Effectiveness of photobiomodulation in the treatment of primary burning mouth syndrome-a systematic review and meta-analysis

Long-Term Benefits of Photobiomodulation Therapy on Health-Related Quality of Life in Burning Mouth Syndrome Patients: A Prospective Study

Background/Objectives: Burning Mouth Syndrome (BMS) patients experience a reduction in health-related quality of life and an increased intake of medication. Photobiomodulation with low-level laser therapy has been demonstrated to be an efficacious treatment for BMS. However, its long-term benefits remain relatively unknown. This study aimed to evaluate the impact of prolonged Photobiomodulation with low-level laser therapy on BMS patients by examining the efficacy of an outpatient protocol in a real-world setting. Methods: A prospective study was designed to address the research question. Photobiomodulation was performed, irradiating the affected areas once every two weeks for 12 months. Health-related quality of life was assessed using the EQ-5D-5L questionnaire at the initial consultation and after 6 months and 12 months of treatment. Additionally, the patients' pharmacological profile was also monitored. Nonparametric statistical analysis was performed (p < 0.05 was considered statistically significant). Results: The study was completed by 15 individuals, comprising 14 females and 1 male. The results indicated a statistically significant improvement (p < 0.001) in four of the five dimensions of the health-related quality of life questionnaire, namely self-care, usual activities, pain/discomfort, and anxiety/depression, along with the patients' perceived health level. A total of 13 participants reported suspending or reducing their intake of medications for Burning Mouth Syndrome. Conclusions: Therefore, Photobiomodulation with low-level laser therapy has a positive effect on improving patients' quality of life and reducing BMS symptoms, contributing to a subsequent reduction or suspension of previous medications. These findings support the efficacy of the applied protocol. Given the innovative methodology and promising results, further research is warranted.

Toxicity evaluation of indocyanine green mediated photodynamic therapy

BACKGROUND

The aim of the study is to determine the cytotoxic, genotoxic and inflammatory effects of indocyanine green (ICG) mediated photodynamic therapy (PDT) in direct contact with L-929 mouse fibroblast cells and over a dentin barrier.

METHODS

Eight groups were evaluated; control (C), group with a dentin barrier (D), ICG applied directly on the cells (ICG), ICG applied over a dentin barrier (D-ICG), only laser applied (L), laser applied over a dentin barrier (D-L), ICG and laser applied directly on the cells (ICG-L), ICG and laser applied over a dentin barrier (D-ICG-L). Cell viability was evaluated via ATP Assay, DNA damage was evaluated via Comet Assay, and inflammatory markers IL-1β and TNF-α were assessed via ELISA test.

RESULTS

Cell viability decreased in group ICG (p<0.001). Cell viability decrease was higher in Group ICG-L (p<0.001). Cell viability decrease was lower in group D-ICG-L (p>0.05). Group L caused an increase in cell number (p<0.001). DNA damage was observed in ICG, D-ICG, and ICG-L groups (p<0.05). None of the groups displayed an increase of inflammatory markers IL-1β and TNF-α (p>0.05).

CONCLUSIONS

The presence of dentin between ICG and cells acted as a barrier and protected the cells. ICG-mediated PDT did not cause any cytotoxic, genotoxic or inflammatory effect. The use of ICG-mediated PDT for cavity disinfection is acceptable, but at this concentration its use in periodontal pocket disinfection is not recommended due to its cytotoxic and genotoxic properties.

Regeneration of taste through sonic hedgehog upregulation by photobiomodulation

This study investigated photobiomodulation (PBM) effects in Sonic hedgehog (Shh) signaling as a potential approach to taste preservation and regeneration. Primary taste cell (TC) cultures were treated with Shh antagonist vismodegib and irradiated using a continuous wave type 630 nm light-emitting diode (10 mW/cm2 ) array, with single or multiple doses of 30 J/cm2 to determine dose inducing significant upregulation effect. Shh, Ptch, Smo, and Gli1 were significantly upregulated at 120 J/cm2 , used as the minimum dose in vivo. Vismodegib was administered via daily oral gavage for 21 days (30 mg/kg) to induce Shh inhibition in the tongue of rat animal models resulting in taste bud damage and taste dysfunction. PBM treatment using a 630 nm laser (3 W/cm2 ) at a radiant exposure of 120 J/cm2 (24 J/cm2  × 5) successfully upregulated the Shh protein expression, regenerated taste buds, and recovered taste function.

Effects of low-level laser therapy on burning pain and quality of life in patients with burning mouth syndrome: a systematic review and meta-analysis

BACKGROUND

Burning mouth syndrome (BMS) is a complex chronic pain disorder that significantly impairs patients' quality of life. Low-level laser therapy (LLLT) uses infrared or near-infrared light to produce analgesic, anti-inflammatory, and biological stimulation effects. The aim of this systematic review is to evaluate the effect of LLLT on burning pain, quality of life, and negative emotions in patients with BMS.

