Laser Photobiomodulation (PBM)-A Possible New Frontier for the Treatment of Oral Cancer: A Review of In Vitro and In Vivo Studies

The treatment of oral squamous cell carcinoma (OSCC) is particularly complex due to its aggressive behavior, location, the patient’s age, and its spread at diagnosis. In recent years, photobiomodulation (PBM) has been introduced in different medical fields; however, its application, in patients suffering from OSCC for palliative support or to induce analgesia, has been hotly debated due to the possibility that the cell growth stimuli induced by PBM could lead to a worsening of the lesions. The aim of this study is to review the literature to observe the available data investigating the effect of PBM on cancer cells in vitro and in vivo. A review was conducted on the PubMed and Scopus databases. A total of twelve studies met the inclusion criteria and were therefore included for quality assessment and data extraction. The analysis showed that the clinical use of PBM is still only partially understood and is, therefore, controversial. Some authors stated that it could be contraindicated for clinical use in patients suffering from SCC, while others noted that it could have beneficial effects. According to the data that emerged from this review, it is possible to hypothesize that there are possibilities for PBM to play a beneficial role in treating cancer patients, but further evidence about its clinical efficacy and the identification of protocols and correct dosages is still needed.

Individual differences in the neural strategies to control the lateral and medial head of the quadriceps during a mechanically constrained task

We observed that the distribution of the strength of neural drive between the vastus lateralis and vastus medialis during a single-joint isometric task varied across participants. Also, we observed that the proportion of neural drive that was shared within and between these muscles also varied across participants. These results provide evidence that the neural strategies to control the vastus lateralis and vastus medialis muscles widely vary across individuals, even during a mechanically constrained task.

The knowns and unknowns of neural adaptations to resistance training

The initial increases in force production with resistance training are thought to be primarily underpinned by neural adaptations. This notion is firmly supported by evidence displaying motor unit adaptations following resistance training; however, the precise locus of neural adaptation remains elusive. The purpose of this review is to clarify and critically discuss the literature concerning the site(s) of putative neural adaptations to short-term resistance training. The proliferation of studies employing non-invasive stimulation techniques to investigate evoked responses have yielded variable results, but generally support the notion that resistance training alters intracortical inhibition. Nevertheless, methodological inconsistencies and the limitations of techniques, e.g. limited relation to behavioural outcomes and the inability to measure volitional muscle activity, preclude firm conclusions. Much of the literature has focused on the corticospinal tract; however, preliminary research in non-human primates suggests reticulospinal tract is a potential substrate for neural adaptations to resistance training, though human data is lacking due to methodological constraints. Recent advances in technology have provided substantial evidence of adaptations within a large motor unit population following resistance training. However, their activity represents the transformation of afferent and efferent inputs, making it challenging to establish the source of adaptation. Whilst much has been learned about the nature of neural adaptations to resistance training, the puzzle remains to be solved. Additional analyses of motoneuron firing during different training regimes or coupling with other methodologies (e.g., electroencephalography) may facilitate the estimation of the site(s) of neural adaptations to resistance training in the future.

Disinfection of Root Canals with Laser-Activated Irrigation, Photoactivated Disinfection, and Combined Laser Techniques: An Ex Vivo Preliminary Study

Objective: This study aimed to evaluate the efficacy of laser-activated irrigation using photon-induced photoacoustic streaming (PIPS^®) and photoactivated disinfection (PAD) techniques and their combination to improve penetration and activation of toluidine blue in the endodontic space of teeth experimentally infected with Enterococcus faecalis. Materials and methods: Twenty-seven extracted single-root teeth were instrumented, sterilized, and infected with E. faecalis and divided into seven groups of three teeth each: Group A [sodium hypochlorite (NaClO) 5% hand irrigation], Group B [NaClO 5% hand irrigation+ethylenediaminetetraacetic acid (EDTA)+NaClO 5% activated by PIPS], Group C (EDTA+NaClO 5% activated by PIPS), Group D (toluidine blue activated by PAD), Group E (toluidine blue activated by PIPS and PAD), Group F (NaClO 5% hand irrigation+toluidine blue activated by PAD), and Group G (NaClO 5% hand irrigation+toluidine blue activated by PIPS and PAD). Finally, positive and negative group controls were prepared. The presence of biofilms after the treatments was assessed by the BioTimer assay. PIPS was performed with an Er:YAG laser (2940 nm, LightWalker, Fotona^® d.o.o., Slovenia) at 20 mJ, 15 Hz, 0.3 W, and 50-μs pulse duration. PAD was performed with a 635 nm diode laser (Smart M, Lasotronix^®, Poland) at 400 mW in continuous wave (CW). Results: When NaClO was used, significant decontamination (p ≤ 0.05) was obtained in all experimental groups with respect to the positive control, other than Group G. Irrigation with EDTA+NaClO activated by PIPS produced a higher level of decontamination than Group A (p ≤ 0.05). Significant results in reducing biofilm load compared with the control and Group A were observed when NaClO was coupled with toluidine blue activated by PAD (p ≤ 0.05). Conclusions: Disinfection of root canals can be obtained using a combination of different irrigants, photosensitizers, and activation protocols. EDTA+NaClO using the PIPS protocol and toluidine blue activated by PAD (both preceded by NaClO irrigation) can be considered effective tools. The possibility of replacing NaClO with toluidine blue, whatever the method of activation, should be further investigated.

Surface Electromyography: What Limits Its Use in Exercise and Sport Physiology?

The aim of the present paper is to examine to what extent the application of surface electromyography (sEMG) in the field of exercise and, more in general, of human movement, is adopted by professionals on a regular basis. For this purpose, a brief history of the recent developments of modern sEMG techniques will be assessed and evaluated for a potential use in exercise physiology and clinical biomechanics. The idea is to understand what are the limitations that impede the translation of sEMG to applied fields such as exercise physiology. A cost/benefits evaluation will be drawn in order to understand possible causes that prevents sEMG from being routinely adopted. Among the possible causative factors, educational, economic and technical issues will be considered. Possible corrective interventions will be proposed. We will also give an overview of the parameters that can be extracted from the decomposition of the sHDEMG signals and how this can be related by professionals for assessing the health and disease of the neuromuscular system. We discuss how the decomposition of surface EMG signals might be adopted as a new non-invasive tool for assessing the status of the neuromuscular system. Recent evidences show that is possible to monitor the changes in neuromuscular function after training of longitudinally tracked populations of motoneurons, predict the maximal rate of force development by an individual via motoneuron interfacing, and identify possible causal relations between aging and the decrease in motor performance. These technologies will guide our understanding of motor control and provide a new window for the investigation of the underlying physiological processes determining force control, which is essential for the sport and exercise physiologist. We will also illustrate the challenges related to extraction of neuromuscular parameters from global EMG analysis (i.e., root-mean-square, and other global EMG metrics) and when the decomposition is needed. We posit that the main limitation in the application of sEMG techniques to the applied field is associated to problems in education and teaching, and that most of the novel technologies are not open source.

