|Year : 2021 | Volume
| Issue : 3 | Page : 252-259
A comparative evaluation of effectiveness of InGaAsP laser and therapeutic ultrasound administration before the induction of muscle fatigue on healthy young individuals: A clinical study
Roopam Saini1, Upasana Sethi Ahuja1, Nidhi Puri1, Chinthalapalli Siva Ram2, Manu Dhillon1, Akshay Rathore1
1 Department of Oral Medicine and Radiology, I.T.S Dental College, Muradnagar, Ghaziabad, India
2 Department of Physiotherapy, I.T.S College of Physiotherapy, Muradnagar, Ghaziabad, India
|Date of Submission||16-Apr-2021|
|Date of Decision||12-Aug-2021|
|Date of Acceptance||14-Aug-2021|
|Date of Web Publication||28-Sep-2021|
Dr. Nidhi Puri
Department of Oral Medicine and Radiology, I.T.S Dental College, Muradnagar, Ghaziabad
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Muscle fatigue or the inability to maintain muscle strength is a protective mechanism to prevent muscle injury. Phototherapy or low-level laser therapy (LLLT) and therapeutic ultrasound are non-invasive and non-pharmacological forms of treatment modalities that have demonstrated effective and affirmative results when used to prevent muscle fatigue. Aim: The study evaluated the effect of phototherapy and therapeutic ultrasound in reducing muscle fatigue when administered before the induction of fatigue. Methodology: The study design was a blind, randomized, and sham-controlled clinical trial on laser and therapeutic ultrasound. The study sample consisted of 100 healthy young participants randomly allocated to four different groups of lasers, sham laser, therapeutic ultrasound, and sham ultrasound. All the individuals were subjected to clinical examination to record the bite force by the bite force dynamometer, maximum interincisal distance (MID) by using digital vernier calipers, and muscle fatigue by using EMG Retrainer's Device. The laser and therapeutic ultrasound were given on the masseter and anterior temporalis muscle on both sides and both sham groups were submitted to the same procedure but with the devices in the switch-off mode. All the individuals were instructed to chew two pieces of gum (one on each side) for 6 min to induce muscle fatigue and MID, the bite force and muscle fatigue were re-evaluated. Results: Statistically significant improvement was observed between the pre-and post-bite force, MID, and muscle fatigue in both the laser and Therapeutic ultrasound group as compared to the sham control groups with the P-value equal to 0.000. No, statistically significant difference was observed in the improvement of the muscle fatigue when both the treatment groups, i.e., laser and therapeutic ultrasound were compared with a P value >0.05. Conclusion: Muscle fatigue can be effectively reduced if any one of the physical modalities, either laser or therapeutic ultrasound is administered before the long-duration treatments; enabling administration of treatment comfortably and effectively in one appointment.
Keywords: Bite force, LLLT, muscle fatigue, phototherapy, therapeutic ultrasound
|How to cite this article:|
Saini R, Ahuja US, Puri N, Ram CS, Dhillon M, Rathore A. A comparative evaluation of effectiveness of InGaAsP laser and therapeutic ultrasound administration before the induction of muscle fatigue on healthy young individuals: A clinical study. J Indian Acad Oral Med Radiol 2021;33:252-9
|How to cite this URL:|
Saini R, Ahuja US, Puri N, Ram CS, Dhillon M, Rathore A. A comparative evaluation of effectiveness of InGaAsP laser and therapeutic ultrasound administration before the induction of muscle fatigue on healthy young individuals: A clinical study. J Indian Acad Oral Med Radiol [serial online] 2021 [cited 2022 Dec 3];33:252-9. Available from: http://www.jiaomr.in/text.asp?2021/33/3/252/326894
| Introduction|| |
Muscle fatigue which is usually defined as the incapacity to generate or maintain the required muscle strength can be seen as a protective mechanism to prevent muscle injury and irreversible cell damage. Various studies in the literature have demonstrated that fatigue is associated with a decline in muscle strength during and after maximum effort exercises, the inability to maintain the intensity of exercise over time, a reduction in the contraction velocity, and an increase in muscle relaxation time. Among the masticatory muscles, the masseter and the temporalis are more susceptible to fatigue in long-term dental procedures like surgical disimpactions, root canal treatments, various orthodontic treatments, periodontal surgeries, and also in certain pathological conditions, such as temporomandibular joint disorders (TMDs), chronic headaches, and neck injuries.
