Lower-level laser therapy improves neurosensory disorders resulting from bilateral mandibular sagittal split osteotomy: a randomized crossover clinical trial

Nerve Injury and Photobiomodulation, a Promising Opportunity: A Scoping Review on Laser Assisted Protocols for Lesions in the Oral Region

The currently available therapeutic options for restoring function and sensitivity in long-term nervous injuries pose challenges. Microsurgery interventions for direct nerve repair often lead to serious complications and limited success. Non-surgical methods, although somewhat effective, have limited benefits. These methods involve drug administration, such as with analgesics or corticosteroids. Photobiomodulation therapy (PBMT) has emerged as a promising approach based on clinical and laboratory studies. PBMT stimulates the migration and proliferation of neuronal fiber cellular aggregates, as reported in the literature. Experimental studies on animal models with peripheral nerve compression injuries have shown that PBMT can enhance the functionality of damaged nerves, preserving their activity and preventing scar tissue formation. The mechanism of action depends on the wavelength, which can positively or negatively affect photo acceptor resonances, influencing their conformation and activities. These findings suggest that photobiomodulation may accelerate and improve nerve regeneration. This review explores various methodologies used in photobiomodulation for regenerating nerve sensitivity after surgical trauma involving nerve structures, in the oral and peri-oral region. Research was conducted to evaluate which laser-assisted therapeutic protocols are used to improve the recovery of nervous sensitivity, using the JBI methodology for scoping reviews and following the PRISMA methodology.

The effectiveness of photobiomodulation therapy on inferior alveolar nerve injury: A systematic review and META-analysis

OBJECTIVE

The aim of this META-analysis was to evaluate the efficacy of photobiomodulation (PBM) therapy in the treatment of inferior alveolar nerve (IAN) injury due to orthognathic surgeries, extraction of impacted third molars and mandibular fractures.

METHODS AND MATERIALS

A electric search was conducted by a combination of manual search and four electric databases including Pubmed, Embase, Cochrane library and Web of Science, with no limitation on language and publication date. Gray literature was searched in ClinicalTrials.gov and googlescholar. All retrieved articles were imported into ENDNOTE software (version X9) and screened by two independent reviewers. All analysis was performed using the REVMAN software (version 5.3).

RESULTS

Finally, 15 randomized controlled trials met the inclusion criteria for qualitative analysis and 14 for META-analysis from 219 articles. The results showed that PBM therapy had no effect on nerve injury in a short period of time (0-48h, 14 days), but had significant effect over 30 days. However, the effect of photobiomodulation therapy on thermal discrimination was still controversial, most authors supported no significant improvement. By calculating the effective rate of PBM, it was found that there was no significant difference in the onset time of treatment, whether within or over 6 months.

CONCLUSIONS

The results of this META-analysis show that PBM therapy is effective in the treatment of IAN injures no matter it begins early or later. However, due to the limited number of well-designed RCTs and small number of patients in each study, it would be necessary to conduct randomized controlled trials with large sample size, long follow-up time and more standardized treatment and evaluation methods in the future to provide more accurate and clinically meaningful results.

Effectiveness of Physical Therapy in Orthognathic Surgery Patients: A Systematic Review of Randomized Controlled Trials

Orthognathic surgery (OS) can present many complications that affect patients' rehabilitation. However, there have been no systematic reviews that assessed the effectiveness of physiotherapy interventions in the postsurgical rehabilitation of OS patients. The aim of this systematic review was to analyze the effectiveness of physiotherapy after OS. The inclusion criteria were randomized clinical trials (RCTs) of patients who underwent OS and who received therapeutic interventions that included any physiotherapy modality. Temporomandibular joint disorders were excluded. After the filtering process, five RCTs were selected from the 1152 initially obtained (two had acceptable methodological quality; three had insufficient methodological quality). The results obtained showed that the effects of the physiotherapy interventions studied in this systematic review on the variables of range of motion, pain, edema and masticatory muscle strength were limited. Only laser therapy and LED showed a moderate level of evidence in the postoperative neurosensory rehabilitation of the inferior alveolar nerve compared with a placebo LED intervention.

