Background/Objectives: Photobiomodulation (PBM) therapy has shown potential in managing orofacial neuropathic pain (ONP); however, inconsistent PBM dosimetry and methodological variability limit its clinical application. This World Association for Photobiomodulation Therapy (WALT) Position Paper aims to critically appraise current evidence and provide recommendations for Clinical Practice Guidelines (CPG) and Expert Consensus Opinion (ECO) where appropriate. Methods: Evidence evaluation was guided by the HANNA (Holistic Analysis & Novel Normative Actions) Framework, a structured multi-step methodology integrating systematic review, quality appraisal, and expert consensus. A systematic review was conducted in accordance with PRISMA 2020 guidelines. Methodological quality was assessed using validated tools: AMSTAR 2 for systematic reviews, RoB2 for randomized controlled trials (RCTs), and ROBINS-I for non-randomized studies (NRCTs). The AGREE II Reporting Checklist was applied to ensure transparency and rigor in the development of WALT recommendations. The Somerfield Criteria were used to rate the level of evidence (LoE) for each included ONP condition, where deemed appropriate. Results: WALT CPG were established for primary burning mouth syndrome (BMS), supported by robust evidence (LoE I) from 204 patients across six “Low RoB” RCTs and NRCTs, and 557 patients included in a “High-Confidence” systematic review and meta-analysis of “low RoB” RCTs. WALT ECO were developed for idiopathic trigeminal neuralgia (TN) and post-herpetic neuralgia (PHN), both supported by LoE II. Insufficient evidence precluded formal recommendations for post-traumatic trigeminal neuralgia, glossopharyngeal neuralgia, and occipital neuralgia. Conclusions: This Position Paper introduces the HANNA Framework, for the first time, as a robust and transparent methodology for developing WALT recommendations by delivering evidence-based CPG for PBM in the management of neuropathic pain associated with primary BMS, along with ECO for both TN and PHN. These recommendations support PBM as a safe and effective therapeutic approach, and provide a structured roadmap for future research and periodic guidelines updates.

Postoperative pain is a frequent clinical concern following endodontic treatment. This study aimed to develop and validate supervised machine learning models to predict the occurrence of postoperative pain in cases of irreversible pulpitis. A prospective sample of 354 patients aged 18 to 60 years undergoing standardised endodontic treatment was analysed. In the original randomised clinical trials from which the data were derived, each patient had only one eligible tooth included. Clinical variables included postoperative pain at 24 and 72 h, treated tooth group, occlusal reduction, photobiomodulation therapy, use of non-steroidal anti-inflammatory drugs (NSAIDs), sex and age. Eight supervised machine learning algorithms were trained to predict pain occurrence, including Logistic Regression, Support Vector Machine, Gradient Boosting, Random Forest, Decision Tree, K-Nearest Neighbours, AdaBoost and Multilayer Perceptron. The dataset was divided into training (70%) and testing (30%) sets using stratified sampling. Class imbalance in the training set, characterised by a lower proportion of cases with moderate or severe pain, was addressed using the Synthetic Minority Oversampling Technique. Hyperparameters were optimised through grid search combined with stratified five-fold cross validation. Model performance was evaluated using the area under the curve (AUC), accuracy, precision, recall and F1-score, with 95% confidence intervals estimated by bootstrapping. The predictive models achieved good discrimination of pain outcomes. Logistic Regression showed the best test performance at 24 h (AUC 0.74 [95% CI: 0.61 to 0.85], precision 0.81 [95% CI: 0.73 to 0.88]). At 72 h, the Support Vector Machine achieved the highest performance (AUC 0.81 [95% CI: 0.69 to 0.92], precision 0.88 [95% CI: 0.79 to 0.94]). Age and sex emerged as the most influential predictors across models. Supervised machine learning models demonstrated promising performance for predicting postoperative pain following endodontic treatment. Logistic Regression and Support Vector Machine algorithms presented the most consistent results, supporting their potential clinical application for personalised pain management.

Long-term efficacy of photobiomodulation in burning mouth syndrome: A secondary analysis of a randomized controlled trial.

