What are the best parameters of low-level laser therapy to reduce pain intensity and improve mandibular function in orofacial pain? A systematic review and meta-analysis

PURPOSE

To determine the effectiveness of laser therapy for managing patients with orofacial pain (OFP). In addition, to determine which parameters provide the best treatment effects to reduce pain, improve function, and quality of life in adults with OFP.

METHODS

Systematic review. Searches were conducted in six databases; no date or language restrictions were applied. Studies involving adults with OFP treated with laser therapy were included. The risk of bias (RoB) was performed with the Revised Cochrane RoB-2. A meta-analysis was structured around the OFP type, and outcomes. Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) assessed the overall certainty of the evidence.

RESULTS

Eighty-nine studies were included. Most studies (n = 72, 80.9%) were considered to have a high RoB. The results showed that laser therapy was better than placebo in improving pain, maximal mouth open (MMO), protrusion, and tenderness at the final assessment, but with a low or moderate level of evidence. The best lasers and parameters to reduce pain are diode or gallium-aluminum-arsenide (GaAlAs) lasers, a wavelength of 400-800 or 800-1500 nm, and dosage of <25 J/cm2.

CONCLUSIONS

Laser therapy was better than placebo to improve pain, MMO, protrusion, and tenderness. Also, it was better than occlusal splint to improve pain, but not better than TENS and medication.Implications for rehabilitationLaser therapy was found to be good in improving pain, maximal mouth opening, jaw protrusion, and tenderness at the end of the treatment.For patients with all types of temporomandibular disorders (TMDs) (myogenous, arthrogenous, and mixed), the following lasers and parameters are recommended: diode or gallium-aluminum-arsenide (GaAlAs) laser, wavelength of 400-800 or 800-1500 nm, and a dosage <25 J/cm2.For patients with arthrogenous TMDs, the following lasers and parameters are recommended: Diode laser and a wavelength between 400 and 800 nm.For patients with myogenous TMDs, the following lasers and parameters are recommended: diode laser, wavelength between 800 and 1500 nm, and dosage of <25 J/cm2.For patients with mixed TMDs, the following lasers and parameters are recommended: diode, GaAlAs, or infrared laser, a wavelength of 800-1500 nm, a dosage >100 J/cm2, and an application time between 15 and 30 s or >60 seconds.

Pain relief reverses hippocampal abnormalities in trigeminal neuralgia

Chronic pain patients frequently report memory and concentration difficulties. Objective testing in this population points to poor performance on memory and cognitive tests, and increased comorbid anxiety and depression. Recent evidence has suggested convergence between chronic pain and memory deficits onto the hippocampus. The hippocampus consists of heterogenous subfields involved in memory consolidation, behavior regulation, and stress modulation. Despite significant studies outlining hippocampal changes in human and chronic pain animal models, the effect of pain relief on hippocampal abnormalities remains unknown. Trigeminal neuralgia (TN) is a chronic neuropathic pain disorder which is highly amenable to surgical interventions, providing a unique opportunity to investigate the effect of pain relief. This study investigates the effect of pain relief on hippocampal subfields in TN. Anatomical MR images of 61 TN patients were examined before and 6 months after surgery. Treatment responders (n=47) reported 95% pain relief, whereas non-responders (n=14) reported 40% change in pain on average. At baseline, patients had smaller hippocampal volumes, compared to controls. After surgery, responders' hippocampal volumes normalized, largely driven by CA2/3, CA4 and dentate gyrus, which are involved in memory consolidation and neurogenesis. We propose that hippocampal atrophy in TN is pain-driven and successful treatment normalizes such abnormalities.

