The Effects of Photobiomodulation Therapy on Post-Surgical Pain

Pulsed red light photobiomodulation ameliorates oxytocin-induced primary dysmenorrhea in mice by inhibiting oxidative stress and lipid accumulation

Photobiomodulation (PBM) has gained attention as a kind of anti-pain or anti-inflammation therapy, yet its efficacy in mitigating the symptoms and underlying metabolic disturbances of primary dysmenorrhea remains underexplored. Here, 630 nm light reduced menstrual pain and prostaglandin F2a/prostaglandin E2 dysregulation, regulated oxidation and lipid peroxidation levels, and improved uterus damage in oxytocin-induced mice. Notably, pulsed wave (PW) treatment exhibited superior efficacy compared to continuous wave application. Hence, this research focused on the effects of 630 nm PW on oxytocin-induced mice by examining changes in the uterine transcriptome and plasma metabolome. Results from integrated analyses revealed significant modifications primarily in antioxidant and lipid metabolism pathways, alongside shifts in biomarkers related to arachidonic acid metabolism. Quantitative real-time PCR confirmed the downregulation of critical genes associated with oxidative stress and inflammation, as well as the suppression of uterine smooth muscle contractions and lipid overaccumulation. These findings support the potential of 630 nm PW PBM as a viable option for clinical interventions in dysmenorrhea management.

Neoangiogenetic potential of Nd:YAG 1064 nm photobiomodulation in non-surgical healing of trauma induced periapical bone defects: a clinicalprospective pilot study

To evaluate Nd: YAG 1064 nm photobiomodulation as a therapeutic adjunct for non-surgical management of trauma-induced periapical bone defects. The present study was a parallel-group, double arm, single-centre clinical, prospective, pilot study. Thirty systematically healthy individuals with radiographic evidence of trauma-induced periapical bone defects in anterior teeth were recruited. Twenty-four patients meeting the inclusion criteria were selected and randomly placed in two treatment groups. Group A: Non-surgical endodontic treatment with intracanal calcium hydroxide-iodoform paste (CH-I), and Group B: Non-surgical endodontic treatment with intracanal calcium hydroxide and adjunctive extracanal Nd:YAG 1064 nm photobiomodulation therapy (PBMT). Improvement in vascular perfusion, reduction in size, volume, area and echogenicity of the lesion was assessed with ultrasound and colour Doppler imaging. The peak systolic velocity increased statistically significantly (p < 0.05) from baseline to 3 and 6 months, suggesting PBMT as a facilitator of neoangiogenesis. Compared to the calcium hydroxide group, the PBM group showed a more significant mean reduction in size, volume, and surface area of the periapical lesion and lower post-operative pain scores, though not statistically significant. Also, the PBM group presented with more remarkable hard tissue development, as seen by an improvement in echogenicity from hypoechoic to predominantly hyperechoic or hyperechoic. Results suggest that PBMT with Nd: YAG can accelerate healing, enhance perfusion of periapical lesions, provide analgesia, and reduce the need for pharmacological drugs. Although the sample size is limited, this research offers a foundation for further clinical studies with larger sample sizes to evaluate the additional benefits of laser therapy in periapical healing. The study was submitted to the Clinical Trails Registry-India (CTRI), under reference no/2023/02/063428, with a registration number/2023/09/057848, before the commencement of the study.

The Impact of Photobiomodulation Therapy on Swelling Reduction and Recovery Enhancement in Total Knee Arthroplasty: A Randomized Clinical Trial

Background: Total knee arthroplasty (TKA) is commonly performed for severe osteoarthritis but often results in significant postoperative swelling and discomfort, impacting early rehabilitation. Photobiomodulation therapy (PBMT), utilizing low-level laser therapy (LLLT), has emerged as a potential adjunctive treatment to alleviate these symptoms. Methods: In this single-center, nonblinded prospective randomized clinical trial, conducted from May to July 2024, 30 patients undergoing primary TKA were enrolled and divided into two groups. Fifteen patients formed the control group receiving standard postoperative care, while the intervention group consisted of another 15 patients who received additional PBMT from the first to the fifth postoperative day (POD). The swelling was assessed using bioimpedance analysis, which offers a noninvasive, safe, and efficient method for assessing postoperative swelling by measuring tissue impedance, and functional outcomes were measured using the 2-min walk test (2MWT) and active range of motion (aROM). The study was registered with ClinicalTrials.gov (NCT06426251). Results: The PBMT group demonstrated significantly lower impedance, reactance, and phase angle ratios by POD6, suggesting reduced swelling compared to the control group. In the 2MWT, the PBMT group achieved a longer walking distance of 27 m, compared to 16 m in the control group. However, there were no significant differences in aROM or Visual Analogue Scale (VAS) pain scores between the groups. Conclusions: The findings indicate that PBMT effectively reduces postoperative swelling and enhances early mobility post-TKA. These benefits suggest that PBMT can be a valuable addition to conventional postoperative care, potentially accelerating functional recovery, and reducing rehabilitation time.