Systematic mapping review of orthognathic surgery

STUDY DESIGN

Systematic mapping review AIM AND SCOPE: The objective of this mapping review was to identify, describe, and organize clinical research currently available from systematic reviews and primary studies regarding co-interventions and different surgical modalities used in orthognathic surgery (OS) and their outcomes.

METHODS

Systematic reviews (SRs), randomized controlled trials, and observational studies that evaluated perioperative OS co-interventions and surgical modalities were identified in an exhaustive search of MEDLINE, EMBASE, Epistemonikos, Lilacs, Web of Science, and CENTRAL. Grey literature was also screened.

RESULTS

Included were 35 SRs and 253 primary studies, 103 from SRs, and another 150 identified in our search. Overall, SR quality was rated as critically low, with only two SRs rated as of high quality. 19 questions on population, interventions, comparisons, and outcomes (PICO) extracted from the SRs focused on osteosynthesis methods, surgical cutting devices, and use of antibiotics, corticosteroids, and induced hypotension. Also identified were 15 research gaps. Evidence bubble maps were created to graphically depict the available evidence.

CONCLUSION

Future high-quality research, both primary and secondary, is needed to address the knowledge gaps identified in this systematic mapping review.

Efficacy of two low-level laser therapy protocols following lower third molar surgery - a randomized, double-blind, controlled clinical trial

The aim of this study was to test two low-level laser therapy protocols by evaluating pain control, swelling and trismus in the postoperative period of lower third molar surgeries. This was a randomized, double-blind, placebo-controlled, crossover trial. Patients presenting two symmetrically impacted mandibular third molars were included. One side was randomly assigned for LLLT applied immediately after surgery (T1) and then after 24 (T2) and 48 hours (T3) (Protocol A). The other side received LLLT applied immediately after surgery and placebo after 24 and 48 hours (Protocol B). LLLT was given by intraoral application (660nm, 5 J/cm2, 10 s, 20 mW, 4 points) followed by extraoral application (789 nm, 30 J/cm2, 20 s, 60 mW, 8 points). The placebo application was similar to that of the experimental side but with laser simulation. The primary outcomes were pain control, swelling and trismus intensity at T1, T2, T3 and 7 days after surgery (T4). Data were analyzedbyANOVArepeated measures and Wilcoxon test (p<.05). The final sample consisted of 21 patients (42 teeth). There were no statistical differences for pain level between protocols A and B over time (p= .909), although the amount of analgesic medication was lower with protocol A at T2 (p=.022). There were no differences in swelling (p=.958) or trismus (p=.837) between the protocols used over time. Both protocols performed similarly for pain control, swelling and trismus. Therefore, for practical reasons, a single laser application in the immediate postoperative period could be indicated for the management of postoperative discomfort in lower third molar surgery.

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.

Mitochondrial Bioenergetic, Photobiomodulation and Trigeminal Branches Nerve Damage, What's the Connection? A Review

BACKGROUND

Injury of the trigeminal nerve in oral and maxillofacial surgery can occur. Schwann cell mitochondria are regulators in the development, maintenance and regeneration of peripheral nerve axons. Evidence shows that after the nerve injury, mitochondrial bioenergetic dysfunction occurs and is associated with pain, neuropathy and nerve regeneration deficit. A challenge for research is to individuate new therapies able to normalise mitochondrial and energetic metabolism to aid nerve recovery after damage. Photobiomodulation therapy can be an interesting candidate, because it is a technique involving cell manipulation through the photonic energy of a non-ionising light source (visible and NIR light), which produces a nonthermal therapeutic effect on the stressed tissue.

