955 D3000 new imprint Word template Vol 13, No 1 (2025) ISSN 2167-8677 (online) DOI 10.5195/d3000.2025.955 http://dentistry3000.pitt.edu Efficacy of Two Diode Laser Wavelenghts in the Management of Mas- ticatory Disorders and Myofascial Pain Anes Adnan Alshamaa1, Hani Mohammed Al-Kufi2, Anmar Sadaa Al-Halbosi3, Sohaib Mohammed Awad1 1College of Den*stry, University of Almaarif, Ramadi, Iraq 2College of Den*stry, The Islamic University, Najaf, Iraq 3Habbaniyah Primary Health Care Sector, Ministry of Health, Anbar, Iraq Abstract Objec;ve: This study aimed to evaluate the effect of photobiomodulaLon on restricted mouth opening and pain relief in painful temporomandibular paLents by using two wave- lengths of diode laser. Material and Methods: In this study, thirty-six parLcipants—ages 18 to 45 yeas—who suffered from restricted mouth opening, pain in the temporomandibular joint area and tenderness in the temporal and masseter muscles were divided into two groups: Group A (n = 15) received 980 nm laser therapy, and Group B (n = 15) received 635 nm laser therapy. Six parLcipants were excluded. Over the course of two weeks, each group had six therapy sessions. The maximal mouth opening was measured by digital caliper and the pain severity was evaluated using the Visual Analog Scale. The mouth opening and pain scale of the groups were then evaluated staLsLcally using MulLple Wilcoxon sign rank ad- justed by Dunn-Bonferroni method, and Tukey’s HSD tests. The significance level was set to 0.05. Results: The outcomes demonstrated that there were notable improvements in mouth opening and discomfort reducLons in both groups. The 980 nm treatment displayed a con- sistent reducLon from baseline, with staLsLcally significant differences between all-Lme points. The 635 nm treatment showed a more pronounced reducLon, especially between baseline and six weeks or one month, but no significant difference between six weeks and one month. Conclusion: This study demonstrated the significant impact of the therapeuLc efficacy of diode laser wavelengths on the management of masLcatory disorders and myofascial pain. Open Access Cita%on: Alshamaa AA, et al. (2025) Efficacy of Two Di- ode Laser Wavelenghts in the Management of Mas%ca- tory Disorders and Myofascial Pain. Den%stry 3000. 1:a001 doi:10.5195/d3000.2025.955 Received: June 2, 2025 Accepted: June 26, 2025 Published: August 13, 2025 Copyright: ©2025 Alshamaa AA, et al. This is an open ac- cess ar%cle licensed under a Crea%ve Commons ASribu- %on Work 4.0 United States License. Email: anes.adnan@uoa.edu.iq Introduc)on Temporomandibular disorder (TMD) TMD refers to conditions affecting musculo- skeletal system structures, such as the joints (TMJ), masticatory muscles and other re- lated structures. Tenderness in the joints and/or muscles, sounds from the joints, and restricted jaw movement and limitation of mouth opening are the common conditions [1-3]. TMD occur due to injury due, neuro- psychological stress, malocclusion, and stroke-related parafunctional activity [4]. In- tense pain felt in chewing muscles is quite common in temporomandibular disorders. This pain can often be debilitating. Problems with chewing can arise for a variety of causes that affect the muscles of the jaw, which is felt in the pre-auricular area and masticatory muscles [5,6]. PBM and Arndt- Schulz law Photobiomodulation is an application that relies on the use of certain wavelengths in low and sub-ablative power settings that produce minimal and accepted thermal ef- fects on tissues to stimulate cellular re- sponses. Many experiments show high com- pliance with PBM, with no invasiveness, at- raumaticity, and no collateral effects [7,8]. The wavelengths shorter than 600 nm tend to be absorbed excessively by pigmental pro- teins of the cell, while water serves as an ef- fective absorber of the bands longer than 1150 nm [9]. The therapeutic window is the range of