Article

Pulse irradiation low-power laser stimulates bone nodule formation

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Abstract

Although low-power laser irradiation provides many anabolic effects such as acceleration of bone formation, the effects of different pulse frequencies used during laser irradiation on bone formation have not been elucidated. Osteoblastic cells isolated from fetal rat calvariae were irradiated once with a low-power Ga-Al-As laser (830 nm, 500 mW) in two different irradiation modes; continuous irradiation (CI), and 1 Hz pulsed irradiation (PI). We then investigated the effects on cellular proliferation, bone nodule formation, alkaline phosphatase (ALP) activity, and ALP gene expression. Laser irradiation in both groups significantly stimulated cellular proliferation, bone nodule formation, ALP activity, and ALP gene expression, as compared with the nonirradiation group. Notably, PI markedly stimulated these factors, when compared with the CI group. Since 1 Hz pulsed laser irradiation significantly stimulates bone formation in vitro, it is most likely that pulse frequency is an important factor affecting biological responses in bone formation.

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... Calcification of osteoblasts promoted by diode laser irradiation at 0.4-8.3 J/cm 2 has been demonstrated in several studies [23,26,29,33,35,46,49,50,[52][53][54]56,59,[61][62][63]. Significantly enhanced mineralization in osteoblasts was observed at 7 days at the earliest [23], and in many cases, at around 20 days after irradiation [26,33,35,49,[52][53][54]56,59,63]. ...
... J/cm 2 has been demonstrated in several studies [23,26,29,33,35,46,49,50,[52][53][54]56,59,[61][62][63]. Significantly enhanced mineralization in osteoblasts was observed at 7 days at the earliest [23], and in many cases, at around 20 days after irradiation [26,33,35,49,[52][53][54]56,59,63]. Both single irradiation and multiple irradiations significantly promoted the calcification of osteoblasts. ...
... At 1-14 days after irradiation, mRNA expression of ALP was significantly increased by irradiation at 0.4-6.7 J/cm 2 [26,33,35,39,40,46,54,57]. ALP activity was also significantly enhanced at day 1-18 after irradiation at 1-10 J/cm 2 in a number of studies [17,22,23,26,28,29,37,46,49,52,53,56,62,64]. Meanwhile, a previous study revealed that irradiation at 2 J/cm 2 significantly decreased ALP activity in osteoblasts at 48 and 72 h [34]. ...
Article
Photobiomodulation by low-level laser therapy (LLLT) has favorable biological effects on periodontal tissue. We reviewed basic studies on cytological responses of cells in periodontal tissue to LLLT by diode laser in vitro. Low-level diode laser irradiation has been reported to influence proliferation and gene expression in fibroblasts, as well as epithelial and endothelial cells.
... Calcification of osteoblasts promoted by diode laser irradiation at 0.4-8.3 J/cm 2 has been demonstrated in several studies [23,26,29,33,35,46,49,50,[52][53][54]56,59,[61][62][63]. Significantly enhanced mineralization in osteoblasts was observed at 7 days at the earliest [23], and in many cases, at around 20 days after irradiation [26,33,35,49,[52][53][54]56,59,63]. ...
... J/cm 2 has been demonstrated in several studies [23,26,29,33,35,46,49,50,[52][53][54]56,59,[61][62][63]. Significantly enhanced mineralization in osteoblasts was observed at 7 days at the earliest [23], and in many cases, at around 20 days after irradiation [26,33,35,49,[52][53][54]56,59,63]. Both single irradiation and multiple irradiations significantly promoted the calcification of osteoblasts. ...
... At 1-14 days after irradiation, mRNA expression of ALP was significantly increased by irradiation at 0.4-6.7 J/cm 2 [26,33,35,39,40,46,54,57]. ALP activity was also significantly enhanced at day 1-18 after irradiation at 1-10 J/cm 2 in a number of studies [17,22,23,26,28,29,37,46,49,52,53,56,62,64]. Meanwhile, a previous study revealed that irradiation at 2 J/cm 2 significantly decreased ALP activity in osteoblasts at 48 and 72 h [34]. ...
Article
Full-text available
Periodontal disease is a chronic inflammatory disease caused by periodontal bacteria. Recently, periodontal phototherapy, treatment using various types of lasers, has attracted attention. Photobiomodulation, the biological effect of low-power laser irradiation, has been widely studied. Although many types of lasers are applied in periodontal phototherapy, molecular biological effects of laser irradiation on cells in periodontal tissues are unclear. Here, we have summarized the molecular biological effects of diode, Nd:YAG, Er:YAG, Er,Cr:YSGG, and CO2 lasers irradiation on cells in periodontal tissues. Photobiomodulation by laser irradiation enhanced cell proliferation and calcification in osteoblasts with altering gene expression. Positive effects were observed in fibroblasts on the proliferation, migration, and secretion of chemokines/cytokines. Laser irradiation suppressed gene expression related to inflammation in osteoblasts, fibroblasts, human periodontal ligament cells (hPDLCs), and endothelial cells. Furthermore, recent studies have revealed that laser irradiation affects cell differentiation in hPDLCs and stem cells. Additionally, some studies have also investigated the effects of laser irradiation on endothelial cells, cementoblasts, epithelial cells, osteoclasts, and osteocytes. The appropriate irradiation power was different for each laser apparatus and targeted cells. Thus, through this review, we tried to shed light on basic research that would ultimately lead to clinical application of periodontal phototherapy in the future.
... In two studies exploring the effect of 830 nm laser light applied in the pulsed and CW mode-with everything else being equal-Ueda and Shimizu reported on cell proliferation and bone formation in vitro. 2,3 The biological effect of a frequency of 1 Hz was significantly superior to that of CW 2 and that of 1-2 Hz was significantly superior to that of 8 Hz or CW. 3 Earlier, Miyamoto et al. used moderate levels of 514.5 nm laser light (100 mW$cm -2 , 1-10 J$cm -2 , pulsed at 10 Hz and CW) in combination with a photosensitizer used in photodynamic therapy (PDT) to irradiate HeLa cells. 4 Notably, there was a characteristic difference in the modality of cell death: apoptosis in the pulsed mode and necrosis at CW. ...
... Accounting to the limitations in space I report here only the results of cited articles, results which are relevant for an understanding of the data reported in Refs. [1][2][3] Previously, we used biostimulatory levels of 670 nm laser light, applied in a pulsed mode to irradiate HeLa cells supplemented with anticancer agents. 7 The main result of the study was that a pulse frequency of 1 Hz is instrumental in forcing the cells to uptake the drugs dissolved in the culture medium. ...
... Obviously, R-NIR laser irradiation, applied at such low frequencies is capable to maintain a metabolic effect comprising the uptake of molecules, including nutrients, adjacent to the plasma membrane, thus providing a partial explanation to proliferative effects reported in Refs. 1,2 The findings that with increasing laser pulse frequencies the biological effects are less pronounced 3 could be understood on the basis of the inertia of the aqueous fraction of the cytosol. While it instantly responds to low laser pulse frequencies via expan-sion of its volume, 5 the inertia of the aqueous ensemble in the densely crowded intracellular space opposes a similar effect when the cell is irradiated with higher laser pulse frequencies, where other modalities of interaction come into play. ...
Article
Objective: Several reports claim that the enzyme cytochrome c oxidase (CCO) is the primary absorber for red-to-near-infrared (R-NIR) light in cells and causal for mitochondrial adenosine triphosphate (ATP) upregulation, and that pulsed R-NIR light has frequent therapeutic effects, which are superior to those of the continuous wave (CW) mode used in low-level light therapy (LLLT). Background data: Convincing evidence that the absorption of R-NIR photons by CCO is involved in mitochondrial ATP upregulations as well as a coherent explanation for the superiority of the pulsed irradiation mode is presently lacking in the literature. Methods: A comprehensive literature search and rigorous analysis of the data published on the idea that CCO is the primary absorber for R-NIR light, and of the claim that the effectivity of the pulsed irradiation mode can be derived from the absorption of R-NIR photons by CCO, reveal a number of severe inconsistencies. Results: A systematical analysis covering both the theory that CCO is the primary acceptor for R-NIR light and of its use to interpret differences between the biological effect of pulsed light and CW casts doubt on the general validity of the CCO-based hypothesis. Instead, we are offered a simple and conflict-free model accounting for both ATP upregulation and superiority of the pulsed mode in LLLT, which is in agreement with the results of recent laboratory experiments. Conclusions: CCO is not the primary acceptor for R-NIR light.
... In two studies exploring the effect of 830 nm laser light applied in the pulsed and CW mode-with everything else being equal-Ueda and Shimizu reported on cell proliferation and bone formation in vitro (2,3). The biological effect of a frequency of 1 Hz was significantly superior to that of CW (2) and that of 1-2 Hz was significantly superior to that of 8 Hz or CW (3). ...
... In two studies exploring the effect of 830 nm laser light applied in the pulsed and CW mode-with everything else being equal-Ueda and Shimizu reported on cell proliferation and bone formation in vitro (2,3). The biological effect of a frequency of 1 Hz was significantly superior to that of CW (2) and that of 1-2 Hz was significantly superior to that of 8 Hz or CW (3). Earlier, Miyamoto et al. used moderate levels of 514.5 nm laser light (100 mW/cm 2 , 1-10 J/cm 2 , pulsed at 10 Hz and CW) in combination with a photosensitizer used in photodynamic therapy (PDT) to irradiate HeLa cells (4). ...
... Accounting to the limitations in space I report here only the results of the cited papers, results which are relevant for an understanding of the data reported in refs. (1)(2)(3). ...
... Evidence exists that pulsed light dose has effects that differ from CW [21]. The use of pulsed light is increasing and a review of literature has shown three cellular studies on rat calvarial cells [22][23][24], one in vivo study on the tooth movement speed of rat molars [25], one study on bone turnover in OVX-d rats [26], and one study on healing of partial tibial osteotomy in streptozotocin-induced diabetic rats [27]. ...
... Thus far, the precise roles of PW LLLT in bone remodeling are still not fully understood [21]. In recent years, a number of studies have examined the specific effects and mechanism of action of PW LLLT by using in vivo and in vitro models [22][23][24][25][26][27]. In vitro studies have shown positive effects of 1 Hz pulse frequency and 830 nm on bone nodule formation [22]; 0.48-3.84 ...
