Low-level Laser Therapy Research Articles

The immediate pain relief of low-level laser therapy for burning mouth syndrome: a retrospective study of 94 cases

SignificanceBurning mouth syndrome (BMS) is a chronic orofacial pain disorder that seriously affects quality of life of patients. In recent years, Low-level laser therapy (LLLT) has been regarded as an important innovation in pain management, but there is insufficient evidence of its effectiveness in patients with painful BMS. This study aimed to evaluate the efficacy of LLLT for immediate pain relief due to BMS.MethodsThis retrospective study included 94 BMS patients that were treated with an intraoral semiconductor laser (635 nm, 100 mW/cm2). Pain was self-assessed before and immediately after LLLT sessions using a 0-to-10 visual analogue scale (VAS). Paired-samples t-test and multivariable binary logistic regression were used to analyze overall efficacy and its influencing factors.ResultsAfter standardized LLLT session, 71.3% of patients reported an immediate pain decrease. Compared to pre-LLLT treatment, the VAS immediately post-LLLT was significantly reduced (P < 0.001). Mean post-LLLT VAS reduction was 2.2 ± 2.0, equivalent to 39.9% of the initial pain level. Meanwhile, low VAS before treatment, history of smoking or alcohol, xerostomia, and gingival lesions correlated with worse LLLT efficacy. There were no side effects or adverse reactions were noticed by the practitioner or reported by the patients.ConclusionsLLLT may provide non-pharmacological, non-invasive, side-effect-free, and rapid pain relief for painful BMS patients. No baseline characteristics affecting overall efficiency were found except for VAS before treatment, history of smoking or alcohol, xerostomia, and gingival lesions.

Favorable Changes in Salivary Uric Acid and Acyl Peptide Enzyme Hydrolase Activity in a Photobiomodulation Pilot Study

Photobiomodulation (PBM) therapy has numerous documented health benefits, but the physiological mechanisms are still being elucidated. In this work, a pilot study of salivary biomarkers was investigated to potentially understand physiologic oxidative stress changes associated with PBM therapy. Eighteen participants completed six PBM sessions and provided saliva samples prior to session one and after each of the six sessions. Salivary uric acid, acyl peptide enzyme hydrolase (APEH) activity, and total protein were measured. While salivary uric acid and total protein have been measured before, APEH is a novel salivary marker. When grouped into ‘heightened risk’ categories, 67% of participants with high starting uric acid had a reduction in salivary uric acid and 57% of participants with low starting APEH activity had an increase in salivary APEH activity over the six PBM sessions. While a larger and more comprehensive study is required to make conclusions, this pilot study suggests that PBM therapy has beneficial outcomes to selected oxidative stress markers, thereby providing a physiological mechanism that may accompany reported positive biological outcomes.

Effects of high and low level lasers on soreness following dry needling in patients with chronic myofascial neck pain. A randomized-controlled trial.

This research was designed to study effects of high versus low-level laser therapy (HILT and LLLT) on post-dry needling soreness (PNS) at patients with chronic neck pain. We also studied effects of HLLT or LLLT application plus dry needling (DN) on pain, range of motion (ROM), and neck disability index (NDI) at the identified patients. This is a clinical trial in 48 women with chronic neck pain aged 18-35 who were divided into three groups: HLLT, LLLT, and placebo group. All the participants received one session of DN and laser therapy. The study assessed the soreness using Visual Analog Scale for needle pain (nVAS) and Pressure Pain Threshold (PPT) before, immediately after, 24 and 48h after laser therapy. Pain, ROM, and NDI assessed before and also different time courses after DN plus laser therapy. PPT and nVAS improved in all groups over time. In the placebo group, nVAS increased significantly (p < 0.001) after treatment. VAS, NDI, and ROM improved 48h after treatment in all groups. The VAS scores were substantially decreased (p < 0.001) immediately after treatment for LLLT group and also 24h after treatment for both LLLT and HLLT groups. LLLT and HLLT might prevent immediately increasing the PNS. Adding one session of LLLT or HLLT to DN could effectively eliminate the neck pain at 24h. All groups improved NDI and ROM the same. Registration number: IRCT20190411043241N1.Registered Sep 2, 2019.