The discomfort caused due to the localized muscle pain and twitching as a result of muscle fatigue prevents the patient from opening the mouth properly and ultimately may lead to the termination of the dental procedure till a future appointment. Physical therapies such as phototherapy or low-level laser therapy (LLLT) and therapeutic ultrasound are emerging as the available treatment modalities in relieving muscle fatigue acting by reducing the inflammation, relieving the pain, and restoring the oral motor functions.
The literature suggests that the cell membrane permeability is increased during ultrasound therapy, leading to the improved gas exchange which helps in the healing of the muscle tissue, therefore, alleviating and reducing the muscle pain and fatigue. When the affected muscles are given ultrasonic energy, there is a rise in the tissue temperature due to an increase in molecular motion, which in turn can affect the tissue in many ways.
Another physical therapy that is being recently studied for alleviating muscle pain and has been used for preventing and controlling muscle fatigue is phototherapy, known to be a non-invasive, non-pharmacological form of management modality. In phototherapy, LLLT has been increasingly gaining popularity in recent years in an attempt to improve muscle performance and to delay the process of muscle fatigue. Phototherapy or LLLT can also act on the C fibers of pain, diminishing the permeability of the membrane for Na+ and K+ ions, which results in slower conduction of the nerve stimulus. These effects of laser therapy thus can be linked with their anti-inflammatory effect and enhancement of tissue regeneration processes.
In Dentistry, many times, the dental treatment has to be terminated in-between the procedure due to discomfort of the patient caused by muscle fatigue, and hence, it is considered as one of the major problems in effective and proper dental patient management. Due to muscle fatigue, the patient is not able to withstand long dental procedures involving the opening of the mouth for longer periods. This becomes cumbersome and more expensive for both the dentist and the patients as there is the need for multiple recall visits of the patients to the dental clinics.
Bite force can be used as a valuable parameter to evaluate the efficacy of the masticatory system., The importance of evaluating the bite force parameter along with the muscle fatigue analysis in this study after physical therapies is to implicate it in dental treatments. As more bite force shows more masticatory muscle activity, which can help the patients to keep their mouth open for longer periods during prolonged dental procedures.
Therefore, it is the need of the hour to explore some effective solutions to overcome the problem of muscle fatigue in dental patients. Various studies have reported the effectiveness of LLLT and ultrasound in reducing muscle pain,, but till now no studies have compared these two modalities with an evidence-based, bite force analysis before and after muscle fatigue.
| Methodology|| |
All the patients were thoroughly explained about the study and a written informed consent following the Helsinki Declaration was taken. The institutional ethical committee clearance with registration number ITSCDSR/IIEC/RP/2019/003 was obtained before commencing the study.
Study Design: A blind, randomized sham-controlled trial was conducted among 100 healthy young participants reporting to the OPD of the Department of Oral Medicine and Radiology. Random allocation was done using computer-generated sequences derived for each patient using the random function in Microsoft Excel 2013.
All the participants aged 20–26 years having normal occlusion with no signs and symptoms related to temporomandibular disorders were included in the study.
- Currently undergoing orthodontic treatment and orthopedic jaw treatment and also those patients who have undergone orthodontic treatment previously.
- Patients with any muscular disorders/autoimmune diseases.
- Patients undergoing psychological therapy.
- Patients on muscle relaxants.
- Patients on long-term anti-inflammatory agents.
- Patient giving a history of bruxism/night grinding.
- Patients having temporomandibular disorders.
The participants were comfortably seated on the dental chair and specific clinical examination involving the palpation of the temporomandibular joint, clicking and the various muscles such as trapezius, sternocleidomastoid, temporal, masseter, medial and lateral pterygoid, digastric muscles was carried out.
After the clinical examination, maximum interincisal distance (MID), bite force, and muscle fatigue were calculated (before providing physical therapies) for all the participants of the study.
MID was calculated by digital vernier calipers (linear accuracy of 0.001 mm). The reference point used was the incisal edge of the maxillary central incisor to the incisal edge of the mandibular central incisor at the maximum opening available. The measurements were made and the average value was recorded in millimeters (mm).
The bite force was determined by using the equipment composed of a bite plane called the pinch gauge dynamometer [Figure 1]; which measures the force in pounds (lb) unit. The reference chosen for the measurement of the bite force was the maxillary and mandibular first molar region. All the participants were first explained regarding biting on the equipment and a prior trial was also done to familiarize them with the dynamometer. Three readings were recorded before the induction of fatigue and the mean values were recorded.