Pulsed Red Photobiomodulation Boosts the Inhibition of Oxytocin-Induced Primary Dysmenorrhea in Mice by Suppressing Oxidative Stress and Inflammation

Increasing evidence has underscored the pivotal role of red photobiomodulation (R-PBM) in analgesic and anti-inflammatory processes; nonetheless, research concerning the effects of pulsed wave on primary dysmenorrhea (PD) remains sparse. This study found that pulsed R-PBM significantly diminished pain responses and levels of PGF2α/PGE2, mitigated uterine swelling, augmented antioxidant capacity, and lowered MDA concentrations, which outperformed continuous wave at the same average irradiance. Furthermore, PW treatment substantially reduced ROS levels and enhanced cell viability in PGF2α induced HUSM cells. NOS levels, especially iNOS, were markedly diminished in the uteri of PD mice, accompanied by significant alterations in inflammation-related genes (Jun, Fos, IL1rn, IL17b) and protein levels, along with pronounced downregulation of calcium ion concentrations after pulsed R-PBM intervention. These findings indicated that pulsed R-PBM may mitigate pain by modulating ROS and NO/NOS, mediated oxidative stress and inflammatory responses. Consequently, pulsed R-PBM emerges as a promising therapeutic strategy for PD.

The synergistic effect of pulsed red light and leonurus inhibits primary dysmenorrhea induced by oxytocin in mice by modulating calcium signaling and inhibiting inflammatory responses

Despite increasing evidence suggesting that red light photobiomodulation (R-PBM) and leonurus play important roles in analgesic and anti-inflammatory processes, data on their combined effect on primary dysmenorrhea (PD) are scarce. In this study, we reported the pain assessment of red light at various modes combined with leonurus on the oxytocin-induced model of PD mice. The combined intervention of pulsed R-PBM and leonurus decreased pain responses and PGF2α/PGE2 levels, alleviated uterine swelling and inflammatory infiltration, enhanced antioxidant levels (T-AOC, GSH-PX, SOD), and reduced lipid peroxidation (MDA, LPO) in the uterus, with its synergistic effect surpassing either treatment alone or the combination of continuous wave R-PBM with leonurus. Transcriptomic analysis demonstrated significant changes in differentially expressed genes associated with calcium signaling (Cav1, Cacna1c, Kcnmb1, Cnn1, and Myh11) and inflammatory response (Ptgs2, Jun, Fos, IL1rn, and IL17b) in the combination group, with concurrent downregulation of MLCK, COX-2, p-JNK/JNK, and IL17b protein levels, and upregulation of IL1rn, suggesting that the combined intervention of pulsed R-PBM and leonurus may alleviate pain through disruption of calcium homeostasis and induction of ROS-mediated inflammatory responses. Metabolomics studies of plasma revealed significant changes in lipid metabolism after the combined intervention, consistent with the transcriptomic findings. Hence, pulsed R-PBM combined leonurus has the potential to be an effective therapeutic approach for PD, as well as an alternative option for painful and inflammatory diseases; however, further exploration of its underlying mechanism is still necessary.

Post-surgical photobiomodulation therapy improves outcomes following elective gastropexy in dogs

PURPOSE

To evaluate the effect of post-surgical photobiomodulation therapy in dogs.

METHODS

Twenty dogs were selected for elective gastropexy and randomly divided into a control (CG, n = 10) and a PBMT group (PBMTG, n = 10). Pre‑medication consisted of medetomidine and butorphanol. Meloxicam was administered before the procedure. Induction was performed with propofol and maintained with sevoflurane. Local blocks with lidocaine were used. Incisional gastropexy was performed in all animals. PBMTG received PBMT immediately after surgery. The need for postoperative rescue analgesia, if the animal had eaten by the evaluation momen, and pain scores were collected using the Glasgow Composite Measure Pain Scale - Short Form (CMPS‑SF) at 1, 2, 4, 6, 8, 12, 16, 20, and 24 h post‑endotracheal extubation. CMPS‑SF scores were compared with the Mann-Whitney Test and proportions of animals that required rescue analgesia and had eaten with a χ2 test. P was set at < 0.05.

RESULTS

No rescue analgesia was needed for any animal. Still, significant differences were observed in CMPS-SF scores between CG and PBMTG between 1 and 4 h post-extubation. PBMTG had a significantly higher proportion of animals eating up to the 8 h post-extubation evaluation moment.

