Med Oral Patol Oral Cir Bucal. 2013 Jul 1;18 (4):e603-12. LLLT and TMDs. Review of the literature e603 Journal section: Oral Medicine and Pathology Publication Types: Review The use of low level laser therapy in the treatment of temporomandibular joint disorders. Review of the literature Judit Herranz-Aparicio 1, Eduardo Vázquez-Delgado 2, Josep Arnabat-Domínguez 3, Antoni España-Tost 4, Cosme Gay-Escoda 5 1 DDS. Fellow of the Master degree program of Oral Surgery and Implantology, School of Dentistry, University of Barcelona 2 DDS.MS. Head of the TMJ and Orofacial Pain Unit of the Master of Oral Surgery and Implantology. University of Barcelona, School of Dentistry. Investigator of the IDIBELL Institute. Specialist of the Orofacial Pain Unit of the Teknon Medical Center. Barcelona 3 DDS. MD, MS. PhD. �ssociate Professor of Oral Surgery. Co-director of the Master in Lasers in Dentistry. Barcelona Univer- sity, School of Dentistry. Investigator of the IDIBELL Institute 4 DDS. MD, MS. PhD. �ssociate Professor of Oral Surgery. Professor of the Master of Oral Surgery and Implantology. Direc- tor of the Master in Lasers in Dentistry. Coordinator of the European Master’s Degree in Oral Laser �pplications (EMDOL�). Barcelona University, School of Dentistry. Investigator of the IDIBELL Institute 5 MD, DDS, MS. PhD. Chairman and Professor of Oral and Ma�illofacial Surgery. Director of the Master of Oral Surgery and Im- plantology. Barcelona University, School of Dentistry. Coordinating/ Investigator of the IDIBELL Institute. Head of the Depart- ment of Oral and Ma�illofacial Surgery and Coordinator of the Orofacial Pain Unit, Teknon Medical Center. Barcelona, Spain Correspondence: Centro Médico Teknon C/ Vilana 12 08022 Barcelona, Spain cgay@ub.edu Received: 16/09/2012 �ccepted: 15/02/2013 Abstract Introduction: The temporomandibular disorders (TMDs) have been identified as the most important cause of pain in the facial region. The low level laser therapy (LLLT) has demonstrated to have an analgesic, anti-inflammatory and biostimulating effects. The LLLT is a noninvasive, quick and safe, non-pharmaceutical intervention that may be beneficial for patients with TMDs. However the clinical efficiency of LLLT in the treatment of this kind of disorders is controversial. Objectives: Literature review in reference to the use of LLLT in the treatment of TMDs, considering the scientific evidence level of the published studies. Material and Methods: � MEDLINE and COCHR�NE database search was made for articles. The keywords used were “temporomandibular disorders” and “low level laser therapy” or “phototherapy” and by means of the Boolean operator “�ND”. The search provided a bank of 35 articles, and 16 relevant articles were selected to this review. These articles were critically analyzed and classified according to their level of scientific evidence. This analysis produced 3 literature review articles and 13 are clinical trials. The SORT criteria (Strength of Recom- mendation Ta�onomy) was used to classify the articles. Results: Only one article presented an evidence level 1, twelve presented an evidence level 2, and three presented Herranz-�paricio J, Vázquez-Delgado E, �rnabat-Domínguez J, España- Tost �, Gay-Escoda C. The use of low level laser therapy in the treatment of temporomandibular joint disorders. Review of the literature. Med Oral Patol Oral Cir Bucal. 2013 Jul 1;18 (4):e603-12. http://www.medicinaoral.com/medoralfree01/v18i4/medoralv18i4p603.pdf Article Number: 18794 http://www.medicinaoral.com/ © Medicina Oral S. L. C.I.F. B 96689336 - pISSN 1698-4447 - eISSN: 1698-6946 eMail: medicina@medicinaoral.com Indexed in: Science Citation Inde� E�panded Journal Citation Reports Inde� Medicus, MEDLINE, PubMed Scopus, Embase and Emcare Indice Médico Español doi:10.4317/medoral.18794 http://dx.doi.org/doi:10.4317/medoral.18794 Med Oral Patol Oral Cir Bucal. 2013 Jul 1;18 (4):e603-12. LLLT and TMDs. Review of the literature e604 an evidence level 3. According to the principle of evidence-based dentistry, currently there is a scientific evidence level B in favor of using LLLT for treatment of TMDs. Discussion and conclusions: Publications on the use of LLLT for treatment of TMDs are limited making difficult to compare the different studies due to the great variability of the studied variables and the selected laser parameters. The great majority of the studies concluded that the results should be taken with caution due to the methodological limitations. Key words: Low level laser therapy; phototherapy; temporomandibular joint disorders. Introduction Temporomandibular disorders (TMDs) is a collective term that includes disorders of the temporomandibular joint (TMJ), and of the masticatory muscles and their as- sociated structures; characterized by pain, joint sounds, and restricted mandibular movement (1,2). TMD etiolo- gy is currently known to be multifactorial, including the presence of parafunctional habits, trauma stress, as well as emotional, systemic, hereditary, and occlusal factors (2).The etiology is related to an