JOURNAL OF LASERS IN MEDICAL SCIENCES
Year:2019 | Volume:10 | Issue:3|Papers Count:17

Introduction: Low-level lasers are successfully used to prevent and treat diseases in soft oral and bone tissues, particularly diseases in oral cavity caused by chemotherapy and radiotherapy in oncology. However, controversy exists as to whether these lasers induce molecular side effects, mainly on DNA. The aim of this work was to assess the effects of low-power lasers on mutant Escherichia coli cells in DNA repair. Methods: Escherichia coli wild type cultures as well as those lacking recombination DNA repair (recA-) and la SOS responses (lexA-) irradiated with lasers at different energy densities, powers, and emission modes for cell viability and morphology assessment were used in this study. Results: Laser irradiation: (i) did not affect cell viability of non-mutant and lexA-cells but decreased viability in recA-cultures; (ii) altered morphology of wild type and lexA, depending on the energy density, power, emission mode, and wavelength. Conclusion: Results show that low-level lasers have lethal effects on both recombination DNA repair and SOS response bacterial cells but do not induce morphological modifications in these cells.

Introduction: Bone marrow stromal stem cells (BMSCs), a type of adult stem cells, secrete bioactive molecules such as trophic factors, growth factors, chemokine and cytokines that may be effective against oxidative stress in neurodegenerative diseases. In this study, we examined the protective effect of BMSCs conditioned media (CM) and photobiomodulation therapy (PBMT) on PC12 cells exposed to H2O2 as an oxidative injury model. Methods: BMSCs were cultured and confirmed by flow cytometry analysis and underwent osteogenic and adipogenic differentiation. Then, PC12-H2O2 cells were co-treated with BMSCs-CM and PBMT. The effect of BMSCs-CM and PBMT (He-Ne laser, 632. 8 nm, 3 mW, 1. 2 J/cm2, 378 s) on Bax/Bcl2 expression, cell viability, was assessed by real-time PCR and MTT assay. The length of the Neurite and cell body areas were assessed by Cell A software. Results: Flowcytometry analysis, as well as osteogenic and adipogenic staining, confirmed the BMSCs. The length of the Neurite was the highest in the group which received CM+PBMT and cell body areas were significant in CM+PBMT compared to other groups. Based on our results, elevating H2O2 concentration increased cell death significantly and using concentrations of 250 μ M resulted in a dramatic increase in the mortality compared to the other groups. Conclusion: Our result demonstrated that the combination of CM +PBMT has a protective effect on PC12 cells against oxidative stress.

Introduction: Regarding the limited ability of the damaged cartilage cells to self-renew, which is due to their specific tissue structure, subtle damages can usually cause diseases such as osteoarthritis. In this work, using laser photobiomodulation and an interesting source of growth factors cocktail called the synovial fluid, we analyzed the chondrogenic marker genes in treated hair follicle dermal papilla cells as an accessible source of cells with relatively high differentiation potential. Methods: Dermal papilla cells were isolated from rat whisker hair follicle (Rattus norvegicus) and established cell cultures were treated with a laser (gallium aluminum arsenide diode Laser (λ =780 nm, 30 mW) at 5 J/cm2), the synovial fluid, and a combination of both. After 1, 4, 7, and 14 days, the morphological changes were evaluated and the expression levels of four chondrocyte marker genes (Col2a1, Sox-9, Col10a1, and Runx-2) were assessed by the quantitative real-time polymerase chain reaction. Results: It was monitored that treating cells with laser irradiation can accelerate the rate of proliferation of cells. The morphology of the cells treated with the synovial fluid altered considerably as in the fourth day they surprisingly looked like cultured articular chondrocytes. The gene expression analysis showed that all genes were up-regulated until the day 14 following the treatments although not equally in all the cell groups. Moreover, the cell groups treated with both irradiation and the synovial fluid had a significantly augmented expression in gene markers. Conclusion: Based on the gene expression levels and the morphological changes, we concluded that the synovial fluid can have the potential to make the dermal papilla cells to most likely mimic the chondrogenic and/or osteogenic differentiation, although this process seems to be augmented by the irradiation of the low-level laser.

