Forward mandibular positioning enhances

0.34). Following the second pulse irradiation, REC de- creases from 0.76 to 0.64 although the sample absorp- tance (A = 0.5) before the second pulse is much higher than the undamaged surface value. For 2 < N < 12, REC decreases while the absorptance remains virtually the same. These data clearly show that for low N the en- hanced absorptance compared to the undamaged surface is not the dominant factor for the enhanced residual thermal heating. For N > 20, REC starts to increase with N and reaches a saturation level of about 0.75 at N ≈ 200. Therefore, in the range of N studied in this experiment, about 50% - 75% of incident pulse energy remains in the sample as residual thermal energy (thermal load). The A(N) data in Figure 2 show that the absorptance en- hances from 0.34 (undamaged surface) to 0.5 following single-pulse ablation, then remains approximately con- stant for N < 30. To determine the surface structures as- sociated with the absorptance enhancement, we take SEM images of the sample surface. As shown in Figure 3, the enhanced surface absorptance mainly results from the laser-induced micro- and nano-roughness [9]. With further increasing N, we observe the formation of an ablation-induced crater (see Figure 4(a)) and both REC and absorptance increase as the cavity develops. From Figure 2, we can see that A surpasses K when N > 600.

The results showed a complete wound tissue healing after the first laser-irradiation and there was no significant difference in the healing between the two used irradiation energies. Therefore wound healing may be enhanced by a threshold amount of energy which aid to increase blood flow rate, stimulated cellular activity and control the inflammation.

Group NS: saline (0.9% NaCl) solution via caudal epidural injection, group L: lidocaine (2 mg/kg of body weight) via caudal epidural injection, group LLL: laser radiation (3000 hertz- for 10 minutes), and group LL: The interval between the treatments was one week. Before the experiment, the skin area over the first intercoccygeal (CO1-CO2) space, sacrum to the insertion of semitendinosus muscle was shaved and washed. Then the skin was dried and bag like pockets were sticked on the skin in the area of origin and insertion of semitendinosus muscle on the right and left side of the horse. Two electrodes were placed in each bag on the origin and insertion of the semitendinosus muscle on each side. So the electrical stimulation was performed bilaterally to allow the stimulus to reach the dorsal and ventral branches of the both sensory and motor nerves. Laser type Red type, C 90,Diode-GaAlInp/CE, Wave Length 650, Power 100 mv, Energy 6 Jul/min, Spread 25/0 cm 2 , Radiation Density 4/0 vat/cm2, Radiation Dose 100

The optical fiber tip, in all experiments, was placed 15mm above the surface of heart to allow the laser beam diameter of 10mm. The power density on the myocardium was 7.64mW/cm 2 . Thus, the laser beam could spread over most of lateral wall of left ventricle including the infarct myocardial area. The irradiation lasted for 125seconds constantly. Apparently, the energy density to the myocardium was 0.96J/cm 2 . All the rats in 3 groups were treated with LLLI however the rats in the sham and the control group underwent the same surgical procedure and laser irradiation, but without switching on the laser power supply. After the irradiation was complete, rats were observed for postoperative management and recovery as in the first time surgery.

The treatment was performed with a 980-nm diode laser (Wiser Laser Doctor Smile, Lambda) operating at an 810-nm wavelength (1 W of output power, continuous wave of 66.7 J/cm2) that was equipped with a 0.6-mm optical fiber in continuous-wave mode. The areas were chosen to be irradiated the lingual and buccal periodontal ligament of the canines. Tree areas Cervical, Middle and Apical, were irradiated. The cervical area was equipped with a diode laser for 10 s. The middle area was equipped with a diode laser for 20 s. The apical area was equipped with a diode laser for 10 s. The total energy density (dose) at each application was 8 J (2×40 s×100 mW). Protective eyewear was worn by the patients and the clinician to prevent injury from laser wavelength exposure. The laser regimen was performed after the closed NiTi coil spring was installed or activated (day 0), and on, 3-, 7-, and 14-day intervals after every activation.