Role of diode lasers in oro-facial pain management

With the increasing use of low level laser therapy (LLLT) in clinical dentistry, the aim of the present study was to assess the effectiveness of diode lasers in the management of orofacial pain. Indexed databases were searched without language and time restrictions up to and including July 2016 using different combinations of the following key words: oral, low level laser therapy, dental, pain, diode lasers, discomfort and analgesia. From the literature reviewed it is evident that LLLT is effective compared to traditional procedures in the management of oro-facial pain associated to soft tissue and hard tissue conditions such as premalignant lesions, gingival conditions and dental extractions. However, it remains to be determined which particular wavelength will produce the more favorable and predictable outcome in terms of pain reduction. It is highly recommended that further randomized control trials with well-defined control groups should be performed to determine the precise wavelengths of the diode lasers for the management of oro-facial pain. Within the limits of the present review, it is concluded that diode lasers therapy is more effective in the management of oro-facial pain compared to traditional procedures.

Low Intensity Laser Application in Temporomandibular Disorders: A Phase I Double-Blind Study

The purpose of this study was to evaluate the effectiveness of low intensity laser therapy (LILT) for the control of pain from temporomandibular disorder (TMD) in a random and double-blind research design. Forty-eight (48) patients presenting temporomandibular joint (TMJ) pain were divided into an experimental group (GI) and a placebo group (GII). The sample was submitted to the treatment with infrared laser (780 nm, 70 mW, 10 s, 89.7 J/cm2) applied in continuous mode on the affected temporomandibular region, at one point: inside the external auditive duct toward the retrodiskal region, twice a week, for four weeks. For the control group, two identical probes (one active and one that does not emit radiation) were used unknown by the clinician and the subjects. A tip planned for laser acupuncture was used and connected to the active point of the probe. The parameter evaluated was the intensity of pain after palpation of the condylar lateral pole, pre-auricular region and external auditive duct, according to the Visual Analogue Scale (VAS). Four evaluations were performed: Ev1 (before laser application), Ev2 (after 4th application), Ev3 (after 8th application) and Ev4 (30 days after the last application). Data were submitted to statistical analysis. The results showed a decrease in the pain level mainly for the active probe. Among the evaluations, the Ev3 exhibited lower sensitivity to palpation. In conclusion, the results show that low intensity laser is an effective therapy for the pain control of subjects with TMD.

Evaluation of low-level laser therapy effectiveness on the pain and masticatory performance of patients with myofascial pain

This study investigated the effect of low-level laser therapy (LLLT) on the masticatory performance (MP), pressure pain threshold (PPT), and pain intensity in patients with myofascial pain. Twenty-one subjects, with myofascial pain according to Research Diagnostic Criteria/temporomandibular dysfunction, were divided into laser group (n = 12) and placebo group (n = 9) to receive laser therapy (active or placebo) two times per week for 4 weeks. The measured variables were: (1) MP by analysis of the geometric mean diameter (GMD) of the chewed particles using Optocal test material, (2) PPT by a pressure algometer, and (3) pain intensity by the visual analog scale (VAS). Measurements of MP and PPT were obtained at three time points: baseline, at the end of treatment with low-level laser and 30 days after (follow-up). VAS was measured at the same times as above and weekly throughout the laser therapy. The Friedman test was used at a significance level of 5% for data analysis. The study was approved by the Ethics Committee of the Federal University of Sergipe (CAAE: 0025.0.107.000-10). A reduction in the GMD of crushed particles (p < 0.01) and an increase in PPT (p < 0.05) were seen only in the laser group when comparing the baseline and end-of-treatment values. Both groups showed a decrease in pain intensity at the end of treatment. LLLT promoted an improvement in MP and PPT of the masticatory muscles.

Effectiveness of low-level laser therapy in temporomandibular disorders: a systematic review and meta-analysis

AIM

To assess the scientific evidence on the efficacy of low-level laser therapy (LLLT) in the treatment of temporomandibular disorders (TMD).

METHODS

The databases of PubMed, Science Direct, Cochrane Clinical Trials Register, and PEDro were manually and electronically searched up to February 2010. Two independent reviewers screened, extracted, and assessed the quality of the publications. A meta-analysis- was performed to quantify the pooled effect of LLLT on pain and function in patients with chronic TMD.