... In recent years, a number of studies have examined the specific effects and mechanism of action of PW LLLT by using in vivo and in vitro models [22][23][24][25][26][27]. In vitro studies have shown positive effects of 1 Hz pulse frequency and 830 nm on bone nodule formation [22]; 0.48-3.84 J/cm 2 , 1-8 Hz, and 830 nm on bone nodule formation in rat calvarial cells [24]; and 1.1 and 2.2 J/cm 2 , 6000 Hz, and 650 nm on RANKL and OPG mRNA expression in rat calvarial cells [23]. ...
Article
Full-text available
Osteoporosis (OP) increases vertebral fragility as a result of the biomechanical effects of diminished bone structure and composition. This study has aimed to assess the effects of pulsed wave low-level laser therapy (PW LLLT) on cancellous bone strength of an ovariectomized (OVX-d) experimental rat model and a glucocorticoid-induced OP (GIOP) experimental rat model. There were four OVX-d groups and four dexamethasone-treated groups. A group of healthy rats was used for baseline evaluations. The OVX-d rats were further subdivided into the following groups: control rats with OP, OVX-d rats that received alendronate, OVX-d rats treated with PW LLLT, and OVX-d rats treated with alendronate and PW LLLT. The remaining rats received dexamethasone and were divided into four groups: control, alendronate-treated rats, laser-treated rats, and laser-treated rats with concomitant administration of alendronate. PW LLLT (890 nm, 80 Hz, 0.972 J/cm(2)) was performed on the spinal processes of the T12, L1, L2, and L3 vertebras. We extracted the L1 vertebrae and submitted them to a mechanical compression test. Biomechanical test findings showed positive effects of the PW LLLT and alendronate administration on increasing bending stiffness and maximum force of the osteoporotic bones compared to the healthy group. However, laser treatment of OVA-d rats significantly increased stress high load compared to OVA-d control rats. PW LLLT preserved the cancellous (trabecular) bone of vertebra against the detrimental effects of OV-induced OP on bone strength in rats compared to control OV rats.
... Some investigations have demonstrated that laser irradiation had a positive effect on osteoblasts in vitro. Ueda and Shimizu reported that pulsed wave (PW) laser significantly stimulated cellular proliferation, bone nodule formation, alkaline phosphatase (ALP) activity, and ALP gene expression, compared with a non-irradiation group [12,13]. Sohn et al. report on an investigation on the impact of 635-nm irradiation dose from a light-emitting diode (LED) on osteoclastogenesis in vitro. ...
... This cytokine regulates expression of the nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ) and Runt-related transcription factor 2 (RUNX2) [50]. Laser can promote bone formation and inhibit bone resorption, thus facilitating bone remodeling [12][13][14][15]. However, it was demonstrated that laser significantly decreased IGF-I and BMP-2 in both tested models of OP. ...
Article
Full-text available
The aim of this study was to evaluate the effects of photobiomodulation (PBM) on cancellous bone in rat models of ovariectomized induced osteoporosis (OVX-D) and glucocorticoid-induced osteoporosis (GIOP). The experiment comprised of nine groups. A group of healthy rats was used for baseline evaluations. The OVX-D rats were further divided into groups as follows: control rats with osteoporosis, OVX-D rats that received alendronate (1 mg/kg 60 days), OVX-D rats treated with pulsed wave laser (890 nm, 80 Hz, 900 s, 0.0061 W/cm², 5.5 J/cm², three times a week, 60 days), and OVX-D rats treated with alendronate + pulsed laser. Dexamethasone was administered to the remaining rats that were split into four groups: control, alendronate-treated rats, laser-treated rats, and GIOP rats treated with alendronate + laser. T12, L1, L2, and L3 vertebrae were subjected to laser. Results of the current study demonstrated that OVX-D and GIOP significantly decreased some stereological parameters, and type 1 collagen gene expression compared to the healthy group. There was a significant increase in osteoclast number in both OVX-D and glucocorticoid administration compared to the healthy group. However, the detrimental effect of the OVX-D procedure on bone was more serious than glucocorticoid administration. Results showed that laser alone had a detrimental effect on trabecular bone volume, and cortical bone volume in groups GIOP and OVX-D compared to those in the healthy group. Alendronate significantly improved total vertebral bone volume, trabecular bone volume, and cortical bone volume, in GIOP and OVX-D groups compared to the laser-treated groups. Furthermore, the alendronate + laser in OVX-D rats and GIOP rats produced significantly increased osteoblast number and type 1 collagen gene expression and caused a significant decrease in osteoclast number compared to the controls.
... Oceniano stopień elastyczności tkanek okołostawowych, masę mięśnia brzuchatego łydki i ruchomość badanego stawu. Zaobserwowano również większą poprawę w grupie leczonej wiązką o gęstości mocy 5,8 W/cm2 w porównaniu z grupą, w której zastosowana gęstość mocy wynosiła 3,9 W/cm 2 Eksperymenty Ueda [61] polegające na naświetlaniu osteoblastów wyizolowanych z łydki szczura przy zastosowaniu półprzewodnikowego lasera o mocy 500 mW i długości fali 830 nm wykazały brak różnicy pomiędzy efektami pracy w systemie ciągłym i impulsowym (1 Hz). W obydwu przypadkach stwierdzono przyśpieszenie proliferacji komórek i formowania się kości oraz pobudzenie syntezy fosfatazy alkalicznej. ...
... Powyższe efekty leczenia zaobserwowano w poszczególnych grupach pacjentów: w grupie pacjentów z bólami kręgosłupa u 54% badanych, u których nie stosowano farmakoterapii oraz fizjoterapii , u 97% badanych, u których stosowano niesteroidowe leki przeciwzapalne, przeciwbólo-we, masaż, delikatne techniki mobilizacyjne oraz terapię manualną; w grupie pacjentów z zespołem bolesnego barku u 62% badanych, u których nie stosowano farmakoterapii oraz fizjoterapii, u 82%, po zastosowaniu niesteroidowych leków przeciwzapalnych , przeciwbólowych oraz fizjoterapii; w grupie pacjentów z łokciem tenisisty i golfisty, u 93% bez stosowanej równolegle farmakoterapii i fizjoterapii; w grupie pacjentów z zespołami bólowymi w przebiegu choroby zwyrodnieniowej stawów, u 52% bez stosowanej równolegle farmakoterapii i miejscowych iniekcji dostawowych, u 95% ze stosowaną równolegle farmakoterapią w postaci niesteroidowych leków przeciwzapalnych, przeciwbólowych, w tym również z dostawowymi aplikacjami kortykosteroidów i innymi preparatami oraz fizjoterapią mającą na celu utrzymanie zakresu ruchu w stawach. [61]. ...
Article
Wykorzystanie biostymulacji laserowej i światła VIP w leczeniu chorób narządów ruchu 1 Z Wydziału Medycznego Uniwersytetu Rzeszowskiego, Instytut Fizjoterapii 2 Z Oddziału Rehabilitacji, Szpitala Wojewódzkiego nr 2 w Rzeszowie 3 Z Oddziału Rehabilitacji, Szpitala Powiatowego w Łańcucie Strukturalne i funkcjonalne nieprawidłowości w obrębie narządu ruchu mają znaczący wpływ na sprawność ogólną chorego i jego jakość życia. Ze względu na częstość ich występowania stanowią po-ważny problem zdrowotny i społeczny. Skuteczność leczenia tych chorób mimo wielu różnych stosowanych metod, wymaga dalszych badań i obserwacji klinicznych. W kompleksowym postępowaniu z tymi pacjen-tami istotną rolę odgrywa fizjoterapia. Dane z piśmiennictwa wskazują, że najczęściej stosowanymi meto-dami fizjoterapii w takich przypadkach jest biostymulacja laserowa i terapia światłem VIP. Jako metody łatwo dostępne, nieinwazyjne i bezpieczne dla pacjenta, znajdują także zastosowanie w wielu innych dzie-dzinach medycyny. Celem pracy jest przegląd aktualnego piśmiennictwa dotyczącego możliwości wykorzystania terapii niskoenergetyczną wiązką laserową i światłem VIP stosowanych w leczeniu chorób narządu ruchu. Praca ma również na celu przybliżenie zasad działania omawianych bodźców fizykalnych na poziomie komórko-wym i ogólnoustrojowym oraz zasad dawkowania energii i metodyki wykonania zabiegu. Autorzy po opisie ogólnych właściwości fizycznych i działania biologicznego wiązki laserowej i świa-tła VIP dokonali szczegółowego przeglądu dotychczasowych doniesień naukowych oceniających przydat-ność tych metod. Analizując wyniki badań (baza Medline-EBSCO) można stwierdzić, że fototerapia jest niefarmakologicznym i skutecznym sposobem leczenia chorób narządu ruchu. Dokonany przegląd literatury pozwala sformułować wnioski przemawiające za pozytywnym oddziaływa-niem tego rodzaju terapii także w leczeniu takich przypadków, w których inne czynniki fizyczne są przeciw-wskazane lub nieskuteczne. Wiązkę laserową i światło VIP często wykorzystuje się równolegle z innymi czyn-nikami fizykalnymi. Takie skojarzenie kilku metod daje niejednokrotnie lepsze efekty lecznicze. Wiele jest publikacji wskazujących na celowość stosowania omawianych bodźców fizykalnych w re-habilitacji chorób narządu ruchu, jednak ciągle niewystarczająca jest liczba informacji potwierdzonych badaniami naukowymi. Widoczny jest również brak jednoznacznych zaleceń w zakresie metodyki i daw-kowania zabiegów światłoleczniczych, co pozwoliłoby uzyskać możliwie najwyższą skuteczność terapii. Słowa kluczowe: światło spolaryzowane, laser, biostymulacja, schorzenia narządu ruchu Use of laser biostymulation and the VIP light in treatment of motor system Structural and functional impairments in motor function have huge impact on patient's quality of life. This is serious health and social problem. During holistic treatment of patients the physical therapy is substantial method. Literature data indicates that concerning typical motor impairments, laser biostimula-tion and low energy polarized light (VIP) are most popular methods. This treatment is easy to apply, non-invasive and safe for patient.
... Naukowcy dokonując przeglądów dotychczasowych badań dotyczących zastosowań LLLT w leczeniu różnorakich schorzeń wnioskują o prowadzenie eksperymentów w ujednolicony sposób pozwalający na jednoznaczną, systematyczną ocenę i powtarzalność procedur zabiegowych [47,62,92,94]. Wysuwane są zastrzeżenia do twórców raportów w odniesieniu do braku zestawienia podstawowych parametrów zabiegu [2,46,47,62,72,73,88,[100][101][102][103][104]: długości fali promieniowania i mocy źródła, czasu ekspozycji i obszaru oddziaływania, rozmiaru wiązki na naświetlanym obiekcie, zaaplikowanej dawki energii na jednostkę powierzchni i irradiancji, trybu pracy -reżim ciągły czy impulsowy (jeśli emisja impulsowa to częstość repetycji oraz czas trwania i wypełnienie impulsu), tętna, anatomicznej lokalizacji, harmonogramu naświetlań -ilości zabiegów i przerw między ekspozycjami promieniowaniem. Dokładniejsze raporty powinny natomiast obejmować [47,62,[105][106][107][108]: ...
