Maxillary labial frenectomy: a randomized, controlled comparative study of two blue (445 nm) and infrared (980 nm) diode lasers versus surgical scalpel.

BACKGROUND: This study aimed to compare the intra and postoperative complications of frenectomy procedure with a surgical scalpel versus 445 nm and 980 nm diode lasers. METHODS: This randomized controlled clinical trial was conducted on 174 patients requiring maxillary labial frenectomy. After completion of fixed orthodontic treatment and primary closure of maxillary diastema, the patients were randomly assigned into three groups (n = 58): group 1 (frenectomy via 445 nm diode laser, continuous-wave, 1.5 W), group 2 (frenectomy via 980 nm laser, continuous-wave, 1.7 W), and control group (V-Y plasty technique via scalpel). Intra-operative bleeding, discomfort in chewing and speaking, pain, and tissue healing were compared among the groups immediately, at 7 and 30 days postoperatively using the Kruskal-Wallis, Mann-Whitney, and Chi-square tests. RESULTS: Pain scores were significantly lower in group 1 compared to group 2 (immediately and day 7, P < 0.05). Significant faster tissue healing at days 7 and 30 were observed in group 1 compared to group 2 (P < 0.05). Group 1 was superior to the control group regarding lower intraoperative bleeding, discomfort in chewing and speaking (immediately and day 7), lower pain (immediately and day 7), and tissue healing (day 7) (P < 0.05 for all). Group 2 was significantly superior to the control group in lower intraoperative bleeding, discomfort in chewing and speaking (immediately and day 7), and better tissue healing (day 7) (P < 0.05 for all). CONCLUSIONS: In conclusion, diode laser frenectomy resulted in significantly lower intra and postoperative complications compared to the scalpel. Moreover, 445 nm diode laser showed significantly superior effects compared to 980 nm diode laser. TRIAL REGISTRATION: The study protocol was registered on 29.10.2022 at the Iranian Registry of Clinical Trials ( www.irct.ir ) (registration number: IRCT20220630055326N1).

Comparison of therapeutic effects of 940 nm diode laser acupuncture with transcutaneous electrical nerve stimulation in the myofascial pain dysfunction syndrome: a comparative randomized clinical trial.

Myofascial pain dysfunction syndrome (MPDS) is one of the most common sources of orofacial pain. There are different types of physical therapy for patients with MPDS, but there is insufficient evidence that any one treatment method is superior. This study aimed to compare the clinical efficacy of transcutaneous electrical nerve stimulation (TENS) and laser acupuncture (LA) using a 940-nm diode on MPDS improvement. In this randomized clinical trial, 22 MPDS patients were randomly assigned to TENS (180 HZ, 300 µs, 20 min) and LA (940 nm, continuous wave, 0. 5 w, 40 s, 105 J/cm2) groups. Data on overall facial pain, tenderness in the masticatory muscles, deviation, joint sound, and maximum mouth opening without pain (MMO) were collected from all patients at baseline, before and after each treatment session, and 1 month after the end session. Data were analyzed using an independent t-test, repeated measures ANOVA, and Fisher's exact test at a significance level of P < 0.05. The decreases in overall facial pain (P = 0.000), muscle tenderness (P = 0.000), and increase in MMO (P = 0.01, P = 0.001) were statistically significant compared to the baseline in the TENS and AL groups. No significant differences were detected between TENS and LA for overall facial pain, muscle tenderness, or MMO at 1 month follow-up (P > 0.05). Both LA and TENS are effective physical therapies with promising effects on sign and symptom improvements in MPDS patients.

An evaluation of photobiomodulation effects on human gingival fibroblast cells under hyperglycemic condition: an in vitro study.

An in vitro study was designed to evaluate the effects of photobiomodulation (PBM) with 915-nm diode laser on human gingival fibroblast (HGF) cells under hyperglycemic condition. The HGF cells were cultured in Dulbecco's modified eagle medium (DMEM) medium containing 30 mM glucose concentration for 48 h to mimic the hyperglycemic condition. Subsequently, the cells received three sessions of PBM (915 nm, continuous emission mode, 200 mW, energy density values of 3.2, 6, and 9.2 J/cm2). Twenty-four hours post-irradiation, cell proliferation, expression of interleukin 6 (IL-6), and vascular endothelial growth factor (VEGF) were assessed with MTT and real-time polymerase chain reaction (PCR) tests, respectively. Also, reactive oxygen species (ROS) production was measured using CM-H2DCFDA fluorimetry. No changes were detected in the cell proliferation rate between the high glucose control group and laser-treated cells, while VEGF and IL-6 gene expression levels increased significantly after PBM in the high glucose-treated cells group. ROS level was significantly decreased in the irradiated cells in high-glucose medium compared with the high glucose control group. Our study revealed the inductive role of 915-nm-mediated PBM on VEGF and the inflammatory response while concurrently reducing reactive oxygen species production in HGF cells in hyperglycemic conditions.