association of predis- posing factors that increase the risk of TMD, initiating factors that cause the onset of TMD, and perpetuating factors that interference with healing or enhance TMD progression (3). Epidemiological studies show that about 75% of the population presents one sign of TMD and 35 % present at least one symptom, however, only a minor percentage of the population, 3-7%, presents problems severe enough to look for treatment for TMD (4,5). There is still a lack of consensus on the classification of TMD, largely because there is unclear etiology and clin- ical findings can result from different causes, including psychological causes. One commonly used diagnostic scheme intended for research purposes is the Research Diagnostic Criteria for TMD (RDC/TMD) (6). This standardizes the clinical e�amination of patients with TMD, improves reproducibility among clinicians, and facilitates comparison of results among researchers (7). �ggressive and irreversible treatments, such as com- ple� occlusal therapies and surgeries should be avoided. Nonsurgical treatment of TMDs generally consists of medication, such as nonsteroidal anti-inflammatory drugs (NS�IDs) and antidepressants, splint therapy or/ and physiotherapy. NSAIDs may reduce the inflamma- tion but may also increase the risk of complications, such as gastric ulcer and nephroto�icity. Other treat- ments used are physical therapy (electrotherapy, ultra- sound, acupuncture and laser), treatment of parafunc- tional activities and alternatives therapies. Physical therapy is used in the treatment of TMD because of its analgesic, myorelaxing, anti-inflammatory and stimula- tions effects. Low level laser therapy (LLLT) is an op- tion for the treatment of musculoskeletal disorders, it is easy application, limited treatment time and minimum contraindications, due to its analgesic, anti-inflammato- ry and regenerative effects (3,4,8). The clinical efficacy of LLLT for the treatment of TMDs is controversial. Some authors reported best re- sults comparing the LLLT with a placebo control group, while others found no significant differences. �ccording to some authors there is considerable diver- sity in the results reported, depending on parameters and methodology used. The aim of our study is to make a review of the litera- ture published on the use of LLLT for the treatment of TMDs, considering the level of scientific evidence ac- cording to the principals of evidence-based dentistry. Material and Methods � MEDLINE search was made for articles without re- striction in year publication. The keywords used were “temporomandibular disorders” and “low level laser therapy” or “phototherapy” and by means of the Boolean operator “AND”. The literature identified was then lim- ited to studies in humans and articles written in English. The same process was used in the COCHR�NE data- base of the Cochrane Oral Health Group. Two authors analyzed the abstracts to verify that the articles obtained were pertinent to the topic under study. The irrelevant articles were discarded. Ne�t, the same two authors independently stratified the scientific articles accord- ing to their level of scientific evidence using the SORT criteria (Strength of Recommendation Ta�onomy). Subsequently the authors compared their results; in the event of disagreement the results were discussed. If no consensus regarding the level of scientific evidence of a certain article was possible, a third author was included in the discussion. Subsequently, a recommendation was given for or against the use of LLLT in the treatment of TMD according to the level of scientific evidence of the articles analyzed. Results The MEDLINE search for TMDs and LLLT or pho- therapy when were cross provided a bank of 35 articles. Ne�t, the abstracts of each article were analyzed to de- termine if they were pertinent to the topic under study. The search in the COCHR�NE database provided no relevant articles that agreed with the search crite- ria of this study. �fter this process 16 relevant articles Med Oral Patol Oral Cir Bucal. 2013 Jul 1;18 (4):e603-12. LLLT and TMDs. Review of the literature e605 remained. These articles were critically analyzed and classified according to their level of scientific evidence. This analysis produced 3 literature review articles and 13 are clinical trials. Description of studies. 1. Bjordal JM, Couppé C, Chow RT, Tunér J, Ljunggren E�. Literature systematic review. Evidence level 2. 2. Medlicott MS, Harris SR. Literature systematic re- view. Evidence level 2. 3. McNeely ML, �rmijo Olivo S, Magee DJ. Literature systematic review. Evidence level 2. 4. De Medeiros JS, Vieira GF, Nishimura PY. Clinical trial. Evidence level 3. 5. Carvalho CM, de Lacerda J�, dos Santos Neto FP, Cangussu MC, Marques �M, Pinheiro �L. Clinical trial. Evidence level 3. 6. Fikácková H, Dostálová T, Navrátil L, Klaschka J. Clinical trial. Evidence level 2. 7. Çetiner S, Kahraman SA, Yücetaş S. Evidence level 2. Clinical trial. Evidence level 2. 8. N�ñez SC, Garcez �S, Suzuki SS, Ribeiro MS. Clin- ical trial. Evidence level 3. 