... W zakresie fizycznych parametrów promieniowania wymagane jest określenie parametrów spektralnych, energetycznych, czasowych wiązki światła, ale również stopnia jej spójności i stanu polaryzacji w polu oddziaływania. Do podstawowych wielkości eksperymentu, których znajomość staje się niezbędna do obiektywnego porównania efektów zabiegów należy zaliczyć: długość fali promieniowania, irradiancję spektralną i jej rozkład na próbce, moc optyczną promieniowania źródła -średnią i szczytową, irradiancję i jej rozkład na próbce[100,101], obszar i czas oddziaływania, zastosowaną powierzchniową dawkę energii[2,46,88,[102][103][104], stan polaryzacji wiązki[105], długość drogi spójności[106][107][108], tryb pracy -reżim ciągły czy impulsowy, częstotliwość repetycji i wypełnienie w przypadku ekspozycji impulsowej[72,73].W zakresie materiału biologicznego spełnienie powtarzalności eksperymentu uzyskuje się poprzez badania na liniach komórkowych hodowanych i naświetlanych w ustandaryzowanych warunkach. Próbki takie nie wykazują osobniczej zmienności cech.Do dalszego rozwoju LLLT niezbędne jest w pierwszej kolejności pełne poznanie procesów komórkowych zachodzących podczas ekspozycji promieniowaniem optycznym, weryfikacja i standaryzacja procedur naświetlania, oraz opracowanie spójnego opisu Następnym krokiem powinno być odniesienie wyników do większych struktur biologicznych -tkanek, organów i całego organizmu. ...
Thesis
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Rozprawa doktorska METODA l URZĄDZENIE DO WYZNACZANIA WYBRANYCH PARAMETRÓW OPTYCZNYCH TKANEK PODDANYCH ZABIEGOWI BIOSTYMULACJI LASEROWEJ poświęcona jest problematyce niskoenergetycznego oddziaływania promieniowania optycznego z zakresu spektralnego okna optycznego transmisji tkanek (600-1000) nm na ośrodki biologiczne, czyli procedurom Low Level Light Therapy. Motywacją podjęcia badań były zauważone w dostępnej literaturze przedmiotu niejednoznaczności dotyczące wyników badań odpowiedzi biologicznych komórek, tkanek i narządów powodowanych przez przeprowadzone naświetlania promieniowaniem laserowym o niskiej mocy. Występuje wiele nawzajem wykluczających się konkluzji odnośnie skuteczności danego źródła i parametrów promieniowania bądź metody realizacji zabiegu terapeutycznego. W związku z brakiem narzędzi do standaryzacji badań wpływu parametrów spektralnych i energetycznych promieniowania optycznego na wybrane procesy fizjologiczne komórek przyjęto podstawowe cele dysertacji: Zaprojektowanie, wykonanie i przetestowanie układu do obiektywnej weryfikacji parametrów spektralnych i energetycznych wiązki promieniowania istotnych dla realizowanego zabiegu, odpowiadających za efekty biostymulacyjne. Opracowanie metody i układu pomiarowego realizującego pomiar widma absorpcji ośrodka biologicznego, a także widma odbicia ośrodka w trakcie trwania zabiegu biostymulacji światłem. W wyniku realizacji rozprawy powstał optoelektroniczny układ diagnostyczny pozwalający na naświetlanie ośrodka promieniowaniem elektromagnetycznym (laserowym lub diod LED) z zakresu okna transmisji tkanek (600-1000) nm o w pełni weryfikowalnych parametrach radiometrycznych (w tym widmowych): długość fali promieniowania, moc optyczna promieniowania źródła, irradiancja i jej rozkład na próbce, irradiancja spektralna i jej rozkład na próbce, obszar oddziaływania, powierzchniowa doza energii. Układ umożliwia również pomiar parametrów optycznych próbki (widma absorpcji lub odbicia) w trakcie zabiegu w celu selekcji odpowiedniego emitera dla danej aplikacji. Pochłonięta energia fotonów umożliwia indukowanie zmian w tkankach oraz może pełnić rolę katalizatora reakcji biochemicznych. Do najważniejszych i oryginalnych osiągnięć niniejszej rozprawy doktorskiej należy zaliczyć: Opracowanie i zestawienie układu oświetlacza laserowego z wyselekcjonowanego zestawu laserów półprzewodnikowych średniej mocy zapewniającego możliwość dostrojenia długości fali źródła do pasm absorpcyjnych chromoforów istotnych dla procedur LLLT. Układ zapewnia możliwość strojenia długości fali w całym zakresie spektralnym (625-990) nm - oknie optycznym tkanek. Opracowanie i zestawienie układu szerokopasmowego oświetlacza LED-owego emitującego w zakresie spektralnym (620-980) nm jednorodny rozkład spektralnej gęstości mocy - będącego źródłem dla pomiarów parametrów widmowych ośrodka biologicznego. Do układu wyselekcjonowano zestaw diod LED dużej mocy. Opracowanie i zestawienie układu aplikatora zapewniającego obiektywizację naświetlań LLLT: równomierny rozkład irradiancji i irradiancji spektralnej w polu oddziaływania z ośrodkiem poddanym oddziaływaniu oraz zwiększającego skuteczność dozowania energii promieniowania eksponowanym liniom komórkowym. Opracowanie i zestawienie układów sprzęgaczy optycznych dla promieniowania oświetlaczy: laserowego (zwiększającego kąt rozbieżności wiązki) i LED-owego, celem wprowadzenia promieniowania do komory pomiarowej. Opracowanie i weryfikacja metod analizy spektralnej promieniowania zaabsorbowanego bądź odbitego od biologicznego ośrodka. Weryfikacja opracowanych układów do obiektywizacji procedur biostymulacyjnych na liniach komórkowych - przeprowadzono szereg badań doświadczalnych na liniach komórek śródbłonka naczyniowego pobranych z krwi pępowinowej - HUVEC. Eksperymentalna weryfikacja wpływu parametrów energetycznych i spektralnych wiązki promieniowania stosowanej w procedurach biostymulacyjnych na odpowiedź biologiczną linii komórkowych HUVEC. Uzyskano mierzalne zmiany parametrów komórkowych wiążące odpowiedź biologiczną komórek (proliferację komórek oraz ekspresję genów czynnika wzrostu) z parametrami fizycznymi zabiegu. Wyniki pracy stanowić mogą punkt wyjścia do dalszych prac badawczych konfrontujących wpływ parametrów promieniowania na odpowiedź biologiczną komórek i być może rozwiązania zagadnienia jak przebiegają szlaki sygnalizacyjne w komórkach i wybór najistotniejszego z nich oraz dobór najefektywniejszego źródła promieniowania optycznego dla danej aplikacji biostymulacyjnej. Opracowany układ może też posłużyć do weryfikacji problemu wpływu stanu polaryzacji wiązki promieniowania, stosowanej w procedurach biostymulacyjnych na skuteczność zabiegów. PhD thesis METHOD AND DEVICE FOR DETERMINING SELECTED OPTICAL PARAMETERS OF TISSUES IN LASER BIOSTIMULATION THERAPY is devoted to the problems of Low Level Light Therapy procedures. Low Level Light Therapy uses low-power optical radiation correlated with tissue optical window spectral range (600-1000) nm to effect on biological media. The ambiguities of biological responses results of cells, tissues and organs as consequence of low-power irradiation found in available literature were the motivation to take the study. There are many other conflicting conclusions on the effectiveness of the radiation source, radiation parameters or realization methods of therapeutic treatment. Due to the lack of tools to standardize the investigations the effect of spectral and energy parameters of optical radiation to the selected physiological processes in cells were adopted the basic aims of the dissertation: - to design, implement and test the set for objective verification of spectral and energy parameters of radiation beam relevant for the realized procedure – responsible for biostimulation effects. - to develop the method and the measurement system realizing measurement of the absorption spectrum of the biological medium, as well as reflection spectrum of the biological center during light biostimulation procedure. As a result of the thesis realization optoelectronic diagnostic set was made. It allows to irradiate medium with electromagnetic radiation (laser or LED) in the range of tissue transmission window (600-1000) nm with fully verifiable radiometric and spectral parameters: radiation wavelength, optical power of the radiation source, irradiance and its distribution on the sample surface, spectral irradiance and its distribution on the sample surface, area of irradiation, surface energy dose. The set also enables the measurement of optical parameters of the sample (absorption or reflection spectra) during procedure in order to select the appropriate emitter for the application. Absorbed photon energy enables to induce changes in the biological tissues and can act as a catalyst for biochemical reactions. The most important and original achievements of the present PhD thesis are: - Developing and building the laser illuminator from selected set of medium-power semiconductor lasers providing the ability to tune the wavelength of the source to the chromospheres absorption bands relevant to the LLLT procedures. The set provides the ability to tune wavelength in the entire spectral range (625-990) nm – tissue optical window. - Developing and building the broadband LED illuminator emitting homogeneous distribution of spectral power density in the spectral range (620-980) nm – it is the source for the measurement of spectral parameters of the biological medium. High power LEDs were selected to the set. - Developing and building the applicator providing the objectification of LLLT irradiation: uniform distribution of irradiance and spectral irradiance in the irradiation area with the medium subjected to irradiation and increasing the effectiveness of application of radiation energy to exposed cell lines. - Developing and building optical couplers systems for illuminators radiation: laser illuminator (which increasing beam divergence angle) and LED illuminator in order to introduce radiation into the measuring chamber. - Developing and verifying methods of spectral analysis of absorbed and reflected radiation from the biological medium. - Verifying the system developed for objective biostimulation procedures on cell lines – a series of experiments were carried out on the series of vascular endothelial cells lines taken from umbilical cord blood – HUVEC. - Analyzing the problem of the effect of energy and spectral parameters of the radiation beam used in the biostimulation procedures on the biological response of HUVEC cell lines. Measurable cellular effects binding a biological response of cells (cell proliferation and growth factor gene expression) with procedure parameters were obtained. The results of the thesis can be the starting point for further research confronting the effect of different parameters of radiation on the biological cells response. Perhaps it resolves issues as signaling pathways run in the cells and choice the most important of them. Then could be selection the most efficient source of optical radiation for a given application of biostimulation. The developed set can also be used to verify the problem of the effect of polarization state of the radiation beam used in the biostimulation procedures on the effectiveness of treatments. Results and solutions of semispherical applicator may also be used for other (non-biological) studies. For example, to measurements of luminescence, there the important problem is the optical excitation efficiency of the tested elements and systems.