cause of the significant decrease of the levels of CRP released from the liver. The result of the study agreed with the result of Tanzila, (2017), who examined the influence of low level laser therapy (LLLT) on CRP in the recovery process of 20 normal subjects undergo high intensity interval training for 30 minutes. LLLT was found to prevent the occurrence of inflammation due to damage by suppressing the secretion of pro-inflammatory cytokines (especially IL-6 which is the determinant of the concentration of CRP in the circulation) if done before the training session, and then the CRP value was back down. Also the result by Leal et al., (2010), who evaluated the use of LLLT irradiation in preventing the development of skeletal muscle fatigue and biochemical markers of inflammation in nine healthy male volleyball players performing resistive elbow flexion exercises in 75% of their maximum voluntary contraction. Their CRP levels were significantly lower after the exercises when compared to their pre-exercise values, after receiving the LLLT treatment. This was related to the LLLT capability of reducing reactive oxygen species release and creatine phosphokinase activity, in addition to improving the mitochondrial function and reversing the induced dysfunctional state. The erythrocyte sedimentation rate (ESR) is another marker of the acute inflammatory phase reaction. During an inflammatory reaction, the sedimentation rate is affected by increasing concentrations of fibrinogen, the main clotting protein, and alpha globulins. The test mainly measures the plasma viscosity by assessing the tendency for red blood cells to aggregate and fall through the variably viscous plasma.The ESR slow response to the acute inflammatory reaction leads to false negatives early in an inflammatory process. Normalization of an elevated erythrocyte sedimentation rate once an immunoglobulin response has occurred may take weeks to months, (Osei- Bimpong et al., 2007). This can explain the ESR result in our study as there was no significant drop in ESR values in the study group, although the drop happened in the other inflammatory marker tested, the C-reactive protein.

exercises; in group 2, sham HILT and stabilization exercises were used; and in group 3, only high-energy laser sessions were performed. The therapeutic program in all groups lasted for 4 weeks. In addition, measurements of the lumbar spine flexion were taken; however, in contrast to our design, a back range- of-motion device, which involves a patented inclinometer, was used. The intergroup comparison showed no significant differences between the placebo group (group 2) and the HILT group (group 3), as well as the advantage of group 1 (com- bining HILT + exercises) over others. Interestingly, similar to our study, significant improvement in tested parameters within groups was noted in early results, and relapse occurred 2 months after the end of the treatment procedure.

In medicine and dentistry, diode lasers have been used predominantly in applications that are broadly termed as LLLT or biostimulation [26], and many studies have evaluated the therapeutic effects of LLLT on a broad range of disorders. LLLT applications, which have been promoted by some authors and manufacturers of the LLLT devices, included the acceleration of wound heal- ing, enhancement of the remodeling and repair of bones, restoration of normal neural function following injury, pain attenuation, and modulation of the immune system [27]. Recently, research on the use of LLLs in dentistry has proceeded gradually, and the range of clinical appli- cations has been extended. The term LLL includes soft lasers, mid-lasers, low-energy lasers, and cold lasers. A new international definition considers LLLT to be laser therapies that do not increase tissue temperature over 36.5 °C or normal body temperature. The wavelength of such lasers is reported to be 500 – 1200 nm. Recent liter- atures regarding pre-osteoblast stimulation with red laser were reported [28 – 31]. We used a Ga – As – Al laser with a wavelength of 808 nm, which is within the prescribed range. It is still unclear as to which of the pa- rameters has the greatest effect on therapeutic efficacy, even though there are information about total energy dose, energy density, and laser spectrum. In this study, the greatest biostimulatory effect was observed when a dose of 3.6 J/cm 2

The application of phototherapy or low-level laser therapy (LLLT) has generated considerable interest within surgery, dentistry, dermatology, somatology, pain management and wound healing. It is a therapeutic method that involves the application of laser light, at a particular wavelength and at low intensities, to the tissue to stimulate biological processes. The choice of wavelength is dependent on the depth of penetration. In some instances, light from light-emitting diodes (LEDs) is used. It is important to understand that the effects of LLLT arise because of chemical and biological changes within a cell, and not because of thermal changes. Photon energy is absorbed by photoacceptors or chromophores within a cell. The main photoacceptor is thought to be the mitochondrion. Research has shown that following laser irradiation, there is an increase in mitochondrial metabolism. 14 This leads to an

Like any other electromagnetic treatment, the primary effects of laser interaction with a biological tissue are divided into thermal and non thermal. LLLT is basically a non thermal energy application. Although delivery and absorption of any energy to the body will produce heat in some extent, non thermal in this context means no accumulative thermal energy occurs or temperature elevation in macroscopic scale is averaged zero. Photobioactivation is a common term for LLLT and indicates stimulating various biological events using light energy without significant temperature changes. There are some other alternative terms such as photobiostimulation and photobiomodulation. When a laser beam, or- a photon, alters the energy level of an atom through shifting between e 2 and e 3 , this event establishes a change in physicochemical cellular function which acts as a trigger agent for beginning a mimicry cascade system. A second photon that will be in phase, propagate in the same direction as the excited photon. This phenomenon, that is called stimulated emission, is the basic of laser light generation. It has been mentioned that in most of the biological tissues, photons are preferably scattered in forward direction.