METHODS

The review was based on the following questions: (1) Can photo-biomodulation by red and NIR light affect mitochondrial bioenergetics? (2) Can photobiomodulation support damage to the trigeminal nerve branches? (preclinical and clinical studies), and, if yes, (3) What is the best photobiomodulatory therapy for the recovery of the trigeminal nerve branches? The papers were searched using the PubMed, Scopus and Cochrane databases. This review followed the ARRIVE-2.0, PRISMA and Cochrane RoB-2 guidelines.

RESULTS AND CONCLUSIONS

The reliability of photobiomodulatory event strongly bases on biological and physical-chemical evidence. Its principal player is the mitochondrion, whether its cytochromes are directly involved as a photoacceptor or indirectly through a vibrational and energetic variation of bound water: water as the photoacceptor. The 808-nm and 100 J/cm2 (0.07 W; 2.5 W/cm2; pulsed 50 Hz; 27 J per point; 80 s) on rats and 800-nm and 0.2 W/cm2 (0.2 W; 12 J/cm2; 12 J per point; 60 s, CW) on humans resulted as trustworthy therapies, which could be supported by extensive studies.

The effect of delayed photobiomodulation on neurosensory disturbance recovery after zygomatic trauma: A parallel controlled clinical trial

INTRODUCTION

Zygomatic fractures are usually accompanied with neural complications, which are routinely treated by surgery or medication. However, photobiomodulation has been proven as a non-invasive method with better results in nerve's regeneration and repair. Therefore, in this study, we aimed to investigate the healing effect of photobiomodulation on neurosensory defect after facial trauma.

PATIENTS AND METHODS

In this parallel controlled clinical trial, 35 control cases and 36 patients with zygomaticomaxillary complex (ZMC) fractures as well as the sustained infraorbital nerve paresthesia were included. Afterward, Laser irradiation was applied using a GaAlAs diode laser (810 nm, 27 J/cm², 200 mW) on 12 points on malar area of paresthesia during 12 sessions within six weeks. Neurosensory evaluations were performed in four sessions as follows: at baseline, the end of treatment, one month, and three months after the last session of irradiation, which were achieved through three tests including visual analogue scales (VAS) for general sensitivity, two-point discrimination, and pain discrimination. Repeated measure ANOVA, independent t-test, and Chi-square test were used for comparing time trends, each time point, and gender, respectively. P-values less than 0.05 were considered to be statistically significant.

RESULTS

The patients and controls were matched in both terms of age and gender. Baseline results showed non-significant differences between the two groups based on the VAS, pain, and two-point discrimination. Moreover, for VAS scale, some significant differences were observed between the groups by passing "one month and three months from therapy". Pain and two-point discriminations showed a significant difference between the intervention and control groups in "one month after therapy" and "at the end of the therapy, one month after therapy, and three months after therapy", respectively.

CONCLUSION

Photobiomodulation could be considered as an effective treatment option for post-traumatic neurosensory disturbance of facial area in terms of VAS, pain and two-point discrimination, even if not performed early after trauma.

Effectiveness of low-level laser therapy on recovery from neurosensory disturbance after sagittal split ramus osteotomy: a systematic review and meta-analysis

Background

Orthognathic surgery such as bilateral sagittal split ramus osteotomy (BSSRO) for the treatment of mandibular deformities is one of the most common procedures in maxillofacial operations that may lead to neurosensory disturbance. In this study, we aimed to evaluate the effectiveness of low-level laser therapy (LLLT) on augmenting recovery of neurosensory disturbance of inferior alveolar nerve (IAN) in patients who underwent BSSRO surgery.

Methods

A comprehensive literature search was conducted by two independent authors in PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, Embase, and Google Scholar electronic databases. Besides, a manual search of all textbooks and relevant articles were conducted. Searches took place in August 2020 and were limited to published and peer-reviewed articles from 2000 to 2020. All analysis was performed using the comprehensive meta-analysis (CMA) and the STATA MP (version:16) software. The weighted mean difference (WMD) using the inverse variance method and the standard mean difference (SMD) was considered for continuous variables.