BackgroundHippocampal synaptic dysfunction driven by toxic amyloid-β oligomers (AβO) is an early event in the progression of neurodegeneration and cognitive decline in Alzheimer's disease (AD). Non-invasive photobiomodulation therapy (PBM) is a promising intervention that has been shown to reduce amyloid and tau pathology, improve synaptic function, and preserve hippocampal neurogenesis in animal models of AD. Nano-pulsed laser therapy (NPLT) is a type of PBM therapy using pulsed 808 nm near-infrared laser light and optoacoustically generated ultrasound waves to stimulate deeper brain structures than would be accessible by traditional PBM therapy. We hypothesize that NPLT can effectively modulate hippocampal neurogenesis to induce resilience against AD.ObjectiveTo assess resilience of hippocampal neurons derived from NPLT-treated neural stem cells (NSC) against AβO toxicity.MethodsWe use NPLT to stimulate adult hippocampal neural stem cells (NSC) then induce neuronal differentiation in vitro and assess the mature neurons for AβO binding capacity and mitochondrial toxicity, and gene expression changes after NPLT.ResultsWe found that neurons differentiated from NPLT-treated NSC are resilient against AβO binding and mitochondrial toxicity, and show increased expression of genes associated with autophagy and proteostasis.ConclusionsOur findings support the hypothesis that NPLT modulation of hippocampal neurogenesis can be an effective non-invasive approach to induce resilience against AD toxic oligomers.

Objective: the aim of this systematic review and meta-analysis was to evaluate the effectiveness of photobiomodulation therapy (PBM) on perineal pain and wound healing following episiotomy. Methods: Electronic databases were searched for randomized controlled trials (RCTs) and non-RCTs investigating PBM after episiotomy. Risk of bias was assessed using RoB 2 for RCTs and ROBINS-I for non-RCTs. The certainty of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Meta-analyses were performed using random-effects models. Results: Eight studies were included in the systematic review, and six studies were included in the meta-analysis. According to RoB 2, one trial was judged at low risk of bias, two trials raised some concerns, and three trials were at high risk of bias. ROBINS-I showed the serious risk of bias of two non-RCTs. GRADE for both pain and wound-healing outcomes was rated as very low. Meta-analysis of pain showed no significant difference between PBM and control groups (SMD = 0.04; 95% CI −0.60 to 0.68; p = 0.89), with considerable heterogeneity (I2 = 91%). For wound-healing outcomes, meta-analysis showed no significant difference (MD = 0.94; 95% CI −0.69 to 2.56; p = 0.26), with substantial heterogeneity (I2 = 94%). Conclusions: PBM therapy did not demonstrate a significant benefit for reducing perineal pain or improving wound healing after episiotomy compared with control interventions. Interpretation of these findings should be made cautiously due to small study numbers, substantial heterogeneity, and the inability to perform sensitivity or subgroup analyses, highlighting the need for high-quality RCT with standardized PBM protocols before clinical recommendations can be made.

Photobiomodulation as an adjuvant for pain relief and healing pre-orthodontic mandibular third molar surgery: double-blinded randomized clinical trial.

This study aimed to evaluate the effects of laser photobiomodulation (PBM) therapy in SaOs-2 osteosarcoma cells treated with zoledronic acid (ZA), a bisphosphonate, in vitro, mimicking a bisphosphonate-related osteonecrosis of the jaw (BRONJ) situation. Cells were treated with 100 μM ZA for 24 h and subjected to PBM using wavelengths of 660 nm and 808 nm at energy delivered of 1, 5, 10, and 20 J. After 24 h, metabolic activity, apoptosis, and BAX and BCL-2 gene expression were analyzed. Data were compared using one-way ANOVA followed by Tukey's post hoc test (p < 0.05). ZA significantly reduced metabolic activity (p < 0.05), an effect attenuated by PBM at 808 nm with 1 J, while BCL-2 expression increased with 1 J at 660 nm and with 1 J and 20 J at 808 nm. However, PBM did not reverse ZA-induced apoptosis. In conclusion, PBM modulated the response of SaOs-2 osteoblastic cells treated with ZA in a wavelength- and dose-dependent manner. PBM at 808 nm and 1 J stimulated cell metabolic activity and upregulated BCL-2 expression, suggesting a potential protective effect against ZA-induced cytotoxicity.