Photo-Biomodulation as a Prevention Modality of Oral Mucositis in Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

The aim of the study was to observe the effectiveness of a photo-biomodulation (PBM) protocol for the prevention of oral mucositis (OM) in patients undergoing allogeneic hematopoietic stem cell transplantation (aHSCT). A case-control study was conducted on 40 patients undergoing aHSCT. The patients were divided into two groups; the preventive group (PG) included 20 patients (7 females and 13 males) who were subjected to intra-oral PBM for five sessions a week, starting one day before the conditioning regimen and continuing until the 10th day after transplantation (D+10). In each session, ten points on the at-risk mucosal surfaces were irradiated using a double diode laser that emits two wavelengths simultaneously at 650 nm and at 904–910 nm with the following parameters at each point: energy of 4 J, and power of 88.9 mW. The control group (CG) included 20 patients (10 females and 10 males) who were not subjected to laser therapy and were selected retrospectively to compare the obtained results. For all patients, OM was assessed by the World Health Organization (WHO) grading scale. Eight patients in the PG did not experience OM during their hospitalization period (with grade 0). Severe OM was observed in 40% of the patients in the PG, while in the CG, severe OM was shown in 85% of the patients. The mean duration of OM in the PG was significantly lower than that of CG (4.7 days in the PG and 15 days in the CG) (p < 0.001). The study demonstrated that the preventive PBM protocol reduced the severity and duration of OM in patients undergoing aHSCT.

Non-invasive analysis of motor neurons controlling the intrinsic and extrinsic muscles of the hand

OBJECTIVE

We present a non-invasive framework for investigating efferent commands to 14 extrinsic and intrinsic hand muscles. We extend previous studies (limited to a few muscles) on common synaptic input among pools of motor neurons in a large number of muscles.

APPROACH

Seven subjects performed sinusoidal isometric contractions to complete seven types of grasps, with each finger and with three combinations of fingers in opposition with the thumb. High-density surface EMG (HD-sEMG) signals (384 channels in total) recorded from the 14 muscles were decomposed into the constituent motor unit action potentials. This provided a non-invasive framework for the investigation of motor neuron discharge patterns, muscle coordination and efferent commands of the hand muscles during grasping. Moreover, during grasping tasks, it was possible to identify common neural information among pools of motor neurons innervating the investigated muscles. For this purpose, principal component analysis (PCA) was applied to the smoothed discharge rates of the decoded motor units.

MAIN RESULTS

We found that the first principal component (PC1) of the ensemble of decoded motor neuron spike trains explained a variance of (53.0 ± 10.9) % and was positively correlated with force (R = 0.67 ± 0.10 across all subjects and tasks). By grouping the pools of motor neurons from extrinsic or intrinsic muscles, the PC1 explained a proportion of variance of (57.1 ± 11.3) % and (56.9 ± 11.8) %, respectively, and was correlated with force with R = 0.63 ± 0.13 and 0.63 ± 0.13, respectively.

SIGNIFICANCE

These observations demonstrate a low dimensional control of motor neurons across multiple muscles that can be exploited for extracting control signals in neural interfacing. The proposed framework was designed for hand rehabilitation perspectives, such as post-stroke rehabilitation and hand-exoskeleton control.

Comparison of the Effects of Photobiomodulation with Different Lasers on Orthodontic Movement and Reduction of the Treatment Time with Fixed Appliances in Novel Scientific Reports: A Systematic Review with Meta-Analysis

Background: The duration of orthodontic treatment is one of the most important aspects considered by patients. Photobiomodulation (PBM) depends upon the exposure of the tissue to particular, therapeutic wavelengths of light in the "therapeutic window" (from 600 to 1200 nm). PBM increases cell metabolism, which leads to higher ATP production. Increasing the amount of ATP in well-vascularized bone cells promotes cell proliferation and differentiation, creating a favorable environment for tooth movement. Objective: The aim of the study is to discuss and compare the use of PBM in accelerating the orthodontic movement and reducing the time of treatment. Materials and methods: A systematic review was conducted. Literature searches were performed using Medline (PubMed), Web of Science, and Scopus (from September 13 to September 20, 2019). The quality assessment was performed using the Jadad scale for reporting randomized controlled trials for randomized clinical trial and randomized control clinical trial studies, and the Newcastle/Ottawa Quality Assessment Form for case/control studies. Results: Thirty-three articles from PubMed, 46 from Scopus, 5 from Web of Science were selected. After removal of duplicates, 82 articles were analyzed. Subsequently, 74 articles were excluded because they did not meet the inclusion criteria. The remaining eight articles were included in the qualitative synthesis. Conclusions and summary: PBM is an efficient, effective, and noninvasive method to accelerate orthodontic tooth movement. PBM should be introduced into the daily practice of treating various malocclusions as an additional procedure. Intraoral application gives better results and its introduction to treatment seems more reasonable.

Comparison of the Effects of Photobiomodulation with Different Lasers on Orthodontic Movement and Reduction of the Treatment Time with Fixed Appliances in Novel Scientific Reports: A Systematic Review with Meta-Analysis

Background: The duration of orthodontic treatment is one of the most important aspects considered by patients. Photobiomodulation (PBM) depends upon the exposure of the tissue to particular, therapeutic wavelengths of light in the "therapeutic window" (from 600 to 1200 nm). PBM increases cell metabolism, which leads to higher ATP production. Increasing the amount of ATP in well-vascularized bone cells promotes cell proliferation and differentiation, creating a favorable environment for tooth movement. Objective: The aim of the study is to discuss and compare the use of PBM in accelerating the orthodontic movement and reducing the time of treatment. Materials and methods: A systematic review was conducted. Literature searches were performed using Medline (PubMed), Web of Science, and Scopus (from September 13 to September 20, 2019). The quality assessment was performed using the Jadad scale for reporting randomized controlled trials for randomized clinical trial and randomized control clinical trial studies, and the Newcastle/Ottawa Quality Assessment Form for case/control studies. Results: Thirty-three articles from PubMed, 46 from Scopus, 5 from Web of Science were selected. After removal of duplicates, 82 articles were analyzed. Subsequently, 74 articles were excluded because they did not meet the inclusion criteria. The remaining eight articles were included in the qualitative synthesis. Conclusions and summary: PBM is an efficient, effective, and noninvasive method to accelerate orthodontic tooth movement. PBM should be introduced into the daily practice of treating various malocclusions as an additional procedure. Intraoral application gives better results and its introduction to treatment seems more reasonable.