Introduction: Transurethral lithotripsy (TUL) is an appropriate treatment for ureteral stones and is usually used for stones in the middle and lower part of the ureter. Different devices such as the Holmium laser, the stone basket, and the stone cone exist to prevent any fragments from retropulsion during TUL. The present study aims to compare the advantages and disadvantages of the Holmium laser, the stone basket, and the stone cone. Methods: A retrospective study was conducted from September 2016 to January 2018 comparing various TUL methods in 88 subjects with proximal ureteral calculi. The study participants were divided into 4 matched groups. The first one included 20 patients undergoing TUL with no device (group 1), the second group included 22 patients undergoing TUL while using the stone retrieval basket, the third group included 18 patients undergoing TUL while utilizing the stone cone and the fourth group included 28 patients undergoing TUL while using the Hol-YAG laser. Results: A residual stone ≥ 3 mm was recorded in 15. 9% of the patients. The stone free rate was seen in 100%, 90. 9, 83. 3%, and 55% of the Holmium laser group, the retrieval basket group, the stone cone group and the no device group respectively (P = 0. 001). The lowest rate of surgery complications including ureteral perforation, post-operative fever, and mucosal damage between the 4 groups (P = 0. 003) and the highest time of surgery (P = 0. 001) belonged to the laser group. If we want to ignore the laser group, the success rate for lithotripsy was better in both groups with a stone retrieval device compared to the no device group, but no advantage existed between the stone basket and the stone cone. Conclusion: We can safely conclude that lasers significantly help to prevent stone migration during TUL. If we want to ignore the laser group, the success rate for lithotripsy was significantly better in both groups with a stone retrieval device compared to the no device group, but no advantage existed between the stone basket and the stone cone.

Introduction: Ureteral stones are among the most common disorders in the urologic field. Miniaturization of endoscopic devices in urology and extracorporeal shock wave lithotripsy (ESWL) has revolutionized the management of ureteral stones. The aim of this study was to compare the efficacy and results of laser versus pneumatic lithotripsy (PL) with semi-rigid ureteroscope in a randomized prospective clinical trial in removing stones. Methods: 117 adult patients underwent transurethral lithotripsy (TUL) in a single academic center and by a single surgeon. The patients were randomized in 2 groups: In group 1, 58 patients with ureteral stones underwent ureteroscopy and stone fragmentation was done by Ho: YAG laser lithotripsy (LL) and in group 2, 59 patients underwent PL (Swiss LithoClast) by using the same ureteroscope. Results: Mean age was 41. 77 years and 41. 1years in group one and 2 respectively (P = 0. 79), there was no significant difference in male to female ratio and mean stone in both groups. The success rate for stone clearance was 79. 31% and 77. 96% in group 1 and 2 respectively (P = 0. 52). No difference between complications was seen in both groups, but the duration of operations was different (significantly lower in group 2). Conclusion: In both techniques, acceptable results were achieved. We have found a significant statistical difference in duration of operation between our results (P = 0. 001) and similar studies, while this was shorter in the pneumatic group in our study, it was longer in other similar ones. This might be a result of more experience in working with PL in our center.