Bone regeneration remains a clinical challenge, particularly in critical-size defects, motivating the investigation of biomaterials and adjuvant therapies that may support tissue repair. This experimental study evaluated bone healing in critical-size calvarial defects created in rats, using different combinations of regenerative strategies, including heterologous fibrin biopolymer gel, bovine cortical bone biological membrane, and photobiomodulation. Standardized 5.0 mm calvarial defects were surgically created in sixty Wistar rats, which were randomly allocated into six experimental groups according to the filling material and the application or absence of photobiomodulation. The treatments included clot alone, fibrin biopolymer gel, biological membrane, photobiomodulation, or their respective combinations. Animals were euthanized at 14 or 42 days, and bone repair was evaluated by histomorphometric analysis. At 14 days, differences in the extent of newly formed bone were observed among the experimental groups, with higher bone formation values detected in groups receiving combined treatments and lower values in groups treated with fewer regenerative components. At 42 days, all groups showed progression of bone repair, with greater bone formation observed in groups in which a biological membrane was used, regardless of photobiomodulation. Overall, the findings indicate that the association of different regenerative approaches was related to variations in bone repair patterns over time, suggesting that photobiomodulation, when applied in combination with biomaterials, may be associated with differences in early bone healing, without implying a direct causal effect.

BackgroundRadiodermatitis is one of the most common radiotherapy-related side effects, which can influence patients’ quality of life and affect therapeutic efficacy. Photobiomodulation therapy (PBMT) appears as a low-cost technology, with significant results in the tissue repair process.MethodsIt is a triple blind randomized controlled trial. A total of 96 patients undergoing radiotherapy for breast cancer are estimated for the sample, which will be randomly assigned to a control group to receive a placebo and the institution’s standard protocol (n = 48) or to an intervention group to receive PBMT, in addition to standard therapy (n = 48). The intervention consists of applying Laser Therapy EC (DMC™, São Carlos—SP, Brazil), with power of 100mW, continuous emission mode, red wavelength (660 ± 20 nm), fluence of 10.16 J/cm2, and energy of 1 J per point, three times a week since day one, right before the radiotherapy session. Blinding will be applied to patients, evaluators, and the statistician. Skin reactions will be assessed weekly using the Acute Radiation Morbidity Scoring Criteria developed by the Radiation Therapy Oncology Group and thermal images of the irradiated area that will be captured. In addition, the impact of radiodermatitis on the quality of life will be assessed through the application of the Cancer Quality of Life Questionnaire (EORTC QLQ-30) and the Breast Cancer Quality of Life Questionnaire (EORTC QLQ -BR23) at the beginning and in the end of treatment. Data will be processed and analyzed by the statistical package R using descriptive and inferential statistics.DiscussionPhotobiomodulation stands out for being a non-invasive and low-cost therapy that has not been associated with adverse events. It used to stimulate wound healing by promoting tissue repair, by reducing inflammation, by stimulating collagen synthesis, and relieving pain. Cientific literature have been highlighted PBMT as an effective tool in preventing or reducing the severity of radiodermatitis and its associated symptoms, which expected to be demonstrated with this ongoing study.Trial registrationBrazilian Clinical Trials Registry (ReBEC – Registro Brasileiro de Ensaios Clínicos) – Id. RBR-7gkw3d4; Universal Trial Number (UTN) – Id. U1111-1279–1686; Plataforma Brasil/Research Ethics Committee – Id. 5.788.390, registered on 24 August 2022. https://ensaiosclinicos.gov.br/rg/RBR-7gkw3d4.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13063-025-09294-8.

Refined photobiomodulation therapy ameliorates inflammatory bowel disease via modulation of immune pathways and gut microbiota.

Effect of photobiomodulation on femoral fracture specimens in rats with experimentally induced osteoporosis.

This manuscript examines the pivotal role of neuroinflammation in the central nervous system (CNS), particularly considering the impact of the COVID-19 pandemic. Neuroinflammation serves as a defense mechanism against various insults, including toxins, infections, and trauma. However, if left untreated, neuroinflammation can become chronic, leading to significant symptomatic and structural brain damage. Notably, neuroinflammation can mimic psychological disorders, complicating diagnosis and treatment. Current diagnostic methods for neuroinflammation-such as lumbar punctures, MRIs, brain biopsies, blood tests, and PET scans-are often hindered by inaccuracy, invasiveness, and cost. This study posits that electroencephalography (EEG), particularly identifying spindling excessive beta (SEB) activity, offers a promising, non-invasive, and cost-effective alternative for detecting neuroinflammation. This study investigates the relationship between SEB activity and neuroinflammation, focusing on traumatic brain injury (TBI). Through statistical analysis of EEG data from 1,233 psychiatric patients, we identified and compared two groups: 75 non-benzodiazepine-using adults without TBI and 79 non-benzodiazepine using adults with TBI exhibiting SEB activity. We identified a significant prevalence of SEB in individuals with refractory psychiatric conditions, underscoring the significance of this biomarker for neuroinflammation. Furthermore, we examine the therapeutic implications of reducing SEB through interventions such as guanfacine combined with N-Acetyl Cysteine (NAC), photobiomodulation, and hyperbaric oxygen therapy, all of which have demonstrated efficacy in mitigating neuroinflammation. These findings suggest that EEG could play a transformative role in the early detection and management of neuroinflammatory conditions, paving the way for more personalized and effective treatments for mental health disorders.