9. Venancio Rde �, Camparis CM, Lizarelli RF. Clini- cal trial. Evidence level 1. 10. Emshoff R, Bösch R, Pümpel E, Schöning H, Strobl H. Clinical trial. Evidence level 2. 11. Kato MT, Kogawa EM, Santos CN, Conti PCR. Clinical trial. Evidence level 2. 12. Hotta PT, Hotta TH, Bataglion C, Bataglion S�, Coronatto E�S, Siesseré S, Regalo SCH. Clinical trial. Evidence level 2. 13. Katsoulis J, �usfeld- Hafter B, Windecker-Gétz I, Katsoulis K, Blagojevic N, Mericske-Stern R. clinical trial. Evidence level 2. 14. Mazzetto MO, Hotta TH, Pizzo RC�. Clinical trial. Evidence level 2. 15. Shirani �M, Gutknecht N, Taghizadeh M, Mir M. Clinical trial. Evidence level 2. 16. Kulekcioglu S, Sivrioglu K, Ozcan O, Parlak M. Clinical trial. Evidence level 2. The results of the clinical trials that study the effects of LLLT are summarized in table 1, the results of studies that compare LLLT with the use of TENS application are summarized in table 2, the results of studies that compare LLLT with the use of laser acupuncture are summarized in table 3 and the results of laser applica- tion parameters are summarized in table 4. In accord- ance with the principals of evidence- based dentistry, the analysis produced a level B recommendation strength in favor of using LLLT in the treatment of TMDs. Howev- er, these results should be taken with caution since these recommendations are based on studies with important methodological defects such as insufficient sample size and/or lack of homogeneity among the studied popula- tions or the laser application parameters. Discussion Many clinical applications of laser light can be found in medicine, dentistry, surgery and many types of lasers in different wavelengths have been offered clinicians and researchers (9). The use of LLLT has gained much popu- larity in recent years as a method of management of many localized, painful, musculoskeletal conditions (9). LLLT makes use of the electromagnetic radiation of a single wavelength, usually in the red or infrared re- gions. LLLT provides treatment for several pathologies, including impaired wound healing, pain conditions, and inflammatory situations (10). Its basic effects are bio-stimulative, regenerative, anal- gesic and antinflammatory. It also seems to act on the immune, circulatory and haematological systems (3). The mechanism of analgesic effect of LLLT is not well understood, but according to some reports, LLLT may promote analgesic effects via several mechanisms (e.g. increases liberation of endogenous opiates, increases urinary e�cretion of glucocorticoids, improves local mi- crocirculation, increases lymphatic flow thus reducing edema, decreases permeability of the nerve cell mem- brane, decreases release of algesic agents in pathologi- cal sites, increases �TP production, decrease tissue as- phy�ia and acceleration of wound healing) (3,5,8,11-13). Other authors such as Gam et al. (14), suggested that there is no scientific evidence to show that laser light can penetrate deeper structures, and some studies ques- tioned the clinical an biological benefits of the physical therapy in the treatment of musculoskeletal pain, while other authors demonstrate the effectiveness of the low level laser therapy for musculoskeletal disorders (2,9). The importance of investigating the actual analgesic efficacy of LLLT lies on the fact that TMD symptoms have been treated by a wide array of methods sepa- rately, such as interocclusal splint, medication, physi- cal therapy, and transcutaneous electric nerve stimula- tion; in most cases, however, better outcome is achieved when the therapies are associated, where lasers can be of great value (12). LLLT is a noninvasive, quick and safe, non-pharmaceu- tical intervention that may be beneficial for patients with TMJ pain disorders (4,11). Like in any therapy, patients respond similarly to LLLT. Patient response depend not only on the type of laser, but also on the target tissue an immunological system conditions. �n unsatisfactory outcome can be due to very low or high dose, incorrect diagnosis, small number of sessions, inadequate energy density, among others (12). Publications are scarce on the specific case of using LLLT on TMDs. Our research found only 35 which re- lated the two terms. The relative clinical efficacy of LLLT for treatment of TMD is controversial (4). For most authors, such as Kulekcioglu et al. (5) Fikácková et al. (7), Carvalho et Med Oral Patol Oral Cir Bucal. 2013 Jul 1;18 (4):e603-12. LLLT and TMDs. Review of the literature e606 Au th or s an d ye ar Ty pe of st ud y an d L ev el of Ev id en ce Su bj ec ts In clu sio n an d Ex clu sio n Cr ite ria CG CO Ev al ua tio ns Ev al ua tio n m et ho ds Au th or ’s co nc lu sio ns de M ed eir os et al. 2 00 5 Pr os pe cti ve cli ni ca l t ria l. Bl in di ng tec hn iq ue s? . 