... The data proves that pulsed wave (PW) light has different effects than CW light in an experimental environment (18). The use of pulsed light is becoming more popular, and the literature includes three cellular studies on rat calvarial cells (19)(20)(21). The first in vivo study was on tooth movement acceleration in rat molars (22), the second in vivo study was on bone turnover in ovariectomized rats (23), and a final report was conducted on the healing of partial tibial osteotomy in streptozotocin-induced diabetic rats (24). ...
... In this circumstance, pulsed light can be of benefit. Although CW LLLT causes the increase in temperature at the site of target tissues, PW LLLT has not caused a measurable change in the temperature of the irradiated area for the same delivered energy density (19). In this regard, Ilic et al. (40) have shown that pulsed light with peak power densities of 750 mW/cm 2 administered for 120 seconds produced no neurological or tissue damage, whereas the same power density delivered by CW (for the same number of seconds) caused neurological deficits. ...
Article
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Background: Fractures pose a major worldwide challenge to public health, causing tremendous disability for the society and families. According to recent studies, many in vivo and in vitro experiments have shown the positive effects of PW LLLT on osseous tissue. Objectives: The aim of this study was to evaluate the outcome of infrared pulsed wave low-level laser therapy (PW LLLT) on the fracture healing process in a complete tibial osteotomy in a rat model, which was stabilized by an intramedullary pin. Materials and methods: This experimental study was conducted at Shahid Beheshti University of Medical Sciences in Tehran, Iran. We performed complete tibial osteotomies in the right tibias for the population of 15 female rats. The rats were divided randomly into three different groups: I) Control rats with untreated bone defects; II) Rats irradiated by a 0.972 J/cm(2) PW LLLT; and III) Rats irradiated by a 1.5 J/cm(2) PW LLLT. The right tibias were collected six weeks following the surgery and a three-point bending test was performed to gather results. Immediately after biomechanical examination, the fractured bones were prepared for histological examinations. Slides were examined using stereological method. Results: PW LLLT significantly caused an increase in maximum force (N) of biomechanical repair properties for osteotomized tibias in the first and second laser groups (30.0 ± 15.9 and 32.4 ± 13.8 respectively) compared to the control group (8.6 ± 4.5) LSD test, P = 0.019, P = 0.011 respectively). There was a significant increase in the osteoblast count of the first and second laser groups (0.53 ± 0.06, 0.41 ± 0.06 respectively) compared to control group (0.31 ± 0.04) (LSD test, P = 0001, P = 0.007 respectively). Conclusions: This study confirmed the efficacy of PW LLLT on biomechanical strength, trabecular bone volume, callus volume, and osteoblast number of repairing callus in a complete tibial osteotomy animal model at a relatively late stage of the bone healing process.
... 4,5 Various biostimulatory effects of LIL have been reported with regard to wound healing and collagen synthesis via in vitro and in vivo studies. 6 With respect to the bone, LIL has been shown to modulate inflammation, accelerate cell proliferation, 7 and enhance healing. 7,8 Distraction osteogenesis (DO) elongates bones by creating gaps and filling them with newly formed bone without the need for soft or hard tissue grafting. ...
... 6 With respect to the bone, LIL has been shown to modulate inflammation, accelerate cell proliferation, 7 and enhance healing. 7,8 Distraction osteogenesis (DO) elongates bones by creating gaps and filling them with newly formed bone without the need for soft or hard tissue grafting. [9][10][11][12] Early treatment of patients with oral and/or craniofacial anomalies using orthodontic and maxillary orthopedic therapy and DO is recommended when the patient is a child or an adolescent. ...
Article
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Objective: To assess the effects of low-level laser irradiation vs ultrasound irradiation on bone healing after distraction osteogenesis. Materials and methods: Distraction osteogenesis was performed with rapid maxillary expansion devices (Hyrax-Morelli, Sorocaba, São Paulo Brazil) in 24 rabbits (Oryctolagus cuniculus). After a 2-day latency period, the distraction devices were activated for 10 days at a rate of 1 mm/d. Four groups of six animals were treated as follows: (1) control, (2) laser irradiation on the right side, (3) ultrasound irradiation on the right side, and (4) laser irradiation on the right side and ultrasound on the left side. Histomorphometric analysis was used to assess the bone healing area. Analysis of variance was used to perform the statistical analyses. Results: The influence of low-intensity laser associated with ultrasound irradiation on bone healing was statistically significant. The analyses showed the greatest amount of bone healing in the jaws of animals in group 4, which received treatment with both ultrasound and laser. Conclusion: This study concluded that bone healing is accelerated with the application of laser irradiation. The greatest effects were observed with combined ultrasound and laser treatment.
... 4,5 Various biostimulatory effects of LIL have been reported with regard to wound healing and collagen synthesis via in vitro and in vivo studies. 6 With respect to the bone, LIL has been shown to modulate inflammation, accelerate cell proliferation, 7 and enhance healing. 7,8 Distraction osteogenesis (DO) elongates bones by creating gaps and filling them with newly formed bone without the need for soft or hard tissue grafting. ...
... 6 With respect to the bone, LIL has been shown to modulate inflammation, accelerate cell proliferation, 7 and enhance healing. 7,8 Distraction osteogenesis (DO) elongates bones by creating gaps and filling them with newly formed bone without the need for soft or hard tissue grafting. [9][10][11][12] Early treatment of patients with oral and/or craniofacial anomalies using orthodontic and maxillary orthopedic therapy and DO is recommended when the patient is a child or an adolescent. ...
Article
Full-text available
Objective: To compare the pattern and amount of stress and displacement during maxillary sagittal distraction osteogenesis (DO) between a patient with unilateral cleft lip and palate (UCLP) and a noncleft patient. Materials and methods: Three-dimensional finite element models for both skulls were constructed. Displacements of the surface landmarks and stress distributions in the circummaxillary sutures were analyzed after an anterior displacement of 6 mm was loaded to the elements where the inferior plates of the distractor were assumed to be fixed and were below the Le Fort I osteotomy line. Results: In sagittal plane, more forward movement was found on the noncleft side in the UCLP model (-6.401 mm on cleft side and -6.651 mm on noncleft side for the central incisor region). However, similar amounts of forward movement were seen in the control model. In the vertical plane, a clockwise rotation occurred in the UCLP model, whereas a counterclockwise rotation was seen in the control model. The mathematical UCLP model also showed higher stress values on the sutura nasomaxillaris, frontonasalis, and zygomatiomaxillaris on the cleft side than on the normal side. Conclusions: Not only did the sagittal distraction forces produce advancement forces at the intermaxillary sutures, but more stress was also present on the sutura nasomaxillaris, sutura frontonasalis, and sutura zygomaticomaxillaris on the cleft side than on the noncleft side.
... Irradiation of primary rat calvaria cells using a low-power Ga-Al-As laser at 1.1 J/cm 2 has been shown to increase OPG gene expression significantly. 27 Nd: YAG laser irradiation of human osteoblast-like cells was also found to increase OPG gene expression in another previous study. 28 In the present study, similar results were obtained using an Er: YAG laser. ...
Article
Introduction: A variety of laser treatments have been applied in numerous medical fields. In dentistry, laser treatments are used for caries, root canals, and periodontal disease, as well as surgical resection. Numerous reports have recently been published on the use of lasers for bone regeneration. If laser irradiation is found to promote the activation of bone metabolism, it might also be effective for periodontal treatment, peri implantitis, and bone regeneration. Therefore, the present in vitro study aimed to elucidate the mechanisms underlying the effects of erbium-doped yttrium aluminum garnet (Er: YAG) laser irradiation on the bone using osteoblast-like cells. Methods: Osteoblast-like Saos 2 cells (5.0×104 cells) were seeded in 24-well plates. 24 hours after being seeded, the cells were subjected to 0.3 W, 0.6 W, and 2.0 W Er: YAG laser irradiation and then allowed to recover for 48 hours. The expression levels of bone metabolism-related factors alkaline phosphatase (ALP), bone sialoprotein (BSP), and osteoprotegerin (OPG) were then evaluated using reverse transcription–quantitative polymerase chain reaction and western blot analyses. Results: Saos 2 cells subjected to Er: YAG laser irradiation at 0.3 W, 0.6 W, and 2.0 W showed normal growth. When the Er: YAG laser irradiation and control groups were compared after 48 hours, increases were observed in ALP, BSP, and OPG gene and protein expression in the 2.0 W group. Similar results were obtained in the western blot analysis. Conclusion: These findings suggest that the Er: YAG laser irradiation of osteoblast-like cells is effective for activating bone metabolism factors.
... Moreover, it was concluded that the cellular proliferation of periodontal ligament cells, and mineralized bone formation were accelerated by using diode laser irradiation during orthodontic tooth movement in rats (18). Additionally, it was reported that it has a great role in increased production of type I collagen (19). ...
Article
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Aggressive periodontitis is a severe form of periodontal disease characterized by rapid and severe periodontal tissue destruction around the onset of puperty. Low level laser treatment (LLLT) and demineralized bone matrix putty (DBM) are known to be effective in periodontal regeneration. The study aimed to clinically and radiographically evaluate the effect of DBM alone versus a combination of both (LLLT and DBM) in treatment of intrabony defects in cases of localized aggressive periodontitis (LAP). Methods: 20 defects were divided into two groups. 10 defects were treated with open flap debridement then, DBM application while, the other 10 defects were treated with DBM and LLLT after open flap debridement. Clinical parameters including pocket depth, clinical attachment level, with assessment of hard tissue parameters (bone density and percentage of alveolar bone level) using direct digital radiography. Evaluation of changes in all these parameters were recorded before and six months post treatment. Results: Patients treated with DBM and LLLT showed a statistically significant improvement in all tested parameters, when compared to the other treatment modality. Conclusion: Within the limitation of this study, it could be concluded that combining LLLT and DBM showed significant reduction in PD, gain in CAL, increase in BD with better improvement in ABL%, when compared to DBM alone in treatment of intrabony defects in localized aggressive periodontitis patients.