Photobiomodulation enhances cognitive function in aging rats and modulates cytochrome c oxidase activity and c-Fos expression in memory-related circuits.

Repeated concussion traumatic brain injury (TBI) results in long-term brain damage and cognitive dysfunctions, leading to neurodegenerative diseases. The brain clearance system plays a crucial role in TBI recovery and neurodegenerative disease amelioration by draining waste macromolecules from the brain. Pharmacological therapeutics have failed to demonstrate benefits in human TBI. Photobiomodulation (PBM) has gained interest in neuroscience and has been shown to improve brain drainage. Here, we evaluated the efficiency of PBM in the treatment of multiple concussions in mice and the augmentation of the brain clearance system. Three consecutive closed-head concussive TBIs were induced with a 1-h interval to the left hemisphere in C57BL/6 male mice. A near-infrared irradiation (1270nm, 10mW/cm2) was used for PBM 4h after the last TBI and the following 3 days twice a day. Laser speckle contrast imaging was used to assess cerebral blood flow (rCBF). In vivo 2-photon laser scanning microscopy assessed PBM effects on cerebral microcirculation, tissue oxygen supply (NADH), and meningeal lymphatics clearance. Brain compliance was evaluated by intracranial pressure waveform analysis. Neurological severity scores were obtained at 0-3days after TBI. Two-way ANOVA for multiple comparisons was used to test intergroup differences, with the statistical significance set at p<0.05. Multiple concussions progressively impaired rCBF, cortical microcirculation, tissue oxygen supply, and brain drainage function (p<0.05). Compared to the sham-treated group, PBM improved rCBF, microcirculation, tissue oxygenation, and the brain drainage system (p<0.05). Neurological function was more preserved in the PBMT group than in sham-treated mice (p<0.05). Our study demonstrated that PBMT can be used as an adjunct therapy even in the acute period of TBI.

Several parameters influence the effectiveness of photobiomodulation therapy (PBMT) in improving skin flap viability, yet the role of the number of treatment sessions remains underexplored. The present study aimed to evaluate the effect of different numbers of laser PBMT sessions on skin flap viability. Thirty-two Wistar rats were randomly divided into four groups: G1 (PBMT simulation), G2 (PBMT for 2 consecutive days), G3 (PBMT for 5 days), and G4 (PBMT for 7 consecutive days). Treatment began immediately after surgery with the following parameters: GaAlAs diode laser, 660 nm wavelength, continuous mode, spot size of 0.04 cm² (probe in contact with the skin), 90 J/cm² fluence, 40 mW output power, 90 s application time, and 3.6 J of energy per point with irradiation at three points and 24-hour intervals between sessions according to each group's protocol. On the 7th postoperative day, tissue was collected from the irradiated area for analysis of necrotic area, vessel and mast cell morphometry and immunohistochemistry for angiogenesis markers. G2 showed the smallest necrotic area and a higher percentage of VEGF- and HIF-1α-positive cells compared to G1. Short PBMT protocols improved flap viability versus controls and produced outcomes comparable to extended regimens, supporting relevance for translational research.

