Temporomandibular disorder (TMD) is defined as a series of clinical problems involving muscles of mastication, temporomandibular joints (TMJ), and related structures, identified by facial pain in the TMJ region and masticatory muscle, limited or deviated mandibular movement, and TMJ sounds during jaw movement and action [
In the last few years, laser light has been extensively used in clinical dentistry for the treatment of soft tissue disorders, hypersensitivity of dentine, bone regeneration, and musculoskeletal pain. In TMD patients, LLLT has been used by conservative treatment methods to enhance function and decrease symptoms [
Therefore, the aim of this systematic review was to find out the effectiveness of laser application in temporomandibular joint pain and review the evidence from previous studies with their sample size and methodology in the management of TMD. This review will provide a precise and obvious knowledge about the benefits and procedures of laser application, which have already been successfully established in TMD management.
Articles were searched in five electronic databases (Figure
Five electronic databases searched for this review.
Here, the prime concern was to find out the uses of laser in temporomandibular disorder patients in terms of reduction of pain and tenderness, improvement of mouth opening and joint sounds, and improvement in the range of jaw motion. The criteria for inclusion have been established as papers using the search keywords mainly TMJ problems and laser application. At the other side, the papers that use laser in TMJ diseases along with other problems such as anatomical defects, anomalies, myofascial pain disorder syndrome (MPDS), soft and hard tissue pathology (tumor, cancer), and previous record of TMJ surgery were excluded from the study. In the context of the exclusion criteria, it also added that those studies were not conducted in human (such as animal studies), and publications in other languages beside English were excluded. The case reports and letter to editor were also excluded from this review. Titles and abstracts of identified studies were assessed independently to judge if the studies match the inclusion criteria.
Data were extracted based on the first author, year of publication, number of samples, age and gender of samples, types of TMJ problem, laser types, laser energy and application rate, and results. The data were extracted and double-checked by the authors.
At the beginning, this research search strategy provided a total of 5889 papers from databases such as PubMed, Web of Science, Google Scholar, SCOPUS, and ScienceDirect. The remaining 2378 papers were further screened after eliminating 3511 papers in the detection phase (nonhuman topics, summary documents, case reports, editorials, letters and comments, and duplicate studies). A total of 72 studies were considered worthy, but due to unusable data format, forty studies were excluded. Thus, eventually, based on the research goals and inclusion and exclusion requirements, 32 studies (1172 TMD patients in total) were included in this study (Figure
PRISMA flow chart diagram of search strategy and selection of the studies.
The key characteristics of the included studies are presented in Table
Major key characteristics of the included studies in this systematic review.
Author and year | Study population | Sample size | Study design | Age/gender | Problem | Laser type | Energy and application rate | Results |
---|---|---|---|---|---|---|---|---|
Kulekcioglu et al., 2003 [ | Turkey | 35 patients | RCT | 20–59 years (female = 28, male = 7) | Orofacial pain, TMJ sounds, limited mouth opening, or TMJ locking | Ga-Al-As (LLLT), 904 nm wavelength | 180 seconds, dosage: 3 J/cm2 (15 sessions) | Significant reduction of pain and improvement in maximum mouth opening and lateral motion |