... The positive effect of photobiomodulation on tooth movement was reinforced in the relevant literature [3,12], but their relationship with tooth root resorption is still a new issue. The biological basis of acceleration of orthodontic tooth movement using this method involves the growth of fibroblasts and collagen fibers, regeneration of blood vessels, and the stimulation of neuronal growth [24]. The absorption of LED and laser photons by the cytochrome-C enzyme increases the synthesis of adenosine triphosphate (ATP). ...
Article
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Objectives The aim of this study is to investigate the effect of photobiomodulation therapies on root resorption compared with the placebo group. Materials and methods Thirty patients who were admitted to the Gaziantep University Faculty of Dentistry Orthodontics Department for treatment, with an indication of upper right first premolar tooth extraction were included. Before the individuals’ orthodontic treatment, 0.022 slot MBT brackets and tubes were placed on the maxillary first premolar and molar. A 150-g buccal tipping force was applied to the first premolar. Cantilever spring with 0.017 × 0.025 Beta Titanium wire was used for force application. Individuals were then randomly divided into three groups. For the first group, laser application was performed with an 810-nm GaAlAs laser device at 0, 3, 7, 14, 21, and 28 days to 8 J/cm². For the second group, an LED application according to the manufacturer’s instructions with an 850-nm wavelength and 20 mW/cm² output power for 10 min per day during the experiment. For the third group, a placebo therapy was completed whereby a laser device that did not make active pulses was used. At the end of 4 weeks, the amount of root surface resorption was compared using micro-CT imaging after the extraction of the teeth. Results No significant difference was found between the groups in terms of regional and total crater volumes. It was observed that photobiomodulation therapies were not different from the control group in terms of forming root resorption. Conclusions It is seen that laser and LED photobiomodulation therapies used for accelerate orthodontic tooth movement do not differ from the control group in terms of forming root resorption. Clinical relevance According to the results of this pilot study on this subject, which needs to be clarified with new findings in the future, LED and laser applications may not increase the risk for root resorption.
... Laser therapy was given for 3days then 1 day rest and continued as the same system for three weeks in which 15 min. per day for each session [9] . The dose was measured in joules, and means that a certain amount of energy per cm 2 ...
Research
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The objective of this study was to evaluate the effects of platelet rich plasma and low level laser therapy (diode laser) on the healing of proximal sesamoid bone fracture. Twelve healthy adult donkeys were used during the period from June 2015 to August 2017. Animals were divided into three equal groups: First group was used as control, second was treated by platelet rich plasma and third group was treated by diode laser. All animals were exposed experimentally to transverse mid body fracture of proximal sesamoid bone, in first group the bone fixed internally by screw and followed by external fixation with Plaster of Paris under general anesthesia, the second and third groups were exposed to similar surgical procedure except in second group injected of autologous platelet rich plasma in the fracture site, and the third group exposed to serial session of low level laser. All experimental animals were in a good health postoperatively, except hyper granulation tissue at the site of surgical incision was observed in one animal of the first group and another in the second group exhibited superficial exudate at the site of operation. At 60 post-operative days, the x-rays of the fracture line show a slight visible fracture line, new bone formation with still visible fracture line and denser fracture line, in first, second and third groups respectively. At 90 post-operative days, in three groups, they showed invisible fracture line, but with superior of third group in compared with first and second groups.
... During the last decade, it was discovered that low-power laser irradiation had stimulatory effects on bone tissue, in the microscopic cell proliferation (Barushka et al., 1995, Ueda andShimizu, 2001), gene expression (Tamura et al., 1998) and macroscopic (Shlomi et al., 2001) biological systems. Both irradiated groups significantly stimulated cellular proliferation, bone nodule formation, ALP activity and ALP gene expression, compared to their control counterparts. ...
Thesis
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Abstract The objectives of this study were to evaluate the effects of platelet rich plasma and low level laser therapy on the proximal sesamoid bone fracture healing. Eighteen healthy adult donkeys were used in this study which was divided into three equal groups, control group, platelet rich plasma group and low level laser group. Each group was divided into two equal subgroups depending on postoperative follow up which included; macroscopic, radiological examination each two weeks and the histopathological examination at one month and three months post operation. In all animals of the study, a transverse mid-fracture of proximal sesamoid bone was made under general anesthesia. The operations were made under the effect of acepromazine (0.05mg/kg B.W/IV), and a 7% of chloral hydrate was injected intravenously. Lag full-thread screw was used to approximate the two fragments of bone. In addition to that plaster of Paris with window was used to cover the carpal joint and extended distally including the hoof to support the internal fixation. In the platelet rich plasma group autologous of platelet rich plasma was prepared before operation and injected at fracture site after fixation. While, in the laser group, diode laser at serial sessions (1 session (15 min) for 3 days /animal and resting one day then repeated sessions as the same manner for 21 days post operation. The results of clinical examination revealed that all experimental animals were healthy postoperatively except one animal in the control group was suffering from hyper granulation tissue and one animal in platelet rich plasma group exhibited superficial exudates at the surgical site. In control group the macroscopic observation showed that the fracture line was filled with tissue in one month and covered with hard tissue at three months postoperative. But in platelet rich plasma group was obliterated especially at three months postoperative, while in laser group, the fracture line was disappeared, three months post operation. Radiographical findings of the control group revealed visible fracture line at 15 days and slightly visible at 30 days postoperative, while very slight visible at 60 days. After 90 days post operation the fracture line was invisible. In the laser group, new bone formation was started after 30 postoperative days and the fracture line was disappeared faster than the control and platelet rich plasma groups. Result of histopathological examination showed a granulation tissue infiltrated with inflammatory cells in the control group which continued up to three months postoperative, but less inflammatory cells and granulation tissue were in the platelet rich plasma group. While in laser group there was small amount of granulation tissue after three months. Conversion of trabecular bone into compact bone was seen at three months post operation in the control group, while lamellar bone and thickened compact bone formation were seen in platelet rich plasma group and compact bone with large haversian canal filled the fracture gap in laser group. In conclusions, this study exhibited that the laser group and platelet rich plasma group enhanced the proximal sesamoid bones fracture healing with superiority of laser group.
... Laser therapy was given for 3days then 1 day rest and continued as the same system for three weeks in which 15 min. per day for each session [9] . The dose was measured in joules, and means that a certain amount of energy per cm 2 ...
Article
Full-text available
The objective of this study was to evaluate the effects of platelet rich plasma and low level laser therapy (diode laser) on the healing of proximal sesamoid bone fracture. Twelve healthy adult donkeys were used during the period from June 2015 to August 2017. Animals were divided into three equal groups: First group was used as control, second was treated by platelet rich plasma and third group was treated by diode laser. All animals were exposed experimentally to transverse mid body fracture of proximal sesamoid bone, in first group the bone fixed internally by screw and followed by external fixation with Plaster of Paris under general anesthesia, the second and third groups were exposed to similar surgical procedure except in second group injected of autologous platelet rich plasma in the fracture site, and the third group exposed to serial session of low level laser. All experimental animals were in a good health postoperatively, except hyper granulation tissue at the site of surgical incision was observed in one animal of the first group and another in the second group exhibited superficial exudate at the site of operation. At 60 post-operative days, the x-rays of the fracture line show a slight visible fracture line, new bone formation with still visible fracture line and denser fracture line, in first, second and third groups respectively. At 90 post-operative days, in three groups, they showed invisible fracture line, but with superior of third group in compared with first and second groups.
... Several of these studies did not describe the levels of laser energy used to stimulate stimulatory effects or the exposure parameters. This caused controversy when determining whether or not these lasers influence healing effect [16,17]. ...
Article
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AIM The aim of the study was to evaluate the effect of Low-Level Laser Therapy (LLLT) on bone formation in cystic defects following cyst enucleation. PATIENTS AND METHODS The sample was composed of sixteen patients with enucleated maxillary bony cystic lesions. With an age range from 20 - 44 grouped as eight Laser and eight Control patients. Laser group was subjected to low intensity diode laser immediately after surgery and then for three times per week for two weeks using a therapeutic laser irradiation. Group B (control group): patients were not subjected laser therapy. RESULTS The predictor variable was exposure of bone defect to LLLT or none. The outcome variable was bone density changes measured by digital radiographs at day 1 and days 90 postoperatively. Descriptive and bivariate statistics were computed. There were no statistically significant differences between the 2 groups for the bone density at day 1. There was a statistically significant difference in bone density changes in each group at day 90: Significant at P ≤ 0.05. After adjusting for differences in day 1 for bone density, the estimated mean change in bone density changes at day 90 was significantly larger for Laser compared with control. CONCLUSION The results of this study suggested that LLLT can enhance bone healing in maxillary cystic defects. This can serve as an adjunct method in preventing possible delayed healing and pathological fractures This also will be helpful for more researchers in early loading in case of dental implants to accelerate osseointegration.
... Also, McCullen et al. studied the effect of sinusoidal alternating current electric fields on ASCs and demonstrated significant increase in intracellular calcium [189]. Other modalities are currently being investigated including magnetic fields [190,191], ultrasound [192,193], and laser irradiation [194,195]. All these mechanical stimuli BioMed Research International 9 provide practical and promising methods to accelerate and facilitate the differentiation and proliferation of MSCs into osteogenic lineage cells that would be extremely significant in bone regeneration and tissue engineering. ...
Article
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Bone is one of the most dynamic tissues in the human body that can heal following injury without leaving a scar. However, in instances of extensive bone loss, this intrinsic capacity of bone to heal may not be sufficient and external intervention becomes necessary. Several techniques are available to address this problem, including autogenous bone grafts and allografts. However, all these techniques have their own limitations. An alternative method is the technique of distraction osteogenesis, where gradual and controlled distraction of two bony segments after osteotomy leads to induction of new bone formation. Although distraction osteogenesis usually gives satisfactory results, its major limitation is the prolonged duration of time required before the external fixator is removed, which may lead to numerous complications. Numerous methods to accelerate bone formation in the context of distraction osteogenesis have been reported. A viable alternative to autogenous bone grafts for a source of osteogenic cells is mesenchymal stem cells from bone marrow. However, there are certain problems with bone marrow aspirate. Hence, scientists have investigated other sources for mesenchymal stem cells, specifically adipose tissue, which has been shown to be an excellent source of mesenchymal stem cells. In this paper, the potential use of adipose stem cells to stimulate bone formation is discussed.