Vocal fatigue (VF) is a significant occupational burden for professional voice users, such as teachers, for whom rapid and effective interventions remain limited. Photobiomodulation (PBM), a noninvasive therapy that uses low-intensity light to mitigate inflammation and promote tissue repair, is a promising therapeutic strategy. In this study, we investigated the immediate effects of a single PBM session on key acoustic and respiratory parameters in female teachers with VF.In this single-arm, pre-post clinical trial, we enrolled 41 female primary school teachers (age range: 28-40 years) with symptoms of vocal fatigue classified as mild (n = 19), moderate (n = 18), or severe (n = 4). A single 5-minute PBM session was administered to the laryngeal region using a light-emitting diode (LED) device delivering 1 W of optical power across two wavelengths (640 and 940 nm). Acoustic parameters (jitter, shimmer, and connected speech frequency) and respiratory capacity were measured before and immediately after the intervention.In the severe subgroup, jitter decreased (p = 0.005) and mean autocorrelation increased (p = 0.024), while connected speech (p = 0.056) and respiratory capacity (p = 0.058) showed trends toward improvement. In the moderate subgroup, peak flow increased (p = 0.002). No meaningful changes were observed in the mild subgroup.A single session of photobiomodulation therapy resulted in immediate and significant improvements in vocal quality and respiratory function, particularly in teachers with severe vocal fatigue. These findings position PBM as a promising non-invasive tool for rapid vocal rehabilitation in individuals with pronounced phonatory deficits. However, these findings should be interpreted in consideration of several limitations, including the small sample size, particularly in the severe subgroup, the absence of a control group, and the short, immediate follow-up period. The uneven distribution of participants across severity levels may also limit generalizability. Despite these constraints, the pronounced improvement observed in the severe vocal-fatigue subgroup underscores the clinical relevance of PBM as a rapid, non-invasive option for individuals with substantial phonatory impairment.

Neuropathic pain (NP) is a chronic and disabling condition resulting from injury or disease of the somatosensory system. Characterized by sensory disturbances such as allodynia, hyperalgesia, and spontaneous pain, NP remains a major clinical challenge due to the limited efficacy and significant side effects of conventional pharmacological treatments. In recent years, photobiomodulation therapy (PBMT), also referred to as low-level laser therapy (LLLT), has emerged as a promising non-pharmacological strategy for managing NP. PBMT involves the application of red or near-infrared light to biological tissues, triggering a range of photochemical and photophysical responses that enhance mitochondrial function, reduce oxidative stress, modulate inflammation, and support neural repair. This review provides a comprehensive synthesis of the current evidence on PBMT for NP, integrating mechanistic insights with preclinical findings. We discuss the biological underpinnings of PBMT, including mitochondrial activation via cytochrome c oxidase, modulation of cytokines and oxidative stress markers, and upregulation of neurotrophic factors such as BDNF. Preclinical studies in well-established NP models (e.g., chronic constriction injury, spared nerve injury, diabetic neuropathy) demonstrate consistent analgesic effects and neuroprotective outcomes following both local and remote/systemic PBMT applications. We also highlight key limitations and knowledge gaps in the field, including the need for standardized protocols, greater exploration of remote PBMT strategies, and improved consideration of sex-based responses. Finally, we outline future directions, such as integration with multimodal therapies, personalized dosimetry, and the development of wearable and transcranial PBMT technologies. Together, the existing body of evidence supports PBMT as a safe and potentially effective tool for NP management, while underscoring the need for more rigorous and translational research.

Objectives: The aim of this systematic review was to evaluate the effectiveness of photobiomodulation (PBM) on pain and function in individuals with Patellofemoral Pain Syndrome (PFPS). Methods: A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines. Search was performed across PubMed/Midline, Scopus, Web of Science, EBSCO, ScienceDirect, Wiley Online Library, Springer, Cochrane CENTRAL, PEDro, ResearchGate, and Google Scholar from inception to January 2025. Randomized controlled trials (RCT) examining PBM in individuals with PFPS were included. Data extraction, risk-of-bias assessment (RoB 2), and quality of evidence evaluation (GRADE) were performed independently by multiple reviewers. Primary and secondary outcomes were pain and function, respectively. A random effect meta-analysis was performed to estimate the standardized mean difference (SMD) at 95% confidence interval (CI) and overall effect size. Results: Eight trials (340 participants) met the inclusion criteria. PBM significantly reduced pain compared with the control (SMD = -0.83; 95% CI -1.40 to -0.27). Functional outcomes demonstrated a significant improvement favoring PBM (SMD = 0.68; 95% CI 0.08 to 1.27), although substantial heterogeneity was present (I2 = 83%). RoB2 showed five high-risk studies. GRADE showed a very low quality of evidence due to study limitations, imprecision, and inconsistency which limit the confidence to the effect estimate. Conclusions: PBM, combined with exercise, provides improvements in pain and knee function in individuals with PFPS. While findings support PBM as an effective adjunct modality, standardized dosing protocols and larger, high-quality RCTs are needed to strengthen future clinical recommendations.