15 In clu sio n - P ain in pa lp ati on o f m as se ter m us cle . - F irs t m ol ar s ( up pe r a nd lo we r) wi th ou t p er io do nt al di se as e o r s ec on d m ol ar s. tak in g o ve r t he pl ac e o f m iss in g fir st m ol ar s. No NR Be fo re tr ea tm en t, af ter pl ac eb o lam p se ss io n an d af ter 3 0 m in ut es th e l as er w as u se d an d re gi ste re d ag ain . Bi te str en gt h. LL LT is an ef fe cti ve to ol fo r t he tre atm en t o f p ati en ts wi th o ro fa cia l pa in . Ve na nc io et al. 2 00 5 Pr os pe cti ve ra nd om ize d do ub le bl in d cli ni ca l t ria l. 30 (1 5 LG , 1 5 PG ) In clu sio n - D iag no sis o f T M D, w ith pa in re str ict ed to th e j oi nt ar ea , a ss oc iat ed w ith th e ab se nc e o f a ny m us cle te nd er ne ss d ur in g pa lp ati on . I nc lu de d c ap su lit is/ sy no vi tis an d pa in fu l d isk di sp lac em en ts wi th re du cti on . - N ot p ro fe ss io na l t re atm en t f or th e l as t 6 m on th s. E� clu sio n - P sy ch iat ric d iso rd er s, he ar t d ise as es , e pi lep sy , p re gn an cy , r he um ato id ar th rit is, de ge ne ra tiv e j oi nt d ise as es , t um or s a nd su bj ec ts wi th p ac em ak er s. Ye s SC I m m ed iat ely be fo re th e fir st, th ird an d f ift h se ss io ns , a nd at th e fo llo w up ap po in tm en ts af ter 1 5, 3 0 a nd 60 d ay s of th e e nd o f t re atm en t. V� S. PP T. M VO . LE . P. Th e e ffe ct of th e l ow le ve l l as er th er ap y in p ain w as n ot d em on str ate d in th is stu dy , b ec au se it w as si m ila r t o th e pl ac eb o e ffe ct. I t i s s ug ge st th at stu di es in th is ar ea sh ou ld co nt in ue b as ed o n th e no n- in va siv e a sp ec t. Çe tin er et al. 2 00 6 Pr os pe cti ve do ub le bi nd cli ni ca l t ria l. 39 (2 4 LG , 1 5 PG ) In clu sio n -S ys tem ati ca lly h ea lth y wi th m yo ge ni c o ro fa cia l p ain an d l im ite d m ou th o pe ni ng an d wi th ch ew in g di ffi cu lti es o r h av in g ten de r p oi nt s, an d pa in in th e m yo fa cia l ar ea ei th er d ur in g co m pr es sio n or ja w m ov em en ts. E� clu sio n - D isc d isp lac em en ts, ar th ra lg ia an d os teo ar th ro sis . - P ati en ts re gu lar ly ta ki ng m ed ici ne s s uc h a na lg es ics an d a nt i-a n� iet y dr ug s, an d pa tie nt s w ith m iss in g m ol ar te eth . Ye s NR Ju st be fo re , j us t a fte r an d 1 m on th af ter th e tre atm en t. V� S. M VO . LE . LL LT is an ap pr op ria te tre atm en t f or TM D’ s a nd sh ou ld b e c on sid er ed as an alt er na tiv e t o ot he r m eth od s. Em sh of f e t al. 2 00 8 Pr os pe cti ve do ub le bl in d ra nd om ize d co nt ro l t ria l. 52 (2 6 LG , 2 6 PG ) In clu sio n - � re po rt of o ro fa cia l p ain re fe rre d to th e T M J a s w ell as th e p re se nc e o f u ni lat er al TM J p ain d ur in g f un cti on . - � bs en ce o f a cl in ica l T M J d iso rd er co nd iti on . - P re op er ati ve V �S p ain le ve l g re ate r t ha n 20 m m an d les s t ha n 8 0 m m . - R ec en tly of pa in o ns et of 2 y ea rs or le ss . - B e a m bu lat or y a nd ab le to be tr ea ted as an o ut pa tie nt . - B e a va ila bl e f or th e s tu dy sc he du le. E� clu sio n - P ati en ts wi th a m ya lg ia, co lla ge n va sc ul ar di se as e, or a hi sto ry o f t ra um a. Ye s No Be fo re , a nd w ee k 2, 4 , an d 8 a fte r t he fi rst las er th er ap y. V� S. No si gn ifi ca nt d iff er en ce be tw ee n LL LT an d p lac eb o in th e o ut co m e m ea su re o f T M J p ain d ur in g fu nc tio n. It su gg es ted th at LL LT is n ot be tte r th an pl ac eb o a t r ed uc in g T M J p ain . Sh ira ni et al. 2 00 9 Pr os pe cti ve do ub le bl in d cli ni ca l t ria l. 16 (8 LG , 8 PG ) In clu sio n - P ati en ts wi th m yo fa sc ial pa in dy sfu nc tio n sy nd ro m e w ho d id n ot h av e a ny ot he r TM D’ s. - H ad su ffe re d un ila ter al pa in in th eir m as tic ato ry m us cle s f or u p t o 1 m on th . E� clu sio n -P ati en ts wi th p sy ch iat ric d iso rd er s, ep ile ps y, h ea rt di se as es , o r w ho w er e pr eg na nt , a nd th os e w ith pa ce m ak er s, tu m or s, in tra -c ap su lar di so rd er s l ik e de ge ne ra tiv e j oi nt d ise as e, rh eu m ato id ar th rit is an d di sc d isp lac em en t. - H ad n ot u nd er go ne an y tre atm en t f or m yo fa cia l p ain be fo re th is stu dy . Ye s No B ef or e a nd im m ed iat ely af ter tre atm en t, 1 we ek af ter , an d on th e d ay of co m pl ete p ain re lie f. V� S. Th e t re atm en t w ith th e c om bi na tio n of tw o di ffe re nt d io de la se r w av ele ng th s (6 60 an d 89 0 nm ) w er e p ro ve n t o b e ef fe cti ve tr ea tm en ts fo r p ain re du cti on in p ati en ts wi th m yo fa sc ial pa in dy sfu nc tio n sy nd ro m e. Ta bl e 1. L ow le ve l l as er th er ap hy c lin ic al tr ia ls . Med Oral Patol Oral Cir Bucal. 2013 Jul 1;18 (4):e603-12. LLLT and TMDs. Review of the literature e607 M az ze tto et al. 20 10 Pr os pe cti ve cli nic al tri al. Bl in di ng tec hn iq ue s? . 40 (2 0 LG , 2 0 PG ) In clu sio n - P ati en ts wi th art icu lar sy mp to ms . E� clu sio n - U se of m ed ica tio ns fo r p ain co ntr ol , u se of oc clu sa l s pl in t, an d c lin ica l c on dit io ns in w hi ch L LL T co ul d b e c on tra in di ca ted su ch as ag gr es siv e t um or an d i nf ec tio ns . Ye s NR Be fo re ap pl ica tio n, im me di ate ly aft er ea ch se ss io n, 7 d ay s a fte r t he las er ap pl ica tio n, 30 da ys af ter th e l as er ap pl ica tio n. V� S. M VO . LE . LL LT ca n b e a su pp or tiv e t he rap y i n th e t re atm en t o f T M D’ s, th e r es ult s sh ow ed de cre as ed pa in fu l s ym pt om s an d i nc re as ed M VO an d L E. Ca rv alh o e t al. 20 10 Pr os pe cti ve cli nic al tri al. Bl in di ng tec hn iq ue s? . 