Journal of Lasers in Medical Sciences
Volume:9 Issue: 4, Autumn 2018

The capacity of the liver to regenerate is an important clinical issue after major hepatectomies and makes the difference between life and death in some cases of post-operative malfunction when the liver remnant is too small or has an impaired regenerative capacity. Several approaches have been tested to stimulate hepatic regeneration after post-operative hepatic failure syndrome; however, they have produced controversial results. A quick, simple, and harmless method that can be used intraoperatively and capable of promoting an increased regenerative capacity of the remaining liver would be very welcome. Thus, based on the data in the literature, we presented low-power laser irradiation (LPLI) as a quick, simple, and harmless method to improve liver regeneration after major hepatectomies. This article highlights the current evidence about the effects of LPLI on liver regeneration, and also suggests laser therapy as an important tool for regenerative stimulation in clinical practice.

Hemangioma is a congenital vascular soft tissue tumor, defined as a vascular lesion present in the newborn, with a progressive developmental pattern related to age. It has a progressive and regressive periodic growth mode, in comparison with arteriovenous malformation (AVM). Although there are many treatment approaches for curing this lesion such as; surgery, cryotherapy, sclerosant agents, laser therapy has more advantages in comparison to the other methods. Such as, hemostasis and clean operating field, decreased amount of pain and edema. There are many types of lasers manufactured that could be used for therapeutic purposes. This article focuses on different types of laser applications in the treatment of these lesions.

Several different modalities are available for ureteral stone fragmentation. From them pneumatic and holmium: yttrium-aluminum-garnet (Ho: YAG) lithotripsy have supportive outcomes. In this study we studied 250 subjects who had ureteroscopic pneumatic lithotripsy (PL) or laser lithotripsy (LL). Two-hundred fifty patients with ureteral stones underwent ureteroscopic lithotripsy (115 subjects in the PL group, 135 subjects in the LL group) from August 2010 to April 2016. The purpose of this investigation was to evaluate stone-free rate (SFR), mean operation time (MOT), mean hospital stay (MHS), stone migration and complications. Two groups were similar in age, gender, mean size of stones, side of stone, and complications. There was a statistical difference in terms of SFR, stone migration and MHS in favor of the LL group (P ≤ 0.05, P ≤ 0.05 respectively), and MOT in favor of the PL group (P ≤ 0.05). Both the PL and LL techniques were effective and safe for ureteral stones, however a slightly higher SFR was found in the LL group.

Increased temperature due to the application of laser during root canal disinfection may damage periodontium, alveolar bone, and permanent dental germ. The aim of this study was to evaluate the temperature increase of the external surface of primary roots due to the application of 810 nm and 980 nm diode lasers. A total of 58 extracted human primary teeth were prepared and randomly divided into two groups: (a) 810 nm diode laser and (b) 980 nm diode laser. Then, each group was divided into 4 subgroups based on the location of the temperature measurement, including subgroup 1: external root surface of primary anterior roots (A); subgroup 2: external root surface of posterior teeth at inter-root space (IS); subgroup 3: external root surface of posterior teeth at outer-root space (OS) and subgroup 4: external surface of furcation area of posterior teeth (F). The mean temperature rise in group a (7.02±2.95ºC) was less than that of group b (10.62±4.59ºC) (P < 0.001). Also, a significant difference was found between the laser groups in terms of the mean temperature rise of the external root surface at IS, OS and F, with higher temperature increase occurring in all points in laser b. The comparison of irradiation points in each laser showed a higher mean temperature rise for IS than OS, but this difference was only significant in group b (P < 0.001). Within the studied parameters, 810 nm and 980 nm diode lasers should be used cautiously in primary root canals because of their temperature rise during their application.

Many studies have shown the positive effect of laser radiation and application of the mesenchymal stem cells (MSCs) and their secretion in stimulating bone regeneration. The aim of this study was determining effects of MSC conditioned media (CM) and low-level laser (LLL) on healing bone defects in the hypothyroid male rat. We assigned 30 male Wistar rats randomly to 3 groups: control, hypothyroidism, CM+LLL. Four weeks after surgery, the right tibia was removed. Biomechanical examination and histological examinations were performed immediately. Our results showed significant increase in bending stiffness (116.09 ± 18.49), maximum force (65.41 ± 8.16), stress high load (23.30 ± 7.14), energy absorption (34.57 ± 4.10), trabecular bone volume (1.34 ± 0.38) and the number of osteocyte, osteoblast, and osteoclast (12.77 ± 0.54, 6.19 ± 0.80, 1.12 ± 0.16 respectively) in osteotomy site in the LLL + CM group compared to the hypothyroidism group (P < 0.05). The results indicated that using the LLL + CM may improve fracture regeneration and it may hasten bone healing in the hypothyroid rat.