Background/Objectives: The zebrafish is a widely used research model due to its characteristics, such as being transparent during development, sharing 70% of its genes with humans, and having conserved features of vertebrate aging, including deterioration of mitochondrial and cognitive functions. While affecting approximately 15% of the world population, neurodegenerative diseases, such as Alzheimer’s disease (AD), are currently incurable, requiring testing of alternative treatment strategies. Hence, this study was conducted to test the hypothesis that an optimized photobiomodulation (PBM) therapy improves AD pathology through its multifaceted beneficial effects, including enhancing mitochondrial function and reducing oxidative stress and neuroinflammation. Methods: A pharmacological zebrafish model of AD was developed by adding small amounts (100 nM) of okadaic acid (OKA) directly to fish tanks for nine days. Next, some of OKA-treated and control zebrafish were subjected to an optimized near-infrared PBM therapy while others remain untreated. Results: When examined after OKA treatment, zebrafish brains displayed histological hallmarks of AD including, neurofibrillary tangles, vacuoles, and neuroinflammation. Behavioral tests using a T-maze revealed that OKA-treated zebrafish spent significantly less time in the reward arm than untreated controls (15.2% vs. 50%). In contrast, a sequential PBM therapy significantly reduced formation of neurofibrillary tangles, vacuoles, neuroinflammation, and improved mitochondrial biogenesis in brains of OKA-treated zebrafish while also improving their cognitive function as evidenced by being able to recall the reward arm and spending more time there similar to controls (55 and 57%, respectively). Conclusions: These findings suggest that (1) a fast, cost-effective zebrafish AD model can be developed using OKA treatment and (2) PBM therapy holds promise to ameliorate AD pathology.

Background: Type 2 diabetes mellitus (T2DM) and chronic periodontitis (CP) have a bidirectional association; scaling and root planing (SRP) alone has limited efficacy in their comorbidity, with controversial photobiomodulation therapy (PBMT) adjunctive efficacy. Objective: To quantify PBMT + SRP's effects on periodontal [probing depth (PD), clinical attachment level (CAL)], glycemic [fasting plasma glucose (FPG), glycated hemoglobin (HbA1c)], and inflammatory [high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α)] indices in patients with T2DM + CP and explore heterogeneity (PBMT parameters, study region) for clinical optimization. Methods: Following PRISMA 2020, we searched six databases (PubMed, Cochrane Library, etc.) from inception to August 24, 2025, for PBMT-adjuvanted SRP randomized controlled trials (RCTs). Bias was assessed via RoB 2.0, meta-analysis via RevMan 5.4, with preset subgroup analyses. Results: Six RCTs (n = 319) were included. At 3 months of follow-up, PBMT + SRP significantly improved key periodontal indices (PD: MD = -0.87 mm, 95% CI: [-1.00, -0.74]; CAL: MD = -0.47 mm, 95% CI: [-0.65, -0.29]; both p < 0.00001), glycemic control (FPG: MD = -0.79 mmol/L, 95% CI: [-1.41, -0.17], p = 0.01), and systemic inflammation (hs-CRP: MD = -0.99 mg/L, 95% CI: [-1.12, -0.86]; TNF-α: MD = -2.78 pg/mL, 95% CI: [-3.17, -2.39]; both p < 0.00001) versus SRP alone. HbA1c showed borderline significant reduction (MD = -0.81%, 95% CI: = [-1.62, -0.01], p = 0.05). Subgroup analyses suggested 808/810 nm + 0.8-1.5 W as potentially optimal PBMT parameters, though high-power efficacy relied on one small-sample study (n = 40). Notable limitations included high inter-study heterogeneity (most I2 > 90%) and maximum 6-month follow-up. Conclusions: PBMT adjunctive to SRP significantly improves periodontal indices (PD, CAL), FPG, and hs-CRP in patients with T2DM and CP, with borderline HbA1c reduction and good safety. Subgroup analyses identify 808/810 nm + 0.8-1.5 W as potentially optimal PBMT parameters, though high-power efficacy relies on one small-sample study. Given high inter-study heterogeneity (most I2 > 90%) and short follow-up (maximum 6 months), conclusions require validation by standardized, large-sample, long-term, high-quality RCTs.