Dentinal tubule blockage using nanobioglass in the presence of diode (980 nm) and Nd:YAG lasers: an in vitro study.

OBJECTIVES: The main objective of this study was to enhance the blockage of dentinal tubules using nanobioglass in the presence of diode (980 nm) and Nd:YAG lasers in order to reduce permeability and dentin hypersensitivity. MATERIALS AND METHODS: Thirty-six dentinal samples were randomly divided into 6 subgroups (n = 6): (A) control, (B) diode laser (980 nm, 3-W), (C) Nd:YAG laser (1064, 1.0-W), (D) nanobioglass, (E) nanobioglass + diode laser (980 nm), (F) nanobioglass + Nd:YAG laser. The average number of open dentinal tubules was qualitatively and quantitatively evaluated by scanning electron microscopy (SEM). Data were evaluated by SPSS software version 22, Kruskal-Wallis test, and Mann-Whitney tests with Bonferoni's correction (α = 0.008). RESULTS: Based on the results of Mann-Whitney test, there was a significant difference in the mean number of open dentinal tubules between the control group and the other groups (p < 0.008). However, the difference among the other groups was not statistically significant (p > 0.008). CONCLUSIONS: Findings of this study showed that high-power laser radiation, such as Nd:YAG and diode (980 nm) alone or with nanobioglass, has a significant effect on the blockage of dentinal tubules. CLINICAL RELEVANCE: Introduction of non-invasive methods with long-term and lasting effect on reducing pain and discomfort caused by dentin hypersensitivity.

Assessment of photobiomodulation therapy by an 8l0-nm diode laser on the reversal of soft tissue local anesthesia in pediatric dentistry: a preliminary randomized clinical trial.

During the injection of local anesthesia in pediatric dental procedures, from the injection time until the elimination of tissue anesthesia, inevitable problems were reported. According to the encouraging results of previous studies addressing the positive effects of laser therapy on increasing the microcirculation, we aimed to investigate the clinical effect of photobiomodulation therapy on the reversal of soft tissue anesthesia in children. Using a split-mouth design, 34 children aged 4 to 8 years old, candidate for receiving local infiltration injection at both right and left side in mandible, were enrolled in the study. The mandibular right and left quadrants were randomly assigned to groups of laser or sham laser: in laser side, patients received 810-nm laser irradiation, and in the sham laser group, the patients had the laser in off mode at 45 min after injection with an interval of 7-10 days between two sessions of each quadrant treatments. The degree of anesthesia was evaluated using the palpation technique alternately every 15 min. Data were analyzed using paired sample t test and multiple linear regression test. The mean duration of anesthesia expressed in minutes was equal to 145.15 ± 23.27 and 188.82 ± 12.31 for the laser group and sham laser group, respectively. There was a significant difference in duration of anesthesia between two groups (P < 0.001). Considering the results and limitations of the present study, photobiomodulation therapy by 810-nm diode laser can be proposed as a non-invasive method in order to reduce the duration of anesthesia in pediatric patients.

Efficacy of photobiomodulation therapy on pain perception reduction associated with dental anesthetic infiltration injection: A systematic review and meta-analysis.

Dental anesthetic injections, a common source of patient discomfort, often deter individuals from seeking dental care. Recently, there has been a growing focus on photobiomodulation therapy (PBMT) and its potential role in pain reduction. This systematic review explored the efficacy of PBMT in alleviating pain associated with dental anesthetic infiltration injections. A systematic literature search of different databases was performed up to December, 2023 using specific search strategy to find eligible studies that assessed the impact of PBMT on pain during local anesthesia injections. Data extraction was done based on the inclusion/exclusion criteria. A total of 13 studies, involving 972 patients were included. The studies employed various PBMT parameters, including wavelengths, and energy densities. Meta-analyses revealed a significant reduction in pain with PBMT compared to controls (MD = -0.90, 95% CI: -1.36 to -0.44, and p = 0.0001), with notable heterogeneity (I2 = 91.79%). Stratified analyses by age demonstrated consistent pain reduction in both adults (MD = -0.59, 95% CI: -1.11 to -0.08, and p < 0.0001) and children (MD = -0.59, 95% CI: -1.11 to -0.08, and p = 0.025). In conclusion, it seems that PBMT using infrared diode lasers can effectively reduce injection pain in both pediatric and adult populations. Further research should focus on optimizing PBMT parameters for enhanced pain management during dental procedures.