The two principal design parameters for a semiconductor laser are population inversion and quantum efficiency. For intersubband lasers, the quantum efficiency for a single ac- tive region is generally very low and, in the quantum cascade devices, is magnified by growing a multiple stack of active regions. Some control of the quantum efficiency can be achieved by layer design to optimise the intersubband optical matrix element, but any advantages thus obtained are likely to be dominated by the strong decrease in this matrix ele- ment with decreasing frequency. 4 However the attainment of population inversion, which is dependent on the relative re- population and de-population rates of the participant states, is more amenable to optimisation by adjustments in layer thicknesses and material compositions; this is the focus of the theoretical work described below.

We expected that the effect of laser ir- radiation should be limited to a small area in the vicinity of the irradiation point. Therefore we followed local circu- lation in the flap before and after laser irradiation by means of an LDI system. Neither infusion of NO-Hb alone, nor laser irradiation without NO-Hb infu- sion, did not influence local circulation. Only a combination of NO-Hb infusion and laser irradiation resulted in a re- markable increase of blood flow. We ob- served the main effect of epigastric ar- tery irradiation directly distal to the laser focus. This indicates a targeted and strictly local limited irradiation ef- fect, which can explain the unchanged cGMP levels in systemic circulation. Lo- cally produced cGMP was simply di- luted in systemic blood to undetectable concentrations. Our data suggest that laser irradiation induces the release of NO from nitrosyl complexes of hemo- globin followed by increased perfusion Figure 6. (A) Overview of superficial perfusion of the rodent epigastric area. (B) Control

THz semiconductor lasers Semiconductor device requirements: ¥ Low enough energy level separation for THz photon emission ¥ More electrons at high energy than low energy i.e., a populatio[r]

All the patients reported functional complications dur- ing chewing, brushing and even speaking. The function- al disturbances before and after treatment were de- creased by 8.57±1.50, 7.50±2.19 and 6.00±2.44 in group 1, 2 and 3, respectively. The difference was sig- nificant between groups 1 and 3 (p= 0.012), but statisti- cally no reduction of functional disturbance was ob- served between groups 1 and 2, and also groups 2 and 3. The comparison of the efficacy of the utilized la- sers on the duration of ulcer repair showed no signifi- cant differences in the repair time of the lesions (p> 0.05) between the three groups. The percentages of healed ulcers of all groups on the follow-up days are demonstrated in Table 2. Statistically, the three groups revealed no satisfaction of laser treatment (p> 0.05).

Biophysical and biochemistry studies have shown the biological effects of visible light on cellular function. The laser is a monochromatic, non-aggressive, non- ionizing, and electromagnetic centralized beam (11). Most of the performed studies demonstrated the efficacy of laser on animals, in which it had led to a rapid rate of wound healing and improved epithelial tissue proliferation (12). Significant biological effects caused by non-thermal devices include cell proliferation, collagen synthesis, release of intracellular growth factor from the vessels, activation of cells, stimulation of photoreceptor in mitochondrial respiratory chain, change in cellular ATP or cAMP level, enhancing muscle performance through metabolic photochemical effects, protein synthesis, reduction of fatigue index, tissue repair and tensile strength (11,13,14). Lasers have various types of Helium-Neon (HeNe), Indium, Gallium-Aluminum-Phosphide (InGaAlP), Gallium- Aluminum-Arsenide (GaAlAs), and Gallium-Arsenide (GaAs). The vast majority of therapeutic lasers are semiconductor lasers (15,16).

[Figure 2]. Findings were recorded and assessment done when wound healed completely [Figures 3 and 4]. Clinical history and examination were done at the time of each dressing to look for any adverse effect related to laser therapy. Any pigment changes, itching, erythema or burning of normal skin were considered as adverse effects related to laser therapy.