Comparison of the Effects of Photobiomodulation with Different Lasers on Orthodontic Movement and Reduction of the Treatment Time with Fixed Appliances in Novel Scientific Reports: A Systematic Review with Meta-Analysis

Background: The duration of orthodontic treatment is one of the most important aspects considered by patients. Photobiomodulation (PBM) depends upon the exposure of the tissue to particular, therapeutic wavelengths of light in the "therapeutic window" (from 600 to 1200 nm). PBM increases cell metabolism, which leads to higher ATP production. Increasing the amount of ATP in well-vascularized bone cells promotes cell proliferation and differentiation, creating a favorable environment for tooth movement. Objective: The aim of the study is to discuss and compare the use of PBM in accelerating the orthodontic movement and reducing the time of treatment. Materials and methods: A systematic review was conducted. Literature searches were performed using Medline (PubMed), Web of Science, and Scopus (from September 13 to September 20, 2019). The quality assessment was performed using the Jadad scale for reporting randomized controlled trials for randomized clinical trial and randomized control clinical trial studies, and the Newcastle/Ottawa Quality Assessment Form for case/control studies. Results: Thirty-three articles from PubMed, 46 from Scopus, 5 from Web of Science were selected. After removal of duplicates, 82 articles were analyzed. Subsequently, 74 articles were excluded because they did not meet the inclusion criteria. The remaining eight articles were included in the qualitative synthesis. Conclusions and summary: PBM is an efficient, effective, and noninvasive method to accelerate orthodontic tooth movement. PBM should be introduced into the daily practice of treating various malocclusions as an additional procedure. Intraoral application gives better results and its introduction to treatment seems more reasonable.

Comparison of the Effects of Photobiomodulation with Different Lasers on Orthodontic Movement and Reduction of the Treatment Time with Fixed Appliances in Novel Scientific Reports: A Systematic Review with Meta-Analysis

Background: The duration of orthodontic treatment is one of the most important aspects considered by patients. Photobiomodulation (PBM) depends upon the exposure of the tissue to particular, therapeutic wavelengths of light in the "therapeutic window" (from 600 to 1200 nm). PBM increases cell metabolism, which leads to higher ATP production. Increasing the amount of ATP in well-vascularized bone cells promotes cell proliferation and differentiation, creating a favorable environment for tooth movement. Objective: The aim of the study is to discuss and compare the use of PBM in accelerating the orthodontic movement and reducing the time of treatment. Materials and methods: A systematic review was conducted. Literature searches were performed using Medline (PubMed), Web of Science, and Scopus (from September 13 to September 20, 2019). The quality assessment was performed using the Jadad scale for reporting randomized controlled trials for randomized clinical trial and randomized control clinical trial studies, and the Newcastle/Ottawa Quality Assessment Form for case/control studies. Results: Thirty-three articles from PubMed, 46 from Scopus, 5 from Web of Science were selected. After removal of duplicates, 82 articles were analyzed. Subsequently, 74 articles were excluded because they did not meet the inclusion criteria. The remaining eight articles were included in the qualitative synthesis. Conclusions and summary: PBM is an efficient, effective, and noninvasive method to accelerate orthodontic tooth movement. PBM should be introduced into the daily practice of treating various malocclusions as an additional procedure. Intraoral application gives better results and its introduction to treatment seems more reasonable.

Comparison of the Effects of Photobiomodulation with Different Lasers on Orthodontic Movement and Reduction of the Treatment Time with Fixed Appliances in Novel Scientific Reports: A Systematic Review with Meta-Analysis

Background: The duration of orthodontic treatment is one of the most important aspects considered by patients. Photobiomodulation (PBM) depends upon the exposure of the tissue to particular, therapeutic wavelengths of light in the "therapeutic window" (from 600 to 1200 nm). PBM increases cell metabolism, which leads to higher ATP production. Increasing the amount of ATP in well-vascularized bone cells promotes cell proliferation and differentiation, creating a favorable environment for tooth movement. Objective: The aim of the study is to discuss and compare the use of PBM in accelerating the orthodontic movement and reducing the time of treatment. Materials and methods: A systematic review was conducted. Literature searches were performed using Medline (PubMed), Web of Science, and Scopus (from September 13 to September 20, 2019). The quality assessment was performed using the Jadad scale for reporting randomized controlled trials for randomized clinical trial and randomized control clinical trial studies, and the Newcastle/Ottawa Quality Assessment Form for case/control studies. Results: Thirty-three articles from PubMed, 46 from Scopus, 5 from Web of Science were selected. After removal of duplicates, 82 articles were analyzed. Subsequently, 74 articles were excluded because they did not meet the inclusion criteria. The remaining eight articles were included in the qualitative synthesis. Conclusions and summary: PBM is an efficient, effective, and noninvasive method to accelerate orthodontic tooth movement. PBM should be introduced into the daily practice of treating various malocclusions as an additional procedure. Intraoral application gives better results and its introduction to treatment seems more reasonable.

Comparison of the Effects of Photobiomodulation with Different Lasers on Orthodontic Movement and Reduction of the Treatment Time with Fixed Appliances in Novel Scientific Reports: A Systematic Review with Meta-Analysis

Background: The duration of orthodontic treatment is one of the most important aspects considered by patients. Photobiomodulation (PBM) depends upon the exposure of the tissue to particular, therapeutic wavelengths of light in the "therapeutic window" (from 600 to 1200 nm). PBM increases cell metabolism, which leads to higher ATP production. Increasing the amount of ATP in well-vascularized bone cells promotes cell proliferation and differentiation, creating a favorable environment for tooth movement. Objective: The aim of the study is to discuss and compare the use of PBM in accelerating the orthodontic movement and reducing the time of treatment. Materials and methods: A systematic review was conducted. Literature searches were performed using Medline (PubMed), Web of Science, and Scopus (from September 13 to September 20, 2019). The quality assessment was performed using the Jadad scale for reporting randomized controlled trials for randomized clinical trial and randomized control clinical trial studies, and the Newcastle/Ottawa Quality Assessment Form for case/control studies. Results: Thirty-three articles from PubMed, 46 from Scopus, 5 from Web of Science were selected. After removal of duplicates, 82 articles were analyzed. Subsequently, 74 articles were excluded because they did not meet the inclusion criteria. The remaining eight articles were included in the qualitative synthesis. Conclusions and summary: PBM is an efficient, effective, and noninvasive method to accelerate orthodontic tooth movement. PBM should be introduced into the daily practice of treating various malocclusions as an additional procedure. Intraoral application gives better results and its introduction to treatment seems more reasonable.