... The purpose for proper experiment in the field of photobiology is both: a full characterization the source of electromagnetic radiation allows for accurate reproduction of the carried out experiments, as well as perform investigations on identical biological material under specified conditions. Define the basic quantity becomes necessary for objective comparison of treatments: the wavelength of radiation, the spectral distribution of radiation, the optical power -average and peak, the spectral and surface power density (Lanzafame et al. 2007), the distribution of surface power density (its inequality), the work area and duration of exposure, the dose of used energy (Huang et al. 2009(Huang et al. , 2011, the polarization state of the beam (Karu et al. 2008), the coherence length (Bertoloni et al. 1993), the operation mode -continuous or pulse regime, repetition rate and fill factor of pulse (Ueda and Shimizu 2001). Fulfilling the repeatability of the experiment for the biological material is obtained by investigating the cell lines in standardized conditions. ...
Conference Paper
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In the paper is presented optoelectronic set for controlled, repeatable irradiation of cell lines by low-energy laser and LEDs radiation from the spectral range of tissue transmission window (from 600 nm to 1000 nm). The set allows for an objective selection and control of exposure parameters, allowing a comparison of the results for the variable spectral and energetic parameters of radiation. Using the set it is possible to make an objective diagnosis of the biological medium during the Low Level Light (Laser or LED) Therapy treatment by measuring its absorption spectrum.
... Many processes that have been shown to be stimulated by low-level laser therapy (LLLT) are cell proliferation, 8,9 collagen and protein syntheses, 10 wound healing, 11-13 differentiation of bone and cartilage cells, 14,15 and cell regeneration. 16 LLLT speeds up the blood flow, improves the mechanism of the revitalization processes, reduces the risk of infection, boosts the metabolic activities, and accelerates the healing of the damaged tissue. ...
Article
Objective: The purpose of this study was to evaluate the effects of different laser dose and force levels on the stability of orthodontic mini screws used for anchorage, by histomorphometric analyses. Background data: Low-level laser therapy speeds up blood flow, improves the mechanism of the revitalization processes, reduces the risk of infection, boosts metabolic activities, and accelerates the healing of the damaged tissue. Although there are many research studies about low-level laser therapy applications in a variety of areas, no investigations were found concerning mini screw stability using various laser dose levels with different force level applications. Methods: Seventeen New Zealand white rabbits were used. A total of 68 cylindrical, self-drilling orthodontic mini screws were threaded at the fibula. Experimental subjects were divided into six groups; force application was not performed in the first three groups, whereas 150 g of force was applied via nickel-titanium closed-coil springs placed between two mini screws in the other three groups. Measurements of the initial torque values (10 Ncm) were manipulated by a digital portable torque gauge. Various low-level laser doses were applied to the groups during the postoperative 10 days. After 4 weeks, bone-to-implant contact and cortical bone thickness were histomorphometrically analyzed. Results: In the 150 g force plus 20 J/cm(2) dosage group, the highest bone-to-implant contact values were observed. (p<0.05) There were no statistically significant correlations between cortical bone thickness and bone-to-implant contact values; on the other hand, no significant difference was found among the same groups in terms of cortical bone thickness values (p>0.05). Conclusions: Low-level laser therapy was noticed to induce the mini screw-bone contact area. Low-level laser therapy may be a supplementary treatment method to increase the stability of the orthodontic mini screw.
... The purpose for proper experiment in the field of photobiology is both: a full characterization the electromagnetic radiation what allows to carry out experiments with accurate reproduction, as well as perform investigations on identical biological material under specified conditions. Define the basic quantity becomes necessary for objective comparison of treatments: the wavelength of radiation, the spectral distribution of radiation, the optical power -average and peak, the spectral and surface power density [12], the distribution of surface power density (its inequality), the work area and duration of exposure, the energy dose [4,6], the polarization state of the beam [13], the coherence length [14], the operation mode -continuous or pulse regime, repetition rate and fill factor of pulse [15]. Fulfilling the repeatability of the experiment for the biological material is obtained by investigating the cell lines in standardized conditions. ...
Conference Paper
In the paper is presented optoelectronic diagnostic set for standardization the biostimulation procedures performed on cell lines. The basic functional components of the therapeutic set are two digitally controlled illuminators. They are composed of the sets of semiconductor emitters – medium power laser diodes and high power LEDs emitting radiation in wide spectral range from 600 nm to 1000 nm. Emitters are coupled with applicator by fibre optic and optical systems that provides uniform irradiation of vessel with cell culture samples. Integrated spectrometer and optical power meter allow to control the energy and spectral parameters of electromagnetic radiation during the Low Level Light Therapy procedure. Dedicated power supplies and digital controlling system allow independent power of each emitter . It was developed active temperature stabilization system to thermal adjust spectral line of emitted radiation to more efficient association with absorption spectra of biological acceptors. Using the set to controlled irradiation and allowing to measure absorption spectrum of biological medium it is possible to carry out objective assessment the impact of the exposure parameters on the state cells subjected to Low Level Light Therapy. That procedure allows comparing the biological response of cell lines after irradiation with radiation of variable spectral and energetic parameters. Researches were carried out on vascular endothelial cell lines. Cells proliferations after irradiation of LEDs: 645 nm, 680 nm, 740 nm, 780 nm, 830 nm, 870 nm, 890 nm, 970 nm and lasers 650 nm and 830 nm were examined.
... These types of lasers have been advocated for use in a wide range of medical conditions encompassing musculoskeletal conditions such as chronic low back pain, 3 wound healing 4 and acute and chronic Achilles tendinitis. 5 LLLT has stimulatory effects on bone cell proliferation 6 and gene expression 7 and can be used to enhance bone repair at cellular and tissue levels. 8 Laser effects on tissues may be attributed to thermal and non thermal effects; the non thermal effects of laser beams on tissue include photodynamic therapy and photobiostimulation therapy. ...
Article
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Objective: To study the effect of both laser and ultrasound radiation on bone fracture healing process. Materials and Methods: Nd:YAG laser (1064 nm wavelength, 135 mW power, 16 joules energy) and ultrasound (1 MHz frequency, 50 mW/cm2 power intensity) were used in this work. Fifteen mature, male, albino rats, were divided into three groups and subjected to a partial fracture on the lateral aspect of femur by a sharp blade. The fi rst group of these animals served as control group. The second group was illuminated by the Nd:YAG laser for two minutes; the fi rst dose was given immediately after surgical fracture induction; the other doses were given on days two, three, six and then one dose weekly for the next three weeks while the third group were treated by the addition of the CW ultrasound perpendicular to the laser treatment in the second group. Results: The present study showed that ultrasound increases the penetration of laser power through the tissue. The histological assessments at day 28 after the fracture of fi rst group showed incomplete healing of the bone with disfi guration and disarrangement of Haversian system and the periosteum was not yet well developed. Treatment with laser showed irregularity and lack of Haversian system formation in bone healing of the second group. The laser and ultrasound treated group (third group) expressed a complete healing at the site of fracture with a complete layer of periosteum and a well arranged Haversian system. Conclusion: Combination of laser and ultrasound in therapy can enhance healing process of a fractured bone more than laser therapy alone, as ultrasound increases the depth of laser penetration in tissue.
... Particularly regarding bone tissue, there have been recent reports of a positive effect on bone remodeling. In bone tissue, exposure to low level laser has been seen to regulate the inflammatory response, promote cell division 3) and accelerate the healing process [4][5][6] . Successful implants in jaw bones depend upon the wound healing process and the potential effect of bone-derived cells that are present in the peri-implant. ...
Article
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Objective : The purpose of this study was to evaluate the effects of low level lasers on bone healing and new bone formation around titanium dental implants in canine models. 18 oxidized surface treated implants and a Dens-bio laser were used. Study design : Low level lasers were irradiated with a total of 8J for 4 minutes by pulse wave type and 1 minute by continuous type. For the experimental group, a low level laser was used to irradiate the first premolar implant's insertion area at the time of insertion, a low level laser was used to irradiate the second premolar implant's insertion area daily for one week after implant insertion, and a low level laser was used to irradiate the third molar implant's insertion area daily for 2 weeks postoperatively. At the conclusion of the study, sacrificed tissue sections were made from investing tissue and observed under an optical microscope. Results : The rate of new bone formation around the implant showed no significant difference between the control group and the experimental group. New bone formation rates of the control and experimental group 2 weeks following implant placement were higher than that of immediately after implant placement and 1 week after implant placement. Conclusions : Based on these results, a low-level laser showed no statistically significant increase in bone formation following implant placement.
... There are conflicting reports in the literature concerning the effects of low-level lasers on bone formation. Nagasawa et al., 18 Yamada et al., 27 Trelles et al., 28 Luger et al., 29 Lomnitskiȋ et al., 30 Horowitz et al., 31 Ozawa et al., 32 Ueda et al., 33 and Yaakobi et al. 34 reported significant and positive effects of low-level lasers on the process of bone formation and repair, but Gorjestani et al. 35 and David et al. 36 did not report positive results. ...
Article
Objective: Therapeutic lasers have been shown to influence bone physiology and repair. The aim of the present investigation was to evaluate the use of a GaAlAs (λ:810 nm) laser in distraction osteogenesis. Background data: To reduce problems associated with distraction osteogenesis and shorten the time required for treatment, it is desirable to accelerate the process of bone formation. Materials and methods: Eighteen male rabbits underwent corticotomy of mandibular body, and customized distraction devices were inserted. After a 5-day latency period, the mandibles were lengthened by 0.5 mm/day for 10 days. The rabbits were divided into two groups. A GaAlAs (λ: 810 nm) laser beam with the parameters power (P), 200 mW; energy density (ED), 3 J/cm(2); time (T), 7.5 sec; power density (PD) 400 mW/cm(2); energy (E) 1.5 J and spot diameter, 0.8 mm was directed medially and laterally in the study group; the control group received no laser treatment. The exposure continued with six more doses every other day. Three rabbits from each of the two groups were euthanized on the 10th, 20th, and 40th days post-distraction (consolidation) period. Results: Both light microscopy and scanning electron microscopic (SEM) analysis showed significant improvement in new bone formation in the study group at the 10th and 20th days compared with the control group, but the difference was more prominent on the 10th day. By the 40th day, there were no significant differences between the two groups. Conclusions: This study shows that a low-level GaAlAs (λ:810 nm; P, 200 mW) laser hastens new bone formation only in the early stages of the consolidation period in distraction osteogenesis, and has no significant effect in later stages.
... There are conflicting reports in the literature concerning the effects of low-level lasers on bone formation. Nagasawa et al., 18 Yamada et al., 27 Trelles et al., 28 Luger et al., 29 Lomnitskiȋ et al., 30 Horowitz et al., 31 Ozawa et al., 32 Ueda et al., 33 and Yaakobi et al. 34 reported significant and positive effects of low-level lasers on the process of bone formation and repair, but Gorjestani et al. 35 and David et al. 36 did not report positive results. ...