Introduction: Wound healing is a dynamic, interactive process to achieve the restoration of skin integrity and proper function after damage. Applying a low-level laser (LLL) and light emitting diodes (henceforth LEDs) is introduced in previous studies to accelerate the process of wound healing. The aim of this study is to compare the effect of the LLL and LEDs on wound healing in rabbits. Methods: Full thickness same size square excision wounds were created on the dorsum of the rabbits. Twenty rabbits were randomly divided into four groups, according to the treatment received. Group 1: the AlGalInP (aluminium gallium indium phosphide) laser (4 J/cm² ); group 2: the red LED (30 J/cm² ); group 3: the blue LED (60 J/cm² ) and group 4, as the control group, was not irradiated. After 30 days, the wounds were evaluated both morphologically and histopathologically. Statistical significance was defined as a P value of less than 0. 05. Results: All interfering methods including the LLL and LEDs had better outcome compared with the control group of both sizes and histopathologic features. The red laser group showed better results compared to the control group and either the LED groups. Comparing LEDs, the red LED performed better than the blue LED. Conclusion: This study confirmed the significant effects of the LLL and LEDs on wound healing. Comparing the LLL and LED, the LED may be a better choice, especially for bedridden or debilitated patients. The LED may also more cost effective in wound healing in comparison with the LLL.

Introduction: Application of laser in medicine and cosmetic purposes has raised grossly in recent years. There are contradictory finding about its side effects. In this research critical differentially expressed proteins after irradiation erbium: yttrium– aluminum– garnet (Er: YAG) laser on skin are investigated. Methods: Proteome data including 31 proteins were obtained from a proteomics investigation of laser irradiation, Er: YAG on female mouse skin that are published by Pan et al. The query proteins and 100 related ones were included in the protein-protein interaction (PPI) network. The central nodes were determined and all of nodes were included in action maps. Expression, activation, inhibition, binding, and reaction were considered in action plan. Results: Numbers of 16 proteins were recognized by STRING database and were included in the network. Except PHRF1, the other 15 query proteins were included in the main connected component of the constructed network. Ten central nodes of the network and ten numbers of top query proteins based on degree value were identified as central proteins of the network. All nodes of the network analyzed via action maps and the important acted nodes were determined as RPSA, GAPDH, TPT1, DCTN2, HSPB1, and PDIA3. Conclusion; Two balanced processes including cancer promotion and cancer prevention were after irradiation were identified.

Introduction: This study evaluated the impact of CO2 laser treatment and acidulated phosphate fluoride (APF) on enamel demineralization and biofilm formation, using in vitro and in situ designs. Methods: Demineralized enamel slabs were distributed among 8 groups: placebo, placebo + continuous CO2 laser, placebo + repeated CO2 laser, placebo + ultrapulsed CO2 laser, 1. 23% APF, APF + continuous CO2 laser, APF + repeated CO2 laser and APF + ultrapulsed CO2 laser. In the in vitro study, 15 enamel slabs from each group were subjected to a pH-cycling regimen for 14 days. In the cross over in situ design, 11 volunteers wore palatal appliances with demineralized enamel slabs for 2 periods of 14 days each. Drops of sucrose solution were dripped onto enamel slabs 8×/day. Biofilms formed on slabs were collected and the colony-forming units (CFU) of Streptococcus mutans and Lactobacillus were determined. Results: For both in vitro and in situ studies, there was no significant difference between treatments (P > 0. 05). However, all treatments increased microhardness of demineralized enamel (P < 0. 05). After a further in situ cariogenic challenge, with the exception of the placebo, all treatments maintained microhardness values (P < 0. 05). Microbiological analysis showed no difference in Streptococcus mutans (P > 0. 05) or Lactobacillus (P > 0. 05) counts between groups. Conclusion: The results suggest that APF gel combined with the CO2 laser, regardless of the pulse emission mode used, was effective in controlling enamel demineralization, but none of the tested treatments was able to prevent bacterial colonization.