Kogawa et al., 2005 [ | Brazil | 19 patients | RCT | Mean age, 26.4 years (female = 19, male = 0) | Temporomandibular disorders (TMDs) | Ga-Al-As (LLLT), wavelength of 830–904 nm | 4 J/cm2 (3 times a week, 10 sessions) | Significant increase in maximum mouth opening and a decrease in tenderness |
Abreu Venancio et al., 2005 [ | Brazil | 30 patients | RCT | Not given | Temporomandibular disorders (TMDs) | Ga-Al-As (LILT), 780 nm wavelength | 6.3 J/cm2 (twice a week for 3 weeks, 6 sessions) | No significant changes |
Kato et al., 2006 [ | Brazil | 18 patients | RCT | Mean age, 25.6 years | Temporomandibular disorders (TMDs) | LLLT, wavelength of 830–904 nm | 4 J/cm2 energy density (10 sessions, 3 times a week for 4 weeks) | Significant decrease in pain and improvement in muscle tenderness |
Núñez et al., 2006 [ | Brazil | 10 patients | Non-RCT clinical trials | 18–56 years (female = 8, male = 2) | Temporomandibular disorders (TMDs) | Ga-Al-As (LILT), 670 nm wavelength | 3 J per site, total time 8 minutes | Significant improvement in mouth opening |
Emshoff et al., 2008 [ | Austria | 52 patients | RCT | 18 to 58 years | Patients with unilateral TMJ pain | Red-beam laser, 632.8 nm HeNe laser | 1.5 J/cm2 energy density (2 to 3 treatments per week for 8 weeks) | No significant differences in reducing pain |
Cunha et al., 2008 [ | Brazil | 40 patients | RCT | (Female = 39, male = 1) | Temporomandibular disorders (TMDs) | Ga-Al-As (LLL), 830 nm wavelength | 20 seconds, 100 J/cm2 (once a week for 4 weeks) | No significant changes |
Graciele Carrasco et al., 2008 [ | Brazil | 14 patients | RCT | Not given | Temporomandibular dysfunction (TMD) | Ga-Al-As (LILT), 780 nm wavelength | 60 seconds, 105 J/cm2 (twice per week for 4 weeks) | Significant improvement of masticatory efficiency |
Lassemi , 2008 [ | Iran | 48 patients | RCT | (Female = 24, male = 24) | Temporomandibular disorders (TMDs) | Ga-As (LLLT), 980 nm wavelength | 2 J per point (2 sessions with a 48-h interval) | Significant reduction of pain severity and clicking |
Raheem et al., 2010 [ | Iraq | 34 patients | Non-RCT, convenience sampling | (Female = 21, male = 13) | Temporomandibular disorders (TMDs) | Semiconductor galium-aluminium (gas) LLLT, 785 nm wavelength | Energy density of 16 J/cm2 (twice to thrice weekly and repeated 4 weeks, total 10 sessions) | Significant reduction of pain and improvement in maximum mouth opening, lateral motion, and muscle tenderness |
Mazzetto et al., 2010 [ | Brazil | 40 patients | RCT | Not given | Temporomandibular disorders (TMDs) | Ga-Al-As (LLL), 830 nm wavelength | 10 s, 5 J/cm2 | Significant improvement in pain reduction and mandibular movement |
Dostalová et al., 2012 [ | Prague | 27 patients | Non-RCT | Mean age of male 18.57 and female 27.57 years | Temporomandibular disorders (TMDs) | Ga-Al-As (LLL), 830 nm wavelength | 15 s, 4 J/cm2 (once a week for 5 weeks) | Significant reduction of pain |
De Godoy et al., 2013 [ | Brazil | 85 patients | RCT | 15 and 18 years | Temporomandibular disorders (TMDs) | Ga-Al-As (LLL), 780 nm wavelength | 20 s, 25 J/cm2 (6 weeks, a total of 12 sessions) | Not significant |
Catão et al., 2013 [ | Brazil | 20 patients | RCT | 19 to 58 years (female = 18, male = 2) | Temporomandibular disorders (TMDs) | As-Ga-Al laser (830 nm wavelength), InGaAIP laser (830 nm wavelength) | 4 J/cm2 (three times a week for 4 weeks, 12 sessions) | Significant reduction in pain and improvement in mouth opening |
Madani | Iran | 20 patients | RCT | 35–60 years (female = 19, male = 1) | TMJ osteoarthritis | LLLT (low level laser), 810 nm wavelength | 6 J per point, 3.4 J/cm2 (three times a week for 4 weeks) | No significant differences (for reducing pain and improving mouth opening) |
Pereira et al., 2014 [ | Brazil | 19 patients | RCT | 21–55 years (female = 15, male = 4) | Temporomandibular disorders (TMDs) | LLLT, wavelength: 660 nm (red laser) and 795 nm (infrared laser) | 4 J/cm2 (an interval of 48 hours, total 3 sessions) | Statistically significant in the treatment and remission of TMD symptoms |