suitable wavelengths appropriated for Photobiomodulation. This range lies be- tween 600 and 1150 nm [10]. The phrase "Arndt-Schulz law" refers to a law of treatment effect by medication. It guides the optimal dosing of a therapeutic stimulus. The Arndt-Schulz curve expresses the opti- mum response of a living organism between 0.1 to 10 joules/ cm2 [11]. The curve suggests that: 1. Low doses (low energy densities) < 2 joule/cm2 insufficient for effect or may be weak stimulatory, promoting cellular func- tion and healing. Efficacy of Two Diode Laser Wavelenghts in the Management of MasLcatory Disorders and Myofascial Pain Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.955 http://dentistry3000.pitt.edu 2 2. Moderate doses (1- 10 joules/cm2) lead to an optimal therapeutic effect. 3. At 10 joules/ cm2 indicate the anal- gesic effect 4. High doses (high energy densities) > 10 joules / cm2 can be inhibitory or even harmful. Pain relief and muscle relaxing Low level lasers can improve and restore muscle function and alleviate pain threshold, ultimately leading to the restoration of nor- mal cell and tissue functions. As inhibiting of the pain signals that nerve cells send to the brain, laser treatment affects these cells. The brain and adrenal gland produce large amounts of painkillers including endorphins and encephalin, which is a representation of the pain blocking mechanism [12, 13]. Using a non-invasive approach, laser therapy tar- gets muscle trigger points to relieve muscu- loskeletal discomfort and accelerating angio- genesis, which results in transient vasodila- tation, provides an additional advantage [14]. This study aimed to evaluate the effect of Photobiomodulation on districted mouth opening and pain relief on painful temporo- mandibular patients by use two wavelengths of diode laser. Material and Methods Participants The experimental in vivo trials of this study were approved by Research Ethics commit- tee at Faculty of Dentistry, University of Almaarif, Ramadi, Iraq. (Ref. No. 2, 2024). In this study, thirty-six participants—ages 18 to 45 years—who suffered from restricted mouth opening, pain in the temporomandib- ular joint area and tenderness in the tem- poral and masseter muscles presented to the dental clinic at The University of Almaarif. The established guidelines were used to con- duct a clinical evaluation of the relevant sub- jects. A digital measuring instrument was used to measure the participants’ mouth opening, and the Visual Analog Scale was em- ployed to gauge the patients' subjective pain level [15]. Participants were chosen accord- ing to predefined inclusion criteria. To en- sure excluding unwanted instances and maintain other dental and surgical aspects of the research unaware of it, an MRI was taken. Inclusion participants have been divided into two groups, with Group B receiving la- ser therapy at 635 nm and Group A receiving laser therapy at 980 nm. Diagnosis Extraoral and intraoral examinations are achieved in the counselling dental clinic: Pal- pation, percussion, x- ray, MRI, and the his- tory case of each patient had taken. 2.1 Inclusion and exclusion subjects The study included patients with pain in the temporomandibular joint region, tenderness in the masticatory muscles, and reduced mouth opening. The excluded cases include complicated conditions such as dislocated joint capsules, trauma, tumors, dental pain, and oral lesions, vascular diseases, arthritis, any known neuropsychological or hormonal problems [16]. Six participants were ex- cluded. Laser Equipment 1. The laser system used was a Medency triplo laser device, production date 08/2024. 