Results

Seventy-four papers were retrieved after removing duplicate studies and finally, eight studies were assessed for qualitative synthesis and five for meta-analysis. Totally, 94 patients were included in the meta-analysis. Based on the meta-analysis, it was shown that LLLT was not effective in a short interval (0 to 48 h) after surgery, but in a period of more than 1 month after surgery, the positive results of treatment can be observed strikingly. Also, LLLT side/group showed no significant difference in some aspects of neurosensory recovery such as thermal sensation compared to the placebo side/group.

Conclusions

The meta-analysis of randomized controlled trials revealed that LLLT generally improves IAN sensory disturbance caused by BSSRO. Further high-quality clinical trials with longer follow-up periods and larger sample sizes are recommended.

UC-USP collaborative exercise on photobiomodulation therapy in neurological orofacial disturbances

Background

Neurosensory peripheral disorders are one of the most common risks associated with iatrogenic and/or post-traumatic injuries. It is often related to disability. Photobiomodulation therapy (PBMT) is a nonsurgical and safe procedure which can accelerate and improve the regeneration of injured biological tissue. This study aims to analyze the impact of PBMT, in the quality of life and impairment of individuals with orofacial neurological peripheral disturbance.

Material and Methods

A retrospective analysis in the database of the dental traumatology clinic of the Hospital Centre of the University of Coimbra/Faculty of Medicine of the University of Coimbra was performed.5 out of 50 individuals were selected, according to the selection criteria. The neurosensory activity was assessed by a pinprick nociceptive test and the EQ-5D-5L self-report questionnaire was used to analyse the quality of life. The study was performed in two phases:1) inactive laser or placebo phase, for one month and 2) active laser or treatment phase. A diode low-level laser device (SIROLaserBlue;Sirona,Germany) was used, according to our protocol. A collaborative protocol in the PBMT influence in individuals with neurosensory peripheral disturbances was studied.

Results

There was no improvement in the neurosensory activity nor in the quality of life, in the placebo phase. After the treatment phase, the EQ-5D-5L final results reported no problems in all of the five dimensions, except for anxiety/depression in individuals with long-standing neurosensory peripheral disturbances. The EQ-VAS scores increased in all the individuals.

Conclusions

Our results supported the improvement of quality of life and impairment reduction in the individuals submitted to PBMT.

Key words:Low-level light therapy, peripheral nerve injuries, sensation disorders, quality of life, forensic medicine.

Laser therapy as treatment for oral paresthesia arising from mandibular third molar extraction

Oral paresthesia is a localized condition of sensory abnormality that occurs in the presence of injury in one of the nerves in the region after certain dental procedures. The aim of this study was to present a case report of a patient who received low-level laser therapy as treatment for inferior alveolar nerve paresthesia due to mandibular third molar extraction surgery. A 25-year-old female patient reported lack of sensitivity for 6 months in various regions of the bucomaxillofacial complex after surgery. Laser therapy (808 ± 10nm, 100 mW, 3J per point and 30 seconds per point) was indicated twice a week. The degree of sensitivity was evaluated using a Visual Analog Scale (VAS) and with the aid of a microbrush. Prior to laser therapy, the patient reported VAS = 10, i.e., total lack of sensitivity. After 72 hours of the first session, the patient reported improvement of sensitivity in the chin (VAS = 5) and oral regions (VAS = 5), reporting recovery of sensitivity and that the area of paresthesia decreased. After 8 sessions, the patient reported total recovery of sensitivity in the chin, oral and gum regions (VAS = 0), with paresthesia being limited only to the left lower lip region and below it. After 26 sessions, the patient reported recovery of sensitivity in all affected regions (VAS = 0), with positive responses to the brush touch. Within the parameters used, laser therapy was effective in the treatment of inferior alveolar nerve paresthesia after third molar tooth extraction. Key words:Lasers, paresthesia, oral surgery, low-level laser therapy.