Sayed et al., 2014 [ | India | 20 patients | RCT | 19–47 years (female = 9, male = 11) | Temporomandibular disorders (TMDs) | LLLT semiconductive (diodic) gallium arsenide (GaAs) laser, 904 nm wavelength | 60 s, 4 J/cm2 (3 times a week for 2 weeks) | Statistically significant in reducing the pain intensity, tenderness, joint sounds, and improvement in the range of jaw motion |
Huang et al., 2014 [ | Taiwan | 20 patients | RCT | Not given | Temporomandibular joint disorders (TMDs) | LLLT, 800 nm wavelength | 100.5 J/cm2 (once a week) | Significant reduction of pain |
Hu et al., 2014 [ | Taiwan | 29 patients | Retrospective convenience | 17–67 years (female = 25, male = 4) | Temporomandibular disorders (TMDs) | Ga-Al-As (LLL), 810 nm wavelength | 5s, 0.375 J/cm2 (3 times per week for 4 weeks) | Significant improvement of treatment-resistant TMD |
Seifi et al., 2017 [ | Iran | 40 patients | RCT | 18–50 years | Temporomandibular joint disorders (TMDs) | Ga-Al-As (LLL), 810 nm wavelength | (Four half-hour sessions per week) | Significant decrease in pain and tenderness |
Rezazadeh et al., 2017 [ | Iran | 45 patients | RCT | Not given | Temporomandibular disorders (TMDs) | Ga-Al-As (LLL), 980 nm wavelength | 2.5 minutes, 5 J/cm2 (8 sessions within 2 weeks) | Significant reduction of pain and tenderness |
Douglas de Oliveira et al., 2017 [ | Brazil | 19 patients | RCT | 21–55 years (female = 15, male = 4) | Temporomandibular disorders (TMDs) | Ga-Al-As (LLL), wavelength: 660 nm (red laser) and 790 nm (infrared laser) | 1.06 s, 8 J/cm2 (3 sessions) | Statistically significant in the treatment of TMD |
Basili 2017 [ | Italy | 180 patients | Non-RCT | Not given | Temporomandibular disorders (TMDs) | LLLT, 830 nm wavelength | 3 sessions | Significant reduction of pain |
De Godoy et al., 2017 [ | Brazil | 16 patients | RCT | 14–23 years | Temporomandibular disorders (TMDs) | LLLT, 780 nm wavelength | 20 s, 25 J/cm2 (12 sessions) | No significant changes |
Shobha et al., 2017 [ | India | 40 patients | RCT | 18–40 years | Temporomandibular disorders (TMDs) | Ga-Al-As (LLLT), 810 nm wavelength | 60 s, 6 J/cm2 (2-3 times a week, 8 sessions) | No significant changes |
Kashmoola 2018 [ | Malaysia | 22 patients | Non-RCT | 18–68 years | Temporomandibular disorders (TMDs) | LLLT | 2-3 minutes, 0.5 W, 30 Hz daily for 3 days and then once a week for 2 weeks | Significant reduction of pain |
Buduru et al., 2018 [ | Romania | 20 patients | Non-RCT | Not given | Temporomandibular joint disorders (TMDs) | LLLT, 660 nm wavelength | Energy intensity 90 mW (once each day, five days per week, for a total of 10 sessions | Significant reduction of pain |
Peimani et al., 2018 [ | Iran | 72 patients | RCT | 20–45 years | TMJ dysfunction | LLLT, 808 nm wavelength | 144 J/cm2 (2 times a week for 4 weeks) | Significant reduction of pain, clicking, and tenderness |
Del Vecchio et al., 2019 [ | Italy | 90 patients | RCT | 18–73 years (female = 78, male = 12) | Temporomandibular joint disorders- (TMJDs-) related pain | LLLT, 808 nm wavelength | 5 J/min (twice a day for 7 days) | Significant reduction of pain |
Tortelli et al., 2019 [ | Brazil | 12 patients | RCT | 23–50 years | Temporomandibular disorders (TMDs) | LLLT, 808 nm ± 10 nm wavelength | 2 J, (72h intervals, for a total of 6 sessions) | Significant decrease in pain and improve maximal opening capacity |
Khairnar et al., 2019 [ | India | 42 patients | RCT | 25–45 years | Temporomandibular joint disorders (TMDs) | LLLT, 660 nm wavelength | 2.2 J/min | Significant role in treating TMD-related pain |
Yamaner et al., 2020 [ | Turkey | 62 patients | RCT | Mean age, 31.51 ± 10.32 years (female = 59, male = 3) | Temporomandibular disorders (TMDs) | LLLT, 820 nm wavelength | 10 s, 3 J/cm2 (3 times a week, total 6 sessions) | Significant reduction of pain |
Publication bias was assessed by using
Risk of bias assessment of the study.