Introduction: Titanium tetrafluoride (TiF4) is deemed more effective than the previous fluoride compounds. To enhance the effect of the fluoride compounds, researchers have suggested their association with lasers, although there are conflicting results in this area. We evaluated the acid resistance of enamel after treatment with the CO2 laser and TiF4. Methods: Thirteen human premolar teeth were sectioned into 5 parts and each segment was assigned to a study group: co (control): without treatment, AF: enamel treatment with APF 1. 23% for 4 minutes, TF: enamel treatment with TiF4 4% for 1 minute, TF-L: enamel treatment with TiF4 4% and then the CO2 laser (Peak power: 1 W, pulse duration: 10 ms, interval time: 500 ms, Beam spot size: 0. 2 mm, distance: 2 cm), L-TF: enamel treatment with the CO2 laser and then TiF4 4%. Each sample was kept for 7 days in acidic solution of hydroxyethyl cellulose at pH=4. 5, and the amount of the calcium ion released in the solution was measured by atomic absorption spectrometry. Data were analyzed by ANOVA and Bonferroni tests. The significance level was set at 0. 05. Results: The average concentration of the calcium ion released in acidic solution was 197. 46, 153. 30, 99. 23, 61. 23, 55. 46 ppm in the groups respectively. There was a significant difference between the study groups (P < 0. 0001). Only the difference between TF-L and L-TF was not significant (P > 0. 05). Conclusion: The loss of calcium from the enamel samples in the groups treated with a combination of the laser and TiF4 was significantly lower than the groups treated with fluoride alone, or the control group. It did not make a significant difference whether the CO2 laser was applied before or after TiF4.

Introduction: The removal of ceramic veneers is a time-consuming procedure in a dental office. Little research has been done in alternative removal techniques for ceramic veneers. The objective of this study was to evaluate the removal of feldspathic and lithium disilicate reinforced glass ceramic veneers by Er, Cr: YSGG and to measure debonding time and pulpal temperature increase during veneer removal. Methods: Fifty-seven bovine incisor teeth were prepared and divided into 3 groups. Ceramic specimens with a thickness of 0. 7mm, a width of 4mm and a length of 8 mm were fabricated from feldspathic ceramic, lithium disilicate reinforced glass ceramic HT (high translucency) and lithium disilicate reinforced glass ceramic MO (medium opacity) (19 for each group). Specimens were cemented on the labial surface of incisors using resin cement. The Er, Cr: YSGG laser was applied to each specimen at 2. 5 W and 25 Hz. Debonding time was measured for each specimen, and the intrapulpal temperature was detected in 3 specimens for each group. Data were analyzed via one-way analysis of variance (ANOVA) at significance level of 0. 05 (α = 0. 05). Results: Mean debonding time was 103. 68 (26. 76), 106. 58 (47. 22) and 103. 84 (32. 90) seconds for feldspathic, lithium disilicate MO, and lithium disilicate HT respectively. There was no significant statistical difference among the groups (P value = 0. 96). The intrapulpal temperature increase was less than 1° C in all groups. Conclusion: Er, Cr: YSGG can successfully be used to efficiently debond feldspathic and lithium disilicate reinforced glass ceramic veneers. There was no significant difference for debonding time among these ceramic materials. During ceramic laminate veneer removal by laser irradiation, no irritating temperature rise was detected.

Introduction: Photodynamic inactivation has been developed to kill pathogenic microbes. In addition, some techniques have been introduced to minimize the biofilm resistance to antifungal properties in inhibiting cell growth. The principle of photodynamic inactivation different to antifungal drugs therapy which is resistant to biofilms. The presence of reactive oxygen species (ROS) that generating in photodynamic inactivation mechanisms can be damaging of biofilm cells and the principle of light transmission that could be penetrating in matrix layers of extracellular polymeric substance (EPS) until reaching the target cells at the base layers of biofilm. The present work aims to explore the potential of chlorophyll extract of papaya leaf as an exogenous photosensitizer to kill the Candida albicans biofilms after being activated by the laser. The potential of chlorophyll photosensitizer was evaluated based on the efficacy of inactivation C. albicans biofilm cell through a cell viability test and an organic compound test. Methods: The treatment of photoinactivation was administered to 12 groups of C. albicans biofilm for four days using the 445 nm laser and the 650 nm laser. The 445 nm and 650 nm lasers activated the chlorophyll extract of the papaya leaf (0. 5 mg/L) at the same energy density. The energy density variation was determined as 5, 10, 20, 30 and 40 J/cm2 with the duration of exposure of each laser adjusted to the absorbance percentage of chlorophyll extract of the papaya leaf. Results: The absorbance percentage of chlorophyll extracts of the papaya leaf on wavelengths of 650 nm and 445 nm respectively were 22. 26% and 60. 29%, respectively. The most effective treated group was a group of the laser with the addition of chlorophyll, done by the 650 nm lasers with inactivation about 32% (P = 0. 001), while the 445 nm lasers only 25% (P = 0. 061). The maximum malondialdehyde levels by treatment of the laser 650 nm were (0. 046± 0. 004) nmol/mg. Conclusion: The use of chlorophyll extract of the papaya leaf as a photosensitizer, resulted in the maximum spectrum of absorption at 414 nm and 668 nm, which produced a maximum reduction effect after photoinactivation up to 32% (with chlorophyll) and 25% (without chlorophyll). The utilization of chlorophyll extract of the papaya leaf would increase the antifungal effects with the activation by the diode laser in the biofilm of C. albicans.