Evaluation of the Low-Level Laser Therapy in Pain, Bite Force, and Mouth Opening Following Midfacial Trauma

Low-level laser therapy (LLLT) is known for its biostimulant properties, which can reduce inflammation and promote tissue regeneration. The present study is randomized, blinded, and placebo-controlled and aims to investigate the role of LLLT in the postoperative recovery of facial fractures. Patients with fractures of the zygomatic bone are selected and divided into two groups: low-level laser and red placebo light. The patients are evaluated for bite force, pain, mouth opening, and paresthesia in the pre-operatory day, on days 1, 2, 7, and 14. The trismus data demonstrated better results in the laser with a significant difference in the periods 7 and 14 days, with p-values of 0.0442 and 0.026, respectively. Regarding the bite force analyzed, no statistically significant differences were observed. In the pain scale comparison, there was a difference between the PLACEBO group and the LASER group for day 1 (p = 0.011), day 2 (p = 0.001), 7 (p = 0.001), and 14 days (p = 0.010). In the evaluation of paresthesia, on days 7 and 14, there were better results in the LASER group with p = 0.012 and p = 0.001. The laser acted as a moderator of the healing process, having a considerable effect on the aspects of trismus, pain, postoperative paresthesia, and bite force.

Donor site healing response to low-level laser therapy following skin graft surgery

IntroductionSkin grafting is an essential reconstructive technique for the healing of deep and extensive burns. Donor site problems are common complications after skin graft surgery. Speeding up the healing process at the donor site using low-level laser therapy helps avoid these problems. Objectives: The purpose of this research was to examine the efficacy of low-level laser therapy in promoting donor site healing in burn patients who underwent skin graft surgery.MethodsForty patients of both genders (16 male, 24 female) aged 20–40 years suffered full-thickness burns with a total body surface area varying from 20 to 35% and had undergone split-thickness skin graft surgery were selected randomly and divided into two equal groups. The low-level laser therapy group (study group) attended three sessions per week for three weeks, while the placebo group (control group) received sham laser treatments. All patients received conventional medical treatment and traditional wound care (dressing). Photography and J Image software were used to measure wound surface area before the treatment (day 1 post-operative), day 11 post-operative, and day 21 post-operative in both groups.ResultsThe study and control groups demonstrated a substantial reduction in wound surface area at day 11 and day 21 post-operative compared with day 1 (&lt;i&gt;p&lt;/i&gt; &lt; 0.001), with the percentage of improvement of 88.69% and 98.73% and 50.18% and 80.22%, respectively. On day 21 compared to day 11 (&lt;i&gt;p&lt;/i&gt; &lt; 0.001), the percentage of improvement was 88.81% and 60.30%, respectively. Between-group comparisons revealed a significant decrease in wound surface area at day 11 and day 21 post-operative in the study group compared to the control group (&lt;i&gt;p&lt;/i&gt; &lt; 0.001).ConclusionsLow-level laser therapy is an effective modality for enhancing wound healing of the donor site in burned patients undergoing skin graft surgery.