Effect of Fibroblast Growth Factor 2 and Low-Level Laser Therapy on the Adhesion and Proliferation of Periodontal Ligament Stem Cells.

Introduction: The adhesion ability of mesenchymal stem cells can significantly affect their viability and is considered a prerequisite for cell therapy. The current study sought to evaluate the effect of fibroblast growth factor 2 (FGF2) and low-level laser therapy (LLLT), either individually or in conjunction, on the adhesion and proliferation of periodontal ligament stem cells (PDLSCs) when applied on the first day of cell seeding. Methods: The experimental groups of this study comprised a control group and different combinations of adjunctive FGF2 (50 ng/mL) and LLLT with an 808 nm diode laser in one (LLLT-1) or two sessions (LLLT-2) of irradiation. The proliferation and adhesion of cells were evaluated by using the methylthiazolyl tetrazolium (MTT) assay and 4',6-diamidino-2-phenylindole (DAPI) staining. All experiments were done in triplicates on the first, third, and fifth days after cell seeding. Two-way ANOVA and post hoc Tukey tests were used to analyze the data of the MTT assay. P<0.05 was considered statistically significant. Results: One-day post-culture, only significant differences were found between the control group and the FGF2 (P=0.04) and FGF2+LLLT-2 application (P=0.04) groups. After three days post-cell culture, only a significantly higher proliferation rate was found in the control group than in the FGF2 group (P=0.01). After five days, the control group and LLLT-2 groups showed significantly higher amounts of proliferation compared to the other groups (P<0.05). DAPI staining qualitatively confirmed the results of the MTT assay. Conclusion: The LLLT can be applied to PDLSCs on the day of seeding without causing a notable decrease in their viability and adhesion. Conversely, the administration of FGF2 should be restricted on the seeding day and postponed to subsequent days as it may have adverse effects on their adhesion and proliferation.

An in vitro study on the effects of photobiomodulation by diode lasers (red, infrared, and red-infrared combination) on periodontal ligament mesenchymal stem cells treated with bisphosphonates.

This study evaluated the effect of photobiomodulation therapy (PBMT) using 660 and 808 nm diode lasers (individual and in combination) on periodontal ligament mesenchymal stem cells (PDLSCs) in the presence of zoledronic acid (ZA). PDLSCs were cultured for 48 h in DMEM complete medium containing 5 µM ZA. PBMT was done three times with a 24-h interval in groups 1 (660 nm, 5 J/cm2 ), 2 (880 nm, 3 J/cm2 ), and 3 (660 + 808 nm) either in normal or ZA-treated culture medium. Control groups did not receive PBMT. Twenty-four hours post-irradiation, cell proliferation and expression of RANKL and OPG were assessed using MTT and real-time PCR tests, respectively. The results showed a significant decrease in cell viability in ZA-treated cells (p < 0.001). Additionally, ZA induced the expression of OPG (p = 0.03) while reducing RANKL (p < 0.001). Cell proliferation was significantly increased in 808 and 660 + 808 nm groups. Moreover, all PBMT groups could significantly increase and decrease the RANKL and OPG, respectively, in the presence of ZA (all p < 0.001). A combination of 660 + 808 nm showed the highest effects on both genes. In conclusion, it seems that PBMT can modulate the effects of ZA by inducing PDLSC proliferation and increasing RANKL-to-OPG gene expression ratio.

Effect of photobiomodulation therapy on TGF-ß release from dentin, migration and viability of dental pulp stem cells in regenerative endodontics treatment: An ex vivo study.

