The effect of low-level laser radiation on improving inferior alveolar nerve damage after sagittal split osteotomy: a systematic review

Efficacy of low-level laser therapy and microsurgery on neurosensory recovery following inferior alveolar and lingual nerve injuries: A systematic review

Purpose

This systematic review evaluates the relative effectiveness of low-level laser therapy (LLLT) and microsurgery for neurosensory recovery following sustained iatrogenic injuries to the inferior alveolar nerve (IAN) and lingual nerve (LN) more than 6 months in Oral and Maxillofacial surgery procedures.

Methods

Six articles were included. The mean age of microsurgery studies was 41.5 years and that of LLLT studies was 31.5 with female predominance in all studies. The majority of the included studies have been based on both subjective and objective assessments for neurosensory, two investigating microsurgery and four investigating LLLT following a Six-month post-IAN and LN injury.

Results

Each modality demonstrated positive outcomes in both subjective and objective assessments of neurosensory function. Notably, LLLT exhibited efficacy even when employed beyond a six-month interval following the initial injury. Early intervention is generally recommended, particularly for microsurgical approaches.

Conclusion

LLLT shows exciting promise as a minimally invasive approach for neurosensory rehabilitation even after six months of injury, while microsurgery studies revealed an improvement and the recommendation for early intervention post-nerve injury, the potential of LLLT and optimize its use for neurosensory rehabilitation, additional randomized controlled trials with larger sample sizes, longer follow-up periods, and blinding protocols are necessary.

Expediting the reversal of inferior alveolar nerve block anesthesia in children with photobiomodulation therapy

In pediatric dentistry, complications arising from extended soft tissue anesthesia can negatively impact patient comfort and trust in dental care. This study evaluates the clinical efficacy of diode laser-based photobiomodulation therapy (PBMT) in expediting the resolution of anesthesia in children aged 6-9 receiving inferior alveolar nerve block (IANB) injections. In this split-mouth double-blind randomized clinical trial, 36 pediatric subjects aged 6-9, requiring pulpotomy procedures on both sides of the mandible, received IANBs (single cartridge of 2% lidocaine/1:100,000 epinephrine). PBMT and sham laser were alternately applied to each side of the mandible, in two separate sessions, with the envelope method determining treatment allocation and intervention side on the first treatment day. During the laser session, laser (808 nm, 250 mW, 23s continuous, 0.5 cm², 11.5 J/cm², direct contact) irradiated two points at the injection site, five intra-oral and five extra-oral points along the infra-alveolar nerve's pathway. Soft tissue anesthesia reversal was quantified through tactile assessment. Soft tissue trauma was also assessed by the researcher and reported by parents 24 h post-dental visit. All data were analyzed using IBM SPSS Statistics v25.0 via Paired T-test, two-way repeated measures ANOVA, and McNemar's test. The laser group exhibited a mean lip anesthesia duration of 122.78 ± 2.26 min, while the sham laser group experienced 134.44 ± 21.8 min, indicating an 11.66-minute reduction in anesthesia duration for the laser group. (P < 0.001) Soft tissue trauma occurred in two sham laser group patients and one laser group patient, with no significant difference. (P = 1) The findings indicate that employing laser with defined parameters can reduce the length of IANB-induced anesthesia.

Effects of NGF and Photobiomodulation Therapy on Crush Nerve Injury and Fracture Healing: A Stereological and Histopathological Study in an Animal Model

Study Design

A stereological and histopathological study in an animal model.

Objective

This study explores the effects of the nerve growth factor and photobiomodulation therapy on the damaged nerve tissue and fracture healing.

Methods

A total of 24 rabbits were divided into 4 groups: control group (n = 5), nerve growth factor (NGF) group (n = 7), photobiomodulation (PBMT) group (n = 6), and nerve growth factor and photobiomodulation therapy (NGF+PBMT) group (n = 6). The vertical fracture was performed between the mental foramen and the first premolar, and the mental nerve was crushed for 30 seconds with a standard serrated clamp with a force of approximately 50 N in all groups. The control group received an isotonic solution (.02 mL, .09% NaCl) to the operation site locally. The NGF group received 1 μg human NGF-β/.9% .2 mL NaCl solution for 7 days locally. The PBMT group received PBMT treatment (GaAlAs laser, 810 nm, .3 W, 18 J/cm2) every 48 hours for 14 sessions following the surgery. The NGF+PBMT group received both NGF and PBMT treatment as described above. After 28 days, the bone tissues and mental nerves from all groups were harvested and histologically and stereologically analyzed.

Results

According to the stereological results, the volume of the new vessel and the volume of the new bone were significantly higher in the PBMT group than in other groups (P < .001). According to the histopathological examinations, higher myelinated axons were observed in experimental groups than in the control group.