The Effect of Low-Level Laser Therapy on Accelerating Tooth Movement in Orthodontic Patients: A Randomized Controlled Trial

ABSTRACT Background: An adjuvant treatment, known as low-level laser therapy (LLLT), has been suggested to quicken orthodontic tooth movement and perhaps shorten the course of treatment. Materials and Methods: For 60 orthodontic patients aged between 15 and 25, a randomized controlled experiment was carried out (30 males and 30 females). Two groups, Group A (LLLT group, n = 30) and Group B (control group, n = 30), were randomly allocated to the participants. For the first 8 weeks of therapy, Group A got LLLT three times a week using a diode laser with a wavelength of 808 nm and a power output of 100 mW. The laser was delivered for 30 s on each side of the target tooth. Beyond routine orthodontic care, Group B did not get any extra care. Using computerized models, the rate of tooth movement was monitored every 2 weeks for a duration of 12 weeks. The degree of tooth movement was the main result; patient-reported discomfort and gingival health were the secondary outcomes. Results: The group that had LLLT (Group A) demonstrated a notably elevated frequency of tooth movement in contrast to the control group (Group B). Group A’s average monthly tooth movement was 1.2 mm, whereas Group B’s average monthly movement was 0.8 mm (P &lt; 0.01). Furthermore, throughout the early phases of therapy, patients in the LLLT group reported less discomfort, and there were no significant variations in gingival health between the two groups. Conclusion: With its ability to speed orthodontic tooth movement, LLLT may shorten the course of therapy. Additionally, it seems to lessen pain while starting orthodontic therapy.

Low-level laser therapy on soft tissue healing after implantation: a randomized controlled trial

BackgroundTo explore the effect of low-level laser therapy (LLLT) on the healing of soft tissue around the implant after flap implantation and explore the possible mechanism.MethodsA total of 58 patients who underwent implant surgery were enrolled, with a total of 70 implants. They were randomly divided into the LLLT group and the control group. The LLLT group underwent LLLT with Nd:YAG (Fotona, 1064 nm) immediately after surgery and on the 2nd and 3rd day in the surgical area, while the control group did not receive any intervention. Pain assessment was performed in the first 3 days after surgery. The weight of peri-implant crevicular fluid (PICF), modified sulcus bleeding index (mSBI), gingival index (GI), and the expression levels of tumor necrosis factor-α (TNF-α), and vascular endothelial growth factor (VEGF) on the 7th and 14th days after surgery were evaluated.ResultsOn the first 3 days after surgery, the pain score of the LLLT group was significantly lower than that of the control group. On the 7th and 14th day after surgery, the PICF volume, mSBI, GI, and TNF-α levels of the LLLT group were lower than those of the control group. The VEGF levels in the LLLT group were significantly higher than that in the control group.ConclusionsLLLT can promote the healing of the soft tissue after implantation, effectively relieve postoperative pain, improve clinical indicators, reduce TNF-α, and increase the expression level of VEGF, which is worthy of clinical application.Trial registrationRetrospectively Registered Trials ChiCTR2400087562 (07/30/2024)

Effect of Low-level Laser Therapy on Bone Formation around Dental Implants Placed in Overprepared Sites: A Histological Study in Sheep Mandibles

Effect of Low-level Laser Therapy on Bone Formation around Dental Implants Placed in Overprepared Sites: A Histological Study in Sheep Mandibles

The influence of photobiomodulation on upper body muscular performance in collegiate athletes.

Photobiomodulation (PBM), has been shown to improve muscular performance during single-joint resistance exercises. It is unclear whether this benefit extends to multiple-joint exercises, such as the barbell bench press. In a within-group design, 15 collegiate athletes (mean±SD; age 20.2±1.6 yrs; BMI 26.0±4.5 kg.m-2) received PBM or sham treatment six hours prior and then immediately preceding a bench press protocol. Two treatment sites each on the pectoralis major, triceps, and deltoids were irradiated. Bench press one repetition maximum (1RM), volume load (VL) lifted during five sets to failure at 60% 1RM, and muscular soreness were compared between PBM and sham conditions. Testing was conducted over three sessions separated by a week each, with a baseline testing day occurring first, and the PBM and sham condition testing days following in a counterbalanced fashion. A repeated measures ANOVA was applied for analysis (alpha level=0.05). No significant differences were observed between PBM and sham conditions for bench press 1RM or soreness (P≥0.05). VL was greater in both PBM and sham conditions compared to baseline (P≤0.05). VL was not significantly different between PBM and sham. These findings suggest that muscular performance during multi-joint resistance exercises such as the bench press may not benefit from PBM in the same fashion as single-joint resistance exercises.