TMD management is very complex and contentious due to the difficulty of determining the exact reasons of the disease and its multifactorial character. The severity varies greatly, and the procedure is varying in terms of duration and invasiveness. Nevertheless, TMD treatment is intended to minimize discomfort, enhance mobility, and delay the progression of internal derangement as accepted by the American Society of Temporomandibular Joint Surgeons guidelines [
However, this systematic review tried to overview the role of laser in the management of TMJ disorder patients. After completing this review, the result showed a huge role of laser in TMD management. Most of the studies used LLLT for management of TMD, where it showed a tremendous action in reducing pain, joint clicking, muscle tenderness, and jaw movements.
A study was conducted by Kulekcioglu et al. in 2003 among Turkish population to investigate the effectiveness of low-level laser therapy in the treatment of TMD. Results of the study showed a significant reduction of pain and improvement in maximum mouth opening, lateral motion, and number of tenderness points. According to Kulekcioglu et al. , LLLT in treating TMD may be considered as an alternative physical modality [
On the other hand, some researchers also tried to find out the effectiveness of the laser treatment in TMD patient, and they concluded with no significant role of LLLT. In 2005, Abreu et al. conducted a study to assess the efficacy of low-intensity laser therapy (LILT) in temporomandibular joint (TMJ) pain and mandibular dysfunction patients. The study had 2 groups, placebo and experimental (LILT). They used the infrared laser (780 nm, 30 mW, 10 s, and 6.3 J/cm2) at three TMJ points. Even though the patient treated with laser had good pain reduction, the result showed no significant changes between placebo and laser groups. Therefore, the researcher did not recommend infrared LILT as a better treatment option. Though there are benefits of applying laser in TMDs management because of noninvasiveness and cost efficient, it has no reported side effects [
Although some authors did not notice any important differences, some studies showed better results when comparing the LLLT with a placebo control group. In 2010, Raheem et al. observed that LLLT plays a significant role in TMDs management by reducing pain and improving maximum mouth opening, lateral motion, and muscle tenderness. Raheem et al. advised LLLT as an effective therapeutic option in myofascial pain dysfunction of TMJ for its analgesic and functional improvement [
Even though LLLT is a type of treatment widely applied in physiotherapy of musculoskeletal disorders, there are only some studies that discuss its use in the management of TMD. In 2012, Dostalová et al. performed a research to observe the activity of TMJ and its surrounding tissues and compared the objective results of the effect of LLLT. LLLT was beneficial in the progress of the range of TMD and facilitated a significant pain symptoms reduction [
Few more studies have been performed in 2017 by several researchers to evaluate the effectiveness of laser therapy in the treatment of TMDs. Based on the sample size, population, and study design, the result showed some controversy about laser treatment. In 2017, Rezazadeh et al. examined 45 Iran patients to discover the effectiveness of transcutaneous electrical nerve stimulation (TENS) and LLLT in treatment of TMD patients who did not respond to pharmacological therapy. The result showed a significant reduction of pain and tenderness in TMD patients [
Though, clinically, the use of LLLT is a better procedure in managing TMJ pain. In 2018, a study completed by Buduru et al. showed a significant pain reduction and noticed that there is no disadvantage of LLLT. Thus, the author had recommended the use of LLLT for pain reduction in TMD patients [
In the present year 2020, a study was conducted by Yamaner et al. in Turkey to investigate the impact of the ozone and low-level laser (LLL) therapies on pain and function in TMDs patients with disc displacement with reduction. The results of the study support the application of ozone as an effective therapeutic tool for pain relief and LLL as a supportive therapy for temporomandibular disorders [
Although the present study went through a systematic search strategy and review of the selective articles, one of the limitations of the present study was the database searching. Due to the limited access of database, the author only searched in five specific databases. This study advised to perform another systematic review with meta-analysis by including some more databases searching to strengthen the findings.
TMD patients mostly suffer with pain symptoms along with other problems. Nowadays, LLLT became very popular because of its effective role in pain reduction and no known side effects. This systematic review evaluated the effectiveness of the laser application in TMD patient by thorough investigation of the previous studies that have been conducted on laser. After this systematic review, LLLT can be recommended as a beneficial treatment approach for TMD patients.
The authors declare that they have no conflicts of interest.
All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication. All authors were involved in this study in different phases. AZ, MAA, and MK were involved in the study protocol design and database searching. ZG, AZ, and MK were involved in the study selection. Any dispute was discussed and solved with WMWA, NKK, JAA, KSP, and AH. AZ and MK wrote the manuscript, and all others edited and improved the manuscript for submission standard.
The authors would like to acknowledge USM fellowship.