74 In clu sio n - T M J p ain du rin g i ni tia l e �a mi na tio n - N ot be in g t re ate d w ith an y o th er ty pe of th era pe ut ics . No No B ef or e t rea tm en t a t t he en d o f t he 12 se ssi on s. V� S. Th e a ss oc iat io n o f r ed an d i nf ra red las er li gh t w as ef fe cti ve in pa in re du cti on in T M D’ s o f s ev er al or ig in s. Fi ká ck ov á et al. 20 07 Pr os pe cti ve cli nic al tri al. Bl in di ng tec hn iq ue s? . 80 (6 1 LG , 1 9 PG In clu sio n - M yo fas cia l p ain an d a rth ral gia of th e T M J E� clu sio n - P ain les s j oi nt so un ds , d isc di sp lac em en ts wi th li mi ted op en in g, an d d eg en er ati ve jo in t d ise as es re lat ed to sy ste mi c c au se s. Ye s NR Be fo re th e t re atm en t an d o n t he se co nd da y af ter th e l as t s es sio n. Qu es tio n na ire ab ou t pa in . LL LT ca n b e c on sid er ed as a us ef ul m eth od fo r t he tr ea tm en t o f T M D’ s re lat ed pa in, es pe cia lly lo ng la sti ng pa in . Ku lek cio g lu et al . 20 03 Pr os pe cti ve do ub le bli nd cli nic al tri al. 35 (2 0 LG , 1 5 PG ) In clu sio n - O ro fa cia l p ain , T M J s ou nd s, lim ite d m ou th op en ing , o r T M J l oc kin g. E� clu sio n: - C on ge nit al ab no rm ali ty , c on co mi tan t i nf lam ma to ry or ne op las tic co nd iti on s, an d th os e w ith a re ce nt hi sto ry of ac ut e t rau m a o r a ny fo rm of tr ea tm en t w ith in the la st m on th . Ye s DE P Be fo re , a fte r a nd 1 mo nt h a fte r t he tre atm en t. V� S. NT P. JS . M VO . LE . LL LT ca n b e c on sid er ed as an alt er na tiv e p hy sic al mo da lit y i n t he m an ag em en t o f T M D’ s. Th e r es ul ts we re be tte r i n t he la se r g ro up . Ta bl e 1. C on tin ue . C G = co nt ro l g ro up , C O = C o- tr ea tm en t, N R= n ot re gi st er ed , P G /L G = pl ac eb o gr ou p/ la se r g ro up , M V O = m a� im um v er tic al o pe ni ng , L E= la te ra l e �c ur si on s, P= p ro tr us io n, E � = el ec tr og ra ph a ct iv ity , V� S= v is ua l a na lo g sc al e, L LL T= lo w le ve l l as er th er ap y, T M D = te m po ro m an di bu la r d is or de r, V S= v er ba l s ca le , M P= m us cu la r p al pa tio n, S C = se lf- ca re , P PT = pr es su re p ai n th re sh ol d, D EP = da ily e� er ci se p ro gr am , N TP = nu m be r o f t en de r p oi nt , J S= jo in t s ou nd s. Med Oral Patol Oral Cir Bucal. 2013 Jul 1;18 (4):e603-12. LLLT and TMDs. Review of the literature e608 al. (8), Çetiner et al. (9), Nuñez et al. (10), Shirani et al. (11), Mazzetto et al. (12), Medeiros et al. (13), Kato et al. (2) and Hotta et al. (15) demonstrated that LLLT is an ef- fective therapy for the pain control in subjects with TMD, while other studies, like those published by De �breu Venancio et al. (3), and Emshoff et al. (4), presented controversial results. Medlicott and Harris and McNeely et al. supported that the use of LLLT may improve the treatment results of TMD (16,17). Due to utilization of different parameters such as wavelength, power, irradia- tion time, beam area at the skin, energy/energy density, number of treatments and interval between treatments of laser radiation in various patients groups, the results could not have been standardized (4,18). Light penetration and absorption in biological tissue are dependent on several variables, and one of the most im- portant is the wavelength of the laser. Different wave- lengths have been used for treatment of TMDs: 632.8 nm neon–helium (He–Ne) laser (4), 670 nm (10,13), 690 nm (19), 780 nm (3,15), 830 nm (2,7,9,12), 890 nm (11), wavelengths of 830 nm to 904 nm (2) and 904 nm (5) (2). Carvalho et al. (8) used a combination of different wavelengths: 660 (red laser) and/or 780 nm, 790 nm or 830 nm (infrared laser), thinking that the association of red and infrared laser light could be effective in pain re- duction on TMD’s. The same results are were presented by Shirani et al. (11) who reported that the combination of two wavelength 660 nm (InGa�IP visible red light) and 890 nm (infrared laser), were proven to be effective treatments for pain reduction in patients with myofas- cial pain dysfunction syndrome. Emshoff et al. (4) used a 632 nm rather than the more typical choices of 830 nm or 904 nm. They reported that a 632.8 nm wavelength penetrates more deeply into musculoskeletal tissues than shorter wavelengths. It was also reported a pain reduction with 632 nm compared to 820 nm. These results are in accordance with Bros- seau et al. (20) who reported that here were no statistical difference between wavelengths. However, there was a trend for improved outcome with the 632nm compared to 820 nm for pain although the confidence limits over- lap [SMD 632 nm: -0.7 (95% CI: -1.2, -0.3) vs SMD 820 nm: -0.4 (95% CI: -0.8, 0.1)]. Concerning the energy density in the different stud- ies reviewed, it is possible to observe a great diversi- ty, since that has still not been any definite consensus about. De Medeiros et al. (13) recommend an applied energy density of 2 J/cm2, Venancio et al. (3) 6•3 J/cm2, Authors and year Type of study and Level of Evidence Subjects Inclusion and Exclusion Criteria CG CO Evaluations Evaluationmethods Author’s conclusions Nuñez et al. 2006 Prospective clinical trial. Blinding techniques?. 