The anti-inflammatory role of therapeutic ultrasound and low-level laser in chronic rhinosinusitis: A fractional exhaled nitric oxide outcome hypothesis

Chronic rhinosinusitis is defined as a complex of disorders whose main feature is nasal and paranasal sinus mucosal inflammation for at least three months. Inflammation plays a key role in chronic rhinosinusitis. Fractional exhaled nitric oxide is used to monitor eosinophilic airway inflammation in the human lower airways. Fractional exhaled nitric oxide levels are paradoxically low in some chronic rhinosinusitis patients. This has been attributed to sinus ostia obstruction. However, a recent study has demonstrated that fractional exhaled nitric oxide levels could serve as a chronic rhinosinusitis inflammation biomarker independent of lower airway inflammatory disease and could be used as a treatment response biomarker. Therapeutic ultrasound and low-level laser therapy have been used in chronic rhinosinusitis management. Through a variety of mechanisms, ultrasound enhances bacterial killing. Low level laser therapy increases nitric oxide release and ATP levels. It also reduces inflammation and accelerates tissue repair. Fractional exhaled nitric oxide levels could be used to evaluate the anti-inflammatory actions of therapeutic ultrasound and low-level laser therapy in chronic rhinosinusitis patients. A hypothesis that fractional expired nitric oxide measurements could be a useful biomarker to evaluate their potential anti-inflammatory mechanisms and monitor their treatment efficacy is proposed. This could contribute to a better understanding of these therapies in chronic rhinosinusitis management. An improved understanding of treatment efficacy could lead to improved management strategies.

Synergistic Effects of Platelet-rich Fibrin and Photobiomodulation on Bone Regeneration in MC3T3-E1 Preosteoblasts

Platelet-rich fibrin (PRF) and Photobiomodulation (PBM) are established methods for promoting bone healing. PRF enhances cell proliferation and migration due to its rich concentration of growth factors, while PBM stimulates tissue repair through mitochondrial activation. Despite their efficacies, no in-depth studies have explored the synergistic effects of combining PRF and PBM. PRF was prepared at 50% and 100% concentrations, and PBM was applied using an 830 nm near-infrared laser at a dose of 5 J/cm². Cell viability, migration, and calcium deposition were assessed over seven and fourteen days. The combination of PRF and PBM significantly improved cell viability, migration, and calcium deposition, with the most notable effects observed after seven and fourteen days. However, a slight decrease in calcium deposition was noted in the 100% PRF combined with the PBM group, suggesting a potential feedback mechanism at higher PRF concentrations. This study is the first to explore the synergistic effects of PRF and PBM, offering new insights into optimizing bone tissue engineering strategies. The findings highlight the potential of this combined approach in enhancing bone regeneration, although further research is needed to refine the optimal conditions for these therapies.

Epidural electrical stimulation combined with photobiomodulation restores hindlimb motor function in rats with thoracic spinal cord injury.

Epidural electrical stimulation (EES) could restore motor function of paralyzed limbs of patients with spinal cord injury (SCI). However, its invasiveness limits its application in early stage of injury. Photobiomodulation (PBM) utilizes infrared light for percutaneous irradiation of the spinal cord to protect nerve tissue, delay muscle atrophy, and can be applied in early stage of SCI due to its non-invasiveness. This study tested the effect of the combination of EES and PBM on promoting motor function recovery in SCI rats. Severe contusion was induced at the T9 spinal segment in female rats, EES (applied to the L2 and S1 spinal cord segments) with treadmill training was conducted one week after the injury, and PBM percutaneous irradiation started at the injured segment on the day of surgery. In the third week post-injury, electromyographic and gait performance during training were recorded. Besides, the muscles of the hind limbs and the spinal cord on the caudal side of the injured segment were extracted. The results demonstrate that compared to the EES- or PBM-only group, this combined therapy led to several indicators returning to intact levels, including behavioral and electrophysiological, the gait patterns was also closer to intact rats. Additionally, the combined treatment group showed minimal muscle atrophy and maximal preservation of the injured spinal cord on the caudal side, with this histological improvement correlated with motor function recovery. Taken together, our results showed that this combined therapy was a more effective treatment for improving motor dysfunction after SCI which could protect the damaged spinal cord and promote the recovery of motor function in rats with SCI.