In this research, low-level helium-neon (He-Ne) laser irradiation effects on monkey kidney cells (Vero cell line) mitosis were studied. The experiment was carried out on a monkey kidney cell line “Vero (CCL-81)”. This is a lineage of cells used in cell cultures and can be used for efficacy and media testing. The monolayer cells were formed on coating glass in a spectral cuvette (20×20×30 mm). The samples divided into two groups. The first groups as irradiated monolayer cells were exposed by a He-Ne laser (PolyaronNPO, L’vov, Ukraine) with λ = 632.8 nm, max power density (P) = 10 mW/cm2, generating linearly polarized and the second groups as the control monolayer cells were located in a cuvette protected by a lightproof screen from the first cuvette and also from the laser exposure. Then, changing functional activity of the monolayer cells, due to the radiation influence on some physical factors were measured. The results showed that low-intensity laser irradiation in the range of visible red could make meaningful changes in the cell division process (the mitosis activity). These changes depend on the power density, exposure time, the presence of a magnetic field, and the duration of time after exposure termination. The stimulatory effects on the cell division within the power density of 1-6 mW/(cm2) and exposure time in the range of 1-10 minutes was studied. It is demonstrated that the increase in these parameters (power density and exposure time) leads to destructing the cell division process. The results are useful to identify the molecular mechanisms caused by low-intensity laser effects on the biological activities of the cells. Thus, this study helps to optimize medical laser technology as well as achieving information on the therapeutic effects of low-intensity lasers.

Several techniques such as using citric acid, plastic curettes, ultrasonic devices, and lasers have been suggested for debridement of contaminated implant surfaces. This comparative investigation aimed to assess and compare the effects of Er, Cr: YSGG laser and super-saturated citric acid on the debridement of contaminated dental implant surfaces. In this in-vitro study, 12 contaminated failed implants were collected and randomly divided into 2 groups (6 in group A, and 6 in group B). Also, one implant was considered as the control. The implants were horizontally sectioned into coronal and apical portions and subsequently irradiated by Er, Cr: YSGG laser in coronal and citric acid in apical in group A and the opposite in group B. In order to evaluate the effect of water spray on the laser section, half the laser portion of the implants was irradiated using water, while the other half was irradiated without water with an irradiation time of 1 minute. Results revealed that calculus and plaque removal was greater in the laser part of both groups (with and without water) compared to citric acid parts and the correlation between calculus removal and surface roughness were statistically significant. Furthermore, the surface roughness in the citric acid parts was significantly higher than in laser parts. Water spray during irradiation had a very small influence on understudy factors. Based on the results of this study, the Er, Cr: YSGG laser was more effective in calculus removal and caused less surface roughness compared with citric acid application.

Benign prostatic hyperplasia (BPH) is a disease of the prostate commonly seen in elderly males known to cause lower urinary tract symptoms (LUTS) that may require surgery as a part of treatment. Transurethral resection of the prostate (TURP) is considered the gold standard of surgical treatment, but it is not without complications. Laser photoselective vaporisation of the prostate (PVP), introduced in 1998 as an 80 W Nd:YAG laser which passed through a KTP (potassium-titanyl-phosphate) crystal, emerged as a safe alternative to TURP in selected cases. A recent upgrade to the Greenlight XPS 180 W powered with an LBO (lithium triborate) crystal has been available for use since 2012. Data on the use of this new upgrade is still being collected and analysed, especially in patients with large prostates or high risk cases. We analysed cases done at Jaslok Hospital over a 2-year period. A total of 34 patients who underwent Laser PVP using XPS 180W for LUTS due to BPH at Jaslok Hospital were part of this study. We analysed the pre- and postoperative variables and the intraoperative parameters of all patients. The XPS 180W was found to be safe and efficacious. Eighteen patients were high-risk cases, classified as ASA (American Society of Anesthesiologists) Classes 3 and 4. Average postoperative catheter duration was 40.18 hours. In prostates of size <80 mL, an average of 229 kJ of energy was used. In large prostates (>80 mL), an average of 390 kJ of energy was used. No major complications were seen in any of the high-risk patients, classified as Clavien Dindo Class 3 and 4. The postoperative drop in IPSS (International Prostate Symptom Score) was 8.7. We found that Green Light Laser XPS 180W may be used for large (>80 g) prostates, hitherto an indication for open surgery, and that it may be used in high-risk patients, who were otherwise unfit for TURP. It is safe and efficacious. Further, multicenter trials are required to confirm the findings.

