Effects of laser on the synovial fluid in the inflammatory process of the knee joint of the rabbit

Low-level laser therapy in the treatment of muscle-skelet pain in patients affected by temporo-mandibular disorders

Background

The purpose of the study is to evaluate the effectiveness of Low-Level Laser Therapy in reducing joint and muscle pain in patients with acute and chronic temporomandibular dysfunction.

Materials and methods

The study was conducted on a sample of 180 patients. The sample was divided into two groups according to the time of onset of the disease: acute TMD (<6 months) and chronic TMD (> 6 months). The treatment for all patients provided for the irradiation with Diode Laser Wiser Doctor Smile with tip plane wave at wavelength of 830 nm, continuous beam to 40nW diameter and radius of 6 mm. The irradiated areas were the joint area, temporal, masseter and pterygoid. The irradiation time for each zone was 60s.The protocol adopted consisted of two weekly treatment for six weeks. Pain assessment was performed using the Visual Analog Scale (VAS), in which different scores (s) depending accused of pain by the patient: s0 no pain, s1-3 mild pain, s4-6 moderate pain, s7-9 severe pain and s10 excessive pain. The pain monitoring was performed before treatment, after 15 days and after one month.

Results

The sample included 80 patients with acute TMD and 100 with chronic TMD. The sample belonging to acute TMD group before treatment, was distributed as follows: 0% in s0; 12,5% in s1-3; 31.3% in s4-6; 53.6% in s7-9 and 2.5% in s10. After 15 days the distribution was was as follows: 6.25% in s0; 47.5% in s1-3; 20% in s4-6; 26.3% in s7-9 and 0% in s10. After 30 days the sample was well distributed: 35% in s0; 45% in 1-3; 10% in s4-6; 10% in s7-9 and 0% in s10. The sample belonging to the chronic TMD group, at time zero, was as follows: 0% at s0; 48% in S1-3; 35% in s4-6; 15% in s7-9 and 2% in s10. After 15 days the distribution was: 29% in s0; 28% in S1-3; 33% in s4-6; 10% in s7-9 and 0% in s10. After 30 days the sample was well distributed: 45% in s0; 36% in S1-3; 15% in s4-6; 4% in s7-9 and 0% in s10.

Conclusions

The Low-Level-Laser-Therapy is a valuable tool that can significantly decrease the perception of pain in patients with temporomandibular joint dysfunction, acute and chronic.

Laser acupuncture therapy in patients with treatment-resistant temporomandibular disorders

Objective

To investigate the clinical effects of laser acupuncture therapy for temporomandibular disorders (TMD) after ineffective previous treatments.

Methods

A retrospective observational study was conducted in 29 treatment-resistant TMD patients (25 women, 4 men; age range, 17–67 years). Subjects were treated 3 times per week for 4 weeks with the Handylaser Trion (GaAlAs laser diode, 810 nm, 150 mW, pulsed waves), which delivered 0.375 J of energy (5 s) to ST7, ST6, and LI4 and 3 J (40 s) to each Ashi point, 7.5–26.25 J/cm² in total. The visual analog scale (VAS) and maximal mouth opening (MMO) were evaluated before and after treatment.

Results

VAS analysis showed that the patients were free of pain at rest (endpoint) after 5.90±6.08 sessions of laser acupuncture for acute TMD and after 16.21±17.98 sessions for chronic TMD. The VAS score on palpation of the temporomandibular joint reduced to 0.30±0.67 for patients with acute TMD (p = 0.005) and to 0.47±0.84 for those with chronic TMD (p<0.001). The MMO significantly increased in patients with acute TMD (7.80±5.43 mm, p = 0.008) and in patients with chronic TMD (15.58±7.87 mm, p<0.001).

Conclusions

Our study shows that laser acupuncture therapy improves the symptoms of treatment-resistant TMD. Further studies with a more appropriate design, involving long-term follow-up examinations in a larger patient sample, are needed to evaluate its efficacy.