Article
Background and objective: One of the most frequent treatments for ischemic heart disease is myocardial revascularization, often applying the saphenous vein as a coronary graft. However, postoperative complications may occur, such as saphenous dehiscence. According to the literature, low-level laser therapy (LLLT) has been used in the treatment of several inflammatory processes in patients. Recently, its uses have expanded to include LLLT preventive therapy and postoperative treatment. Despite our department's successful application of LLLT in the treatment of saphenectomy incisions, many colleagues are still uncertain as to laser therapy's benefits. Therefore, the study's purpose was to evaluate tissue repair of prodromal surgical incisions after the administration of LLLT. Materials and methods: The pilot study included 14 patients, divided into two groups. Both groups of patients received the traditional treatment; additionally, the Laser Group (n = 7) received diode laser treatment (λ = 780 nm, fluence = 19 J/cm(2), pulse = 25 mW, time = 30 sec, energy = 0.75 J, irradiance = 625 mW/cm(2), beam spot size 0.04 cm(2)), which was applied on the edges of the saphenectomy incision. The Control Group (n = 7) received conventional treatment exclusively. Results: In the Laser Group: all seven patients showed significant improvement, whereas the Control Group had twice as many complications, including critical rates of incisional dehiscence. Conclusions: LLLT was valuable in preventing prodromal complications in saphenectomy post myocardial revascularization.
... There have been some reports that pulse structure is an important factor in LLLT; for instance Ueda et al [62,63] found better effects using 1 or 2 Hz pulses than 8 Hz or CW 830-nm laser on rat bone cells, but the underlying mechanism for this effect is unclear.. ...
Article
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The use of low levels of visible or near infrared light for reducing pain, inflammation and edema, promoting healing of wounds, deeper tissues and nerves, and preventing tissue damage has been known for almost forty years since the invention of lasers. Originally thought to be a peculiar property of laser light (soft or cold lasers), the subject has now broadened to include photobiomodulation and photobiostimulation using non-coherent light. Despite many reports of positive findings from experiments conducted in vitro, in animal models and in randomized controlled clinical trials, LLLT remains controversial. This likely is due to two main reasons; firstly the biochemical mechanisms underlying the positive effects are incompletely understood, and secondly the complexity of rationally choosing amongst a large number of illumination parameters such as wavelength, fluence, power density, pulse structure and treatment timing has led to the publication of a number of negative studies as well as many positive ones. In particular a biphasic dose response has been frequently observed where low levels of light have a much better effect than higher levels. This introductory review will cover some of the proposed cellular chromophores responsible for the effect of visible light on mammalian cells, including cytochrome c oxidase (with absorption peaks in the near infrared) and photoactive porphyrins. Mitochondria are thought to be a likely site for the initial effects of light, leading to increased ATP production, modulation of reactive oxygen species and induction of transcription factors. These effects in turn lead to increased cell proliferation and migration (particularly by fibroblasts), modulation in levels of cytokines, growth factors and inflammatory mediators, and increased tissue oxygenation. The results of these biochemical and cellular changes in animals and patients include such benefits as increased healing in chronic wounds, improvements in sports injuries and carpal tunnel syndrome, pain reduction in arthritis and neuropathies, and amelioration of damage after heart attacks, stroke, nerve injury and retinal toxicity.
... Several clinical and experimental studies [1][2][3][4][5][6][7][8][9][10][11] reported the potential acceleration of tissue regeneration using light amplification by stimulated emission of radiation (laser) or light-emitting diode (LED) irradiation devices, both operating at low-energy intensity. In vitro studies using low-intensity lasers result in bone matrix formation for osteoblast cultures, 4,12 and proliferation and maturation of human osteoblasts. ...
Article
To compare peri-implant tissue healing at implants installed in sites prepared with conventional drills or a sonic device. In six Beagle dogs, the mandibular premolars and first molars were extracted bilaterally. After 3 months, full-thickness muco-periosteal flaps were elevated and recipient sites were prepared in both sides of the mandible. In the right side (control), the osteotomies were prepared using conventional drills, while, at the left side (test), a sonic device (Sonosurgery(®) ) was used. Two implants were installed in each side of the mandible. After 8 weeks of non-submerged healing, biopsies were harvested and ground sections prepared for histological evaluation. The time consumed for the osteotomies at the test was more than double compared to the conventional control sites. No statistically significant differences were found for any of the histological variables evaluated for hard and soft tissue dimensions. Although not statistically significant, slightly higher mineralized bone-to-implant contact was found at the test (65.4%) compared to the control (58.1) sites. Similar healing characteristics in osseointegration and marginal hard tissue remodeling resulted at implants installed into osteotomies prepared with conventional drills or with the sonic instrument (Sonosurgery(®) ).
... Several clinical and experimental studies [1][2][3][4][5][6][7][8][9][10][11] reported the potential acceleration of tissue regeneration using light amplification by stimulated emission of radiation (laser) or light-emitting diode (LED) irradiation devices, both operating at low-energy intensity. In vitro studies using low-intensity lasers result in bone matrix formation for osteoblast cultures, 4,12 and proliferation and maturation of human osteoblasts. ...
Article
The combination between photosensitivity substances with laser or light-emitting diode (LED) form the photodynamic therapy basis that consists of photosensitivity drug activated by low-frequency light. This mechanism is used in soft tissue healing process to improve the oxygen tension leading to a fast revascularization. The objective of this study was to evaluate the effects of photosensitivity drugs activated through LED on osseointegration process. Eight mongrel dogs underwent implant therapy in four mandibular bone defects using 5.0 mm trephine drill on each side of the mandible. The defects were randomly filled up with (1) Nano emulsion, (2) liposome, (3) blood clot, and (4) autogenous bone. LED with visible and infrared light were applied after 48/72 postoperative hours on four dogs and after 96/120 postoperative hours in the other four dogs. All the animals were euthanized at 15 days after surgery. Ground sections slides were prepared from the experimental site for histomorphometry and histological analysis. No difference was detected in the following parameters: bone-implant contact, bone inside the defect and crest level on LED 48/72. Significant difference was detected inside the defect when filled with autogenous bone (p = .0238) on LED 96/120. When LED 48/72 and LED 96/120 were compared, significant higher bone formation was detected when autogenous bone on bone-implant contact (p = .0043) and bone inside the defect (p = .0008) was used. The use of photosensitivity drugs activated by LED demonstrated a tendency to stimulate bone formation, similar to autogenous bone graft on later time point.
... It has been reported that the frequency of the radiation pulse is an important factor in the effectiveness of LLLT. For example, Ueda [35,36] has shown that better results can be achieved using a pulse repetition frequency of 1 or 2 Hz than at 8 Hz and continuous laser irradiation (λ = 830 nm). The basic mechanism of this phenomenon is not clear. ...
Article
In this article authors present the developed optoelectronic set for controlled, repeatable exposure by electromagnetic radiation of biological structures in the spectral band of tissue transmission window 600-1000 nm. The set allows for an objective selection and control of exposure parameters and comparison of results for variable energetic, spectral and polarization parameters of radiation beam. Possibility of objective diagnostics of tissue state during laser treatment was provided in the presented optoelectronic set.
... Different techniques have been used in dentistry with an ultimate aim of improving the bone quality. Low-level laser therapy (LLLT) has been used to improve bone healing in several conditions such as in alveolus of dental extraction, bone fractures, [7] dental implants, [8][9][10] orthodontic treatment, and orthognatic surgery [11]. ...
Article
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The aim of this work was to evaluate the association of low-level laser therapy (LLLT, 830 nm) and calcitonin in bone repair considering that bone healing remains a challenge to health professionals. Calcitonin has antiosteoclastic action and LLLT is a treatment that uses low-level lasers or light-emitting diodes to alter cellular function. Both are used to improve bone healing. Densitometry is a clinical noninvasive valuable tool used to evaluate bone mineral density (BMD). Sixty male rats were submitted to bone defect with a trephine bur, randomly divided into four groups of 15 animals each: control (C); synthetic salmon calcitonin (Ca); LLLT (La); LLLT combined with calcitonin (LaCa). Animals from Ca and LaCa received 2 UI/Kg synthetic salmon calcitonin intramuscularly on alternate days after surgery. Animals from groups La and LaCa were treated with infrared LLLT (830 nm, 10 mW, 20 J/cm2, 6 s, contact mode). Five animals from each group were euthanized 7, 14, and 21 days after surgery and bone defects were analyzed by densitometry. Statistical analysis showed a significant difference in BMD values in LaCa group at 7 and 21 days (P=0,005). The results of the densitometric study showed that LLLT (830 nm) combined with calcitonin improved bone repair.
... There have been some reports that pulse structure is an important factor in LLLT; for instance Ueda et al. [79,80] found better effects using 1 or 2 Hz pulses than 8 Hz or CW 830 nm laser on rat bone cells, but the underlying mechanism for this effect is unclear. ...
Conference Paper
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In Bangladesh, accidents are happening frequently at the railway crossing due to the use of typical manual railway crossing systems/ boom gates. The main reasons are likely having these accidents in the railway crossings due to not possible to stop the train engine mechanism system automatically or instantly such as cars and other vehicles as well as for fewer safety measures in the railway crossing. Currently, there are very few automatic railway crossing systems (without any obstacle detector, just runs with the schedule of the trains crossing) are available, however, all of them are dependent on the national power grid that has no backup plan for any emergency cases. As Bangladesh is running a bit behind in the power generation of its consumption, hence it is not possible to have a continuous power supply at all times. This paper aims to design and develop a railway crossing system with a smart obstacle detector to prevent very common types of accidents in the railway crossing points in Bangladesh. In the railway system, time consumption is the biggest issue that leads to having most of the accidents in the railway crossings. In this research, we design to use two infrared (IR) sensors for opening and closing the railway crossing systems/ gates and the whole system to be controlled by the Arduino. To run the process without having any interruption, we propose to use renewable energy i.e., mainly the solar photovoltaic (PV) power systems which are economic friendly and apply under the national green energy policy towards achieving the sustainable goal.
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Understanding the compartment fire behavior has a vital importance for fire protection engineers. For design purposes, whether to use a prescriptive code or performance based on design, life safety and property protection issues are required to be assessed. The use of design fires in computer modelling is the general method to determine fire safety. However, these computer models are generally limited to the input of one design fire, with consideration of the complex interaction between fuel packages and the compartment environment being simplified. Of particular interest is the Heat Release Rate, HRR, as this is the commonly prescribed design parameter for fire modelling. If the HRR is not accurate then it can be subsequently argued that the design scenario may be flawed. Therefore, the selection of the most appropriate fire design scenario is critical, and an increased level of understanding of compartment behavior is an invaluable aid to fire engineering assumptions. This thesis studies 3 types of pool fire geometry to enhance the understanding of the impact and interaction that the size and location of pool fires within an enclosure have upon the compartment fire behavior, also Ethanol pool fires were used. In this present work, we have carried out to analysis the effect of water to extinguish the fire and it and it's tested in 4 different ways with and without water. Also in the result, we can see the effect of water to visibility and also the concentration of air.