Comparison of the Effects of Photobiomodulation with Different Lasers on Orthodontic Movement and Reduction of the Treatment Time with Fixed Appliances in Novel Scientific Reports: A Systematic Review with Meta-Analysis

Background: The duration of orthodontic treatment is one of the most important aspects considered by patients. Photobiomodulation (PBM) depends upon the exposure of the tissue to particular, therapeutic wavelengths of light in the "therapeutic window" (from 600 to 1200 nm). PBM increases cell metabolism, which leads to higher ATP production. Increasing the amount of ATP in well-vascularized bone cells promotes cell proliferation and differentiation, creating a favorable environment for tooth movement. Objective: The aim of the study is to discuss and compare the use of PBM in accelerating the orthodontic movement and reducing the time of treatment. Materials and methods: A systematic review was conducted. Literature searches were performed using Medline (PubMed), Web of Science, and Scopus (from September 13 to September 20, 2019). The quality assessment was performed using the Jadad scale for reporting randomized controlled trials for randomized clinical trial and randomized control clinical trial studies, and the Newcastle/Ottawa Quality Assessment Form for case/control studies. Results: Thirty-three articles from PubMed, 46 from Scopus, 5 from Web of Science were selected. After removal of duplicates, 82 articles were analyzed. Subsequently, 74 articles were excluded because they did not meet the inclusion criteria. The remaining eight articles were included in the qualitative synthesis. Conclusions and summary: PBM is an efficient, effective, and noninvasive method to accelerate orthodontic tooth movement. PBM should be introduced into the daily practice of treating various malocclusions as an additional procedure. Intraoral application gives better results and its introduction to treatment seems more reasonable.

Comparison of the Effects of Photobiomodulation with Different Lasers on Orthodontic Movement and Reduction of the Treatment Time with Fixed Appliances in Novel Scientific Reports: A Systematic Review with Meta-Analysis

Background: The duration of orthodontic treatment is one of the most important aspects considered by patients. Photobiomodulation (PBM) depends upon the exposure of the tissue to particular, therapeutic wavelengths of light in the "therapeutic window" (from 600 to 1200 nm). PBM increases cell metabolism, which leads to higher ATP production. Increasing the amount of ATP in well-vascularized bone cells promotes cell proliferation and differentiation, creating a favorable environment for tooth movement. Objective: The aim of the study is to discuss and compare the use of PBM in accelerating the orthodontic movement and reducing the time of treatment. Materials and methods: A systematic review was conducted. Literature searches were performed using Medline (PubMed), Web of Science, and Scopus (from September 13 to September 20, 2019). The quality assessment was performed using the Jadad scale for reporting randomized controlled trials for randomized clinical trial and randomized control clinical trial studies, and the Newcastle/Ottawa Quality Assessment Form for case/control studies. Results: Thirty-three articles from PubMed, 46 from Scopus, 5 from Web of Science were selected. After removal of duplicates, 82 articles were analyzed. Subsequently, 74 articles were excluded because they did not meet the inclusion criteria. The remaining eight articles were included in the qualitative synthesis. Conclusions and summary: PBM is an efficient, effective, and noninvasive method to accelerate orthodontic tooth movement. PBM should be introduced into the daily practice of treating various malocclusions as an additional procedure. Intraoral application gives better results and its introduction to treatment seems more reasonable.

Reproducibility of muscle fibre conduction velocity during linearly increasing force contractions

Muscle fibre conduction velocity (MFCV) is a basic physiological parameter biophysically related to the diameter of muscle fibres and properties of the sarcolemma. The aim of this study was to assess the intersession reproducibility of the relation between voluntary force and estimates of average muscle fibre conduction velocity (MFCV) from multichannel high-density surface electromyographic recordings (HDsEMG). Ten healthy men performed six linearly increasing isometric ankle dorsiflexions on two separate experimental sessions, 4 weeks apart. Each session involved the recordings of voluntary force during maximal isometric (MViF) and submaximal ramp contractions at 35-50-70% of MViF. Concurrently, the HDsEMG activity was detected from the tibialis anterior muscle and MFCV estimates were derived in 250-ms epochs. Absolute and relative reproducibility of MFCV initial value (intercept) and rate of change (regression slope) as a function of force were assessed by within-subject coefficient of correlation (CV_w) and with intraclass correlation coefficient (ICC). MFCV was positively correlated with voluntary force (R² = 0.75 ± 0.12) in all individuals and test conditions (P < 0.001). Average CV_w for MFCV intercept and slope were of 2.6 ± 2.0% and 11.9 ± 3.2% and ICC values of 0.96 and 0.94, respectively. Overall, MFCV regression coefficients showed a high degree of intersession reproducibility in both absolute and relative terms. These results may have important practical implications in the tracking of training-induced neuromuscular changes and/or in the monitoring of the progress of neuromuscular disorders when a full sEMG signal decomposition is problematic or not possible.

Improvement in the Synthesis Conditions and Studying the Physicochemical Properties of the Zeolite Li-A(BW) Obtained from a Kaolinitic Rock

Crystallization of zeolite Li-A(BW) from kaolinite (Standard Porcelain by the IMERYS Minerals Ltd) through a conventional hydrothermal treatment is here achieved for the first time with no additives as reported in the literature. Moreover lower kaolin calcination temperatures and lower synthesis temperatures are tested and verified in this work. The synthesis process is rather simple as the reaction of kaolinite with alkali occurs very readily after calcination of at 650 °C. Metakaolin is mixed with calculated amount of aluminum hydroxide and lithium hydroxide and the experiment is performed at ambient pressure and 180 ± 0.1 °C. Li-A(BW) is characterized by powder X-ray diffraction, high temperature X-ray diffraction, scanning electron microscopy, inductively coupled plasma optical emission spectrometry, thermal analysis and infrared spectroscopy. Calculation of cell parameters (through Rietveld Refinement) and density, specific surface and pore size are also achieved. The amount of amorphous phase in the synthesis powders is estimated with quantitative phase analysis using the combined Rietveld and reference intensity ratio methods. The results become notably attractive in view of a possible industrial transfer of the synthesis protocol.

Neurophysiological correlates of force control improvement induced by sinusoidal vibrotactile stimulation

OBJECTIVE

An optimal level of vibrotactile stimulation has been shown to improve sensorimotor control in healthy and diseased individuals. However, the underlying neurophysiological mechanisms behind the enhanced motor performance caused by vibrotactile stimulation are yet to be fully understood. Therefore, here we aim to evaluate the effect of a cutaneous vibration on the firing behavior of motor units in a condition of improved force steadiness.

APPROACH

Participants performed a visuomotor task, which consisted of low-intensity isometric contractions of the first dorsal interosseous (FDI) muscle, while sinusoidal (175 Hz) vibrotactile stimuli with different intensities were applied to the index finger. High-density surface electromyogram was recorded from the FDI muscle, and a decomposition algorithm was used to extract the motor unit spike trains. Additionally, computer simulations were performed using a multiscale neuromuscular model to provide a potential explanation for the experimental findings.

MAIN RESULTS

Experimental outcomes showed that an optimal level of vibration significantly improved force steadiness (estimated as the coefficient of variation of force). The decreased force variability was accompanied by a reduction in the variability of the smoothed cumulative spike train (as an estimation of the neural drive to the muscle), and the proportion of common inputs to the FDI motor nucleus. However, the interspike interval variability did not change significantly with the vibration. A mathematical approach, together with computer simulation results suggested that vibrotactile stimulation would reduce the variance of the common synaptic input to the motor neuron pool, thereby decreasing the low frequency fluctuations of the neural drive to the muscle and force steadiness.