CONCLUSION

Adding post-surgical photobiomodulation to a standard anesthesia and analgesia protocol reduced CMPS-SF scores and increased the proportion of animals that resumed eating compared to the standard protocol alone.

The use of laser photobiomodulation as pre-anesthetic tissue management technique in reducing injection pain in children

BACKGROUND

One of the main goals for pediatric dentists is to offer a painless anesthesia experience. Laser photobiomodulation is among the suggested strategies to decrease injection pain. So, this study aimed to assess the impact of laser photobiomodulation on local anesthesia (LA) injection pain in children and its effect on the efficacy of LA during pulpotomy and SSC procedures.

METHODS

The research was carried out as a randomized controlled clinical trial with two parallel group design. It involved 64 cooperative healthy children, age range from 5 to 7 years, each having at least one maxillary molar indicated for pulpotomy. Children were randomly allocated to one of the two groups based on the pre-anesthetic tissue management technique used: test group received laser photobiomodulation, while control group received topical anesthetic gel. Pain during injection, pulpotomy, and SSC procedures was assessed using physiological measures (Heart Rate (HR)), subjective evaluation (modified Face-Pain-Scale (FPS), and objective analysis (Sound-Eye-Motor scale (SEM)).

RESULTS

A total of 64 children with mean age 6.23 ± 0.78 participated in this research. The mean HR scores were significantly lower in the laser PBM group during buccal and palatal infiltration injections. The SEM mean scores were significantly lower in the laser PBM group during both injections. For the FPS scale, the number of children who recorded satisfaction during injection was significantly higher in laser PBM group. There was no statistically significant difference in mean HR as well as in SEM and FPS scores between the two groups during pulpotomy and SSC procedures. Comparisons between the two study groups were performed using independent samples t- and Mann-Whitney U tests. Significance was set at p value < 0.05.

CONCLUSION

Laser photobiomodulation is a promising non-pharmacological pre-anesthetic tissue management technique in children that offered less painful injection compared to topical anesthetic gel without compromising the effectiveness of LA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05861154. Registered on 16/5/2023.

Effect of photobiomodulation on alleviating primary dysmenorrhea caused by PGF2α

Photobiomodulation (PBM) has attracted widespread attention in suppressing various pain and inflammation. Primary dysmenorrhea (PD) primarily occurs in adolescents and adult females, and the limited effectiveness and side effects of conventional treatments have highlighted the urgent need to develop and identify new adjunct therapeutic strategies. In this work, the results of pain and PGs demonstrated that 850 nm, 630 nm, and 460 nm all exhibited pain inhibition, decreased PGF2α and upregulated PGE2, while 630 nm PBM has better effectiveness. Then to explore the underlying biological mechanisms of red light PBM on PD, we irradiated prostaglandin-F2α induced HUSM cells and found that low-level irradiance can restore intracellular calcium ion, ROS, ATP, and MMP levels to normal levels. And, red light enhanced cell viability and promoted cell proliferation for normal HUSM cells. Therefore, this study proposes that red light PBM may be a promising approach for the future clinical treatment of PD.

Relationship between Laser Intensity at the Peripheral Nerve and Inhibitory Effect of Percutaneous Photobiomodulation on Neuronal Firing in a Rat Spinal Dorsal Horn

Photobiomodulation is an effective treatment for pain. We previously reported that the direct laser irradiation of the exposed sciatic nerve inhibited firing in the rat spinal dorsal horn evoked by mechanical stimulation, corresponding to the noxious stimulus. However, percutaneous laser irradiation is used in clinical practice, and it is unclear whether it can inhibit the firing of the dorsal horn. In this study, we investigated whether the percutaneous laser irradiation of the sciatic nerve inhibits firing. Electrodes were inserted into the lamina II of the dorsal horn, and mechanical stimulation was applied using von Frey filaments (vFFs) with both pre and post laser irradiation. Our findings show that percutaneous laser irradiation inhibited 26.0 g vFF-evoked firing, which corresponded to the noxious stimulus, but did not inhibit 0.6 g and 8.0 g vFF-evoked firing. The post- (15 min after) and pre-irradiation firing ratios were almost the same as those for direct and percutaneous irradiation. A photodiode sensor implanted in the sciatic nerve showed that the power density reaching the sciatic nerve percutaneously was attenuated to approximately 10% of that on the skin. The relationship between the laser intensity reaching the nerve and its effect could be potentially useful for a more appropriate setting of laser conditions in clinical practice.