After the bite force analysis, muscle fatigue was determined by using the EMG Retrainer's Device [Figure 2], which is a dual-channel menu-based system having two cords placed on the masseter and temporalis muscle extraorally (one cord on each side). The patients were instructed to clench the teeth and the results of the fatigue were recorded as were displayed on the attached LCD screen on the device.
After the assessment of all the parameters, the participants were randomly divided into four groups. Group 1 comprised of the LLLT group, with a total of 25 participants who were given LLLT (diode laser). Laser therapy in the biostimulation mode was given on one point on the anterior temporalis on each side of the face and three points on the masseter muscle (upper, middle, and lower). The diode laser [Figure 3] used was Biolase Soft-Tissue Laser (Indium Gallium Arsenide Phosphide [InGaAsP], Laser Class IV), a wavelength of 940 nm, mean output power of 0.5 Wcm2, power accuracy of ±20%, laser fiber tip diameter of 400 μm with a lithium-ion battery as operating voltage. The LLLT was used for 3 min at each point (three cycles of 60 s each) on both sides in a continuous and non-contact mode. The conventional laser tip was kept approximately 1 cm away from the skin during the procedure.
Group 2 consisted of laser sham therapy which included 25 participants (laser control group). The LLLT biostimulation device was not activated for these participants and only the placebo effect was given. The laser emitted the beep sound to give the participants a sensation of active therapy.
Similarly, 25 participants were included in Group 3, which consisted of the therapeutic ultrasound group. The USG was given with Electron-709 device on the masseter muscle and anterior temporal muscle bilaterally with the frequency of 3 MHz and power of 1.8 W/cm2. The duration of the ultrasound therapy was 5 min on each muscle.
The same procedure was followed on 25 participants of Group 4 which consisted of the sham therapeutic USG [Figure 4] group. In this group, the therapeutic ultrasound device was switched off and the patient only had an illusion of being treated.
The [Figure 5] and [Figure 6] shows use of pinch gauge dynamometer and EMG Retrainer's device on patient. For the next step, the participants were given two pieces of chewing gum to be placed on each side of the mouth. All the sample participants were told to chew the gum for 60 s, and then, rest for 1 min. After this, they were instructed to chew it for a continuous 10 min to create muscle fatigue.
After completion of 6 min, again the MID, bite force, and muscle fatigue were calculated for all the participants in all the four groups. Three readings were recorded after postinduction of fatigue by chewing the gum and the mean value was noted.
All the obtained values were noted down during the initial evaluation, as well as after the completion of 6 min of chewing the gum, and were subjected to statistical analysis for comparative evaluation.
Sample size calculation
It was revealed from the pilot study on the sample size of 8 subjects in each group that the effect size was 1.0452414. For α error 5% and the power (1-β error) 0.95 (95%), the power analysis was done with the help of software G*Power version 22.214.171.124. The actual power was 95.16% and the sample size was 25 for each group and total in 100 for four groups.
A one-way ANOVA (analysis of variance) test was used to compare the mean difference in the MID pre-fatigue and post-fatigue, bite force before and after fatigue, and muscle fatigue pre- and post-chewing of the gum in all the four groups. Post hoc tests were also for the intergroup comparisons.
| Results|| |
A total of 100 healthy volunteers signed the informed consent, and then, all of them were divided into four groups randomly, i.e., laser group, sham laser group, therapeutic ultrasound group, and sham therapeutic ultrasound group.
[Table 1] shows the mean values of the MID, bite force, and muscle fatigue before and after induction of fatigue in all four groups by using a one-way ANOVA test. When the mean MID values were compared among all the four groups, it was observed that the mean value of MID in both the sham groups was found to be decreased post-fatigue as compared to the initial readings which were found to be statistically significant. It was also observed that there was a discrete increase in the final mean MID when compared to the initial mean in both the laser and therapeutic ultrasound groups (Groups I and III) post-fatigue. It was observed that in both Groups I and III, the bite force values significantly increased post-fatigue. Similarly, in Groups I and III where LLLT and ultrasound were given, there was a highly significant reduction of the mean muscle fatigue values, when the readings were taken post-chewing the gum. The muscle fatigue values were noticed to be increased in both the control groups, i.e., Groups II and IV.
|Table 1: Mean pre-fatigue and post-fatigue; MID, bite force, and muscle fatigue values in all the four groups|
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[Table 2] shows the comparison of the mean parameters between the laser and sham laser groups, i.e., Groups I and II by using the t-test. It was observed that on comparing the post-mean values, there was an improvement in the MID, bite force as well as a reduction in the muscle fatigue after laser therapy as compared to that of sham laser with P values of 0.004, 0.000, and 0.000, respectively, for the three parameters.