RESULTS

The literature search identified 323 papers without overlap between selected databases, but after the two-phase study selection, only six randomized clinical trials (RCT) were included in the systematic review. The primary outcome of interest was the change in pain from baseline to endpoint. The pooled effect of LLLT on pain, measured through a visual analog scale with a mean difference of 7.77 mm (95% confidence interval [CI]: -2.49 to 18.02), was not statistically significant from placebo. Change from baseline to endpoint of secondary outcomes was 4.04 mm (95% CI 3.06 to 5.02) for mandibular maximum vertical opening; 1.64 mm (95% CI 0.10 to 3.17) for right lateral excursion and 1.90 mm (95% CI: -4.08 to 7.88) for left lateral excursion.

CONCLUSION

Currently, there is no evidence to support the effectiveness of LLLT in the treatment of TMD.

Low level lasers in dentistry

Low level laser therapy (LLLT) uses light energy, in the form of adenosine triphosphate (ATP), to elicit biological responses in the body. The increased cellular energy and changes in the cell membrane permeability result in pain relief, wound healing, muscle relaxation, immune system modulation, and nerve regeneration. This article investigates the clinical effects of LLLT and explains how it can be applied in the dental field.

Effectiveness of Low-Level Laser Therapy in Temporomandibular Joint Disorders: A Placebo-Controlled Study

OBJECTIVE

Low-level laser therapy (LLLT) treatment for pain caused by temporomandibular joint disorders (TMD) was investigated in a controlled study comparing applied energy density, subgroups of TMD, and duration of disorders.

BACKGROUND DATA

Although LLLT is a physical therapy used in the treatment of musculoskeletal disorders, there is little evidence for its effectiveness in the treatment of TMD.

METHODS

The study group of 61 patients was treated with 10 J/cm(2) or 15 J/cm(2), and the control group of 19 patients was treated with 0.1 J/cm(2). LLLT was performed by a GaAlAs diode laser with output of 400 mW emitting radiation wavelength of 830 nm in 10 sessions. The probe with aperture 0.2 cm(2) was placed over the painful muscle spots in the patients with myofascial pain. In patients with TMD arthralgia the probe was placed behind, in front of, and above the mandibular condyle, and into the meatus acusticus externus. Changes in pain were evaluated by self-administered questionnaire.

RESULTS

Application of 10 J/cm(2) or 15 J/cm(2) was significantly more effective in reducing pain compared to placebo, but there were no significant differences between the energy densities used in the study group and between patients with myofascial pain and temporomandibular joint arthralgia. Results were marked in those with chronic pain.

CONCLUSION

The results suggest that LLLT (application of 10 J/cm(2) and 15 J/cm(2)) can be considered as a useful method for the treatment of TMD-related pain, especially long lasting pain.

Evaluation of Low-Level Laser Therapy in the Treatment of Temporomandibular Disorders

OBJECTIVE

The purpose of this study was to assess the effectiveness of low-level laser therapy (LLLT) in the treatment of myogenic originated temporomandibular disorders (TMD).

BACKGROUND DATA

Limited studies have demonstrated that LLLT may have a therapeutic effect on the treatment of TMD.

METHODS

Thirty-nine patients with myogenic TMD-associated orofacial pain, limited mandibular movements, chewing difficulties, and tender points were included in this study. Twenty-four of them were treated with LLLT for 10 sessions per day excluding weekends as test group, and 15 patients with the same protocol received placebo laser treatment as a control group. These parameters were assessed just before, just after, and 1 month after the treatment.

RESULTS

Maximal mouth-opening improvement, and reductions in pain and chewing difficulty were statistically significant in the test group when compared with the control group. Statistically significant improvements were also detected between two groups regarding reduction in the number of tender points.

CONCLUSION

Based on the results of this placebo-controlled report, LLLT is an appropriate treatment for TMD and should be considered as an alternative to other methods.

