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).

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.

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.

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.

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.

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.

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).

Juvenile Hyaline Fibromatosis Management With a Diode Laser: A Rare Case Report.

Juvenile hyaline fibromatosis (JHF) is an unknown hereditary disorder with variable penetrance. The characterizations of this disease consist of different signs and symptoms such as multiple tumorous (tumor-like) muco-cutaneous proliferation, gingival hypertrophy, perianal lesions, articular contractures, and osteolytic lesions. A 3-year-old girl with numerous painless nodular masses on her gingival, ear and anal areas is presented in this case report. Based on characteristic histological features, the diagnosis of JHF was made. The patient underwent surgery following general anesthesia and the above areas were surgically operated with appropriate laser parameters, and the patient was able to eat and wash away after a day and was discharged with an antibiotic prescription after one day in the hospital and returned to normal after a week. The recurrence occurred in other areas a year later, especially in the cheek, the ears and the anal area. Therefore, this rare case is presented with recurrence.

Recovery of inferior alveolar nerve by photobiomodulation therapy using two laser wavelengths: A behavioral and immunological study in rat.

Postoperative sensory disturbances of inferior alveolar nerve (IAN) are major challenges in dental procedures. We aimed to investigate the effect of photobiomodulation therapy (PBMT) with 810 nm and 980 nm diode lasers on behavioral and immunological factors in a rat IAN crush model. Seventy-two rats were randomly assigned to the four groups of 810 nm laser (crush injury+810 nm laser; 6 J/cm2, 15 sessions, every 48 h), 980 nm laser (crush injury+980 nm laser; same protocol), control (crush injury without irradiation), and sham surgery (no crush injury and no irradiation). The neurosensory response of IAN was evaluated by Von Frey behavioral test before (baseline) and post-surgery in a period of one month. Changes of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), nuclear factor-kappa B (NF-κB), TNF-α, and IL-1ß, were assessed on days 2 and 30 post injury. Data were analyzed for significant differences by repeated measures and one-way ANOVA (p < .05). One day after surgery, all rats subjected to nerve injury showed significant increase in the withdrawal threshold of von Frey test compared to the baseline (p = .02 for control and p = .03 for laser groups). The threshold gradually returned to the baseline scores in 810 nm, 980 nm, and control groups from days 11, 17, and 29, respectively. There was a significant lower withdrawal threshold in 810 nm and 980 nm laser groups compared to the control group in days 11 to 19 and 9 to 23, respectively. At both time points, the levels of NGF and BDNF were significantly higher in 810 nm laser group compared to the control group. There was a significant difference between laser and control groups regarding NF-κB expression (all p values<.001). TNF-α and IL-1ß were significantly lower in laser groups compared to the control group (all p values < .001). PBMT with 810 and 980 nm diode laser protocol used in this study, promoted the neurosensory recovery of IAN after crush injury in rats. In addition, application of 810 nm diode laser was associated with more improvement in immunological responses compared to that of 980 nm laser.

Photobiomodulation Therapy for the Management of Patients With Inferior Alveolar Neurosensory Disturbance Associated With Oral Surgical Procedures: An Interventional Case Series Study.

Introduction: Inferior alveolar nerve (IAN) injury is a serious complication during intraoral surgeries. We aimed to evaluate the outcome of photobiomodulation (PBM) therapy in patients with IAN injury associated with third molar or implant procedures. Methods: Eight patients with an alteration of sensory function of the IAN after third molar or implant surgeries were enrolled in this case series study. The patients received 10 sessions of PBM therapy (810 nm diode laser, 200 mW, 10 J/cm2 per point, three times a week). Pinprick (PP) and visual analogue scale (VAS) neurosensory tests were recorded at each treatment session and 14 days after the last treatment. The association between explanatory variables and the outcome of interest was analyzed using generalized estimating equations. Results: The median percentage change of outcomes from the first to the last visit was as follows: VAS score: +125.00% (range: 50.00 to 166.67); PP score: +350% (range: 150 to 800). The duration of paresthesia was inversely correlated with changes in VAS and PP scores. No significant association was found between patients' gender or age and changes in VAS and PP scores. Conclusion: Considering the limitations of this study, PBM with the parameters used in this study presented positive effects on neurosensory recovery in patients suffering from IAN injury associated with routine intraoral procedures. Patients with shorter duration of paresthesia tended to respond more favorably to PBM therapy.