|Table 2: Comparison of means parameters between group laser and sham laser|
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[Table 3] shows the comparison of the mean parameters between the ultrasound and sham ultrasound groups, i.e., Groups III and IV. There was a significant improvement in the MID, bite force, and reduction in muscle fatigue after the administration of therapeutic ultrasound (Group III) as compared to that of the sham therapeutic ultrasound group with a P value of 0.000.
|Table 3: Comparison of means parameters between group therapeutic USG and sham therapeutic USG|
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[Table 4] shows the comparison of the mean parameters between Groups I and III (post hoc test), i.e., laser and therapeutic ultrasound groups. It was observed that the improvement in all three parameters including improvement in the MID, bite force, and reduction in the muscle fatigue after providing both the therapies, was insignificant with P values of 0.888, 0.983, 0.077, respectively.
|Table 4: Comparison of means parameters between laser and therapeutic USG group|
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On evaluating the phototherapy and therapeutic ultrasound groups, it was found that there was a statistically significant improvement in all the three parameters; the MID, bite force, and reduction of the muscle fatigue in comparison to both the sham groups. Although, on comparing phototherapy that is the laser and therapeutic ultrasound group (Groups I and III), there was no statistically significant difference observed in the improvement of the assessed parameters.
| Discussion|| |
Muscle fatigue as described above is the inability of the muscles to maintain high standards of force and can be visualized as a defense mechanism of the individuals which gets activated to prevent muscle injury and irreversible cell damage. Non-invasive physical therapies like phototherapy or laser therapy and therapeutic ultrasound have been explored recently and widely in pain reduction.
Therapeutic ultrasound has proven its efficacy in pain reduction and is considered to be an important pain management modality with various advantages. It can either have a thermal effect from absorption or a non-thermal effect from the scattering. The thermal and non-thermal effects of therapeutic ultrasound would transiently increase the pain threshold and temporarily increase the blood flow. The thermal effects of the therapeutic ultrasound result in the enhancement of collagenous fibers and consequently improve the elasticity of the spasmed muscle.
The other physical therapy which is used in the present study to alleviate the pain and treat muscle fatigue is phototherapy, i.e., light amplification by stimulated emission of radiation (laser). LLLT has been tried recently to decrease pain and improve muscle performance during muscle fatigue. LLLT provides analgesic as well as anti-inflammatory and angiogenesis effects. The main effects of LLLT are biostimulation, regeneration, analgesic, and anti-inflammatory. LLLT raises the metabolism of endorphins, ACh, serotonin, and cortisol. It also modifies nerve stimulation and transmission and reduces stimulation and perception of pain by providing an analgesic effect. The photochemical effect occurs when the laser light is emitted at low power for prolonged periods and is dependent upon the wavelength, dose, and mode of operation.
Since physical therapies like LLLT and therapeutic ultrasound have widespread use in the field of medical sciences, the present study was planned to be conducted in the dental field for those patients who were unable to open their mouth for a long duration due to muscle fatigue during long dental procedures such as single-sitting root canal treatments, orthodontic treatments, disimpaction surgeries, other minor surgical procedures as cyst and tumor resections under LA, and many more. In the present study, both LLLT and therapeutic ultrasound were found to be significantly effective in improving all the three assessed parameters which were MID, bite force, and muscle fatigue as compared to the sham control groups.
For therapeutic ultrasound, enough literature is available concluding the effectiveness of therapeutic ultrasound in treating the muscle fatigue of calf muscles, back muscles but limited studies have yet evaluated its effectiveness in reducing muscle fatigue in the head and neck region.
Thiago de Santana Santos et al. in 2010 conducted a study and noted that laser therapy increased the mean amplitude of the mandibular movements and decreased significantly the pain intensity measured by the Visual Analog Scale. They concluded that laser therapy decreases the painful symptoms of the patient after application through its analgesic and/or a placebo effect. The results are following the present study.
In our study, therapeutic ultrasound was administered in a continuous mode for 5 min on each side of the masseter and temporalis muscle. There was a reduction in muscle exhaustion when evaluated by the EMG retainer after the induction of fatigue along with a significant improvement in the post-MID and post-bite force parameter.