Potential and Challenges of Transcranial Photobiomodulation for the Treatment of Stroke.

Photobiomodulation (PBM), also known as low-level laser therapy, employs red or near-infrared light emitted from a laser or light-emitting diode for the treatment of various conditions. Transcranial PBM (tPBM) is a form of PBM that is delivered to the head to improve brain health, as tPBM enhances mitochondrial function, improves antioxidant responses, reduces inflammation, offers protection from apoptosis, improves blood flow, increases cellular energy production, and promotes neurogenesis and neuroplasticity. As such, tPBM holds promise as a treatment for stroke. This review summarizes recent findings on tPBM as a treatment for stroke, presenting evidence from both animal studies and clinical trials that demonstrate its efficacy. Additionally, it discusses the potential and challenges encountered in the translation process. Furthermore, it proposes new technologies and directions for the development of light-delivery methods and emphasizes the need for extensive studies to validate and widen the application of tPBM in future treatments for stroke.

Lipid analysis of human primary dermal fibroblasts and epidermal keratinocytes after near-infrared exposure using mass spectrometry imaging

Photobiomodulation (PBM) therapy is the application of near-infrared (NIR) exposure to injuries or lesions to (among others) improve wound healing, reduce inflammation, and decreases acute and chronic pain. However, the understanding of the molecular mechanism of PBM, more specifically the effects of NIR on skin cells is still lacking behind. Lipids are essential components of cellular membranes that are integral to skin structure and function. This study aims to elucidate the impact of NIR exposure on the skin’s lipidome by investigating the molecular effect of NIR exposure on single skin cells. Primary human dermal fibroblasts (NHDFa) and human epidermal keratinocytes (HEKa) were exposed to NIR (850nm) with a dose of 6.5J/cm2 for 5 consecutive days between 09.00 and 12.00 am. A workflow utilizing matrix-assisted laser desorption/ionization mass spectrometry imaging combined with liquid chromatography tandem mass spectrometry for lipidomics analysis was performed. This study provides evidence that adequate exposure of NIR influences lipid metabolism in NHDFa, whereas no alterations were found in HEKa. This work lays the groundwork in explaining the beneficial properties on both skin-related effects and systemic health benefits as seen in clinical studies.

Effectiveness of low-level laser therapy on oral wound healing: A scoping review

Low-level laser therapy (LLLT) has gained attention as a non-invasive approach for enhancing wound healing across various clinical applications. This review evaluates the effectiveness of LLLT on healing rates, pain reduction, and functional improvement across different conditions, including oral ulcers, aphthous stomatitis, diabetic ulcers, knee osteoarthritis (KOA), and bone healing with platelet-rich plasma (PRP). LLLT demonstrated high effectiveness in soft-tissue-related conditions, achieving notable healing rates (88% in aphthous stomatitis) and substantial pain relief (around 80% in oral conditions). However, its effectiveness was lower in bone-related conditions, indicating the potential need for combination therapies. LLLT also showed moderate improvements in functional outcomes, particularly in joint-related conditions like KOA. The photobiomodulatory effects of LLLT stimulate cellular regeneration, reduce inflammation, and promote pain relief, making it especially beneficial for soft-tissue ailments. These findings suggest that LLLT’s effectiveness varies by tissue type and treatment intensity, underscoring the importance of tailoring protocols for different conditions. Future research should focus on standardizing LLLT parameters for consistent outcomes across diverse clinical applications. This study supports the integration of LLLT as an adjunctive therapy, particularly in conditions where rapid tissue repair and pain management are crucial.