The susceptibility of Streptococcus mutans to antibacterial photodynamic therapy: a comparison of two different photosensitizers and light sources

Streptococcus mutans is the main etiological agent for dental caries. Recently, photodynamic therapy (PDT) has been introduced as a new modality in bacterial decontamination. Objective: This in vitro study was carried out to evaluate the susceptibility of Streptococcus mutans to antibacterial PDT using two different photosensitizers and light sources. Material and Methods: Standard suspensions of S. mutans were exposed to laser light at 662 nm and Radachlorin® or LED 630 nm in combination with Toluidine blue O (TBO). Radiation-only groups, photosensitizer alone, and groups with no treatment were used as controls. Bacterial suspension from each treatment was subcultured onto the surface of Mueller-Hinton agar plates and bacterial growth was assessed. The results were analyzed by analysis of variance and Tukey test (p<0.05). Results: PDT with TBO and Radachlorin® significantly reduced S. mutans viability, whereas no difference was observed between two groups of PDT. In the groups treated just with the photosensitizer or irradiated alone, no significant reduction of S. mutans colonies was observed. Conclusion: S. mutans colonies were susceptible to either 662 nm laser or LED light in the presence of Radachlorin® and TBO respectively with no priority. .

The susceptibility of Streptococcus mutans to antibacterial photodynamic therapy: a comparison of two different photosensitizers and light sources.

UNLABELLED: Streptococcus mutans is the main etiological agent for dental caries. Recently, photodynamic therapy (PDT) has been introduced as a new modality in bacterial decontamination. OBJECTIVE: This in vitro study was carried out to evaluate the susceptibility of Streptococcus mutans to antibacterial PDT using two different photosensitizers and light sources. MATERIAL AND METHODS: Standard suspensions of S. mutans were exposed to laser light at 662 nm and Radachlorin or LED 630 nm in combination with Toluidine blue O (TBO). Radiation-only groups, photosensitizer alone, and groups with no treatment were used as controls. Bacterial suspension from each treatment was subcultured onto the surface of Mueller-Hinton agar plates and bacterial growth was assessed. The results were analyzed by analysis of variance and Tukey test (p<0.05). RESULTS: PDT with TBO and Radachlorin® significantly reduced S. mutans viability, whereas no difference was observed between two groups of PDT. In the groups treated just with the photosensitizer or irradiated alone, no significant reduction of S. mutans colonies was observed. CONCLUSION: S. mutans colonies were susceptible to either 662 nm laser or LED light in the presence of Radachlorin and TBO respectively with no priority.

Treatment of oral squamous cell carcinoma using anti-HER2 immunonanoshells.

BACKGROUND: Worldwide, oral squamous cell carcinoma (potentially mediated by HER2) is recognized as the most commonly occurring malignant neoplasm of the oral cavity. Anti-HER2 nanobodies conjugated to gold-silica nanoshells and used as photothermal treatment for oral squamous cell carcinoma may provide a novel therapeutic alternative to current treatment for this disease. METHODS: KB epithelial or HeLaS3 cell cultures (controls) were exposed to these immunonanoshells, and plasmon resonance electron initiation specific to gold was employed to burn the tumor cells. RESULTS: Following this treatment, significant cell death occurred in the KB tumor cell cultures while there was no evidence of cellular damage or death in the HeLaS3 cell cultures. CONCLUSION: These findings suggest that photothermal treatment of oral squamous cell carcinoma has considerable advantages.