SIGNIFICANCE

Our results demonstrate that the decreased variability in common input accounts for the enhancement in force control induced by vibrotactile stimulation.

A wearable neural interface for detecting and decoding attempted hand movements in a person with tetraplegia

We are developing a wearable neural interface based on high-density surface electromyography (HDEMG) for detecting and decoding signals from spared motor units in the forearms of people with tetraplegia after spinal cord injury (SCI). A lightweight, form-fitting garment containing 150 disc electrodes and covering the entire forearm was used to map the myoelectric activity of forearm muscles during a wide range of voluntary tasks of a person with chronic tetraplegia after SCI (C5 motor and C6 sensory American Spinal Injury Association Impairment Scale B spinal cord injury). Despite exhibiting no overt finger motion, myoelectric signals were detectable for attempted movements of individual digits and were highly discriminable. Motor unit decomposition was used to identify the activity of >30 motor neurons, active specifically during rotation, pronation of the wrist (4 units), and flexion of the elbow joint (7 units), and during attempted movements of individual hand digits (1-5 units). In addition, we performed a neural connectivity analysis based on the power of the common oscillations of the identified motor neurons in the delta (~5Hz), alpha (~6-12 Hz), and beta bands (~15-30 Hz). This analysis showed clear common synaptic inputs to the identified motor neurons in all the analyzed frequency bands. This neural interface offers a new potential for the control of assistive technologies, whereby the motor neurons spared after SCI may serve as a direct readout of motor intent that allows proportional control over several distinct degrees of freedom. Moreover, this framework can be used to study the reorganization and recovery of spinal networks after injury and rehabilitation.

A high-density surface EMG framework for the study of motor neurons controlling the intrinsic and extrinsic muscles of the hand

We propose a framework based on high-density surface electromyography (HD-sEMG) to identify the neural drive to muscles controlling the human hand. High-density (320 channels) sEMG signals were recorded concurrently from intrinsic (the four dorsal interossei and thenar) and extrinsic (forearm) hand muscles and then decomposed into the constituent trains of motor unit (MU) action potentials. The participants performed pinch tasks with simultaneous activation of the thumb and one of the other fingers with sinusoidal force variations. The common drive among MUs across different muscles was extracted via principal component analysis (PCA) of the smoothed MU discharge rates. The first principal component of the smoothed discharge rates of all identified motor neurons explained 48.7 ± 15.4% of the total variance across all pinching tasks, indicating a common neural input shared by different muscles of the forearm and the hand.. When considering only the MUs extracted from extrinsic and intrinsic muscles, the percent of variance explained was 48.3 ± 15.3% and 57.1 ± 15.5%, respectively. This framework is conceived to use motor neuron activity for a proportional myoelectric control and rehabilitation technologies. A wearable adaptation of the framework is proposed for future perspectives.

Neural and muscular determinants of maximal rate of force development

The ability to produce rapid forces requires quick motor unit recruitment, high motor unit discharge rates, and fast motor unit force twitches. The relative importance of these parameters for maximum rate of force development (RFD), however, is poorly understood. In this study, we systematically investigated these relationships using a computational model of motor unit pool activity and force. Across simulations, neural and muscular properties were systematically varied in experimentally observed ranges. Motor units were recruited over an interval starting from contraction onset (range: 22–233 ms). Upon recruitment, discharge rates declined from an initial rate (range: 89–212 pulses per second), with varying likelihood of doublet (interspike interval of 3 ms; range: 0–50%). Finally, muscular adaptations were modeled by changing average twitch contraction time (range: 42–78 ms). Spectral analysis showed that the effective neural drive to the simulated muscle had smaller bandwidths than the average motor unit twitch, indicating that the bandwidth of the motor output, and thus the capacity for explosive force, was limited mainly by neural properties. The simulated RFD increased by 1,050 ± 281% maximal voluntary contraction force per second from the longest to the shortest recruitment interval. This effect was more than fourfold higher than the effect of increasing the initial discharge rate, more than fivefold higher than the effect of increasing the chance of doublets, and more than sixfold higher than the effect of decreasing twitch contraction times. The simulated results suggest that the physiological variation of the rate by which motor units are recruited during ballistic contractions is the main determinant for the variability in RFD across individuals.

NEW & NOTEWORTHY An important limitation of human performance is the ability to generate explosive movements by means of rapid development of muscle force. The physiological determinants of this ability, however, are poorly understood. In this study, we show using extensive simulations that the rate by which motor units are recruited is the main limiting factor for maximum rate of force development.

Ex vivo histological analysis of the thermal effects created by a 445-nm diode laser in oral soft tissue biopsy

OBJECTIVE

The aim of this study was to evaluate, ex vivo, the histological effects of 445-nm diode laser (Eltech K-Laser srl, Treviso, Italy), during an oral soft tissue biopsy.

MATERIALS AND METHODS

Thirty samples from pig cadaver tongues were obtained, through five laser settings, in continuous and pulsed wave (CW and PW). Samples were divided into six groups of five pieces each. A control specimen was taken by a scalpel. All samples were examined with an optical microscope by a blinded pathologist. Thermal effects on epithelium and connective tissues were measured with LAS 4.8 software. Finally, a statistical evaluation was made using GraphPadPrism 7.0 software.

RESULTS

All specimens, except one, showed a damage lower than 1 mm. Readability was always optimal; there was a different thermal effect between epithelial and connective tissue and in CW and PW samples, confirmed by statistical analysis too.

CONCLUSIONS

A 445-nm diode laser creates a minimum thermal effect, that has no implications in the histological evaluation of benign lesions. In suspicious lesions, a safety margin of 1 mm, compared with a scalpel, is preferable.

CLINICAL RELEVANCE

A 445-nm diode laser has excellent surgical properties and can manage many arduous clinical cases, such as vascularized lesions. In the excision of suspected lesions, it is necessary to compare, case by case, clinical advantages to possible histological implications.

The relative strength of common synaptic input to motor neurons is not a determinant of the maximal rate of force development in humans

Correlation between motor unit discharge times, often referred to as motor unit synchronization, is determined by common synaptic input to motor neurons. Although it has been largely speculated that synchronization should influence the rate of force development, the association between the degree of motor unit synchronization and rapid force generation has not been determined. In this study, we examined this association with both simulations and experimental motor unit recordings. The analysis of experimental motor unit discharges from the tibialis anterior muscle of 20 healthy individuals during rapid isometric contractions revealed that the average motor unit discharge rate was associated with the rate of force development. Moreover, the extent of motor unit synchronization was entirely determined by the average motor unit discharge rate ( R > 0.7, P < 0.0001). The simulation model demonstrated that the relative proportion of common synaptic input received by motor neurons, which determines motor unit synchronization, does not influence the rate of force development ( R = 0.03, P > 0.05). Nonetheless, the estimates of correlation between motor unit spike trains were significantly correlated with the rate of force generation ( R > 0.8, P < 0.0001). These results indicate that the average motor unit discharge rate, but not the degree of motor unit synchronization, contributes to most of the variance of human contractile speed among individuals. In addition, estimates of correlation between motor unit discharge times depend strongly on the number of identified motor units and therefore are not indicative of the strength of common input.