BACKGROUND AND AIM: Regenerative endodontic procedures (REPs) are oriented by the principles of tissue engineering, incorporating dental pulp stem cells (DPSC), crucial growth factors like Transforming growth factor-ß (TGF-ß1), and scaffolds to facilitate the regeneration of dental pulp tissues. The present study aimed to investigate the effect of photobiomodulation (PBM) therapy, using an 808 nm diode laser on cellular modulation mechanisms in REPs. METHOD AND MATERIAL: A total of 108 human dentin discs obtained from intact single root teeth were randomly assigned into six groups (n = 8): 1. Positive control (EDTA), 2. PBM-1 (3 J/cm2), 3. PBM-2 (5 J/cm2), 4. EDTA+PBM-1, 5. EDTA+PBM-2, and 6. Negative control (NaOCl). Then, an extract solution was prepared from each disc and the concentration of released TGF-ß1 from the discs was measured using enzyme-linked immunosorbent assay (ELISA). Moreover, the extract solution was added to DPSC culture medium to evaluate cell viability and migration through MTT assay and scratch test, respectively. RESULT: The group exposed to PBM-1 showed the highest cell viability, while treatment with EDTA and EDTA+PBM-2 decreased cellular viability. Also, the PBM-treated groups showed significantly higher release of TGF-ß1 compared to the negative control. EDTA and EDTA+PBM-1 showed the highest release among all the groups. No significant difference was found between EDTA and EDTA+PBM-1, as well as between PBM-1 and PBM-2. Moreover, the PBM-1 group exhibited the highest migration after 24 h, which was significantly greater than other groups, except for the PBM-2 group. CONCLUSION: According to the obtained data, 808 nm mediated-PBM (3 J/cm2), both independently and in conjunction with EDTA, enhanced the release of TGF-ß1 from dentin and improved cell viability and migration of DPSCs. It seems that, PBM under the specific parameters employed in this study, could be an effective adjunctive therapy in REPs.

Photobiomodulation effects of pulsed and continuous wave near-infrared laser on the proliferation and migration of human gingival fibroblasts: An in vitro study.

There are limited data on comparison of pulsed and continuous wave in photobiomodulation therapy (PBM). This study aimed to investigate the effect of PBM with 980 nm laser in pulsed and continuous wave on the proliferation and migration of human gingival fibroblasts (HGF) cells. Cultured HGF were divided into three main groups: (1) irradiated in pulsed mode (frequencies of 50 and 25 KHz; energy densities of 3 and 5 J/cm2 ), (2) irradiated in continuous mode (energy densities of 3.2 and 5.2 J/cm2 ), and (3) no irradiation as control group. HGF proliferation rate was measured by MTT assay at 24, 48, and 72 h post irradiation. In addition, HGF migration rate was measured by scratch test at 24 h post PBM. At 24 h, the group received continuous irradiation at 5.2 J/cm2 showed significantly higher proliferation compared with the control group (p = 0.012). At 48 and 72 h, the groups received continuous, and 50 Hz pulsed irradiation at energy densities of 5.2 and 5 J/cm2 respectively, had significantly higher HGF proliferation rates compared to the control (p < 0.05). Only the continuous irradiations were effective in significant increase of the cell migration. In conclusion, continuous PBM at energy density of 5.2 J/cm2 showed promising effect on HGF proliferation and migration.

Evaluation the antibacterial efficacy of sodium hypochlorite in combination with two different photodynamic therapy protocols against Enterococcus Faecalis in Infected root canals: An in-vitro experiment.

BACKGROUND: Photodynamic therapy (PDT) is an antimicrobial approach that can be used as an adjunctive safe technique for root canal disinfection. In this study, we aimed to evaluate the antibacterial efficacy of PDT with indocyanine green and toluidine blue in combination with sodium hypochlorite (NaOCl) in compared with NaOCl alone against Enterococcus faecalis in infected root canals. METHODS: Sixty five root canals of sound human premolars were collected. First, the teeth were sterilized, then 60 root canals were inoculated with the E. faecalis, and 5 samples served as negative control remained uncontaminated. The contaminated root canals were randomly assigned into 4 experimental groups (n=15): (1) NaOCl, (2) NaOCl+ PDT-1 (toluidine blue + 630nm LED), (3) NaOCl+ PDT-2 (indocyanine green + 808nm diode laser), and (4): positive control (no treatment). Then, the colony-forming units (CFU/mL) of E. faecalis were calculated in all the groups. Moreover, 5 samples from each group were examined under a scanning electron microscope. The data were analyzed by independent T-test and the Mann-Whitney U test at the significance level of 0.05. RESULTS: The CFU count was significantly lower in the indocyanine green-PDT group in comparison with other groups (p˂0.05). The mean of CFU in the positive control group was significantly higher than the other groups (p˂0.05). No significant difference was detected between NaOCl and toluidine blue -PDT group (p=1.00). CONCLUSION: Indocyanine green- PDT improved the antibacterial effects of NaOCl against E. faecalis, while toluidine blue - mediated PDT had no significant additional effect on NaOCl.

