Light-emitting diode phototherapy: pain relief and underlying mechanisms

Can diode laser 810 nm decrease post endodontic pain in patients with asymptomatic necrotic maxillary incisors? A four-arm randomized controlled trial

AIM

To find the best method for applying the diode laser 810 nm to relieve post-endodontic pain on necrotic maxillary incisors with periapical lesions within a single-visit treatment.

METHODS

Eighty patients with a necrotic incisor, diagnosed with asymptomatic apical periodontitis, received standardized cleaning and shaping procedures, then divided randomly with a 1:1:1:1 allocation ratio into four groups: Group 1: control group with no laser application, Group 2: applying the diode laser as an irrigation activation system (IAS), Group 3: applying the diode laser from the buccal and palatal mucosa, Group 4: applying the diode laser as an IAS and from buccal and palatal mucosa. The postoperative pain was assessed using the visual analog scale (VAS) 1, 3, 7, and 14 days after the treatment. The mean values of the VAS score were statistically analyzed used Kruskal-Walis and Mann-Whitney U tests. The level of significance was set at a = 0.05.

RESULTS

During 14 days after treatment, there was a statistically significant difference between mean values of VAS scores in the four groups (P value < 0.05); Group 1 scored the highest score, whereas Group 4 showed the lowest one. Moreover, Group 4 showed favorable outcomes compared with Group 2 and Group 3 during the first three days after treatment.

CONCLUSION

Diode laser reduced postoperative pain after necrotic teeth with large-sized apical lesion treatment, whereas using diode laser either as an IAS or LLLT reduced the postoperative pain compared with the control group. Moreover, the usage of a diode laser in both previous techniques represents the best protocol for postoperative pain relief during 14 days of treatment.

CLINICAL RELEVANCE

The clinical significance of this study is to investigate the best method to reduce postoperative pain using diode lasers 810 nm; where the results of this study indicated that the more diode laser exposer in LLLT and IAS, the less postoperative pain after endodontic procedures.

Effects of light-emitting diode (LED) therapy on sensory changes in the inferior alveolar nerve after surgical treatment of mandibular fractures: a randomized controlled trial

PURPOSE

A randomized controlled trial was performed to evaluate the effects of light-emitting diode (LED) therapy on sensory changes in the inferior alveolar nerve after surgical treatment of mandibular fractures.

METHODS

Patients admitted with surgically treated mandibular fractures between January 2018 and December 2019 were evaluated. Personal data, fracture location, fracture type, and dislocation degree were obtained. The cases were randomly allocated into two groups: LED therapy (LEDT) (57 points of 660 nm and 74 points of 850 nm, 6.4 mV/cm2, and 7.64 J) with the use of a prototype device and control (CTRL). For 6 months, tactile and thermal tests were used in the mental region. Data were analyzed using the Mann─Whitney U test and likelihood ratio test (p ≤ 0.050).

RESULTS

The study included 42 patients, 25 of whom had bilateral fractures and 17 had unilateral fractures, totaling 67 fractures. The mean values of the tactile and thermal sensitivity tests were lower in the LEDT group in all evaluation periods. There was a significant difference between the groups in the parasymphysis location, displacement < 5 mm, and intraoral access. Sensory changes were observed in 68.7% of all fractures upon admission, with 91.2% in the LEDT group and 78.8% in the CTRL group demonstrating complete remission during the final period of the study.

CONCLUSION

LED photobiomodulation accelerated the process of sensory change remission. There was an influence of the fracture location, degree of displacement, and surgical access, with a better response in the LEDT group.