NEW & NOTEWORTHY It is commonly assumed that motor unit synchronization has an impact on the rate of force development of a muscle. Here we present computer simulations and experimental data of human tibialis anterior motor units during rapid contractions that show that motor unit synchronization is not a determinant of the rate of force production. This conclusion clarifies the neural determinants of rapid force generation.

You are as fast as your motor neurons: speed of recruitment and maximal discharge of motor neurons determine the maximal rate of force development in humans

KEY POINTS

We propose and validate a method for accurately identifying the activity of populations of motor neurons during contractions at maximal rate of force development in humans. The behaviour of the motor neuron pool during rapid voluntary contractions in humans is presented. We show with this approach that the motor neuron recruitment speed and maximal motor unit discharge rate largely explains the individual ability in generating rapid force contractions. The results also indicate that the synaptic inputs received by the motor neurons before force is generated dictate human potential to generate force rapidly. This is the first characterization of the discharge behaviour of a representative sample of human motor neurons during rapid contractions.

ABSTRACT

During rapid contractions, motor neurons are recruited in a short burst and begin to discharge at high frequencies (up to >200 Hz). In the present study, we investigated the behaviour of relatively large populations of motor neurons during rapid (explosive) contractions in humans, applying a new approach to accurately identify motor neuron activity simultaneous to measuring the rate of force development. The activity of spinal motor neurons was assessed by high-density electromyographic decomposition from the tibialis anterior muscle of 20 men during isometric explosive contractions. The speed of motor neuron recruitment and the instantaneous motor unit discharge rate were analysed as a function of the impulse (the time-force integral) and the maximal rate of force development. The peak of motor unit discharge rate occurred before force generation and discharge rates decreased thereafter. The maximal motor unit discharge rate was associated with the explosive force variables, at the whole population level (r2  = 0.71 ± 0.12; P < 0.001). Moreover, the peak motor unit discharge and maximal rate of force variables were correlated with an estimate of the supraspinal drive, which was measured as the speed of motor unit recruitment before the generation of afferent feedback (P < 0.05). We show for the first time the full association between the effective neural drive to the muscle and human maximal rate of force development. The results obtained in the present study indicate that the variability in the maximal contractile explosive force of the human tibialis anterior muscle is determined by the neural activation preceding force generation.

Evaluation of the efficacy of a new low-level laser therapy home protocol in the treatment of temporomandibular joint disorder-related pain: A randomized, double-blind, placebo-controlled clinical trial

Objective: This study analyzed a home, low-level laser therapy (LLLT) protocol to manage temporomandibular joint disorders (TMJDs)-related pain.Methods: Ninety TMJD patients (12M, 78F) between 18 and 73 years were randomly subdivided into three groups. Study group (SG) received 1-week home protocol LLLT by B-cure Dental Pro: 808 nm, 5 J/min, 250 mW, 15 KHz for 8', 40 J each, over pain area, twice daily. Placebo group (PG) followed the same protocol using sham devices. Drugs group (DG) received conventional drugs. Pain was evaluated by visual analog scale (VAS) before and after therapy.Results: Statistical analysis showed that treatment was effective (F(2,83) = 4.882; p = .010). Bonferroni post-hoc analysis indicated a lower pain decrease in PG. SG registered a 34-point decrease per patient, while in PG and DG, the reduction was 25.6 and 35.3, respectively.Conclusion: The study supports the efficacy of home LLLT management of TMJD related pain.

The increase in muscle force after 4 weeks of strength training is mediated by adaptations in motor unit recruitment and rate coding

KEY POINTS

Previous studies have indicated that several weeks of strength training is sufficient to elicit significant adaptations in the neural drive sent to the muscles. There are few data, however, on the changes elicited by strength training in the recruitment and rate coding of motor units during voluntary contractions. We show for the first time that the discharge characteristics of motor units in the tibialis anterior muscle tracked across the intervention are changed by 4 weeks of strength training with isometric voluntary contractions. The specific adaptations included significant increases in motor unit discharge rate, decreases in the recruitment-threshold force of motor units and a similar input-output gain of the motor neurons. The findings suggest that the adaptations in motor unit function may be attributable to changes in synaptic input to the motor neuron pool or to adaptations in intrinsic motor neuron properties.

ABSTRACT

The strength of a muscle typically begins to increase after only a few sessions of strength training. This increase is usually attributed to changes in the neural drive to muscle as a result of adaptations at the cortical or spinal level. We investigated the change in the discharge characteristics of large populations of longitudinally tracked motor units in tibialis anterior before and after 4 weeks of strength training the ankle-dorsiflexor muscles with isometric contractions. The adaptations exhibited by 14 individuals were compared with 14 control subjects. High-density electromyogram grids with 128 electrodes recorded the myoelectric activity during isometric ramp contractions to the target forces of 35%, 50% and 70% of maximal voluntary force. The motor unit recruitment and derecruitment thresholds, discharge rate, interspike intervals and estimates of synaptic inputs to motor neurons were assessed. The normalized recruitment-threshold forces of the motor units were decreased after strength training (P < 0.05). Moreover, discharge rate increased by 3.3 ± 2.5 pps (average across subjects and motor units) during the plateau phase of the submaximal isometric contractions (P < 0.001). Discharge rates at recruitment and derecruitment were not modified by training (P < 0.05). The association between force and motor unit discharge rate during the ramp-phase of the contractions was also not altered by training (P < 0.05). These results demonstrate for the first time that the increase in muscle force after 4 weeks of strength training is the result of an increase in motor neuron output from the spinal cord to the muscle.

The influence of musculoskeletal pain disorders on muscle synergies-A systematic review

Background

Musculoskeletal (MSK) pain disorders represent a group of highly prevalent and often disabling conditions. Investigating the structure of motor variability in response to pain may reveal novel motor impairment mechanisms that may lead to enhanced management of motor dysfunction associated with MSK pain disorders. This review aims to systematically synthesize the evidence on the influence of MSK pain disorders on muscle synergies.

Methods

Nine electronic databases were searched using Medical Subject Headings and keywords describing pain, electromyography and synergies. Relevant characteristics of included studies were extracted and assessed for generalizability and risk of bias. Due to the significant heterogeneity, a qualitative synthesis of the results was performed.

Results

The search resulted in a total of 1312 hits, of which seven articles were deemed eligible. There was unclear consistency that pain reduced the number of muscle synergies. There were low consistencies of evidence that the synergy vector (W weights) and activation coefficient (C weights) differed in painful compared to asymptomatic conditions. There was a high consistency that muscle synergies were dissimilar between painful and asymptomatic conditions.