Combined Photobiomodulation and Static Magnetic Fields to Reduce Side Effects from Laser and Radiofrequency Treatments for Dermatological Conditions

Background

Photobiomodulation therapy (PBMT) can significantly reduce inflammation and relieve pain, including postoperative pain and edema. The study aimed to evaluate the performance of a photobiomodulation-based device that includes a static magnetic field (SMF) to treat laser- or intensive and fractional radiofrequency-related side effects, such as pain, redness, and edema in patients treated for different dermatological conditions.

Methods

The study had a prospective, non-randomized, single-center design. Male and female patients aged 18 years or older underwent one or two PBMT-SMF (anti-inflammatory or anti-edematous) sessions on the same day, once or twice a week, after laser or radiofrequency facial treatments due to various dermatological disorders. Variables and efficacy assessments were pain, redness, edema, and their reduction from baseline to the last visit.

Results

Twenty-seven patients were included, seven (25.9%) men and 20 (74.1%) women, with a mean (SD) age of 43.7 (14.1) years. Seven (25.9%) patients were treated with radiofrequency, and 20 (74.1%) patients with a vascular laser (three [15%] for angioma, two [10%] for scars, three [15%] for erythrosis, and 12 [60%] for rosacea). After the PBMT-SMF protocol, overall mean pain reduction was 40 percent, and redness and edema reduction were shown by the pictures taken before and after the PBMT-SMF procedure.

Limitations

The primary limitations were the small number of patients and no quantitative variables for redness and edema.

Conclusion

PBMT-SMF reduced edema and inflammation after treatment with lasers or intensive or fractional radiofrequency for facial conditions, and probably, analgesic and anti-inflammatory drugs.

TECAR Therapy Associated with High-Intensity Laser Therapy (Hilt) and Manual Therapy in the Treatment of Muscle Disorders: A Literature Review on the Theorised Effects Supporting Their Use

Background: It has been estimated that between 30 and 50 per cent of all injuries that take place throughout participation in a sport are the consequence of soft tissue injuries, and muscle injuries are the primary cause of physical disability. Methods: The current literature review was designed between October 2021 and April 2022, according to the PRISMA standards, using the PubMed, Scopus, and Web of Science databases. At the screening stage, we eliminated articles that did not fit into the themes developed in all subchapters of the study (n = 70), articles that dealt exclusively with orthopaedics (n = 34), 29 articles because the articles had only the abstract visible, and 17 articles that dealt exclusively with other techniques for the treatment of musculoskeletal disorders. The initial search revealed 343 titles in the databases, from which 56 duplicate articles were automatically removed, and 2 were added from other sources. Results: The combination of these three techniques results in the following advantages: It increases joint mobility, especially in stiff joints, it increases the range of motion, accelerates tissue repair, improves tissue stability, and extensibility, and it reduces soft tissue inflammation (manual therapy). In addition, it decreases the concentration of pro-inflammatory mediators and improves capillary permeability, resulting in the total eradication of inflammation (HILT). It warms the deep tissues, stimulates vascularity, promotes the repose of tissues (particularly muscle tissue), and stimulates drainage (TECAR). Conclusions: TECAR therapy, combined with manual therapy and High-Intensity Laser therapy in treating muscle diseases, presented optimal collaboration in the recovery process of all muscle diseases.

Therapeutic Effect of a Low-Level Laser on Acute Pain and Post-operative Mouth Opening After Closed Reduction of Mandibular-Condylar Fracture

Introduction: The purpose of this study was to determine the therapeutic effect of low-level laser therapy (LLLT) on acute pain and the range of mouth opening after condylar closed reduction surgery. The use of low-level lasers, especially to reduce inflammation and pain, has received more attention in recent years. The results of many studies performed in this field are contradictory, and the effectiveness of low-level lasers in the treatment of patients is still uncertain. Methods: This study was performed as a randomized, double-blinded clinical trial on 40 patients with condylar closed reduction surgery. Patients were randomly assigned to two groups of 20 patients, including the placebo and intervention groups. In the intervention group, the patients received LLLT (100 mw, 2 J/cm², 20 S/point, 14 extraoral points, 7 days). The range of jaw movements after opening the intermaxillary-fixation was measured. Patients' pain was assessed using the visual analog scale (VAS). Data were analyzed using SPSS software version 21, the chi-square test, and repeated measures ANOVA. Results: There was no significant difference between the study groups in terms of the range of jaw motions. The mean VAS score was 56.85 (SD=3.817) in the intervention group and 60.95 (SD=4.861) in the placebo group, showing a statistically significant difference between the two groups at the end of the study (P=0.007) Conclusion: The results of this study indicated the effectiveness of low-level lasers in reducing acute pain in patients undergoing closed condylar surgery. Iranian Registry of Clinical Trials (IRCT20200520047519N1).