Pain relief by single low-level laser irradiation in orthodontic patients undergoing fixed appliance therapy

INTRODUCTION

The objective of this study was to analyze the effect of single low-level laser therapy (LLLT) irradiation on pain perception in patients having fixed appliance treatment.

METHODS

Seventy-six patients (46 women, 30 men; mean age, 23.1 years) enrolled in this single-blind study were assigned to 2 groups. The patients in group 1 (G1; 38 patients, 13 men, 25 women; mean age, 25.1 years) received a single course of LLLT (Mini Laser 2075, Helbo Photodynamic Systems GmbH & Co KG, Linz, Austria; wavelength 670 nm, power output 75 mW) for 30 seconds per banded tooth. The patients in group 2 (G2; 38 patients, 17 men, 21 women; mean age, 21.0 years) received placebo laser therapy without active laser irradiation. Pain perception was evaluated at 6, 30, and 54 hours after LLLT by self-rating with a standardized questionnaire.

RESULTS

Major differences in pain perception were found between the 2 groups. The number of patients reporting pain at 6 hours was significantly lower in G1 (n = 14) than in G2 (n = 29) (P <.05), and the differences persisted at 30 hours (G1, n = 22; G2, n = 33) (P <.05). At 54 hours, no significant differences were seen between the number of patients reporting pain (G1, n = 20; G2, n = 25), although the women had a different prevalence between G1 (n = 11) and G2 (n = 15) (P = .079). At 6, 30, and 54 hours, more than 90% of the subjects in both groups described the pain as "tearing."

CONCLUSIONS

LLLT immediately after multibanding reduced the prevalence of pain perception at 6 and 30 hours. LLLT might have positive effects in orthodontic patients not only immediately after multibanding, but also for preventing pain during treatment.

Antinociceptive effect of Er:YAG laser irradiation in the orofacial formalin test

Low-power, soft, or low-level laser irradiation has been successfully used to provide analgesia in injured or diseased tissues. In this study, we tested the possible antinociceptive effect of laser irradiation when applied to a normal tissue before the onset of a painful stimulus. Male Wistar rats (350-380 g) were used. A 1.5% formalin solution (50 microL s.c., diluted in saline) was injected into the right upper lip of the test animals (n = 9) immediately after 10 min of low-power Er:YAG laser irradiation (wavelength: 2.94 microm; energy: 0.1 J/cm(2)/pulse at 10 Hz). Control animals (n = 9) were restrained for 10 min without laser application. The nociceptive response, i.e., the amount of time the rats spent rubbing the formalin injected area, was measured by an investigator blind to whether the animals had been laser irradiated or not. On laser irradiated rats, significantly less nociceptive behavior was observed only during the late phase (12-39 min) of the test. This result is similar to that reported for nonsteroid antiinflammatory drugs (NSAIDs) and other peripherally acting antiinflammatory agents. We conclude that low-power laser irradiation have a tonic antinociceptive effect on inflammatory pain even when applied before tissue injury.

Effectiveness of low-level laser therapy in temporomandibular disorder

OBJECTIVE

To investigate the effectiveness of low-level laser therapy in the treatment of temporomandibular disorder and to compare treatment effects in myogenic and arthrogenic cases.

METHODS

Thirty-five patients were evaluated by magnetic resonance imaging and randomly allocated to active treatment (n=20) and placebo treatment (n= 15) groups. In addition to a daily exercise program, all patients were treated with fifteen sessions of low-level laser therapy. Pain, joint motion, number of joint sounds and tender points were assessed.

RESULTS

Significant reduction in pain was observed in both active and placebo treatment groups. Active and passive maximum mouth opening, lateral motion, number of tender points were significantly improved only in the active treatment group. Treatment effects in myogenic and arthrogenic cases were similar.

CONCLUSION

Low-level laser therapy can be considered as an alternative physical modality in the management of temporomandibular disorder.