Conclusions

MSK pain alters the structure of variability in muscle control, although its specific nature remains unclear. Greater consistency in muscle synergy analysis may be achieved with appropriate selection of muscles assessed and ensuring consistent achievement of motor task outcomes. Synergy analysis is a promising method to reveal novel understandings of altered motor control, which may facilitate the assessment and treatment of MSK pain disorders.

Associations between motor unit action potential parameters and surface EMG features

The surface interference EMG signal provides some information on the neural drive to muscles. However, the association between neural drive to muscle and muscle activation has long been debated with controversial indications due to the unavailability of motor unit population data. In this study, we clarify the potential and limitations of interference EMG analysis to infer motor unit recruitment strategies with an experimental investigation of several concurrently active motor units and of the associated features of the surface EMG. For this purpose, we recorded high-density surface EMG signals during linearly increasing force contractions of the tibialis anterior muscle, up to 70% of maximal force. The recruitment threshold (RT), conduction velocity (MUCV), median frequency (MDF_MU), and amplitude (RMS_MU) of action potentials of 587 motor units from 13 individuals were assessed and associated with features of the interference EMG. MUCV was positively associated with RT (R² = 0.64 ± 0.14), whereas MDF_MU and RMS_MU showed a weaker relation with RT (R² = 0.11 ± 0.11 and 0.39 ± 0.24, respectively). Moreover, the changes in average conduction velocity estimated from the interference EMG predicted well the changes in MUCV (R² = 0.71), with a strong association to ankle dorsiflexion force (R² = 0.81 ± 0.12). Conversely, both the average EMG MDF and RMS were poorly associated with motor unit recruitment. These results clarify the limitations of EMG spectral and amplitude analysis in inferring the neural strategies of muscle control and indicate that, conversely, the average conduction velocity could provide relevant information on these strategies.NEW & NOTEWORTHY The surface EMG provides information on the neural drive to muscles. However, the associations between EMG features and neural drive have been long debated due to unavailability of motor unit population data. Here, by using novel highly accurate decomposition of the EMG, we related motor unit population behavior to a wide range of voluntary forces. The results fully clarify the potential and limitation of the surface EMG to provide estimates of the neural drive to muscles.

Color-Doppler US features of a pyogenic granuloma of the upper dorsum tongue

The diagnosis of oral lesions is based on clinical history, clinical examination and imaging exams. Different imaging modalities are available for the diagnosis and follow-up of these lesions such as computed tomography, magnetic resonance imaging, color-Doppler ultrasound, angiography and positron emission tomography. To date, color-Doppler ultrasound is considered the first-line imaging approach since it provides a non-invasive, cost-effective, real-time evaluation of oral anomalies. It provides both morphological and vascular information which are useful to determine the best therapeutic options. Differential diagnosis of a bleeding lobular mass of the tongue is, however, not always easy and includes several vascular and non-vascular lesions. We present herein a case of pyogenic granuloma of the tongue that at Color-Doppler US appeared as hypervascular lesion.

Focal epithelial hyperplasia in a human immuno-deficiency virus patient treated with laser surgery

Focal epithelial hyperplasia (FEH), or Heck’s disease, is a rare disease of the oral mucosa; it is mostly found in children or young adults who are immunosuppressed and who live in regions with low socioeconomic status. It is characterized by asymptomatic papules on the oral mucosa, gingiva, tongue, and lips. Healing can be spontaneous, and treatment is indicated if there are aesthetic or functional complications. Human papillomavirus, especially genotypes 13 and 32, has been associated with FEH and is detected in the majority of lesions. Histopathologically, FEH is characterized by parakeratosis, epithelial hyperplasia, focal acanthosis, and fusion and horizontal outgrowth of epithelial ridges. A 37-year-old male patient was referred to the Department of Oral and Maxillofacial Sciences at the Sapienza University of Rome, complaining of numerous exophytic lesions in his mouth. He stated that the lesions were not painful but he had experienced occasional bleeding after incidental masticatory trauma. He had received no previous treatment for the oral lesions. His medical history revealed that he was human immuno-deficiency virus positive and was a smoker with numerous, asymptomatic oral papules clinically and histologically corresponding to FEH. The labial and buccal mucosa were especially affected by lesions. Surgical treatment was performed using a 532-nm potassium titanyl phosphate laser (SmartLite, Deka, Florence, Italy) in continuous mode with a 300 μm fiber and power of 1.4 W (power density 1980.22 W/cm²). After anesthesia without vasoconstrictors, the lesions were tractioned with sutures or an Allis clamp and then completely excised. The lesions were preserved in 10% formalin for histological examination, which confirmed the clinical diagnosis of FEH. In this case, the laser allowed excellent control of bleeding, without postoperative sutures, and optimal wound healing.

Oral proliferative verrucous leukoplakia treated with the photodynamic therapy: a case report

AIMS

About 60% of the oral cancer arise on a pre-existent potentially malignant disorder of oral mucosa like the oral proliferative verrucous leukoplakia. The treatment with the photodynamic therapy of these lesions represents, in the last years, an innovative, non-invasive and effective therapeutic possibility to achieve the secondary prevention of oral cancer. In the last decade, case reports have described patients with similar treated through a photochemical reaction induced by laser light. The aim of this study is to evaluate the effectiveness of the topical 5-ALA photodynamic therapy in the treatment of a case of Oral proliferative verrucous leukoplakia.

CASE REPORT

A female patient of 80 years old affected by white verrucous plaques on the right buccal mucosa was recruited for our case report. The right side lesion was treated with the photodynamic therapy with topical administered 5-aminolevulinic acid using the 635 nm laser light to activate the photosensitizer.

RESULTS

The lesion showed complete response after 4 sessions of photodynamic therapy and no recurrence was noticed after 12 months.

CONCLUSIONS

The photodynamic therapy can be considered an effective treatment in the management of oral verrucous proliferative leukoplakia, but more clinical trials, with prolonged follow-up controls, are necessary to evaluate its effectiveness in the mid and long time period.

Laser treatment of 13 benign oral vascular lesions by three different surgical techniques

OBJECTIVES

Benign Oral Vascular Lesions (BOVLs) are a group of vascular diseases characterized by congenital, inflammatory or neoplastic vascular dilations clinically evidenced as more or less wide masses of commonly dark bluish color. If traumatized BOVLs are characterized by a great risk of hemorrhage and their treatment usually requires great caution to prevent massive bleeding. In the last decades lasers have dramatically changed the way of treatment of BOVLs permitting the application of even peculiar techniques that gave interesting advantages in their management reducing hemorrhage risks. The aim of this study was to evaluate the capabilities and disadvantages of three laser assisted techniques in the management of BOVLs.