In Vitro Effect of Photobiomodulation Therapy with 980 nm Diode Laser on Gene Expression of Key Regulators of Bone Remodeling by Human Periodontal Ligament Cells under Mild Orthodontic Forces.

This study investigated the effect of photobiomodulation (PBM) with 980 nm diode laser as monotherapy and in combination with compressive and tensile orthodontic forces on expression of osteoprotegerin (OPG), receptor activator of nuclear factor-κB ligand (RANKL), sclerostin (SOST) and periostin (POSTN), by human periodontal ligament cells. Isolated cells were cultured and subjected to either tensile (10% elongation) or compressive forces (25 g cm-2 ) for 24 and 48 h. Subsequently, the cells received PBM (100 mW power, 3 or 6 J cm-2 energy density) immediately after load cycle. RT-PCR was applied to assess the genes expression. Data were analyzed by one-way ANOVA, followed by post hoc Tukey test (P ≤ 0.05). We found that PBM in combination with orthodontic forces led to upregulation of bone resorption genes (RANKL and SOST) at the pressure side and their downregulation at the tension side. The expression of osteogenic genes (OPG and POSTN) increased at the tension side and decreased at the pressure side. PBM alone did not affect gene expression. In conclusion, these findings suggest that this PBM protocol may be effective in enhancement of the gene expression in favor of bone remodeling acceleration that should be confirmed in future animal and human studies.

The Effect of Photobiomodulation on Temporomandibular Pain and Functions in Patients With Temporomandibular Disorders: An Updated Systematic Review of the Current Randomized Controlled Trials.

Introduction: Temporomandibular disorders (TMDs) are the most prevalent non-dental origin orofacial pain conditions affecting the temporomandibular joints (TMJs) and/or orofacial muscles. Photobiomodulation therapy (PBMT) is a conservative way to improve function and reduce symptoms in TMD patients. This systematic review was conducted to update evidence about the effects of PBMT on pain intensity, TMJ movements, electromyography (EMG) activity, pressure pain threshold (PPT), and TMJ sound in patients with TMDs. Methods: A systematic literature search was conducted in Web of Science, PubMed/Medline, and Scopus databases using appropriate keywords and specific strategies from January 2000 to September 2022. Data extraction was done based on the inclusion/exclusion criteria. Results: A total of 40 studies were included. All included studies except one provided information on pain intensity; 27 studies showed a reduction in pain intensity in PBMT groups compared to control groups. Seven out of 15 studies, which reported maximum mouth opening (MMO), showed a greater MMO in PBMT groups than in placebo groups. In addition, the figures for passive maximum mouth opening (PMMO) and active maximum mouth opening (AMMO) in all the studies reporting PMMO and AMMO were higher in PBMT groups. In eight out of ten studies, lateral movement (LM) was greater in PBMT groups. Moreover, in three studies out of four, protrusive movement (PM) was reported to be greater in the PBMT group. Four out of nine studies showed a greater PPT in the PBMT group. Reduced TMJ sounds in the PBMT group were reported in two out of five studies. In addition, in most studies, no difference in EMG activity was detected between the two groups. Conclusion: This updated systematic review showed the promising effects of PBMT on the alleviation of pain and improvement in MMO. Using the infrared diode laser with a wavelength ranging between 780-980 nm, an energy density of<100 J/ cm2, and an output power of≤500 mW for at least six sessions of treatment seems to be a promising option for treating mentioned TMDs signs and symptoms based on the previously reported findings.

Effect of Photobiomodulation Therapy With an 810-nm Diode Laser on Pain Perception Associated With Dental Injections in Children: A Double-Blind Randomized Controlled Clinical Trial.