Low-level laser therapy is an important tool to treat disorders of the maxillofacial region

OBJECTIVES

The authors report on the effects of low-level laser therapy (LLLT) in the treatment of maxillofacial disorders.

SUMMARY AND BACKGROUND DATA

Further to our previous studies, this paper reports the results of the use of LLLT on the treatment of several disorders of the oral and maxillofacial region. This paper presents LLLT as an effective method of treating such disorders.

METHODS

Two hundred and five female and 36 male patients ages between 7 and 81 years old (average 38.9 years old), suffering from disorders of the maxillofacial region, were treated with 632.8, 670, and 830 nm diode lasers at the Laser Center of the Universidade Federal de Pernambuco, Recife, Brazil (UFPE). The disorders included temporomandibular joint (TMJ) pain, trigeminal neuralgia, muscular pain, aphatae, inflammation, and tooth hypersensitivity postoperatively and in small hemangiomas. Most treatment consisted of a series of 12 applications (twice a week) and in 15 cases a second series was applied. Patients were treated with an average dose of 1.8 J/cm2.

RESULTS

One hundred fifty four out of 241 patients were asymptomatic at the end of the treatment, 50 improved considerably, and 37 were symptomatic.

CONCLUSIONS

These results confirm that LLLT is an effective tool and is beneficial for the treatment of many disorders of the maxillofacial region.

Soft laser irradiation induced pain reduction in orthodontic treatment

It has been emphasized that pain reduction without analgesic drugs is necessary in orthodontic treatment. Especially, needed is reduction after the initial wire application. Soft laser irradiation has been applied in dental clinics, and we reported its effectiveness in pain reduction in orthodontic treatment. In this study, we evaluated the continuous effects of the laser irradiation by questionnaire and pulp sensitization measured by pulp electrodiagnosis. The laser irradiation time required for pain reduction was also examined. We confirmed that soft laser irradiation produced an effective pain reduction in orthodontic treatment.

Low level laser therapy in the treatment of temporomandibular disorders (TMD): a double-blind pilot study

The aim of this paper was to evaluate the efficacy of a Low-Level Laser therapy in patients with Temporomandibular Disorders (TMD) using a double-blind design. A sample of 20 patients with a chief complaint of pain was divided into myogenous and arthrogenous groups. The sample was also divided on the basis of the treatment rendered: real versus placebo treatment. An 830 nm Ga-Al-As Laser device with a energy power of 4 joules was used (OMNILASE, LASERDYNE PTY LTD.) in three treatment sessions. To evaluate the effectiveness of laser treatment, a Visual Analogue Scale (VAS) was used for pain and active range of motion (AROM) was used to measure changes in mandibular function. Using real laser treatment, the author found that there was a reported improvement in pain only for the myogenous pain patients (p < or = 0.02). For the arthrogenous pain patients, real laser treatment resulted in an improvement in Total Vertical Opening (TVO) (p < 0.05), Protrusive excursion (PROT) (p < 0.02) and Left lateral excursion (LATLEF) (p < 0.02). The placebo control group showed improvement in TVO and PROT for those patients having myogenous pain and LATLEF for those patients having arthrogenous pain. A repeated measurement one-way ANOVA demonstrated no significant differences between real and placebo groups. Considering the non-invasive and harmless characteristics of this modality, more research is recommended, using higher power and increased frequency of laser applications.

Clinical analysis of mid-laser versus placebo treatment of arthralgic TMJ degenerative joints

Laser therapy has been found effective in the management of pain associated with rheumatoid and degenerative joint arthritis and disease. The efficacy of mid-laser therapy has been tested specifically on patients with degenerative joint disease (DJD) involving the temporomandibular joint (TMJ). The following controlled clinical study was designed to test the efficacy of mid-laser therapy to placebo therapy in the reduction of pain associated with TMJ disorders specific to arthralgic DJD.