Introduction: The treatment of a true unilateral posterior crossbite often requires asymmetric maxillary expansion; however, this is challenging to achieve with conventional expansion methods because of several biomechanical limitations. In this paper, we introduce a new protocol for the treatment of a unilateral posterior crossbite in adults based on maxillary orthodontic expansion assisted by corticotomy and low-level laser therapy (LLLT) performed on the crossbite side. Methods: The study sample included 15 adults (8 females, 7 males) affected by a true unilateral posterior crossbite, with a mean age of 21. 6 ± 3. 1 years at the at the beginning of treatment. After the application of orthodontic appliances (palatal expander and self-ligating brackets), corticomy was performed at the buccal aspect of the crossbite side while LLLT was monthly administered up to the correction of the crossbite. The efficacy of the technique was evaluated through measurements performed on maxillary digital models. Results: All subjects reported successful correction of the posterior unilateral crossbite, and functional occlusion was achieved as well. The average expansion was greater at the crossbite side compared to the unaffected side and such difference was significant at the levels of first premolars (P < 0. 05), second premolars (P < 0. 05) and first molars (P < 0. 05). Conclusion: Orthodontic maxillary expansion assisted by unilateral corticotomy and LLLT was effective in the treatment of the true unilateral crossbite.

Introduction: Rhinosinusitis is a frequent disease in children but may be underdiagnosed, that is to say, several causes of the disease are missed in children. Therefore, it seems essential to provide other modalities to treat chronic health conditions like such cases. This controlled clinical study was conducted to compare the effect of two non-pharmacological, painless, safe modalities; low-level laser therapy (LLLT), with pulsed electromagnetic field (PEMF) on mucosal membrane thickening in children with chronic rhinosinusitis. Methods: Thirty children with chronic sinusitis participated in this study, their ages ranged from 6 to 13 years old, recruited from the outpatients ENT clinic, Kasr Al Aini teaching hospital. They were classified into 2 groups of equal number; study group A (PEMF group) and study group B (LLLT group). These children were evaluated before the starting and after the end of the study through CT scan full examination (coronal and axial) for all children. Results: This study showed that there were statistically significant improvements in mucosal membrane thickness in both groups (P < 0. 05), while there was no statistically significant difference between groups (P > 0. 05). Conclusion: From the obtained outcomes it can be concluded that both the laser and electromagnetic field can be used effectively in the management of symptoms in children with chronic rhinosinusitis, while no significant difference between these modalities obtained.