2. Therapy handpiece (DIRECTO HAT-TOP). Directo is a special collimated handpiece de- veloped to increase therapy’s reliability with no energy dispersion. Laser parameters each patient received irradiance per session as the following equations: [17] Power density = Power / Area of laser beam Energy Density = E /Area of laser beam Peak Power = E/ duration of each treatment session in seconds. a. 980 nm wavelength Power 0.8 W, Beam spot diameter 2.2 cm, power density 0.2105 W/cm2 exposure time 30 seconds per trigger points in continuous mode, energy density per session 6.32 J/cm2 b. 635 nm wavelength power 0.5 W, beam spot diameter 2.2 cm, power density per point 0.1315 W/cm2 ex- posure time 30 seconds per trigger points in continuous mode. Energy density of each ex- posure 3.95 J/cm2 Treatment Approach Participants in the treatment groups re- ceived laser therapy sessions, during which the Directo Hat-Top handpiece was placed over the trigger points, with each exposure time for 30 seconds. Each participant under- went a total of six treatment sessions, which included three laser therapy sessions per week over a duration of two weeks. Subjects in Group A were treated with a 980 nm wavelength at a power setting of 800 mw and an energy density of 6.32 J/cm2. Mean- while, Group B was administered 635 nm la- ser therapy at a power setting of 300 mw and an energy density of 3.95 J/cm2 [18]. For every participant, the maximal mouth opening and baseline VAS pain scores were documented. A mean value of pain and MO during function was to be recorded by the patients over two days in between each treatment session. The laser beam was ap- plied in a contact delivery with continuous mode. The contributors monitored patients pain intensity using the Visual Analog Scale before, during, and after the therapy. Mouth opening was measured using a digital cali- per. IBM SPSS software version 22 was used for the statistical analysis (SPSS Inc., Chicago, IL, USA). For the categorical and nominal variables, descriptive statistics included to characterize the study variables, while means and standard deviations were used to present the continuous variables. Results After completion of laser treatment, the drop in pain intensity and development of mouth opening has been recorded for one month (Tables 1 through 7 and Figures 1 and 2). Discussion The values of laser parameters and usable settings were included in therapeutic range of photobiomodulation curve. Laser therapy is a treatment that is effective in alleviating pain and discomfort. It is also useful for relaxing muscle spasms and in- creasing circulation to speed up inflamma- tion healing. When the measurements were obtained after treatment period, there was a significant drop in the levels of pain. Those receiving treatment from the 635 nm laser had better results when it comes to mouth opening compared to those receiving treat- ment from the 980 nm laser. It was helpful that laser light's anti-inflammatory and pain- relieving impact took place in the target tis- sues. The differing results of 980 and 635 nm laser treatments were possibly due to the varying depth of penetration and biological effects of these two laser wavelengths. Nor- mality test of Maximal mouth opening among periods and groups. PBM transfers energy to intracellular light- absorbing molecules. Chromophores are present as porphyrins and the mitochondrial e- transport chain. The result is a metabolic energy through the respiratory chain direct to redox change of photons and production of adenosine triphosphate (ATP), and re- lease of nitric oxide (NO) may act as a potent extracellular vasodilator [19,20]. Photore- ceptors are present as two complementary groups inside mitochondria. The respiratory chain enzymes at the mitochondrial level act as the main photoreceiver for Photobiomod- ulation outcomes within wavelengths of the visible band. ion channels embedded on the cell membrane act as the primary photore- ceiver for PBM outcomes at infrared wave- length bands [21-23]. Laser-tissue interac- tion determines the absorption and scatter- ing nature of light, especially the wavelength and its chromophores inside the tissues Both laser treatments