Introduction: This study investigated the photobiomodulation effect of an 810-nm diode laser in adjunction with topical anesthesia on pain perception during infiltration anesthesia of primary maxillary molars in children. Methods: This double-blind randomized controlled clinical trial was conducted on 64 children (aged 5-9 years) requiring extraction or stainless steel crown for their primary maxillary molars. The patients were randomly allocated into two groups (n=32) of laser and control. In the laser group, the injection site (buccal and palatal mucosa) was irradiated with an 810-nm laser (200 mW, 5.2 J/cm2) after 20% benzocaine topical anesthetic application, while the control group received a placebo laser following topical anesthesia. The pain intensity experienced by children during needle insertion into the buccal and palatal mucosa was determined using a visual analog scale (VAS) and modified behavioral pain scale (MBPS). Results: According to the results of the VAS and MBPS, no significant difference was detected in pain scores between the laser and control groups neither in the buccal nor in the palatal mucosa (P>0.05). Conclusion: Photobiomodulation therapy with an 810-nm laser with the current setting adjunct to topical anesthesia did not promote significant additional effects on the pain intensity.

Assessment of the methylene blue mediated photodynamic therapy on BCL2 and BAX genes expression at mRNA level and apoptosis of head and neck squamous cell carcinoma cell line.

AIM: This study aimed to assess the effect of photodynamic therapy (PDT) on apoptosis of head and neck squamous cell carcinoma (HNSCC) cells by flow cytometry and evaluating BAX and BCL2 genes expression.

The Role of Photobiomodulation on Dental-Derived Mesenchymal Stem Cells in Regenerative Dentistry: A Comprehensive Systematic Review.

BACKGROUND: Photobiomodulation therapy involves exposing tissues to light sources, including light-emitting diodes or low-level lasers, which results in cellular function modulation. The molecular mechanism of this treatment is revealed, demonstrating that depending on the light settings utilized, it has the potential to elicit both stimulatory and inhibitory reactions. OBJECTIVE: The current systematic review aimed to evaluate the impact of photobiomodulation therapy on dental stem cells and provide an evidence-based conclusion in this regard. METHODS: This systematic review was performed and reported based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) revised guidelines. PICO(S) components were employed to define the inclusion criteria. Web of Science, Scopus, Medline as well as grey literature, and google scholar were searched up to September 2021 to retrieve relevant papers. RESULTS: Photobiomodulation therapy showed promising effects on the proliferation, viability, and differentiation of dental stem cells. This finding was based on reviewing related articles with a low risk of bias. CONCLUSION: Despite the positive benefits of photobiomodulation therapy on dental stem cells, the current data do not provide a definitive conclusion on the best physical parameters for enhancing cell viability, proliferation, and differentiation.

In Vitro Anti-tumor Effects of Photodynamic Therapy on Oral Squamous Cell Carcinoma: A Review.

Introduction: Due to the increasing prevalence and high mortality rate of oral squamous cell carcinoma (OSCC) and problems with its routine treatments, more recent modalities like photodynamic therapy (PDT) have been developed. PDT effectively destroys tumor cells with minimum side effects. Research on in vitro effects of PDT may be helpful in determining the molecular mechanisms responsible for its effectiveness and can lead to the development of more efficient techniques. The aim of this study was to review the use of PDT in OSCC among in vitro studies. Methods: A literature search for English articles on PDT in OSCC was performed in PubMed, Scopus, Google Scholar, and Web of Science. Data were extracted based on the inclusion/exclusion criteria, which were detailed using the PICO framework: all eligible in vitro studies evaluating the effects of PDT on the viability of OSCC compared to controls without PDT were included. Results: Forty-one out of 567 studies were selected. The tongue was the most common OSCC site, 5-aminolevulinic acid was the most used photosensitizer (PS), cell viability/toxicity and apoptosis were the most evaluated outcomes, and lasers with wavelengths of 600-700 nm were the most common light sources and wavelengths respectively. Conclusion: PDT showed promising effects on reducing the viability of OSCC cells. Cell lines from various sources or even those originating from the same location sometimes responded differently to the same protocol. Considering the favorable results obtained from natural PSs and regarding their additional health-promoting properties, their use in future investigations with different cell lines and light specifications is recommended.

Effect of Photobiomodulation Therapy on Differentiation of Mesenchymal Stem Cells Derived from Impacted Third Molar Tooth into Neuron-like Cells.