Photobiomodulation for Lowering Pain after Tonsillectomy: Low Efficacy and a Possible Unexpected Adverse Effect

Background: Tonsillectomy is one of the most common surgical procedures performed in children as a treatment for obstructive sleep apnea due to tonsil hypertrophy or highly recurrent tonsillitis. Odynophagia, associated with food refusal for the first few days, is a common post-operative complaint. Available drugs for pain management, while efficacious, present some drawbacks, and a novel strategy would be welcome. Photobiomodulation (PBMT), in this context, can represent a possible choice, together with pharmacological therapy. The aim of this study was to evaluate PBMT effects compared to standard pain therapy on nociceptive sensation at different time points and administration of painkiller. Methods: A registered, controlled, randomized, double-blind clinical trial was performed. Twenty-two patients were recruited and divided into laser-treated (T) or untreated (UT) groups, based on random assignment. In T group, immediately after tonsillectomy, performed with cold dissection technique, laser light was applied to the surgery site (using a Cube 4 from Eltech K-Laser s.r.l., Treviso, Italy), and then hemostasis was performed using bismuth subgallate paste. In C group, the same procedure was performed, except that laser light was switched off. The primary outcome was the difference in pain scores between subject receiving photobiomodulation (PBMT) and subjects receiving standard care after 24 h; the secondary outcomes were pain scores at awakening and at 48 h together with distress (delirium) at awakening. Results: Two patients from the T group experienced a post-surgery bleeding, and one of them required revision of the hemostasis under general anesthesia. A preliminary analysis of pain sensation reported by the patients or caregivers did not show differences between treated and untreated subjects. Conclusion: These data suggest that PBMT could increase post-surgical bleeding.

Treatment of carpal tunnel syndrome by low-level laser therapy versus corticosteroid injection: a randomized, prospective clinical study

To compare the effects of low level laser therapy (LLLT) and corticosteroid injection in patients with moderate carpal tunnel syndrome (CTS). Eighty-seven patients (143 wrists) with moderate CTS were randomized to the corticosteroid or LLLT groups. 40 mg of triamcinolone acetate solution was applied to carpal tunnel of 44 patients (74 wrist). LLLT was applied to 43 patients (70 wrist) five times a week, for a total of 15 sessions (fluence of 6 j/cm² for 1 min per point at a wavelength of 830 nm). Outcome measures were numbness and pain, QuickDASH questionnaire, grasping tests, Tinel and Phalen tests, electrophysiological tests and MRI evaluations, which were tested at the baseline and 1st and 6th months after the treatment. Eighty patients (133 wrists) completed the study at the end of 6 months. VAS and Quick DASH scores were better in the corticosteroid group in the 1st month, but there were no significant differences between groups in the 6th month. Phalen and Tinel tests, strength tests, and motor distal latency improved significantly and similarly in both groups at the 1st and 6th months. Sensory distal latency and sensory nerve conduction velocity showed significant improvements in the 1st and 6th months only in the corticosteroid group. In both groups, median nerve intensity rate and palmary spring rate improved significantly after the treatment. Based on this study, corticosteroid injection and LLLT groups showed statistically significant difference at the 1st month (short-term), whereas there was no significant difference at the 6th month (intermediate-term).

Low-level laser therapy is effective in controlling postoperative pain in lower third molar extractions: a systematic review and meta-analysis

This systematic review aimed to evaluate the effectiveness of low-level laser therapy in controlling postoperative pain in lower third molar extractions. A search was carried out in MEDLINE/PubMed, Web of Science and Cochrane Library (CENTRAL) databases, using the "low-level laser therapy", "photobiomodulation therapy", "impacted mandibular third molar", "mandibular third molar", "third molar extraction" descriptors and 2625 studies were found, including only randomized clinical trials published until July 2020, with no restrictions on language and country of study. Selected studies were submitted to initial screening based on the reading of titles, abstracts and full article, and duplicate studies were excluded. Overall, 2562 articles were found, of which only 15 randomized clinical trials were included in this review. A total of 648 patients (16-44 years) who received low-level laser therapy as an intervention and placebo in their control group were evaluated. The pain evaluation criterion was the Visual Analog Scale (VAS) on the second and seventh days after surgery. Photobiomodulation with low-level laser showed statistically significant reduction in postoperative pain in lower third molar extractions, both on the second (MD: - 0.59; CI: - 0.92, - 0.27) and seventh day after surgery (MD: - 0.76; CI: - 1.21, - 0.32).