show significant re- ductions in maximal mouth opening over time. The 980nm treatment displays a con- sistent reduction from baseline, with statis- tically significant differences between all- Efficacy of Two Diode Laser Wavelenghts in the Management of MasLcatory Disorders and Myofascial Pain Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.955 http://dentistry3000.pitt.edu 3 time points. The 635 nm treatment shows a more pronounced reduction, especially be- tween baseline and six weeks The study's kindings concur with those of other researchers, such as Mortazavi and Martins-Júnior. The most prevalent age for the development of this condition is between 20 and 40 years old, according to another re- search conducted by Lipton and Glass & Gla- ros [24, 25]. This study supports Minghella's kindings that 68% of patients with these dis- eases were young adults [26]. The present study contradicts Emshoff and De Abreu Venancio, who found no alleviation of TMJ pain with LLLT treatment [27]. Ac- cording to Petrucci, LLLT is insufkicient for easing TMJ pain [28]. Numerous research concurs with this one since they found that LLLT application is a useful treatment for TMD sufferers. According to Mazzetto, Çetiner, and Venezian's investigations, pa- tients were monitored for up to 30 days fol- lowing their kinal laser application sessions. According to Çetiner and Bisson, the pain de- crease remained statistically signikicant dur- ing this time [29-31]. Mazzetto stated that despite these outcomes, the last laser appli- cation session eliminated the minimal sensi- tivity to palpation. For a year, Lassemi moni- tored the patients and recorded pertinent re- sults in terms of pain relief [32]. According to their research, Arani, Myer used lasers and trigger points to treat the af- klicted area. The study reported a signikicant reduction in pain in all the patients with a la- ser beam at a wavelength of 980 nm and 635 nm. The corresponding outcomes of PBM with 980 nm were documented in previous studies [33-35]. The mean VAS between the two groups reached a signikicant difference (P < 0.05) after the fourth session which con- tinued till the 6th session and one month fol- low-up period. According to Turky index, the procedure is considered successful if there is 50 % reduction in the VAS. It is rec- orded as 75 % reduction in 635 nm group. The mean MMO between the two groups reached a signikicant difference (p < 0.05) af- ter the sixth session which continued till month follow-up period. The result was in accordance with the study by Khalighi et al., in which results demonstrated 33.6% in- crease in mouth opening in the laser group which started from the eighth session [36]. The application of photobiomodulation la- sers with different wavelengths become popular for pain reduction and healing accel- eration after surgeries. Infrared lasers are the best because of their deeper penetration, according to the kindings of last research and the laser's wavelength ranged from 635 to 980 nm [37-38]. Conclusions This study has demonstrated the signikicant impact of the therapeutic efkicacy of diode la- ser wavelengths on management of mastica- tory disorders and myofascial pain. By exam- ining two diode laser wavelengths 980 nm, 635 nm, the research highlights relaxing muscle spasms and increasing circulation to speed up inklammation healing. When the measurements were obtained after treat- ment period, there was a signikicant drop in the levels of pain to use a 635 nm laser ther- apy as a biostimulaton aids with myogenic TMD. While the study determines key as- pects of diode laser effect on soft tissue, fur- ther investigation is needed to explore as ap- plying other laser wavelengths. However, since there were no further side effects of two wavelengths observed after laser ses- sion. It is possible to recommend the use of a 635 nm as a photo-biomodulation second option in treatment of masticatory disorders and myofascial pain patients. Acknowledgements This research has the academic and kinancial support by University of Almaarif and dean- ship College of Dentistry. 