Conclusions

As a result, PBMT has beneficial effects on bone regeneration. Based on the light microscopic evaluation, more regenerated axon populations were observed in the NGF group than in the PBMT and PBMT + NGF groups in terms of myelinated axon content.

Effect of delayed photobiomodulation therapy on neurosensory recovery in patients with mandibular nerve neurotmesis following traumatic mandibular fracture: A randomized triple-blinded clinical trial

INTRODUCTION

There is a possibility of neurotmesis of the inferior alveolar nerve (IAN) in mandibular fractures, which leads to neurosensory impairment. In this study, we aimed to investigate the efficacy of photobiomodulation therapy (PBMT) in patients with neurotmesis following trauma and mandibular fracture.

MATERIALS AND METHODS

This triple-blind randomized trial was carried out on patients who suffered neurotmesis of the IAN following mandibular angle and body fracture at least for 6 months. In the intervention group, laser irradiation was applied with a low-level GaAlAs diode laser (continuous wave of 810 nm wavelength, power of 200 mW, and energy density of 12-14 J/cm²). In the control group, the laser probe was turned off and placed on the affected area. LLLT was done for 12 sessions (2 times/week for 6 weeks). Light touch sensations, two-point discrimination, thermal discrimination (cold and warm stimulus), electric pulp test (EPT), and oral health impact profile (OHIP)-14 questionnaire were performed before the intervention, immediately after each PBMT session, and after 3, 6, 9 and 12 months.

RESULTS

In both groups, 3 and 23 patients were female and male, respectively. The results showed significantly improved light (cotton swab), light (wooden cotton swab), and sharp (dental needle) touch sensations, and two-point discrimination test in the PBMT group after the 10th, 11th, 10th, and 10th session, respectively. Two-way repeated measure ANOVA revealed that the trend of light touch sensation with cotton swab and two-point discrimination test was statistically significant (p-value = 0.002 and 0.001, respectively). The results of OHIP-14 test showed a significantly higher mean in the PBMT group 3 months after PBMT. There was no statistically significant difference in EPT and thermal discrimination tests regarding the patients' group.

CONCLUSION

PBMT could be an effective treatment for late post-traumatic nerve neurotmesis following a traumatic mandibular fracture.

Therapy of Neurophysiological Changes after Oral and Maxillofacial Surgery—A Systematic Review

Introduction: The purpose of this systematic review was to critically analyze the recent literature to present a guideline for management of neurophysiological changes after implant placement and oral and maxillofacial surgical procedures. Materials and methods: Three electronic databases and manual search approaches were used to identify relevant articles on neurophysiological changes. Only studies with a randomized controlled study design were included. Primary outcome was defined as the status of recovery and relief of pain states under various therapies. Two independent reviewers evaluated the data. Results: A total of eight studies from 2891 records identified met the inclusion criteria. Therapy options for patients with neurophysiological changes after implant placement and oral and maxillofacial surgery were low-level laser (LLL), stellate ganglion block (SGB), medication, and surgical removal of implants. Six studies dealt with LLL, providing a significant improvement in mechanical sensation. Only one study revealed the whole neurosensory profile including neuropathic pain states. All the included RCT studies presented at least one bias, and a considerable heterogeneity of the included studies was revealed. Conclusions: Reduced thermal sensation may be due to irritation of small fibers. LLL might help to improve nerve recovery.

Does the use of low-level light therapy postoperatively reduce pain, oedema, and neurosensory disorders following orthognathic surgery? A systematic review

The aim of this study was to evaluate the efficacy of low-level light therapy (LLLT) in improving pain, oedema, and neurosensory disorders of the inferior alveolar nerve (IAN) after orthognathic surgery. This systematic review was performed in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Searches were conducted in the PubMed, Embase, and Web of Science databases for randomized clinical trials (RCTs) published up to September 2020. After evaluating eligibility, 15 RCTs were selected. None of the studies reported an evaluation of all of the outcomes within the same publication. It was possible to determine the effect of LLLT in controlling pain following orthognathic surgery. Of the three studies evaluating this outcome, all observed a positive effect. Of the four studies that evaluated oedema, two found a positive effect. Of the 11 studies that evaluated neurosensory disorders of the IAN, all of them observed a positive effect, at least in one of the sensory evaluation tests. A meta-analysis was not possible due to the heterogeneity across studies. Considering the limitations of this review, but given the fact that LLLT is a minimally invasive intervention, its use merits consideration in immediate postoperative orthognathic surgery.