10 Inclusion - Limitation of mouth opening due to pain, and not having medical or pharmacological treatment for TMD in the past 6 months. E�clusion - Patients with systemic disease. No No Before and immediately after therapies MVO. Both therapies (LLLT and TENS) are effective in improving the MVO. LLLT was more effective than TENS therapy. Kato et al. 2006 Prospective double bind clinical trial. 18 (9 LG and 9 TENS group) Inclusion - Individuals presenting signs and symptoms of pain on the masticatory muscles (temporal and masseter). E�clusion - Patients presenting with more than 5 posterior missing teeth (e�cept for third molars) or other occlusal risk factors for TMD. - Subjects with muscle tenderness caused by systemic diseases, dental-related pain. - Patients with psychological disturbances. - �ny restriction for the employment of electrical therapy. No No Immediately before and 5 minutes after each session. V�S. MVO. MP. Both therapies were effective for decreasing the symptoms of patients with TMD’s. The cumulative effect may be responsible. Table 2. Clinical trials with TENS and low level laser application. CG= control group, CO= Co-treatment, NR= not registered, PG/LG= placebo group/laser group, MVO= ma�imum vertical opening, LE= lateral e�cursions, P= protrusion, E�= electrograph activity, V�S= visual analog scale, LLLT= low level laser therapy, TMD= temporoman- dibular disorder, VS= verbal scale, MP= muscular palpation, SC= self-care, PPT= pressure pain threshold, DEP= daily e�ercise program, NTP= number of tender point, JS= joint sounds. Med Oral Patol Oral Cir Bucal. 2013 Jul 1;18 (4):e603-12. LLLT and TMDs. Review of the literature e609 A ut ho rs  an d ye ar  Ty pe o fs tu dy  an d L ev el o f Ev id en ce  Su bj ec ts  In cl us io n an d Ex cl us io n Cr it er ia  CG  CO  Ev al ua ti on s  Ev al ua ti on  m et ho ds  A ut ho r’ s co nc lu si on s Ka ts ou lis  et a l. 20 10  Pr os pe ct iv e cl in ic al tr ia l.  G ro up 1 :n ot  bl in di ng . G ro up 2 a nd  3: d ou bl e bl in d.  11 (7 L G ,4 P G ) In cl us io n - D ia gn os is o f t en do m yo pa th y of th e m as tic at or y m us cu la tu re - M a� im um p ai n in te ns ity o n th e V � S >3 0 (m an di bu la r p ai n an d fa ci al pa in ) d ur in g th e la st 1 4 da ys . - N o ot he r t he ra py o ne m on th b ef or e an d du rin g th e st ud y (a to ta l o f f ou r m on th s) . - � ge b et w ee n 18 a nd 7 0 ye ar s. Ex cl us io n  ͲD ia gn os is o fa rt hr op at hy o ft he  te m pe ro m an di bu la r jo in tw ith  ar th ra lg ia o rr ed uc ed m ob ili ty o ft he  m an di bl e.  ͲT em pe ro m an di bu la r jo in ta rt hr iti s or a ny re ce nt c ra ni al o r fa ci al  fr ac tu re s.  ͲA cu te d en ta lp ro bl em s . ͲH is to ry o fe ar ,n os e or th ro at  ill ne ss es . ͲG en er al m ed ic al c om pl ic at io ns  re qu ir in g tr ea tm en t, p sy ch ol og ic al  ill ne ss ,c lin ic al d ia gn os is o f rh eu m at oi d ar th ri tis ,c ur re nt  pr eg na nc y, a bu se o fa nt ip sy ch ot ic  m ed ic at io n, d ru gs o ra lc oh ol o r on go in g ot he rt re at m en to fM A P pr ob le m s ou ts id e th e pr os th od on tic s cl in ic . Ye s  N o  A tt he b eg in ni ng  (w ee k 0) a nd a t th e en d (w ee k 16 ).  VA S.  VS . Th e nu m be r of p at ie nt s tr ea te d w as to o sm al lt o al lo w g en er al iz ed  co nc lu si on s. T hi s th er ap y ha d no d et ri m en ta le ff ec t on p at ie nt ’s c om pl ai nt s.  La se r ac up un ct ur e is a n op tio n fo r pa tie nt s in te re st ed in a n on  in va si ve ,c om pl em en ta ry  th er ap y H ot ta e t al .2 01 0 Pr os pe ct iv e cl in ic al tr ia l.  Bl in di ng  te ch ni qu es ?.  10  (N R th e nu m be r of P G ) In cl us io n - P re se nc e of te m po ro m an di bu la pa in . Ex cl us io n - U se o f o th er tr ea tm en t f or p ai n co nt ro l a nd c lin ic al c on di tio ns th at la se r b ea m m ay b e da ng er ou s. Ye s  N o M VO ,L E, P ,E A : A ft er e ac h se ss io n of  ap pl ic at io n.  VA S: p re a nd  po st tr ea tm en t.  VA S.  M VO . LE . P.  EA . LL LT in s pe ci fic  ac up un ct ur e po in ts  pr om ot ed im pr ov em en t of s ym pt om s an d it m ay  be u se d as  co m pl em en ta ry th er ap y fo r TM D ’s . Ta bl e 3. C lin ic al tr ia ls w ith a cu pu nt ur e an d lo w le ve l l as er a pp lic at io n. C G = co nt ro l g ro up , C O = C o- tr ea tm en t, N R= n ot re gi st er ed , P G /L G = pl ac eb o gr ou p/ la se r g ro up , M V O = m a� im um v er tic al o pe ni ng , L E= la te ra l e �c ur si on s, P= p ro tr us io n, E � = el ec tr o- gr ap h a ct iv ity , V � S= v is ua l a na lo g sc al e, L LL T= lo w le ve l l as er th er ap y, T M D = te m po ro m an di bu la r d is or de r, V S= v er ba l s ca le , M P= m us cu la r p al pa tio n, S C = se lf- ca re , P PT = pr es su re p ai n th re sh ol d, D EP = da ily e �e rc is e pr og ra m , N TP = nu m be r o f t en de r p oi nt , J S= jo in t s ou nd s. Med Oral Patol Oral Cir Bucal. 