Pain Relief and Efficacy of Surgical vs Nonsurgical Management of TMJ Disorders: A Systematic Review

ABSTRACT Temporomandibular disorders (TMDs) affect the jaw muscles and joints, with treatments ranging from surgery to nonsurgical methods like physiotherapy and medication. A systematic review of studies from January 2020 to May 2024 compared these treatments’ effectiveness in relieving pain and improving function. From 7,459 initial records, 18 studies were included, examining interventions like NSAIDs, low-level laser therapy, botulinum toxin A, and occlusal splints. Results varied, highlighting the need for personalized treatment and standardized outcomes to improve patient care.

Comparative Evaluation of Low-level Laser Therapy and Intralesional Injection in OSMF Patients: A Quasi-randomized Trial.

The aim of the present study was to compare the effectiveness of low-level laser therapy and intralesional injection in oral submucous fibrosis (OSMF) patients. The present study comprised of 52 grade II OSMF patients aged between 20 and 60 years. A pretreatment assessment was done for each patients. And 52 patients were divided into two groups (26 patients in each group). Group I received intralesional injections, and group II received low-level laser therapy (LLLT). The intralesional injection group received 0.5 mL 1500 I.U. Hyaluronidase with 2 mL dexamethasone biweekly for a month. The LLLT group underwent sessions of 0.1 watt laser only once for 3 cycles, each lasting 1 minute with 5-minute intervals. Evaluation of overall accessibility, burning sensation and mouth opening was done for both the treatment modalities on 0, 3rd, 7th and 15th day. All data were recorded and statistically analyzed. On comparison of burning sensation in intralesional Injection group, at baseline, the mean value was 4.00 ± 0.84 and it reduced to 1.19 ± 0.40 while in LLLT group from 4.15 ± 0.96 at baseline, it reduced to 2.65 ± 0.68 at the end of 15 days, respectively. On comparison of mouth opening in intralesional Injection group, at baseline, the mean value was 21.73 ± 1.56 and it increased to 32.53 ± 0.97 while in LLLT group from 22.70 ± 2.17 at baseline, it increased to 24.50 ± 1.31 at the end of 15 days, respectively. There was a statistically significant difference found between the two groups. The present study concluded that intralesional injections are more effective in treating grade II OSMF compared with LLLT. Several different treatment options are available to treat OSMF, including medical approaches, surgical management, and physiotherapy. One of the important therapeutic modalities is intralesional injection therapy with corticosteroids as they reduce inflammation and immunosuppression while hyaluronidase increases tissue permeability. How to cite this article: Pattnayak A, Das A, Rana P, et al. Comparative Evaluation of Low-level Laser Therapy and Intralesional Injection in OSMF Patients: A Quasi-randomized Trial. J Contemp Dent Pract 2024;25(8):745-750.

The Impact of Low-Level Laser Therapy on Spasticity in Children with Spastic Cerebral Palsy: A Systematic Review

Context: Spastic cerebral palsy (SCP) is a condition characterized by muscle stiffness and involuntary movements, which greatly affect movement abilities and overall well-being. Low-level laser therapy (LLLT) has emerged as a treatment option for managing spasticity, though the current evidence varies. Objective: This systematic review seeks to assess the efficacy of LLLT on spasticity in children with cerebral palsy. We hope it will pinpoint areas where more research is needed and suggest directions for future studies. Method: A search of the literature was performed across databases, such as PubMed, Google Scholar, Scopus, and Elicit. The search utilized keywords and the Medical Subject Headings (MeSH) terms. Only studies conducted in English that focused on children with cerebral palsy (CP) and explored the effects of LLLT on spasticity were considered. The quality of the selected studies was evaluated using assessment tools. Results: The search identified 534 references, out of which eight studies met the screening criteria for inclusion. All cited papers indicated reductions in spasticity with further mention of reduced pain and greater muscle strength by some authors. Conclusions: This review indicates that LLLT shows promise in decreasing spasticity in children with cerebral palsy. Nevertheless, a lack of treatment parameters, heterogeneity in research methods, and a lack of objective outcome measures weaken the results. This review underscores the importance of standardized procedures and carefully planned randomized controlled trials to establish conclusive findings on the effectiveness of LLLT in this population.