Comparative effects of photobiomodulation therapy at wavelengths of 660 and 808 nm on regeneration of inferior alveolar nerve in rats following crush injury

The aim of the present study was to investigate the therapeutic effects of 660-nm and 880-nm photobiomodulation therapy (PBMT) following inferior alveolar nerve (IAN) crush injury. Following the nerve crush injuries of IAN, 36 Wistar rats were randomly divided into three groups as follows: (1) control, (2) 660-nm PBMT, and (3) 808-nm PBMT (GaAlAs laser, 100 J/cm², 70 mW, 0.028-cm² beam). PBMT was started immediately after surgery and performed once every 3 days during the postoperative period. At the end of the 30-day treatment period, histopathological and histomorphometric evaluations of tissue sections were made under a light and electron microscope. The ratio of the inner axonal diameter to the total outer axonal diameter (g-ratio) and the number of axons per square micrometer were evaluated. In the 808-nm PBMT group, the number of nerve fibers with suboptimal g-ratio ranges of 0-0.49 (p < 0.001) is significantly lower than expected, which indicates better rate of myelinization in the 808-nm PBMT group. The number of axons per square micrometer was significantly higher in the 808-nm PBMT group when compared with the control (p < 0.001) and 660-nm PBMT group (p = 0.010). The data and the histopathological investigations suggest that the PBMT with the 808-nm wavelength along with its settings was able to enhance IAN regeneration after nerve crush injury.

Low-level laser therapy for treatment of neurosensory disorders after orthognathic surgery: A systematic review of randomized clinical trials

BACKGROUND

Low-level laser has been widely used in Dentistry and many studies have focused on its application in oral surgeries. This study was conducted with the aim of searching for scientific evidence concerning the effectiveness of laser to reduce pain or paresthesia related to orthognathic surgery.

MATERIAL AND METHODS

An electronic search was performed in PubMed, Scopus, Science Direct, LILACS, SciELO, CENTRAL, Google Scholar, OpenGrey, and ClinicalTrials.gov, up to November 2016, with no restrictions on language or year of publication. Additionally, a hand search of the reference list of the selected studies was carried out. The PICOS strategy was used to define the eligibility criteria and only randomized clinical trials were selected.

RESULTS

Out of 1,257 identified citations, three papers fulfilled the criteria and were included in the systematic review. The risk of bias was assessed according to the Cochrane Guidelines for Clinical Trials and results were exposed based on a descriptive analysis. One study showed that laser therapy was effective to reduce postoperative pain 24 hours (P=0.007) and 72 hours (P=0.007) after surgery. Other study revealed the positive effect of laser to improve neurosensory recovery 60 days after surgery, evaluated also by the two-point discrimination (P=0.005) and sensory (P=0.008) tests. The third study reported an improvement for general sensibility of 68.75% for laser group, compared with 21.43% for placebo (P=0.0095), six months after surgery.

CONCLUSIONS

Individual studies suggested a positive effect of low-level laser therapy on reduction of postoperative pain and acceleration of improvement of paresthesia related to orthognathic surgery. However, due to the insufficient number and heterogeneity of studies, a meta-analysis evaluating the outcomes of interest was not performed, and a pragmatic recommendation about the use of laser therapy is not possible. This systematic review was conducted according to the statements of PRISMA and was registered at PROSPERO under the number CRD42016043258.

Is Low-Level Laser Therapy Effective for Treatment of Neurosensory Deficits Arising From Sagittal Split Ramus Osteotomy?

PURPOSE

This study investigated the effectiveness of low-level laser therapy (LLLT) for treating neurosensory impairment after bilateral sagittal split osteotomy (BSSO).