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Transcranial photobiomodulation therapy (PBMT) also known as low-level laser therapy (LLLT) relies on the use of red/NIR light to stimulate, preserve and regenerate cells and tissues. In this review, we will present the most important laser types and sources used in the treatment of the brain, required energy densities to provide treatment, and laser delivery techniques to the brain through the cranium, eye, internal ear, and nostril. Various forms of light therapy have been practiced all over the world for many years. Among them, laser therapy has flourished in recent years. More and more laser equipment is being used in this area. The use of PBMT for neuronal stimulation has been studied in various animal and human models and has been shown to improve cerebral metabolic activity and blood flow and provide neuroprotection through anti-inflammatory and antioxidant pathways. In recent years, the concept of thermotherapy for the treatment of brain tumors has become more widespread. Traditionally, heat therapy is divided into hyperthermia, with a moderate increase in the temperature of the treated tissue above the physiological baseline level, and heat ablation, in which even higher temperatures are reached. Recently, intranasal light therapy, light delivery to the brain through the ear and other channels have become attractive and potential treatments for brain diseases. Here we summarize the various methods of delivering light through the nostrils and ear canals using lasers or light-emitting diodes (LEDs), which can be used alone or in combination with transcranial devices or (applied directly to the scalp) to treat a wide range of brain conditions such as the lungs cognitive impairment, Alzheimer's disease, Parkinson's disease, cerebrovascular disease, depression and anxiety, and insomnia. Evidence shows that low-intensity laser therapy improves blood rheology and cerebral blood flow, so there is no need to pierce blood vessels.
Article
Purpose: Low reactive level laser therapy(LLLT)is known to promote bone defect healing. This study was designed to investigate the effects of LLLT on bone defect healing using an experimental rat model. Material and Methods: Eight-week-old male Sprague Dawley rats were used in this study. Bone defects reaching into the bone marrow located 10mm from the femur articular surface on either side were created using a low-speed round bur(ø1.6 mm)under sterile saline. After hemostatic wound closure was attained, one side was irradiated with He-Ne laser(Soft Laser 632, wavelength: 632.8nm)and the other was left unirradiated(laser group and control group, respectively). The laser irradiation was performed transcutaneously to the bone defects for 5minutes(output power: 25mW, distance: 25mm)every 24hours for 4days immediately after the operation(5times in all). The rats were sacrificed after either 7 or 14days, and the resected femurs were subjected to radiological evaluation for bone volume(BV), bone surface area(BS), bone density(BD), trabecular number(Tb.N), trabecular thickness(Tb.Th), trabecular separation(Tb.Sp)and trabecular spacing(Tb.Spac). All experiments were approved by the Animal Experimental Committee at the School of Dentistry, Aichi Gakuin University(AGUD 266). Results: Micro-CT examination demonstrated that both Tb.Sp and Tb.Spac in the laser group were lower than those in the control group at 7 days but were higher at 14days. The laser group exhibited more BV, BD, Tb.N and Tb.Th at 7days but less at 14days. The progress of bone healing was observed at the early stage in the laser group. Conclusion: This particular study revealed the positive LLLT effects of He-Ne laser in promoting bone healing of experimental bone defects in a rat model.
Article
Objective: The aim of this article is to examine current concepts and the future direction of implementing photobiomodulation (PBM) for fracture treatment. Background data: The effectiveness of PBM for bone regeneration has been demonstrated throughout in vitro studies and animal models. Yet, insufficient clinical trials have been reported on treating fractures with PBM. Materials and methods: A narrative review was composed on the basis of a literary search. Inclusion criteria consisted of studies between 2000 and 2019 using animal or human fracture models. Exclusion criteria consisted of studies that did not pertain to complete fractures or used other forms of intervention. Results: Ten animal studies on rats and rabbits and four clinical trials were found on using PBM for complete fractures. Conclusions: Based on positive outcomes in animal trials, parameter optimization of PBM for human fractures still requires extensive research on factors such as dosage, wavelength, penetration depth, treatment frequency, and the use of pulsed waves.
Article
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Low level laser has been conducted for treatment of bone fracture on animal and had shown positive results. If laser energy is delivered at optimal dose with appropriate parameters, it might get best results however a little research in the literature has conducted on the effect of low level laser on human bone fracture. The aim of the study was to assess the radiological and clinical difference of the effect of low level laser therapy on the delayed bone healing of patients with different bone fractures. This was a prospective study conducted in Benha university hospital on 33 patients with delayed and non-union of bone fractures via low level laser diode laser with a wavelength 905nm. There were 27 male 5 female patients, mean age group ±34.43 range (24 years to 67 years), the mean delayed of union was ± 6,68 range (3 months to 15 months ). At the end of the study, union is achieved in mean period±1,7( 1 month to 4,1 month)which led to success of about 70% improvement of the treated group, union mean number of sessions used ±23,375 (range 15 sessions to 50 sessions), Mean Visual Analog Scale (VAS) ± 1,3 range from (0 to 6). the present study indicate that Low level laser therapy is an effective modality for treatment of delayed bone fracture, can relieve pain and increase range of motion of the associated stiff joints with no adverse effect provided that adequate patient selection has conducted.
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BACKGROUND The use of laser therapy in the biostimulation of bone repair has been growing steadily. AIM This study aimed to evaluate the radio-densitometric effect of low-intensity laser therapy on the osseointegration of immediately loaded dental implants in patients under vitamin C, omega-3 and calcium therapy. PATIENTS AND METHODS A single implant was placed in the mandibular first molar region of twenty patients which were equally divided into two groups. In the non-laser group, the healing phase was left to progress spontaneously without any intervention, while in the laser group it was augmented with low-level laser therapy of wavelength 904 nm in contact mode, continuous wave, 20 mW output power and exposure time 30 sec with a dose 4.7 J/cm². Patients in both groups were given vitamin C, calcium and omega-3 starting one month preoperatively. Postoperative digital panoramas were taken immediately after surgery, 1.5 months and 6 months postoperatively. Changes in bone density along the bone-implant interface at the mesial, distal and apical sides were assessed using the Digora software. RESULTS Independent student t-test was used to compare means of variables between the laser and the non-laser group while repeated measures ANOVA was used to compare bone densities at different times for the same group. Significant increased differences were observed at the mesial, distal and apical sides surrounding the implants of both groups per time. However, the rate of increase was significantly higher in the laser group. The mean difference at the mesial side after 6 months was 21.99 ± 5.48 in the laser group and 14.21 ± 4.95 in the non-laser group, while it read 21.74 ± 3.56 in the laser group and 10.78 ± 3.90 in non-laser group at the distal side and was 18.90 ± 5.91 in the laser group and 10.39 ± 3.49 in non-laser group at the apical side. Significance was recorded at P = 0.004, P = 0.0001, and 0.001 at the mesial, distal and apical sides respectively. CONCLUSION The low-intensity laser irradiation significantly promoted bone healing and speeded up the osseointegration process emphasising the laser’s biostimulatory effect.
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Title: Effects of low level laser(Diode-830 nm) therapy on human bone regeneration: Objective: Laser (Semiconductor diode, Ga-Al-As, 830nm) is effective in human bone regeneration, i.e. it enhances bone fracture healing. Background Data: Tissue healing is a complex process that involves both local and systemic responses, and the healing process of bone is much slower than that of soft tissues which is a great challenge of medical science. The use of Laser Therapy (LLLT) for wound /bone healing has been shown to be effective in modulating both local and systemic response by enhancing- cellular & mitochondrial ion exchange, bone mineralization, nitric oxide formation, lymphatic circulation, osteoblast proliferation, effects on osteoblast gene expression, osteoclast inhibition (prevents bone mineral resorption) and by bone engraftment on synthetic materials. Methods: 40 (Twenty in laser & Twenty in control group) otherwise healthy men and women with, closed appendicular bone fracture (Radius/ ulna, or Femur / Tibial shaft /Clavicle / Meta carpal /Meta-tarsal) was enrolled for fracture management by laser therapy adjunctive to regular management, and were evaluated by clinical and radiological findings (X-ray)/at 2nd , 3rd, 4th and 6th week post fracture: Assessment included fracture line/ margins, fracture gap, external callus appearance, callus-to-cortex ratio, bridging, and radiologic union as well as clinical assessment of the fracture- compliance of patient, and onwards follow-up of patients, in comparison to controlled group. Results: Early significant bone regeneration /callus formation achieved by early application of Low Level laser therapy (Ga-Al-As, 830 nm) on human fractured long (appendicular) bone. Conclusions: Treatment with 830 nm diode laser has substantially reduced the fracture healing time as well as improved the quality/quantity of callus formation of the patient, thus enhancing fracture healing. Laser biostimulative effects on bone could be a new dimension for bone regeneration which significantly reduce healing period, lessen cost of treatment, and enhance patient compliance in medical science. By- Dr. Md Nazrul Islam.
Article
Background: Pulsed wave (PW) lasers exhibit biostimulatory effects on fractures in healthy and diabetic animals. Objective: This study aims to assess the effects of photobiomodulation on bone strength and Hounsfield unit (HU) for repair of a bone defect in an experimental rat model of type I diabetes mellitus (TIDM) and osteoporosis (OP). Methods: We divided 30 female rats into six groups of n = 5 per group: (1) ovariectomy (OVX) control, (2) OVX + PW laser and no TIDM, (3) OVX control + TIDM, (4) OVX + TIDM + PW laser, (5) OVX + TIDM + alendronate, and (6) OVX + TIDM + PW laser + alendronate. TIDM was induced in rats by streptozotocin (STZ). A partial osteotomy was made in the right tibia of each rat. We used an infrared laser (890 nm, 80 Hz, 1.5 J/cm(2)) 3 times per week. At 30 days after surgery, the callus areas within the rats' tibias were submitted to computed tomography scanning followed by the three-point bending test. Results: The PW laser + alendronate group had significantly increased HU and biomechanical properties of repairing bone defect in STZ + OVX rats compared with the control groups. Conclusions: Combined treatment of PW laser and alendronate significantly enhanced bone repair in an experimental model rat of TIDM and OP.
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