The effect of low-level laser radiation and doxycycline on the levels of osteoprotegerin and receptor activator of nuclear factor kappa-B ligand

The present in vitro study was conducted to investigate the effect of low-level laser (LLL) radiation and doxycycline on the levels of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) derived from MG-63 osteosarcoma cell line. MG-63 cells were divided into four groups. In the first group, 2 mg/mL of doxycycline was injected into the cell culture medium. Diode laser (810 nm, 100 mw, 75 s) was radiated to the culture medium of the second group. The third group received both doxycycline and laser radiation. In the fourth group (control), the culture medium was replaced daily, similar to the above three groups. Mentioned interventions were performed once a day for 4 consecutive days. Then, on the sixth day, the levels of OPG and RANKL mediators were measured using real-time polymerase chain reaction by isolating the cells from the samples. OPG expression had the highest to lowest levels in the laser + doxycycline, doxycycline, laser, and control groups, respectively. The level of OPG was significantly different between all the study groups (p < 0.05) except in the doxycycline + laser and doxycycline groups (p = 0.061). The highest to lowest levels of RANKL was observed in the doxycycline, laser + doxycycline, control, and laser groups, respectively. The RANKL expression was not significantly different between all the study groups (p > 0.05). The results of this study revealed that LLL and doxycycline reduced the RANKL/OPG ratio derived from the MG-63 osteosarcoma cell line, which may result in the diminished activity of osteoclasts and osteoclastogenesis.

Low-level laser therapy for neurosensory recovery after sagittal ramus osteotomy

BACKGROUND

Dento-skeletal deformities are treated combining orthodontic treatment with orthognathic surgery. One of the techniques most used in this type of surgery is the sagittal osteotomy of the mandible. This technique offers many advantages, but within its disadvantages is the inferior alveolar nerve paresthesia. There are various treatments that aim to recovery of the nerve bundle, and one of them is low intensity laser treatment. The aim of this study was to evaluate the effectiveness of low intensity laser therapy in the recovery of neurosensorial tissues after mandibular sagittal osteotomy during orthognathic surgery.

METHODS

Twelve patients submitted to surgery, using mandibular sagittal osteotomy, were treated unilaterally with low intensity infrared (808 nm, GaAIAs active medium) laser, following the inferior alveolar nerve path. The other part of the mandible was treated by placebo. The parameters used were 100 mW of power, irradiancy of 3.6 W/cm2, 2.8J energy per point, an energy density of 100 J/cm2, 28 seconds at each point with a distance of 1.0 cm between points, two sessions per week with a minimum of 10 sessions, starting 48 hours after surgery. Mechanical evaluation was performed in first, fourth, seventh and tenth session.

RESULTS

Significant improvement on the treated side was observed. Comparing the behavior among the variables between the treatment (T) group and the control (C) group in the General Recovery was showed a tendency to better results in the T group when compared to the C group, with statistical difference (P≤0.05) after the 10th laser therapy session.

CONCLUSIONS

The treatment of neurosensorial disorders with infrared low intensity laser could be effective in accelerating recovery, providing greater comfort to the patient, and it presents advantages over other existing methods.

Effect of photobiomodulation on recovery from neurosensory disturbances after sagittal split ramus osteotomy: a triple-blind randomised controlled trial

We have investigated the effect of photobiomodulation on the recovery of neurosensory function of the lip and chin after bilateral sagittal split osteotomy (BSSO). Laser irradiation was applied with a GaAs diode laser (continuous wave 980nm wavelength, power 100mW, and energy density 12J/cm²). It was maintained within a 0.5cm² area in a total of 12 points for 60seconds at each visit on each point. Unilateral extraoral contact photobiomodulation treatment was applied the day before operation and then on days 1, 3, 7, 14, 21, and 28 postoperatively. One side of the mandible was the intervention side and the other the control side. On the control side, the laser probe was turned off and placed on the chosen area. Neurosensory evaluations were made before and immediately after operation, and 30 days and 60 days postoperatively. Twenty-five patients were screened, and 18 who met the inclusion criteria were included in the study; 14 were women and the mean (SD) age was 23 (5) years. Analysis of the visual analogue scales for general sensibility, pain discrimination, directional discrimination, and 2-point discrimination showed a significant difference between the intervention and control sides after 30 days (p=0.0011, 0.0034, 0.0023, and 0.0160, respectively). The difference was also significant after 60 days (p=0.0001, 0.0002, 0.0003, and 0.0010, respectively). The thermal discrimination rate was significantly higher in the laser group than the control group 30 days after surgery (p=0.002), but after 60 days the difference was not significant (p=1.000). We found no side effects from the laser radiation during the two-month follow up. The results suggest that photobiomodulation accelerated the patients' improvement from neurosensory disturbance after BSSO.