Introduction: One of the main applications of laser in dentistry is the removal of dental caries and preparation of restorative cavities. The morphology and wettability of laser prepared surfaces are different from that of those prepared with conventional method which may affect the quality of the adhesive potential of bonding agents in these surfaces. This study aimed to assess the shear bond strength of a total-etch and self-etch adhesive system to primary tooth dentin prepared by two different energy densities of Er: YAG laser in comparison with surfaces prepared by bur. Methods: A total of 60 human primary second molars extracted for orthodontic purposes were selected and randomly divided into 3 main groups of equal (n = 20). Group A: Preparation of dentin surface by bur; group B: Preparation of dentin surface by laser with 300 mJ energy level; group C: Preparation of dentin surface by laser with 400 mJ energy level. In each of the main groups, the teeth were randomly assigned to 2 subgroups. Composite resin material was bonded with the total-etch adhesive system in subgroups A1, B1, and C1 and with the self-etch adhesive system in subgroups A2, B2, and C2. The samples were thermo-cycled, and composite restorations shear bond strength was measured in MPa. Data were analyzed using two-way analysis of variance (ANOVA), and P values less than 0. 05 were considered statistically significant. Results: The highest and the lowest shear bond strength values were observed in group A2 (Preparation by bur-Composite resin material bonded by Clearfil SE Bond) and group C2 (Preparation by laser with 400 mJ energy level-Composite resin material bonded by Clearfil SE Bond), respectively. The results showed no statistically significant differences between the study subgroups (P > 0. 05). Conclusion: It is concluded that in terms of shear bond strength to dentin, Single Bond and Clearfil SE Bond adhesive agents adequately perform in primary tooth dentin prepared by Er: YAG laser with energy levels of 300 and 400 mJ and frequency of 10 Hz.

Periodontitis is one of the most common inflammatory diseases of the periodontium, which results in the inflammatory destruction of supporting structures around teeth and is closely associated with the development of systemic disease. Due to a wide variety of antibiotic resistance periodontopathic bacteria, photodynamic therapy (PDT) is a non-invasive adjunctive therapeutic modality that is capable of destroying the whole range of microbes. Metformin (Metf) is an antidiabetic drug, and recent studies suggest that cancer patients who receive Metf and are exposed to radiotherapy and chemotherapy show better outcomes. Our surveys in this review introduce Metf as a potent stimulus in increasing the efficacy of PDT in the induction of destruction in microbial cells.

Introduction: Mycosis fungoides (MF), a type of cutaneous T-cell lymphoma, is a rare condition with a variety of treatment options. A frequently utilized method in the treatment of early-stage MF is phototherapy. Full body phototherapy can be associated with photoaging of the skin and an increased risk of developing skin cancer. Targeted phototherapy, with a 308-nm excimer laser, may be just as effective and of a lower risk. This makes it especially useful in the treatment of patients with dysplastic nevi (DN) or other conditions which can put them at a higher risk of developing skin cancer. There are currently limited data on the treatment of early-stage MF with an excimer laser. Case Report: This study reports on a 43-year-old female patient presented to the clinic with early-stage (Ia) MF. Given her history of DN, she wished to pursue targeted phototherapy with an excimer laser. Localized light treatment was performed via a 308-nm excimer laser, 3 times weekly, for a total of 17 treatments to affected lesions. Following excimer laser treatment, she had a clinical resolution of her patches. On the follow-up clinic visits, she maintained her excellent response 12 months out. Conclusion: Targeted phototherapy with a 308-nm excimer laser may be a safer and equally effective alternative to generalized phototherapy in the treatment of early-stage MF. This case report demonstrates its efficacy and advantages over traditional generalized phototherapy.

A digital tourniquet with/without epinephrine is commonly used in local anesthetics when operating on digits. However, such a complication as digital ischemia could occur following tourniquet application. We reported an elderly patient with atherosclerotic risk factors and she subsequently underwent a digital tourniquet, partial nail plate removal, and a carbon dioxide laser treatment for subungual wart with digital gangrene development. The successful treatment consisted of wound-dressing, medication, and adjuvant low-level light therapy (LLLT) to enhance the wound healing process, thereby resulting in almost complete recovery of skin color and function of the digit in 3 months. In conclusion, the digital tourniquet should be cautiously applied, especially in elderly patients with atherothrombosis, under minimal pressure and appropriate length of time. Moreover, LLLT could be an effective adjuvant treatment to prevent the vascular complications of the digit.