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Oral Maxillofac Implants 30(5), 1028–1035 (2015). Table 1. Pain relief 1-10. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 980 nm Pre 7 7 8 6 7 8 8 9 9 10 9 7 8 9 6 Post 1st 5 3 5 2 5 4 5 5 6 7 7 7 5 6 2 Post 6th 1 2 2 0 2 0 2 1 2 2 4 5 3 2 0 1 month 1 2 1 0 2 2 3 4 2 5 7 7 5 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 635 nm Pre 8 6 7 7 9 7 6 7 6 9 8 8 7 10 8 Post 1st 5 4 3 3 6 5 3 4 4 6 5 6 3 6 5 Post 6th 2 0 1 0 2 1 1 2 0 4 2 2 1 2 2 1 month 0 0 1 0 2 2 0 4 0 4 0 0 0 2 2 Efficacy of Two Diode Laser Wavelenghts in the Management of MasLcatory Disorders and Myofascial Pain Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.955 http://dentistry3000.pitt.edu 5 Figure 1. Mean pain relief over time. Table 2. Maximum mouth opening (mm). No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 980 nm Pre 25 27 24 31 27 24 23 21 21 21 25 27 25 24 30 Post 1st 37 39 34 37 41 40 36 32 36 32 38 34 36 36 44 Post 6th 42 44 40 41 42 49 46 41 48 40 45 40 44 40 52 1 month 37 40 40 41 40 44 46 37 42 40 40 36 44 42 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 635 nm Pre 22 32 23 25 20 26 30 25 33 22 24 22 27 20 22 Post 1st 26 36 30 31 28 36 40 35 41 28 34 30 37 30 31 Post 6th 40 52 42 42 40 51 55 52 53 41 47 43 54 41 44 1 month 42 50 44 43 41 54 55 50 50 40 45 43 52 40 40 Efficacy of Two Diode Laser Wavelenghts in the Management of MasLcatory Disorders and Myofascial Pain Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.955 http://dentistry3000.pitt.edu 6 Figure 2. Mean mouth opening over time. Table 3. Maximum mouth opening comparison using Shapiro Wilk test at p>0.05. Period Groups 980nm 635nm Statistic df P value Statistic df P value Baseline 0.930 15 0.274 0.898 15 0.090 One 0.956 15 0.631 0.947 15 0.475 Six 0.885 15 0.054 0.886 15 0.055 1month 0.928 15 0.257 0.884 15 0.054 Table 4. Mean maximum mouth opening comparisons. Period Groups T test P-value 980nm 635nm Mean ±SD Mean ±SD Baseline 25.000 3.024 24.867 4.086 0.102 0.920 One 36.800 3.278 32.867 4.518 2.729 0.011 Six 41.267 3.654 45.933 5.351 2.789 0.010 1 month 43.600 3.757 46.467 5.705 1.625 0.117 F 89.200 239.857 P-value 0.000 0.000 Effect size 0.957 0.984 Efficacy of Two Diode Laser Wavelenghts in the Management of MasLcatory Disorders and Myofascial Pain Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.955 http://dentistry3000.pitt.edu 7 Table 5. Multiple pairwise comparison of Maximum mouth opening. Groups Period Mean Difference P value 980nm Baseline One -11.800 0.000 Six -16.267 0.000 1 month -18.600 0.000 one Six -4.467 0.000 1 month -6.800 0.000 Six 1 month -2.333 0.018 635nm Baseline One -8.000 0.000 Six -21.067 0.000 1 month -21.600 0.000 one Six -13.067 0.000 1 month -13.600 0.000 Six 1 month -0.533 1.000 Table 6. Mean pain scores comparisons. Period Groups WSR P-value 980nm 635nm Median Mean rank1 Mean rank 2 Median Mean rank1 Mean rank 2 Baseline 8 16.77 3.93 7 14.23 4.00 0.812 0.436 One 5 16.83 2.93 5 14.17 2.97 0.852 0.412 Six 2 16.77 1.30 2 14.23 1.60 0.839 0.436 1 month 2 19.13 1.83 0 11.87 1.43 2.339 0.023 Friedman 40.664 42.277 P-value 0.000 0.000 Effect size 2.03 2.11 WSR=Wilcoxon sum rank, Mean rank 1=between groups, Mean rank 2 between periods. Table 7. Multiple pairwise comparisons of pain (multiple Wilcoxon sign rank adjusted by the Dunn-Bonferroni method). Groups Sample 1-Sample 2 Wilcoxon sign rank P-value 980nm Pain1-Pain0 2.121 0.034 Pain6-Pain0 5.586 0.000 Pain1month-Pain0 4.455 0.000 Pain6-Pain1 3.465 0.001 Pain1month-Pain1 2.333 0.020 Pain6-Pain1month 1.131 0.258 635nm Pain1-Pain0 2.192 0.028 Pain6-Pain0 5.091 0.000 Pain1month-Pain0 5.445 0.000 Pain6-Pain1 2.899 0.004 Pain1month-Pain1 3.253 0.001 Pain1month-Pain6 0.354 0.724