Dosage Effects of an 810 nm Diode Laser on the Proliferation and Growth Factor Expression of Human Gingival Fibroblasts

Introduction: A substantial amount of evidence supports the positive effect of photobiomodulation on the proliferation and differentiation of various cell types. Several laser wavelengths have been used for wound healing improvement, and their actual outcome depends on the settings utilized during irradiation. However, the heterogeneous wavelengths and laser settings applied in the existing literature make it difficult to draw solid conclusions and comparison of different studies. The aim of the present study is to evaluate and compare the effects of various doses of laser energy, provided by an 810 nm diode, on human gingival fibroblasts in terms of proliferation and expression of growth factors with a pivotal role in wound healing. Methods: Human gingival fibroblasts were cultured on plastic tissue culture and irradiated with 2, 4, 6 or 12 J/cm². The effects of the low-level laser therapy (LLLT) using an 810 nm diode laser on growth factor expression (EGF, TGF and VEGF) were evaluated by qPCR at 72 hours and 7 days after irradiation. Cell proliferation was evaluated at 24, 48 and 72 hours after LLLT using MTT assay. Results: Energy density of 12 J/cm² provoked irradiated gingival fibroblasts to demonstrate significantly higher proliferation as well as higher gene expression of Col1, VEGF and EGF. LLLT positive effects were obvious up to 7 days post-irradiation. Conclusion: LLLT with 810 nm presents beneficial effects on proliferation, collagen production and growth factor expression in human gingival fibroblast cells. The application of 12 J/cm² can be suggested as the optimal energy density for the enhancement of the wound healing process.

Mechanisms and Pathways of Pain Photobiomodulation: A Narrative Review

A growing body of evidence supports the modulation of pain by light exposure. As such, phototherapy is being increasingly utilized for the management of a variety of pain conditions. The modes of delivery, and hence applications of phototherapy, vary by wavelength, intensity, and route of exposure. As such, differing mechanisms of action exist depending upon those parameters. Cutaneous application of red light (660 nm) has been shown to reduce pain in neuropathies and complex regional pain syndrome-I, whereas visual application of the same wavelength of red light has been reported to exacerbate migraine headache in patients and lead to the development of functional pain in animal models. Interestingly visual exposure to green light can result in reduction in pain in variety of pain conditions such as migraine and fibromyalgia. Cutaneous application typically requires exposure on the order of minutes, whereas visual application requires exposure on the order of hours. Both routes of exposure elicit changes centrally in the brainstem and spinal cord, and peripherally in the dorsal root ganglia and nociceptors. The mechanisms of photobiomodulation of pain presented in this review provide a foundation in furtherance of exploration of the utility of phototherapy as a tool in the management of pain. PERSPECTIVE: This review synopsizes the pathways and mechanisms through which light modulates pain and the therapeutic utility of different colors and exposure modalities of light on pain. Recent advances in photobiomodulation provide a foundation for understanding this novel treatment for pain on which future translational and clinical studies can build upon.

Photobiomodulation therapy reduces postoperative pain after third molar extractions: A randomized clinical trial

Background

To assess the efficacy of PBMT on reducing postoperative pain scores in patients submitted to third molar extractions.

Material and Methods

A randomized controlled trial (ReBEC:RBR-94BCKZ) was designed according to the SPIRIT and followed the CONSORT. Patients were randomly allocated according to control or PBMT groups. PBMT consisted of the application of GaAlAs laser (808nm;50mW) applied in six points (1.23 min;11 J/cm2) after extraction. Pain scores were assessed using the Visual Analogue Scale (VAS) in millimeters evaluated after 6 (T6), 24 (T24), and 48 (T48) hours. The Wilcoxon Mann–Whitney test was used to check for possible associations between VAS scores and treatment groups.

Results

A total of 101 third molar extractions were performed in 44 patients. The mean age was 28 years old(SD±11.54). Comparing control and intervention, PBMT group showed a significant effect on the reduction of postoperative pain at T6(mean VAS=0.9; C.I:0.63–1.16) compared to control (mean VAS=2.5;C.I:2.1–2.88)(p<0.001). The same statistically significant effect on the reduction of postoperative pain was observed at T24 (PBMT mean VAS=0.72;C.I:0.51–0.93; control mean VAS=2.86;C.I:2.40–3.31;p<0.001) and T48 (PBMT mean VAS=0.64;C.I:0.36–0.92; control mean VAS=2.86;C.I:2.37–3.34;p<0.001).

Conclusions

PBMT significantly reduce the postoperative pain scores when assessed 6, 24, and 48 hours after third molar extractions.

Key words:Controlled clinical trial, gallium aluminium arsenide lasers, third molar.