Safoora Ebadi et al. (2013) conducted a study and concluded that there was a considerable improvement in the pain and function of iliocostalis and multifidus muscles along with a few seconds of increase in the holding time with the use of ultrasound. Stacey E Aaron and Diana C. Delgado-Diaz (2017) concluded that continuous therapeutic ultrasound reduced pain perception and increased the mechanical pressure threshold in the biceps brachii after muscle damage. Xia et al. in 2017 conducted a systematic review and meta-analysis and concluded that there may be a significant effect of the Ultrasound therapy on the pain in the MPS patients.
Budakoti et al. 2019 conducted a study and concluded that both therapeutic ultrasound and LLLT are subjectively better in improving the VAS scores of muscle pain, mouth opening, and impediment to daily life after treatment. Shweta et al. in 2018 conducted a study which proved that ultrasound therapy has a profound effect on myofascial pain dysfunction syndrome to reduce muscle tension, spasm, and improving jaw function. These results are comparable to the present study although most of the studies in the literature evaluated pain reduction by USG rather than its effect on the muscles postinduction of fatigue.
In the present study, LLLT was another promising modality used in relieving muscle fatigue which was found to be equally effective as therapeutic ultrasound in improving all the assessed parameters. Likewise, Vieira et al. used laser at a wavelength of 808 nm on the vastus medialis, vastus lateralis, and rectus femoris muscles and concluded that the fatigue resistance increased when the laser was administered during rest intervals (thrice in a day).
In our study, the wavelength of the laser used was 940 nm for 2 min on each point of the upper, middle, and lower part of the masseter and also on the point of the anterior temporalis muscle which has shown significant results in the reduction of muscle fatigue and increasing resistance of the muscle for fatigue even when the parameters were calculated after the induction of fatigue.
Leal-Junior et al. concluded that LLLT with a wavelength of 230 nm had no effect on fatigue, but led to an improvement in muscle performance. Since, in our study, the wavelength of LLLT used was of 940 nm, we found a reduction of muscle fatigue as well as improvement in the post-MID and post-bite force. The reason attributed to the reduction in muscle fatigue could be that the effects of LLLT on the muscles are wavelength-dependent and LLLT at suitable wavelength and doses has potential in the improvement of fatigue of the muscles, and therefore, increases the resistance of the muscles to fatigue.
In contrast to the above-mentioned study, Vassão et al. found that LLLT with a wavelength of 808 nm did not increase in muscle performance, but was effective in reducing the degree of muscle fatigue. In our study, the disparity between the laser parameters like higher wavelength, power, and duration used as described in the methodology could be the reason attributed for the better positive outcome as compared with the other studies which report negative or lesser effects in the results with the use of lower wavelength LLLT.
Our study also compared the pre-and post-MID, bite force, and reduction in muscle fatigue in the laser (phototherapy) and therapeutic ultrasound group. Although individually, both the modalities have proven to be significantly effective in the improvement of all the three parameters assessed after the induction of fatigue but the results obtained on comparing the two modalities using the one-way ANOVA and post hoc test revealed non-significant P values suggesting that both the physical therapies are equally effective in increasing the bite force and decreasing the muscle fatigue. As per the best of our knowledge, no study till now has been conducted which has compared the effectiveness of both the non-invasive physical modalities in terms of the assessment of all the three parameters, i.e., MID, bite force, and muscle fatigue post exhausting the muscles.
Clinical Significance: The clinical relevance of the study lies in the fact that long-duration dental treatments could be carried out conveniently if our patients are less prone to fatigue. As it is a well-known fact that prevention is better than cure, thus, as a preventive or precautionary measure, either the LLLT or therapeutic USG can be administered to the patients before commencing the dental procedures which are time-consuming and require a longer duration of mouth opening like orthodontic treatment, disimpaction surgeries, periodontal surgeries, and many more. This might lead to better patient compliance and cooperation, thus, enabling the dentists to provide a better treatment environment to the patients by comfortably completing their treatment procedures in one go.
Limitations and Future prospects
The effect of therapeutic USG and LLLT could have been assessed on a larger sample size. Future studies with the patients undergoing actual longer dental treatment can be done to prove the efficacy of both physical modalities.
| Conclusion|| |
The results of the present study led to the conclusion that both the physical modalities, i.e., LLLT and therapeutic ultrasound were observed to be equally effective in diminishing muscle fatigue. Further studies need to be conducted to evaluate the best parameters effective for LLLT and therapeutic USG for developing fatigue resistance in the muscles.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Instruments for evaluation of bite force and muscle fatigue was taken from the Department of Physiotherapy.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2], [Table 3], [Table 4]