2013 Jul 1;18 (4):e603-12. LLLT and TMDs. Review of the literature e610 Emshoff et al. (4) 1,5 J/cm2,Fickácková et al. (7) 10 or 15 J/cm2, Carvalho et al. (8) 1-2 J/cm2, Çetiner et al. (9) 7 J/ cm2, Shirani et al. (11) 6.2 J/cm2 and 1 J/cm2, Mazzeto et al. (12) 5 J/cm2, Kulekcioglu et al. (5) and Nuñez et al. (10) 3 J/cm2, Kato et al. (2) 4 J/cm2 and Hotta et al. (15) 35 J/cm2. The radiation penetration depth is also a controversial issue, and more objective data about tissue optics is necessary (10). Kulekcioglu et al. (5), suggested that infrared laser penetrates deeper than ultraviolet la- ser, and is most effective between the frequency ranges of 700- 1000Hz. Further studies are required to establish a radiation time and energy dose for significant effects on pathologi- cal conditions (9). Given the large range of treatment parameters involved in this therapy (i.e. wavelength, fluence, intensity, exposure time, total duration of the treatment), it is not difficult to understand that results differ from one study to the ne�t (10). Bjordal et al. (21) refers that literature on LLLT is full of conflicting re- ports, which is caused by the lack dosage consensus, suggesting that some poor results in some studies may have been caused by insufficient irradiation. Kulekcioglu et al. (5) and Çetiner et al. (9), reported a reduction of pain and chewing difficulties in myogenic TMDs, referring that one month follow-up is a mean- ingful time to get effective results with LLLT. Most of the reviewed studies evaluated the patients using a V�S (2-5,8,9,11,12,15,19) fact that makes very important to remark the psychological component. Pa- tients with diagnoses of TMDs are rendered suscepti- ble to placebo effects of any treatment carried out and has been shown to be effective in more than 40% of the cases (10). The conflicting results may be due too for the placebo effects in the treatment period (9), psychologi- cal factors, such as the desire to feel better, may have influenced physiological processes thereby resulting in the desired outcome (4). Venancio et al. (3) suggested that the power of the placebo effects has been widely demonstrated in the treatment of TMDs because a good relationship between professional and patient, associ- Authors and year Wavelength(nm) Power Output (mW) Total time of each session (seconds) Number of total laser sessions/ Number of sessions for week/ Number of weeks LLLT clinical trials de Medeiros et al. 2005 670 nm 15 mW 858 1/1/1 Venancio et al. 2005 780 nm 30 mW 10 6/2/3 Çetiner et al. 2006 830 nm NR 162 100/50/2 Emshoff et al. 2008 632.8 nm 30 mW 120 20/ 2-3/8 Shirani et al. 2009 660 nm 17.3 mW ( 0 Hz) 360 6/2/3 (combination of two lasers) 890 nm 9.8 W (1,500Hz) 600 Mazzetto et al. 2010 830 nm 40 mW 10 8/2/4 Carvalho et al. 2010 660 nm and/or 780nm, 790 nm or 830 nm 30-40 mW or 40-50 mW The time of laser application was automatically set by the laser units according to the dose selected, following the calibration of the manufacturer. 12/NR/6 Fikácková et al. 2007 830 nm 400 mW Not registered 10/not registered/4 Kulekcioglu et al. 2003 904 nm 17 mW (1,000Hz) 180 15/NR/NR Clinical trials with TENS and LLLT Nuñez et al. 2006 670 nm 50 mW 60 1 week (1 laser session for week and 1 TENS sessions for week). Kato et al. 2006 830 – 904 nm 100 mW 240 10/3/4 Clinical trials with acupuncture and LLLT Hotta et al. 2010 780 nm 70 mW 20 10/1/10 Katsoulis et al. 2010 690 nm 40 mW 900 6/2/3 Table 4. Low level laser technical characteristics. NR=not registered. Med Oral Patol Oral Cir Bucal. 2013 Jul 1;18 (4):e603-12. LLLT and TMDs. Review of the literature e611 ated with the appearance of the high technology of the laser, might e�plain the V�S reduction for laser and placebo groups in clinical control group trials. Kulekci- oglu et al. (5) reported that pain was significantly im- proved in the placebo group and this might be e�plained in two ways; the placebo effect which is frequently encountered when evaluating subjective symptoms in similar studies and the indirect influence of daily ex- ercise program. The literature has associated placebo analgesia with 2 potential mechanisms: one sustained and engaged for the duration of placebo analgesia, the other transitory, that is the feedback mechanism (22). In the others parameters, significantly improvements were found, only in the laser group. Double blind studies are more appropriate when a new therapeutic modality is being tested, because the placebo effect seems to be very strong, especially in chronic patients (3). Other or additional way to evaluate the patients is by measuring the different jaw movements (3,5,9,10,12,15). On the other