Non-lethal exposure to short-wavelength light-emitting diodes modulates tight-junction structure in human corneal epithelial cells via cAMP-dependent signaling

Light-emitting diodes (LED)-derived lights have been widely used as a medical treatment in photobiomodulation (PBM). However, the PBM effects in ophthalmology are less well investigated. Herein, we explored the effect of LED-generated light on the tight-junction (TJ) formation in human corneal epithelial cells (HCEs). The HCEs were separately exposed to monochromatic LEDs at wavelengths of 365 nm (UVA), 420 nm (violet), 470 nm (blue), 530 nm (green), 590 nm (amber), 660 nm (deep red), and 740 nm (far red) at 10 J/cm2/day for 1 and 2 days. Long-term cultivation of HCEs without LED exposure for up to 14 days was established as a control. The effects of both LED wavelength and culture duration on cell morphology, cAMP-regulated proteins, TJ-associated proteins, and cell growth-associated proteins were also analyzed. Together with the increase in cell number during prolonged cultivation, cAMP, ZO-1, ZO-2, CLDN1, and CLDN4 all increased significantly during long-term cultivation without LED exposure. There was no difference in HCE viability after exposure to all monochromatic LEDs at an accumulated dose of 20 J/cm2. As determined by immunoblotting, UVA, violet, and blue light increased intracellular cAMP, ZO-1, ZO-2, CLDN1, and CLDN4 expression, respectively. UVA and violet, but not blue, light increased PKAreg-pS77 expression. However, none of the other treatments changed the expression of PKAcat-pT197, VASP-pS157, Bax, Bcl-2, or Bcl-xL. Immunofluorescence staining confirmed the formation of TJ structures. The expressions of ZO-1, ZO-2, CLDN1, and CLDN4 as well as TJ structures 2 days following UVA, violet, and blue exposure were similar to those of control cells after 9 days of cultivation. We conclude that short-wavelength LEDs at non-lethal exposure intensities accelerated the formation of TJ structure in HCEs via a cAMP-dependent regulatory cascade.

Devices for osteoarthritis symptoms treatment: a patent review

INTRODUCTION

Osteoarthritis is a musculoskeletal disease that can lead to the loss and inability of those affected to perform normal daily functions, which leads to a decrease in quality of life. The main symptoms of osteoarthritis are tenderness, joint pain, stiffness, crepitus, limited movement, and local inflammation.

AREAS COVERED

The selected patents were deposited from 2010 to April 2022 involving 57 documents that were in line with the study objective in the final selection. The patents were classified in years, country, and applicants. Also, the therapeutic fields that presented the most documents were electrical stimulation, phototherapy, and ultrasound, followed by magnetic, electromagnetic, and thermotherapy. Therefore, the most current therapies used in the documents are already on the market.

EXPERT OPINION

Although the OA is cureless, non-surgical treatments are classified as the primary management approach for this disease. The pharmacological and non-pharmacological therapies are employed to reduce its prevalence and ensure the effectiveness of treatments. A strategy for relieving OA symptoms is non-pharmacological treatment, which can be based on exercise and patient education, combined with other alternative therapies. These therapies are used as supplements to the main OA treatments, enhancing the effectiveness of treatment outcomes.

Unraveling the parameters and biological mechanisms of CO2 laser therapy for acute pain relief

Acute pain-related pathology is a significant challenge in clinical practice, and the limitations of traditional pain-relief drugs have made it necessary to explore alternative approaches. Photobiomodulation (PBM) therapy using CO2 laser has emerged as a promising option. In this study, we aimed to identify the optimal parameters of CO2 laser irradiation for acute pain relief through in vivo and in vitro experiments. First, we validated the laser intensity used in this study through bone marrow mesenchymal stem cells (BMSCs) experiments to ensure it will not adversely affect stem cell viability and morphology. Then we conducted a detailed evaluation of the duty cycle and frequency of CO2 laser by the hot plate and formalin test. Results showed a duty cycle of 3% and a frequency of 25 kHz produced the best outcomes. Additionally, we investigated the potential mechanisms underlying the effects of CO2 laser by immunohistochemical staining, and found evidence to suggest that the opioid receptor may be involved in its analgesic effect. In conclusion, this study provides insights into the optimal parameters and underlying mechanisms of CO2 laser therapy for effective pain relief, thereby paving the way for future clinical applications.