Effect of low-level laser therapy on metalloproteinase MMP-2 and MMP-9 production and percentage of collagen types I and III in a papain cartilage injury model

Osteoarthritis (OA) resulting from injury or disease is associated with increased levels of several matrix metalloproteinases (MMPs), which degrade all components of the complex extracellular matrix in the cartilage. The objective of this study is to investigate the effect of low-level laser therapy (LLLT) on papain-induced joint damage in rats by histopathology and analysis of metalloproteinase 2 and 9 production. Sixty male Wistar rats were randomly distributed into four groups of 15 animals: (1) non-injury negative control, (2) injury positive control, (3) treated with LLLT at 50 mW, and (4) treated with LLLT at 100 mW. OA was induced in animals using papain (4 % solution) followed by treatment with LLLT. After 7, 14, and 21 days, the animals were euthanized. The articular lavage was collected and centrifuged; then, the supernatant was stored prior to protein analysis by western blot. The material was stained with hematoxylin and eosin for histopathological analysis, and Picrosirius Red was used to estimate the percentage of collagen fibers. To determine normal distribution, ANOVA and Tukey's post hoc test were used for comparison between and within each group at each time period. All data are expressed as mean and standard deviation values, with the null hypothesis considered as p < 0.05. Both laser groups (50 and 100 mW) were effective in tissue repair, decreasing collagen type III expression and increasing type I expression in all experimental periods; however, LLLT at 50 mW reduced metalloproteinase 9 more than at 100 mW in 21 days. LLLT at 50 mW was more efficient in the modulation of matrix MMPs and tissue repair.

Low-level laser reduces the production of TNF-α, IFN-γ, and IL-10 induced by OVA

Delayed, or type IV, hypersensitivity reactions are a useful model to study the effects of new substances on the immune system. In this study, the experimental model of the delayed type hypersensitivity (DTH) reaction to ovalbumin (OVA) was used to evaluate the immunomodulating effects of low-level laser therapy (LLLT), which is used as an adjuvant therapy in medicine, dentistry, and physical therapy because of its potential anti-inflammatory and analgesic effects observed in several studies. The effects of LLLT (λ 780 nm, 0.06 W/cm(2) of radiation, and fluency of 3.8 J/cm(2)) in reaction to ovalbumin in Balb/C mice were examined after the induction phase of the hypersensitivity reaction. The animals treated with azathioprine (AZA), the animals that received a vehicle instead of ovalbumin, and those not immunized served as controls (n = 6 for each group). Footpad thickness measurements and hematoxylin-eosin histopathological exams were performed. Proliferation tests were also performed (spontaneous, in the presence of concanavalin A and ovalbumin) to determine the production in mononuclear cells cultures of tumor necrosis factor-alpha (TNF-α), INF-γ, and IL-10. In the group of animals irradiated with lasers and in the group treated with AZA, footpad thickness measurements were significantly reduced in comparison to the control group (p < 0.05). This reduction was accompanied by a very significant reduction in the density of the inflammatory infiltrate and by a significant reduction in the levels of TNF-α, INF-γ, and IL-10. LLLT radiation was shown to have an immunomodulating effect on DTH to OVA in Balb/C mice.

Comparison between pulsed ultrasound and low level laser therapy on experimental haemarthrosis

The use of pulsed ultrasound (PUS) and low level laser therapy (LLLT) in patients with haemophilia has been recommended for supportive treatment of acute and chronic phases of haemarthrosis but its role has not been supported by experimental evidence. The purpose of the present study was to evaluate the effect of these modalities on joint swelling, friction and biomechanical parameters of articular cartilage. An experimental rabbit knee haemarthrosis model was used to test the hypothesis that LLLT and PUS favourably impacted on the biotribological and biomechanical properties of cartilage after joint bleeding. To test this, 35 male albino rabbits weighing 1.5-2 kg were used. The left knee of 30 rabbits was injected with 1 mL of fresh autologous blood two times per week for four consecutive weeks to simulate recurrent haemarthrosis; five rabbits served as non-bleeding controls. Ten rabbits were treated with PUS and 10 with LLLT and the remaining 10 were not treated. The treatments were started after 2 days and the treatment duration was planned for 5 days (sessions) in ultrasound and laser groups. A low level Ga-Al-As laser was applied with an 810 nm wavelength, 25 mW power, and 1 J cm(-2) dosage for 200 s duration. The PUS treatment was applied with a duty cycle of 1/9, frequency of 1 MHz, and power of 0.4 W cm(-2) for 150 s. Joint perimeter was measured before the procedure at the beginning of therapies and after cessation of the procedure. Friction and biomechanical parameters were measured immediately after the killing of the animals. The results demonstrate that PUS was more effective in reducing knee joint swelling than LLLT. Moreover, PUS had the unique ability of reducing the joint friction below normal values. However, it was not successful in returning the articular cartilage force and stiffness to normal state. LLLT was more effective in increasing equilibrium force of the articular cartilage than PUS, however, neither therapy normalized this parameter. From these data, we conclude that PUS is more effective than LLLT in reducing joint swelling and articular joint friction after experimental haemarthrosis.