MATERIALS AND METHODS

This randomized, double-blinded, split-mouth trial included patients requiring BSSO. After surgery, 1 side of each patient was randomly assigned to laser therapy and the other side served as the control. At 24, 48, and 72 hours after surgery, LLLT was accomplished by intraoral application of a 660-nm laser around the surgical site (200 mW, 10 seconds, 2 J, 1.5 J/cm²) followed by extraoral irradiation by an 810-nm laser (200 mW, 10 seconds, 2 J, 7 J/cm²) along the distribution of the inferior alveolar nerve. Subsequently, extraoral irradiation was repeated 2 times per week for 3 weeks along the path of the inferior alveolar nerve, lower lip, and chin. On the control side, the treatment was similar to the laser side but with laser simulation. The main outcome was assessing nerve damage by a "2-point discrimination test" before and up to 60 days after surgery.

RESULTS

The sample consisted of 16 patients. No significant difference was found between the laser and control sides before and after surgery and on postoperative days 15 and 30 (P > .05). The 2-point discrimination distance was significantly shorter on the laser side than on the control side on postoperative days 45 and 60 (P < .05).

CONCLUSION

LLLT was effective in the treatment of neurosensory disturbances arising from BSSO. Therefore, LLLT can be recommended to accelerate the recovery of sensory aberrations in patients undergoing BSSO.

Effect of low-level laser irradiation on proliferation of human dental mesenchymal stem cells; a systemic review

CONTEXT

Identification of factors that enhance the proliferation of human dental mesenchymal stem cells (DMSCs) is vital to facilitate tissue regeneration. The role of low-level laser irradiation (LLLI) on proliferation of human DMSCs has not been well established.

OBJECTIVE

To assess the effect of LLLI on proliferation of human DMSCs when applied in-vitro.

DATA SOURCES

Electronic search of literature was conducted (2000-2016) on PubMed, Web of Science, and Scopus databases. Search terms included low-level light therapy, low-level laser irradiation, low-level light irradiation, LLLT, humans, adolescent, adult, cells, cultured, periodontal ligament, dental pulp, stem cells, dental pulp stem cells, mesenchymal stem cells, periodontal ligament stem cell, deciduous teeth, cell proliferation, adult stem cells, radiation, and proliferation.

RESULTS

The literature search identified 165 studies with 6 being eligible for inclusion; all used diode lasers; 5 studies used InGaAIP diode lasers; 4 used 660nm, and the other two applied 810nm or 980nm wavelength LLLI. The distance between the DMSCs and the laser spot ranged between 0.5mm to 2mm. The time intervals of cell proliferation analysis ranged from 0h to 7days after LLLI. After 660nm LLLI, an increase in the DMSC's proliferation was reported [DMSCs extracted from dental pulp of deciduous teeth (two irradiations, 3J/cm(2), 20mW was more effective than 40mW), adult teeth (two irradiations, 0.5 and 1.0J/cm(2), 30mW), and from adult periodontal ligament (two irradiations, 1.0J/cm(2) was more effective than 0.5J/cm(2), 30mW)]. Similarly, an increase in the proliferation of DMSCs extracted from dental pulp of adult teeth was reported after 810nm LLLI (7 irradiations in 7days, 0.1 and 0.2J/cm(2), 60mW) or 980nm LLLI (single irradiation, 3J/cm(2), 100mW). However, 660nm LLLI in one study did not increase the proliferation of DMSCs (single irradiation, energy densities of 0.05, 0.30, 7, and 42J/cm(2), 28mW).

CONCLUSION

There is limited evidence that in-vitro LLLI (660/810/980nm, with energy densities of 0.1-3J/cm(2)) increases the proliferation of DMSCs. Considering the limited evidence and their method heterogeneity it is difficult to reach a firm conclusion. Further research is necessary to identify the optimal characteristics of the LLLI setting (wave length, energy density, power output, frequency/duration of irradiations, distance between the cells and the laser spot/probe) to increase proliferation of DMSCs, and assess its impact on replicative senescence, as well as determine feasibility of the use in the clinical setting.