STUDY DESIGN

In this study 13 BOVLs were treated by three different laser techniques: the traditional excisional biopsy (EB), and two less invasive techniques, the transmucosal thermocoagulation (TMT) and the intralesional photocoagulation (ILP). Two different laser devices were adopted in the study: a KTP laser (DEKA, Florence, Italy, 532 nm) and a GaAlAs laser (Laser Innovation, Castelgandolfo, Italy, 808 nm) selected since their great effectiveness on hemoglobin.

RESULTS

In each case, lasers permitted safe treatments of BOVLs without hemorrhages, both during the intervention and in the post-operative period. The minimally invasive techniques (TMT and ILP) permitted even the safe resolution of big lesions without tissue loss.

CONCLUSIONS

Laser devices confirm to be the gold standard in BOVLs treatment, permitting even the introduction of minimal invasive surgery principles and reducing the risks of hemorrhage typical of these neoplasms. As usual in laser surgery, it is necessary a clear knowledge of the devices and of the laser-tissue interaction to optimize the results reducing risks and disadvantages.

Enamel pearls as a predisposing factor to localized periodontitis

Enamel pearls are enamel anomalies on primary and permanent teeth roots that usually appear at furcation areas, especially in maxillary second and third molars. Enamel pearls usually occur singularly, but as many as four have been observed on the same tooth. This report describes an unusual case of multiple enamel pearls associated with periodontal pockets localized on all maxillary first and second molars. Because the patient had an advanced stage of periodontitis, the maxillary right first and left second molars were extracted. The remaining two maxillary molars were included in a strict follow-up protocol. Enamel pearls were confirmed as the cause of localized periodontitis; therefore, it is very important to recognize their radiologic aspect to ensure proper treatment of the involved teeth.

Effects of KTP laser on oral soft tissues. An in vitro study

A biopsy is a surgical procedure performed to establish a clear diagnosis of a lesion in order to clarify a clinical diagnostic suspicion. During a biopsy procedure it is fundamental to maintain safe and readable cut margins in order to permit histological visualization of possible marginal infiltrations or malignant transformation of a lesion. The aim of this study was to evaluate the histological peripheral damage caused by application of a KTP (potassium titanium phosphate) laser during oral soft tissue biopsy procedures. A KTP laser (lambda 532 nm) at different power settings and fluences was used to obtain 45 samples from pig cadaver tongues. The samples were then subdivided into five groups of nine samples each. A final specimen was taken by scalpel as a control. All samples were put into test tubes containing 10% buffered formalin solution, and were examined separately under an optical microscope by two pathologists to evaluate the peripheral thermal damage induced by the laser. In all specimens the cut edges of the incision were free from histological artefacts, especially when lower settings were applied. Statistical analysis showed no differences among the groups. The KTP laser demonstrated surgical effectiveness and caused little peripheral damage to the cut edges, and therefore would always allow a safe histological diagnosis to be obtained.

The low level laser therapy in the management of neurological burning mouth syndrome. A pilot study

BACKGROUND AND OBJECTIVE

Burning Mouth Syndrome (BMS) is a common disease but still a diagnostic and therapeutic challenge for clinicians. Despite many studies its nature remains obscure and controversial; nowadays there is no consensus about definition, diagnosis and classification. BMS is characterized clinically by burning sensations in the tongue or other oral sites, often without clinical and laboratory findings. According to the etiology, BMS cases should be subdivided into three subtypes: BMS by local factors (lfBMS), BMS by systemic factors (sfBMS) and neurological BMS (nBMS), the most frequent, in which the symptom is caused by central or peripheral neurological malfunctions affecting in particular the taste pathway. To establish the type of BMS, both anamnesis and clinical examination, including laboratory tests, are necessary; nBMS cases will be recognized by exclusion of any other type. In case of lfBMS or sfBMS, the treatment of the main pathology will be resolutive; in nBMS cases many Authors proposed different pharmacological trials without satisfactory results and the current opinion is that a multidisciplinary approach is required to keep the condition under control. This pilot study aimed to investigate whether the biostimulative effect of Low Level Laser Therapy (LLLT) could enhance the symptoms of nBMS cases, improving patients' quality of life.

STUDY DESIGN/MATERIALS AND METHODS

Among 160 patients affected by oral burning sensation attending to the Oral Pathology Complex Operative Unit of the Department of Stomatological Sciences of Sapienza University of Rome, 77 resulted affected by nBMS. Twenty-five of these patients, 16 females and 9 males, were randomly selected for low level laser applications. All the patients were irradiated with a double diode laser (Lumix 2 Prodent, Italy) emitting contemporarily at 650 nm and 910 nm, with a fluence of 0.53 J/cm(2) for 15 minutes twice a week for 4 weeks. The areas of irradiation were the sides of the tongue on the path of taste fibers. A NRS (numerical rating scale) evaluation of maximum and minimum pain was registered before and after the treatment. In each case to the total value of NRS rates registered before the treatment was deducted the total NRS rate registered after the treatment. The difference was estimated effective if over two points. The Kruskall-Wallis test revealed the significance of the study (p<0.0001) and the Dunn's Multiple Comparison test, applied to compare NRS rates before and after the treatment, showed that there is not a statistically relevant difference between min NRS ratings before and after treatment, while there are statistically significant differences between max NRS ratings (p<0.05).

RESULTS

All the patients agreed the treatment confirming the general good compliance related to laser treatments. No side effects were registered and all the patients completed the therapy without interruption. Seventeen patients (68%) had relevant benefits from the treatment with valid reduction of NRS ratings. In 8 cases the differences of NRS rates were not relevant being under the limit of reliability established in study design. In no case there was a worsening of the symptoms.

CONCLUSIONS

According to the results of this pilot study it is reasonable to suppose that LLLT may play an important role in the management of nBMS cases, more investigations are needed to clarify, by a greater number of cases and a placebo control group, the real effectiveness of this innovative LLLT application.

Bone damage induced by different cutting instruments--an in vitro study

The aim of this study was to compare the peripheral bone damage induced by different cutting systems. Four devices were tested: Er:YAG laser (2.94 mm), Piezosurgery, high-speed drill and low-speed drill. Forty-five bone sections, divided into 9 groups according to different parameters, were taken from pig mandibles within 1 h post mortem. Specimens were fixed in 10% buffered formalin, decalcified and cut in thin sections. Four different parameters were analyzed: cut precision, depth of incision, peripheral carbonization and presence of bone fragments. For statistical analysis, the Kruskal-Wallis test was applied to assess equality of sample medians among groups. All sections obtained with the Er:YAG laser showed poor peripheral carbonization. The edges of the incisions were always well-shaped and regular, no melting was observed. Piezosurgery specimens revealed superficial incisions without thermal damage but with irregular edges. The sections obtained by traditional drilling showed poor peripheral carbonization, especially if obtained at lower speed. There was statistically significant differences (p<0.01) among the cutting systems for all analyzed parameters. Er:YAG laser, gave poor peripheral carbonization, and may be considered an effective method in oral bone biopsies and permits to obtain clear and readable tissue specimens.