Low-level laser therapy in different stages of rheumatoid arthritis: a histological study

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease of unknown etiology. Treatment of RA is very complex, and in the past years, some studies have investigated the use of low-level laser therapy (LLLT) in treatment of RA. However, it remains unknown if LLLT can modulate early and late stages of RA. With this perspective in mind, we evaluated histological aspects of LLLT effects in different RA progression stages in the knee. It was performed a collagen-induced RA model, and 20 male Wistar rats were divided into 4 experimental groups: a non-injured and non-treated control group, a RA non-treated group, a group treated with LLLT (780 nm, 22 mW, 0.10 W/cm(2), spot area of 0.214 cm(2), 7.7 J/cm(2), 75 s, 1.65 J per point, continuous mode) from 12th hour after collagen-induced RA, and a group treated with LLLT from 7th day after RA induction with same LLLT parameters. LLLT treatments were performed once per day. All animals were sacrificed at the 14th day from RA induction and articular tissue was collected in order to perform histological analyses related to inflammatory process. We observed that LLLT both at early and late RA progression stages significantly improved mononuclear inflammatory cells, exudate protein, medullary hemorrhage, hyperemia, necrosis, distribution of fibrocartilage, and chondroblasts and osteoblasts compared to RA group (p < 0.05). We can conclude that LLLT is able to modulate inflammatory response both in early as well as in late progression stages of RA.

Evaluation of low-level laser therapy in patients with acute and chronic temporomandibular disorders

The purpose of this study was to address the following question: among patients with acute or chronic temporomandibular disorders (TMD), does low-level laser therapy (LLLT) reduce pain intensity and improve maximal mouth opening? The sample comprised myogenic TMD patients (according Research Diagnostic Criteria for TMD). Inclusion criteria were: male/female, no age limit, orofacial pain, tender points, limited jaw movements and chewing difficulties. Patients with other TMD subtypes or associated musculoskeletal/rheumatologic disease, missing incisors teeth, LLLT contra-indication, and previous TMD treatment were excluded. According to disease duration, patients were allocated into two groups, acute (<6 months) and chronic TMD (≥ 6 months). For each patient, 12 LLLT sessions were performed (gallium-aluminum-arsenide; λ = 830 nm, P = 40 mW, CW, ED = 8 J/cm(2)). Pain intensity was recorded using a 10-cm visual analog scale and maximal mouth opening using a digital ruler (both recorded before/after LLLT). The investigators were previously calibrated and blinded to the groups (double-blind study) and level of significance was 5% (p < 0.05). Fifty-eight patients met all criteria, 32 (acute TMD), and 26 (chronic TMD). Both groups had a significant pain intensity reduction and maximal mouth opening improvement after LLLT (Wilcoxon test, p < 0.001). Between the groups, acute TMD patient had a more significant pain intensity reduction (Mann-Whitney test, p = 0.002) and a more significant maximal mouth opening improvement (Mann-Whitney test, p = 0.011). Low-level laser therapy can be considered as an alternative physical modality or supplementary approach for management of acute and chronic myogenic temporomandibular disorder; however, patients with acute disease are likely to have a better outcome.