hand, de Medeiros et al. (13) studied the effect of 670 nm on the bite strength of the masseter muscle using a gnathodynamometer and observed and improvement in muscle contraction strength in all pa- tients with only one application of 14 minutes. (13) They remark that the placebo effect did not affect the meas- urement of bite strength since it is evaluate before treat- ment, after placebo lamp session and after laser treat- ment. The use of this kind of devices, like the algometer, is an attempt to quantify pain better, standardizing data collection and making their comparison possible (3). Hotta et al. (15) and Katsoulis et al. (19) studied the effect of LLLT in acupuncture points, and they concluded that laser acupuncture is a good complementary therapy op- tion for patients with TMDs. Katsoulis et al. (19) reported that the effectiveness of LLLT seems to be comparable to that splint therapy; however it is less costly and less time consuming. On the other way, Kato et al. (2) and Nuñez et al. (10) compared LLLT with the TENS therapy and reported a stronger analgesic effect and greater improve- ment with LLLT than with TENS, but both therapies show good results for the treatment of TMDs. Few clinical studies, systematic reviews and meta- analysis investigated the efficacy of the LLLT in other musculoskeletal disorders and pain relief. Chow et al. (23), in a systematic review, evaluated the efficacy of LLLT in the management of neck pain, and concluded that the LLLT reduces pain immediately after treatment in acute neck pain and up to 22 weeks after completion of treatment in patients with chronic neck pain. These results are consistent with a double blind, randomized, placebo- controlled study published by themselves (24). Bjordal et al. (21), in other systematic review, analysed the efficacy of LLLT in pain reduction associated in chronic joint disorders. They also concluded that LLLT, in correct doses, can reduce significantly the pain and improve health status in chronic joint disorders. Bros- seau et al. (20) also made a systematic review about the efficacy of LLLT in the treatment of rheumatoid arthri- tis. It was concluded that LLLT could be considered in short-term treatment for pain relief and morning stiff- ness for rheumatoid arthritis patients, particularly since there were few side-effects. Brosseau et al. (20) Bjordal et al. (21), and Chow et al. (23), considered that the in- terpretation of the results should be taken with caution because there was heterogeneity in patient samples, treatment procedures and trial design, remarking the need of further investigations(20,21,23). Jenkins and Carroll (18), in their report e�plain that there is no consensus among manufactures in the way they measure and present the specifications of their de- vices complicating even more this issue. Without some standardization the studies are not reproducible, and outcomes in clinical research and practice will not be consistent. These authors propose a standardized tabu- lar format, in attempt to provide a standardized method for presenting what amount to a quite comprehensive set of parameters, and suggest accompanying procedures for this and other Journals to follow to ensure compli- ance by authors (18). Publications on the use of LLLT for treatment of TMDs are limited. � problem detected in this literature re- viewed is the variation in methodology, dosimetry and other parameters between studies, and the inclusion criteria and diagnosis of the patients. The studies are not standardized and consequently the results differ and comparison is difficult. �ccording to the principal of evidence-based dentistry, there is currently a scientific evidence level B in favor of using LLLT for treatment of TMDs. The results pub- lished in the literature should be analyzed with caution since none have sufficient scientific basis, either because the sample size is inadequate, or methodological defects are present. We believe that the diagnosis based on the Research Di- agnostic Criteria for TMD (RCD/TMD) proposed for Dworkin and LeReserche (6) and the use of tabular for- mat proposed for Jenkins and Carroll(18), could stand- ardize the clinical e�amination for the use of LLLT in patients with TMDs, improving reproducibility among clinicians, and facilitating comparison of results among researchers. Furthermore controlled double- blind clinical trials and multicentric studies are necessary to demonstrate the efficacy of LLLT in TMDs. References 1. Cascos-Romero J, Vazquez-Delgado E, Vazquez-Rodriguez E, Gay-Escoda C. The use of tricyclic antidepressants in the treat- ment of temporomandibular joint disorders: systematic review of the literature of the last 20 years. Med Oral Patol Oral Cir Bucal. 2009;14:E3-7. Med Oral Patol Oral Cir Bucal. 2013 Jul 1;18 (4):e603-12. LLLT and TMDs. Review of the literature e612 2. Kato MT, Kogawa EM, Santos CN, Conti PC. 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This study was performed by the “Dental and Ma�illofacial Pathol- ogy and Therapeutic” research group of the IDIBELL Institute.