Photobiomodulation and Miescher's cheilitis granulomatosa: case report

Background

Miescher's cheilitis granulomatosa (MCG) is a rare chronic inflammatory disease and is known as the monosymptomatic clinical form of Melkersson-Rosenthal syndrome (MRS). It is characterised by swelling of one or both lips and more frequently affects the upper lip. Histopathological findings show the presence of numerous inflammatory infiltrates and granuloma formations. Pharmacological treatments and surgery have provided results that are positive yet insufficiently stable in the long term. The clinical case described is of a 68-year-old female patient with a diagnosis of MCG of the upper lip.

Case presentation

The patient was diagnosed and treated at the Oral Medicine and Oral Pathology outpatient clinic of Maxillofacial and Odontostomatology Unit, Fondazione Cà Granda IRCCS Ospedale Maggiore Policlinico. The patient was recommended localised treatments of photobiomodulation (PBM) using a diode laser with a 635 nm and 980 nm dual-wavelength (λ) approach, a 600-micron fibre, and a handpiece with a 1-cm-diameter lens at 300 mW. Three treatments a week were administered for four weeks for a total of 12 treatment sessions (T ₁-T ₁₂). After that, the patient had a long follow-up period of about 2 years. The therapeutic results were clear from the initial stages of treatment. There was an immediate, gradual, and consistent reduction in labial swelling. A reduction in the size of the lip by about 35% at T ₁₀-T ₁₂ was observed, returning the size and volume of the upper lip within the normal clinical range. The painful symptoms subsided after the seventh treatment (T ₇). The histopathological check at 3 months and the follow-up in particular confirmed the disease was in remission with satisfactorily stable treatment results. Moreover, the patient did not use any other treatments on the area from the early laser treatments through to the end of the follow-up period.

Conclusions

Our experience describes a clinical case of MCG treated with PBM and effectively resolved with a reduction of the lip swelling. The real success of the treatment emerged over time, showing that the tissue healing was stable. In absence of any collateral phenomena, this confirms the effective and documented therapeutic potential of PBM for chronic inflammatory infiltrates.

Laser-photobiomodulation on experimental cancer pain model in Walker Tumor-256

CONTEXT

Cancer Pain is considered a common and significant clinical problem in malignant neoplasms, comprising 20% to 50% of all patients with tumor progression. Laser photobiomodulation (L-PBM) has been used in a multitude of pain events, ranging from acute trauma to chronic articular. However, L-PBM has never been tested in cancer pain.

OBJECTIVES

Evaluate hyperalgesia, edema, COX-1, COX-2, IL-10, and Bdkrb1 mRNA in low-level laser irradiated Walker-256 tumor-bearing rats.

METHODS

Rat hind paw injected with Walker Tumor-256 (W-256) and divided into six groups of 6 rats: G1 (control) - W-256 injected, G2- W-256 + Nimesulide, G3- W-256 + 1 J, G4- W-256 + 3 Jand G5- W256 + 6 J. Laser parameters: λ = 660 nm, 3.57 W/cm², Ø = 0.028 cm². Mechanical hyperalgesia was evaluated by Randall-Selitto test. Plethysmography measured edema; mRNA levels of COX-1, COX-2, IL-10, and Bdkrb1were analyzed.

RESULTS

It was found that the W-256 + 1 J group showed a decrease in paw edema, a significant reduction in pain threshold. Higher levels of IL-10 and lower levels of COX-2 and Bdkrb1 were observed.

CONCLUSION

Results suggest that 1 J L-PBM reduced the expression of COX-2 and Bdkrb1 and increasing IL-10 gene expression, promoting analgesia to close levels to nimesulide.

Photobiomodulation as oedema adjuvant in post-orthognathic surgery patients: A randomized clinical trial

OBJECTIVE

Photobiomodulation therapy (PBMT) has been used in multiple applications in general medicine as powerful anti-inflammatory, analgesic and reducing oedema in different parts of the body. The aim of this study is to compare the effect on post-surgical oedema after mandibular orthognathic surgery, between two different laser power densities and oral medication with non-steroidal anti-inflammatory.

MATERIALS AND METHODS

In a randomized clinical trial, on 60 patients who were subject to mandibular orthognathic surgery were divided into three groups. All groups received sodium naproxen 250mg every 8hours for 6days. Two groups were irradiated with two different laser application protocols and the other was a control group. In G1 group the irradiation parameters three times per week for two weeks were: 940nm, in continuous mode, 2.5W, 120s, 85.71J/cm2, 0.89W/cm2, over the right and left side with a distance from the skin surface of 1mm with the whitening handpiece (spot size of 2.8cm2). In G2, the irradiation parameters three times a week for two weeks were: 940nm, in continuous mode, 4.1W, 120s, 68.33J/cm2, 0.58W/cm2 over the right and left side with a distance from the skin surface of 15mm, with the deep tissue handpiece (spot size of 7.1cm2). In all the groups, millimetric facial measurements were taken from tragus to lateral commissure, and from lateral commissure to gonion in both sides.