Antiinflammatory effect of low-level laser therapy on Staphylococcus epidermidis endophthalmitis in rabbits

A rabbit model of endophthalmitis was established to evaluate the antiinflammatory effect of low-level laser therapy (LLLT) as an adjunct to treatment for Staphylococcus epidermidis endophthalmitis. Rabbits were randomly divided into three groups to receive intravitreal injections into their left eye: group A received 0.5 mg vancomycin (100 μl), group B received 0.5 mg vancomycin + 0.2 mg dexamethasone (100 μl), and group C received 0.5 mg vancomycin (100 μl) and continuous wave semiconductor laser irradiation (10 mW, λ = 632 nm) focused on the pupil. Slit lamp examination and B-mode ultrasonography were conducted to evaluate the symptoms of endophthalmitis. Polymorphonuclear cells and tumour necrosis factor alpha (TNF-α) in aqueous fluid were measured at 0 h, and 1, 2, 3, 7 and 15 days. A histology test was conducted at 15 days. B-mode ultrasonography and histology revealed that groups B and C had less inflammation than group A at 15 days. Groups B and C had fewer polymorphonuclear cells and lower levels of TNF-α in aqueous fluid than group A at 2, 3 and 7 days (P < 0.05). There was no significant difference between groups B and C (P > 0.05). There was no significant difference between groups A, B and C at 15 days (P > 0.05). As an adjunct to vancomycin therapy to treat S. epidermidis endophthalmitis, LLLT has an antiinflammatory effect similar to that of dexamethasone.

SHORT-TERM EFFICACY OF LOW-LEVEL LASER THERAPY IN PATIENTS WITH KNEE OSTEOARTHRITIS: A RANDOMIZED PLACEBO-CONTROLLED, DOUBLE-BLIND CLINICAL TRIAL

OBJECTIVE

This study was designed to evaluate the short-term efficacy of low-level laser therapy (LLLT) for improving pain and function in patients with knee osteoarthritis.

METHODS

Forty-seven patients with knee osteoarthritis (79 knees), of both genders, participated in this randomized controlled double-blind clinical trial. They were randomly allocated to two groups: laser group with 25 patients (41 knees) and placebo group with 22 patients (38 knees). LLLT was performed three times a week, totaling nine sessions, using a AsGa 904 nm laser with mean power of 60 mW and beam area of 0.5 cm(2). Nine points were irradiated on the knee, with energy of 3.0 J/point. The placebo group was treated with the same laser device, but with a sealed probe. Evaluations using Lequesne, visual numerical scale (VNS), Timed Up and Go (TUG), goniometry and dynamometry were conducted before the treatment started and after the nine sessions of LLLT.

RESULTS

A significant improvement in pain and function was found in all the assessments applied to the laser group. On comparing the laser group with the placebo group, significant differences were found in the VNS-resting and Lequesne evaluations.

CONCLUSION

Treatment with LLLT improves pain and function over the short term in patients with knee osteoarthritis.

Measurements of jaw movements and TMJ pain intensity in patients treated with GaAlAs laser

The aim of this study was to evaluate the effectiveness of low-level laser therapy (LLLT) on the improvement of the mandibular movements and painful symptoms in individuals with temporomandibular disorders (TMD). Forty patients were randomly divided into two groups (n=20): Group 1 received the effective dose (GaAlAs laser ? 830 nm, 40 mW, 5J/cm2) and Group 2 received the placebo application (0 J/cm2), in continuous mode on the affected condyle lateral pole: superior, anterior, posterior, and posterior-inferior, twice a week during 4 weeks. Four evaluations were performed: E1 (before laser application), E2 (right after the last application), E3 (one week after the last application) and E4 (30 days after the last application). The Kruskal-Wallis test showed significant more improvements (p<0.01) in painful symptoms in the treated group than in the placebo group. A significant improvement in the range of mandibular movements was observed when the results were compared between the groups at E4. Laser application can be a supportive therapy in the treatment of TMD, since it resulted in the immediate decrease of painful symptoms and increased range of mandibular movements in the treated group. The same results were not observed in the placebo group.