METHODS

The PubMed, Embase, Cumulative Index of Nursing and Allied Health Literature (CINAHL), Cochrane Library, Web of Science, and Scopus databases were searched up January 2023 to identify relevant articles. All randomized controlled trials that were published in English and examined the use of LLLT treatment for BMS were included. The methodological quality of the included trials was assessed using the Cochrane risk of bias tool for randomized controlled trials (RCTs). A meta-analysis was performed to evaluate burning pain, quality of life, and negative emotions. Sensitivity, subgroup, and funnel plot analyses were also carried out.

RESULTS

Fourteen RCTs involving a total of 550 patients with BMS met the inclusion criteria. The results showed that LLLT (measured by the Visual Analog Scale; SMD: -0.87, 95% CI: -1.29 to -0.45, P < 0.001) was more effective for reducing burning pain than placebo LLLT or clonazepam. LLLT improved quality of life (evaluated by the Oral Health Impact Profile-14; SMD: 0.01, 95% CI: -0.58 to 0.60, P = 0.97) and negative emotions (evaluated by the Hospital Anxiety and Depression Scale; SMD: -0.12, 95% CI: -0.54 to 0.30, P = 0.59), but these effects were not statistically significant.

CONCLUSIONS

The meta-analysis revealed that LLLT may be an effective therapy for improving burning pain in patients with BMS, and producing a positive influence on quality of life and negative emotions. A long-term course of intervention, a larger sample size, and a multidisciplinary intervention design are urgently needed in future research.

TRIAL REGISTRATION

PROSPERO registration number: CRD42022308770.

Outpatient Oral Neuropathic Pain Management with Photobiomodulation Therapy: A Prospective Analgesic Pharmacotherapy-Paralleled Feasibility Trial

Neuropathic pain (NP) can be challenging to treat effectively as analgesic pharmacotherapy (MED) can reduce pain, but the majority of patients do not experience complete pain relief. Our pilot approach is to assess the feasibility and efficacy of an evidence-based photobiomodulation (PBM) intervention protocol. This would be as an alternative to paralleled standard analgesic MED for modulating NP intensity-related physical function and quality of life (QoL) prospectively in a mixed neurological primary burning mouth syndrome and oral iatrogenic neuropathy study population (n = 28). The study group assignments and outcome evaluation strategy/location depended on the individual patient preferences and convenience rather than on randomisation. Our prospective parallel study aimed to evaluate the possible pre/post-benefit of PBM and to allow for a first qualitative comparison with MED, various patient-reported outcome measures (PROMs) based on Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT-II) were used for up to a nine-month follow-up period in both intervention groups (PBM and MED). The PBM protocol applied to the PBM group was as follows: λ810 nm, 200 mW, 0.088 cm2, 30 s/point, 9 trigger and affected points, twice a week for five consecutive weeks, whereas the MED protocol followed the National Institute of Clinical Excellence (NICE) guidelines. Our results showed that despite the severe and persistent nature of the symptoms of 57.50 ± 47.93 months at baseline in the PBM group, a notably rapid reduction in PISmax on VAS from 7.6 at baseline (T0) to 3.9 at one-month post-treatment (T3) could be achieved. On the other hand, mean PISmax was only reduced from 8.2 at baseline to 6.8 at T3 in the MED group. Our positive PBM findings furthermore support more patients' benefits in improving QoL and functional activities, which were considerably impaired by NP such as: eating, drinking and tasting, whereas the analgesic medication regimens did not. No adverse events were observed in both groups. To the best knowledge of the authors, our study is the first to investigate PBM efficacy as a monotherapy compared to the gold standard analgesic pharmacotherapy. Our positive data proves statistically significant improvements in patient self-reported NP, functionality, psychological profile and QoL at mid- and end-treatment, as well as throughout the follow-up time points (one, three, six and nine months) and sustained up to nine months in the PBM group, compared to the MED group. Our study, for the first time, proves the efficacy and safety of PBM as a potent analgesic in oral NP and as a valid alternative to the gold standard pharmacotherapy approach. Furthermore, we observed long-term pain relief and functional benefits that indicate that PBM modulates NP pathology in a pro-regenerative manner, presumably via antioxidant mechanisms.