RESULTS

All differences between T1 and T6 were significant for the three groups, (paired T, P<0.05). The differences between the groups were generally not significant (P>0.05) except for commissure - right and left gonion when compared G1 vs CG (P<0.05) and G2 vs CG (P<0.05). Initial changes (T1-T2) between groups were significantly different except for the measurement from commissure to right tragus G1 vs CG (P=0.411) and from commissure to left tragus G2 vs CG (P=0.94). The faster resolution of the oedema occurred in G2 group. PTBM with an energy density of 68.33J/cm2 was the most effective adjuvant to oral medication with non-steroidal anti-inflammatory, to decrease post-surgical oedema after mandibular orthognathic surgery.

The Beneficial Effects of High-Intensity Laser Therapy and Co-Interventions on Musculoskeletal Pain Management: A Systematic Review

Introduction: High-intensity laser therapy (HILT) has been used more recently in the therapeutic protocols of pain managements. Adding therapeutic interventions to laser therapy is usual in clinical practice. This study aimed to evaluate the efficacy of HILT and beneficial effects of adding cointerventions to HILT in musculoskeletal pain management. Methods: The following databases were searched up to August 2018: Medline, PubMed, EMBASE, Cochrane, Google Scholar, Springer and ISI. The keywords of pain, HILT, high power laser therapy, laser therapy, photobiomodulation, physical therapy and rehabilitation were searched. The quality of the articles was assessed using the PEDro scale. The primary measure was pain severity expected to be reported in all studies. Effect size was calculated as standardized mean differences divided by the standard deviation of either the treatment or other group. Results: Initially 52 potential studies were found. Eighteen of these studies were excluded based on title and abstract. The full text of 34 remaining articles was screened and 15 of the studies were excluded. All included studies had high quality (PEDro ≥7). Approximately, 94% of included articles (n=18) revealed positive effects of HILT on pain. The effect sizes for HILT and placebo/comparator groups were 0.9-9.11 and 0.21-11.22 respectively. Also, the differences of effect size between two groups were between 0.03 to 5.85. Conclusion: It is early to determine that HILT may be an effective non-invasive agent in the management of musculoskeletal pain, as few studies have shown its clinical efficacy. Adding related co-interventions to HILT may enhance the beneficial effects of laser therapy. The variability of the study methods and outcomes suggests that further long-term follow-up, randomized controlled clinical trials with appropriate methodological design are needed regarding the effectiveness of HILT on pain.

A comparative study of the dose-dependent effects of low level and high intensity photobiomodulation (laser) therapy on pain and electrophysiological parameters in patients with carpal tunnel syndrome

BACKGROUND

Carpal tunnel syndrome (CTS) is a common peripheral nerve disorder of the wrist. Nonsurgical treatments e.g. laser therapy may cause potential beneficial effects.

AIM

To compare the dose dependent effects of low level laser therapy (LLLT) and high intensity laser therapy (HILT) on pain and electrophysiology studies in patients with CTS.

DESIGN

Double-blind randomized controlled trial.

SETTING

Outpatient physiotherapy clinic.

POPULATION

Ninety-eight participants with CTS, aged between 20 to 60 years, were randomly assigned to five groups.

METHODS

All participants undertook four standard exercises, with one group serving as exercise-only controls. Patients were randomly allocated to either high or low fluence LLLT or high or low fluence HILT received over 5 sessions. All patients were assessed by visual analogue scale, median compound muscle action potential (CMAP) and sensory nerve conduction studies before and 3 weeks after the interventions.

RESULTS

VAS was significantly lower in all groups after 3 weeks (P<0.05). CMAP latency decreased in all groups. The interaction of group and time (5×2) was significant for pain (P<0.001), the latency of CMAP (P=0.001) and CMAP amplitude (P=0.02). The interaction of group and time was not significant for the CMAP conduction velocity, sensory nerve latency and amplitude (P>0.05).

CONCLUSIONS

HILT with a power of 1.6 W and low fluence of 8 J/cm² was superior in reduction of pain and improvement of the median motor nerve electrophysiological studies compared to LLLT and exercise-only control groups.

CLINICAL REHABILITATION IMPACT

LLLT and HILT in conjunction with exercise program are effective in reducing pain and improving median motor nerve conduction studies of the patients with CTS. It seems that high power and low fluence laser therapy is better than LLLT and exercise interventions to treat these patients.