Hypothyroidism delays wound healing by reducing the synthesis of keratinocytes, fibroblast cells, and collagen. Methods for enhancement of wound healing include laser therapy and hormone therapy. The current study evaluated the combined effect of laser and levothyroxine therapy to cure wounds in male rats with hypothyroidism. Sixty male Wistar rats were randomly divided into 5 groups: (1) healthy controls; (2) controls with hypothyroidism; (3) hypothyroidism + laser treatment; (4) hypothyroidism + levothyroxine treatment; (5) hypothyroidism + laser + levothyroxine treatment. Hypothyroidism was induced by dissolving 4 mg of methimazole in 100 mL of drinking water daily for 28 days. After hypothyroidism had been confirmed, a longitudinal incisional wound was created on the dorsal rib cages of the rats. The wounds that received laser treatment were divided into 12 sections and treated at 810 nm wavelength and 0.2 J/cm2 of energy density for 200 seconds. Levothyroxine was administrated in doses of 20 μg/kg/d i.p. All groups were divided into 3 subgroups for testing on days 4, 7 and 14. Samples were collected in all the subgroups. The results showed that hypothyroidism reduced fibrous tissue volume, fibroblasts, and basal cell numbers. The combined effect of laser and levothyroxine improved all parameters. Combined laser and levothyroxine treatment showed the best effect on wound healing and accelerated the closure of the wounds.

American tegumentary leishmaniasis (ATL) is a zoonotic disease caused by protozoan parasites of the genus Leishmania that affects the skin and mucous membrane. Currently, the available drugs for the treatment are injectable, with side effects, long-term treatment regimen and there is the possibility of drug resistance. Thus, alternative therapies have been tested, including photodynamic therapy (PDT). We evaluated the efficacy of PDT on its own and associated with the prescribed ATL treatment. BALB/c mice were infected with Leishmania (Leishmania) amazonensis and divided into 6 groups: Gluc+PDT, treated with Glucantime® and photodynamic therapy (PDT) with methylene blue (MB)/red LED (light-emitting diode); Gluc, treated with Glucantime®; PDT, treated with PDT with MB/red LED; Ampho+PDT, treated with amphotericin and PDT with MB/red LED; Ampho, treated with amphotericin; and control, which were infected but not treated. Two treatment cycles were performed. After 165 days of infection, the parasite load was determined. Statistical differences were not found (P > 0.05) between measures of volume and thickness of the infected footpads in the treated groups when compared with the control group. However, there was a significant reduction (P < 0.05) in the parasitic load of the popliteal lymph nodes of the Gluc+PDT, Gluc, PDT and Ampho groups when compared to the control group. In the histological analysis of the infected footpads, the Gluc+PDT group presented a smaller amount of amastigote nests and lower intensity of the mononuclear infiltrate when compared to the Gluc and PDT groups. The results showed that although there is no significant difference in the evaluations of footpad size (thickness and volume), there is a downward measurement tendency in the Gluc+PDT group, as it can be observed by volume data and corroborated by parasite negative load.

Laser technology as a new modality in dentistry has gained special attention. Among different types of lasers, erbium lasers have gained special attention for management of oral soft and hard tissue simultaneously. This study presents series of cases of crown lengthening (CL) and restorations accomplished by erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG). Case Reports: Seven patients were selected for this study. After complete oral examination and diagnosis, the treatment plan of each patient was designed. All cases needed esthetic CL. In some cases, frenum revision and class V cavity preparation was done by Er;Cr:YSGG laser. All patients treated with Er;Cr:YSGG laser producing a wavelength of 2780 nm (Biolase, Irvine, California, USA); Tip T4, 400 μm Diameter for soft tissue management and Tip G6, 6 mm long, 600 μm diameter for hard tissue management. All patients reflected acceptable results based on clinical evaluation and patients’ declaration of post-surgical status. Using Er;Cr:YSGG laser in class v cavity preparation and flapless CL seemed to be effective and beneficial.

Photodynamic therapy (PDT) has emerged as a powerful tool for conventional endodontic treatment, capable of eradicating microorganisms present in endodontic infections. Despite this, the use of PDT in the surgical endodontic treatment is not well-known.

Case Report

 This paper describes the case of a patient with asymptomatic apical periodontitis in a mandibular incisor submitted to surgical endodontic treatment associated with PDT. After conventional procedures, photosensitizer methylene blue (0.01%) was applied to the retrograde cavity for 3 minutes, followed by irradiation with diode laser (100 mW and 660 nm) for 3 minutes. Six months after the procedure, the patient was asymptomatic, and the radiographic examination showed healthy periradicular tissues.

The association of PDT with surgical endodontic treatment was effective, suggesting that this therapy may provide additional benefits to patients when compared to the conventional surgical technique.