Evaluating the effectiveness of low-level laser therapy in patients undergoing lower third molar extraction: A double-blinded randomized controlled trial.

The use of low-level laser is a therapeutic resource that has been widely used in medicine in general, which has properties capable of modulating inflammatory effects such as pain, edema, and trismus resulting from oral surgeries for the extraction of impacted third molars. This study aimed to evaluate the effect of laser therapy at two different wave frequencies (660nm and 808nm) in patients undergoing impacted 3rd third lower molar extraction. For this, 30 patients were selected and randomly distributed into three groups with 10 individuals each (Control Group, 660nm Group, and 808nm Group). Each participant, according to their experimental group, received irradiation before the start of each surgery and immediately after the surgical procedure. The data regarding edema, pain intensity, and trismus collected before the surgeries, immediately after, and after seven days were spreadsheeted and analyzed to determine the mean and standard deviation. After the Shapiro-Wilk normality test, differences between the experimental groups were determined using Multiple Analyses of Variance, considering a significance level of 5% (p<0.05). The results showed no statistically significant difference between the experimental groups in the analyzed items. Despite this, both groups irradiated with 660nm and 808nm frequencies experienced a reduction in the perception of postoperative pain, thus suggesting the benefit of using low-power laser therapy as an adjunct in the surgical treatment of impacted lower third molars. Despite the results showing no differences between the groups, using LLLT resulted in lower pain perception in the irradiated participants compared to those in the control group. This fact supports the use of LLLT as an adjuvant therapy in patients undergoing oral surgery procedures to remove impacted third molars.

Regenerative endodontic therapy in immature teeth using photobiomodulation and photodynamic therapy; a histomorphological study in canine model

BackgroundRegenerative endodontic therapy (RET) is still coming up short to demonstrate histological evidence for true regeneration with clinically feasible protocol of cell homing in single visit approach.AimThe aim of the present study is to evaluate the regenerative potential of photobiomodulation (PBM) on RET in immature roots when photodynamic therapy (PDT) protocol is implemented for root canal disinfection in canine model.Materials and methodsSeventy-two root canals were recruited, with sixty assigned to experimental groups and twelve to positive and negative controls. Following the induction of pulp necrosis and apical periodontitis, the roots were divided into two experimental groups: Group I received RET followed by PBM (seven sessions with an 808 nm diode laser at 300 mW for 90 s), and Group II received RET without PBM. Follow-ups were conducted at 1, 2, and 3 months (subgroups A, B, and C respectively). Qualitative and quantitative assessment was carried out histologically. All data were statistically analyzed with the Mann-Whitney U test and Bonferroni’s adjustment, as well as Chi square test.ResultsThe newly formed hard tissue highly resembled true dentine where the dentinal tubules looked well organized lined by poly layers palisading pattern of rounded odontoblast-like cells with cytoplasmic processes extending through the predentine layer. GI exhibited statistically significantly higher scores of vital tissue infiltration and hard tissue deposition in subgroups A and B (P ≤ 0.05). The inflammatory cells scores were significantly lower in GI than in GII at all time intervals. However, no significance could be detected regarding apical closure.ConclusionThe disinfection protocol of PDT and subsequent irradiation with low power laser in PBM protocol pose a promising potential for regenerative endodontics in immature teeth.