Efficacy of photobiomodulation in reducing pain and improving the quality of life in patients with idiopathic burning mouth syndrome. A systematic review and meta-analysis

Burning mouth syndrome is a chronic condition, which is characterised by a burning sensation or pain in the mucosa of the oral cavity. Treatment options include antidepressants, antipsychotics, anticonvulsants, analgesics, hormone replacement therapies and more recently photobiomodulation. This study aims to perform a systematic review with meta-analysis in order to determine the effect of photobiomodulation on pain relief and the oral health-related quality of life associated with this condition. A bibliographical search of the Pubmed, Embase, Web of Science and Scopus databases was conducted. Only randomised clinical trials were included. Pain and quality of life were calculated as mean difference and pooled at different treatment points (baseline = T0 and final time point = Tf) and laser modality. From a total of 103 records, 7 articles were retrieved for inclusion. PBM group had a greater decrease in pain than control group at Tf with a mean difference =  − 2.536 (IC 95% − 3.662 to − 1.410; I² = 85.33%, p < 0.001). An improvement in oral health-related quality of life was observed in both groups, although this was more significant in the photobiomodulation group mean difference =  − 5.148 (IC 95% − 8.576 to − 1.719; I² = 84.91%, p = 0.003). For the red laser, a greater improvement than infrared was observed, in pain, mean difference =  − 2.498 (IC 95% − 3.942 to − 1.053; I² = 79.93%, p < 0.001), and in quality of life, mean difference =  − 8.144 (IC 95% − 12.082 to − 4.206; I² = 64.22%, p = 0.027). Photobiomodulation, in particular, red laser protocols, resulted in improvement in pain and in quality of life of burning mouth syndrome patients.

Role of Photobiomodulation Therapy in Neurological Primary Burning Mouth Syndrome. A Systematic Review and Meta-Analysis of Human Randomised Controlled Clinical Trials

Mitochondrial homeostasis is crucial for energy production and neuronal survival in neurological primary burning mouth syndrome (npBMS). Photobiomodulation therapy (PBMT) has been utilised in npBMS management, however, its role of intervention remains controversial. The aim of this systematic review and meta-analysis of CRD 42020198921 PROSPERO registration reference was to oversee and determine the efficacy of PBMT in patients with npBMS, identifying the gaps and bridge them by proposing recommendations for future studies purposes. PRISMA guidelines and Cochrane Collaboration recommendations followed. Various search engines employed to analyse a total of 351 studies of which 12 were included. A wide range of utilised PBM wavelengths was between 635-980 nm and the power output ranged between 30 mW and 4000 mW. A high risk of bias (RoB) was noted in 7 out of 12 included studies (58.3%), as results of qualitative analysis. Meta-analysis findings of 4 out of 12 studies showed statistically significant intergroup differences (SSID) for visual analogue scale (VAS) values (MD = -1.47; 95% CI = -2.40 to -0.53; Z = 3.07 (p = 0.002) whereas meta-analysis on 5 out of 12 studies revealed SSID for anxiety/depression and quality of life (MD = -1.47; 95% CI = -2.40 to -0.53; Z = 3.07 (p = 0.002), favouring PBMT group to the control treatment strategies. Despite the inconsistency and diversity in PBM parameters (wavelength, power, light source, spot size, emission mode, energy per point, total energy) and treatment protocols (exposure time, number of sessions, time interval between sessions, treatment duration)-majority of the included studies showed positive PBM results. The high RoB and meta-analytical heterogeneity in the eligible studies warrant the necessity to perform well-designed and robust RCTs after acknowledging the drawbacks of the available scientific literature and addressing our suggested recommendations highlighted in our review.

Effects of low-level light therapy on xerostomia related to hyposalivation: a systematic review and meta-analysis of clinical trials

Hyposalivation is a condition represented by a reduced salivary flow and may include symptoms such as mouth dryness (xerostomia), loss of taste, pain, dysphagia, and dysphonia, all of which greatly affect an individual's quality of life.The aim of the present study was to systematically review the effects of low-level light therapy irradiation (photobiomodulation) on salivary gland function in patients with hyposalivation.The main question of the systematic review was: "Does low-level light irradiation therapy of the salivary glands affect salivary flow rate or indicators of salivary function (ion and protein concentrations) in patients with xerostomia or hyposalivation?" The question was based on the PICO (participant, intervention, control, outcome) principle and followed the PRISMA guidelines. Databases were explored and papers published between the years 1997 and 2020 were reviewed for the following Mesh-term keywords and their corresponding entry terms in different combinations: "Low-level light therapy," "Xerostomia," "Saliva," "Salivary glands," "Salivation."The initial sample consisted of 220 articles. Of those, 47 articles were used for full-text analysis and 18 were used for a systematic review, 14 were used in meta-analysis. According to their individual quality, most articles were classified as high quality of evidence according to the GRADE score. Meta-analysis of the evidence observed increase of unstimulated salivary flow 0.51 SMD compared to placebo (95% CI: 0.16-0.86), I² = 50%, p = 0.005.The findings of our review revealed evidence of a beneficial effect of photobiomodulation therapy on salivary gland function. The therapy alleviates xerostomia and hyposalivation. However, these effects are reported short term only and did not induce lasting effects of photobiomodulation therapy on patients' quality of life.