Peripheral nerve damages are among the most important consequences of dental and maxillofacial procedures. Tissue engineering using mesenchymal stem cells (MSCs) is a promising method to manage such injuries. Moreover, photobiomodulation therapy (PBMT) can enhance this treatment. The present study aimed to investigate the effect of PBMT on differentiation of MSCs derived from dental follicle (DF) into neurons. MSCs were isolated from an impacted tooth follicle by digestion method. The stem cells were cultured, and differentiated into neurons. The cells received two sessions of PBMT with 810 or 980 nm diode laser (100 mW, 4 J cm-2 ) in either DMEM or neural inductive medium. Phenotypic characterization of the cells was determined using flow cytometry. In addition, ß-tubulin and MAP2 genes expression level changes were analyzed using RT-PCR and western blot technique. After 14 days, flow cytometry analysis confirmed the mesenchymal nature of cells. RT-PCR and western blot affirmed the expression of ß-tubulin and MAP2 genes and proteins respectively. PBMT with both wavelengths significantly increased ß-tubulin and MAP2 expression in neural inductive medium with highest expression mean in 980 nm group. PBMT with 810 and 980 nm lasers could be a promising adjunctive method in differentiation of DF-originated MSCs into neural cells.

Efficacy of Nd:YAG laser-assisted periodontal therapy for the management of periodontitis: A double-blind split-mouth randomized controlled clinical trial.

BACKGROUND: This study aimed to explore the efficacy of Nd:YAG laser-assisted periodontal therapy for management of patients with stage II-IV periodontitis. METHODS: Patients who presented with residual periodontal pockets were enrolled. After non-surgical periodontal therapy (NSPT), test sites received Nd:YAG laser (first entrance to pocket: 3 W, 100 µs, 20 Hz; second entrance: 4 W, 600 µs, 20 Hz) and control sites received placebo (laser off). Periodontal probing depth (PPD), clinical attachment level (CAL), gingival recession (GR), bleeding on probing (BOP), and plaque index (PI) were recorded at baseline and 1, 2, 3, 4 and 6-month visits. RESULTS: Twenty patients completed the 6-month period. Significant reductions in PPD, CAL, BOP, and PI values and a significant increase in GR at all follow-up visits compared to the baseline (all P < 0.001) were revealed in both groups. Test sites showed significantly greater improvement in PPD (P = 0.0002) and greater increase in GR (P < 0.0001) compared to the control sites at 6-month visit. There was no difference between two groups regarding CAL gain through the study period (P = 0.23). CONCLUSION: NSPT+Nd:YAG laser with the current protocol results in greater PPD reduction compared to NSPT alone. However, this reduction is likely because of greater GR rather than attachment gain. Therefore, the adjunction of Nd:YAG laser (with the current setting) to the NSPT for the treatment of residual periodontal pockets did not ameliorate the clinical outcomes (ClinicalTrials.gov ID: NCT03365167).

Efficacy of photobiomodulation therapy on neurosensory recovery in patients with inferior alveolar nerve injury following oral surgical procedures: a systematic review.

OBJECTIVE: The present systematic review aimed to assess the efficacy of photobiomodulation (PBM) therapy on neurosensory recovery of patients with inferior alveolar nerve injury following third molar surgery or dental implant placement. METHOD AND MATERIALS: An electronic search was carried out in Scopus, Embase, Medline, PubMed, Web of Science, Cochrane Library, and Google Scholar databases. Among 1,122 identified papers, seven articles (three RCTs, one observational study, and three case series) met the inclusion criteria.
Results: Time lapse from nerve injury to the onset of PBM therapy varied widely from 2 days to 4 years. The number of patients in each study ranged between 4 and 74. In the majority of the studies, PBM was done using a diode laser at wavelengths ?in the range of 808 to 830 nm with power of 5 to 500 mW and radiation dose of 3 to 244 J/cm2. Two out of three RCTs found significant neurosensory recovery in the patients who received PBM therapy compared to the controls. The observational study and all case series reported significant improvement in the neurosensory status following PBM therapy. The degree of neurosensory recovery was found to be greater in younger patients and those who received the treatment within 6 months following the injury.
Conclusions: Due to the limited number of well-designed RCTs and small number of patients in each study, it is not possible to make a clear conclusion about the efficacy of PBM therapy on neurosensory recovery in patients with inferior alveolar nerve injury following third molar or implant procedures. Considering the possibility of spontaneous inferior alveolar nerve recovery during this period, the conclusion based on the studies with no control group should be interpreted with caution. (Quintessence Int 2021;52:140-153; doi: 10.3290/j.qi.a45430).