Lasers in Medical Science

, Volume 33, Issue 2, pp 385–392 | Cite as

Non-specific effects and clusters of women with painful TMD responders and non-responders to LLLT: double-blind randomized clinical trial

  • Laís Valencise Magri
  • Vinícius Almeida Carvalho
  • Flávia Cássia Cabral Rodrigues
  • César Bataglion
  • Christie Ramos Andrade Leite-PanissiEmail author
Original Article


The aim was to analyze the non-specific effects (placebo, spontaneous remission, and regression to the mean) of the low-level laser therapy (LLLT) in women with myofascial pain (painful temporomandibular disorder (TMD)), as well as to differentiate between responders and non-responder clusters to active and placebo LLLT according to the anxiety levels, salivary cortisol, use of oral contraceptives, and premenstrual period. Sixty-four women diagnosed with myofascial pain (Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD)) were included, divided into laser (n = 20), placebo group (n = 21), and 23 controls (without treatment (WT)). The LLLT applied was 780 nm, masseter and temporal = 5 J/cm2 (20 mW–0.5 W/cm2), and TMJ area = 7.5 J/cm2 (30 mW–0.8 W/cm2), eight sessions, twice a week. The pain intensity (visual analogue scale (VAS)), anxiety (Beck Anxiety Inventory), salivary cortisol, and menstrual cycle’s data at the baseline, T1–T8, and 30 days after LLLT (follow-up) were evaluated. The laser group showed 80% of pain reduction, placebo 85%, and WT 43% in T8. Women with severe anxiety and at the premenstrual period did not reduce pain with any LLLT. Active and placebo LLLT had similar effectiveness during the treatment period; however, women with moderate anxiety, cortisol levels above 10 ng/ml, and without contraceptive use maintain analgesia longer with active LLLT than placebo (follow-up 30 days). Women with low levels of anxiety, salivary cortisol below 10 ng/ml, and with contraceptive use showed the higher pain reduction. The analgesia promoted by LLLT in women with myofascial pain is a result of non-specific effects during the treatment period, although active LLLT is more effective in maintaining the analgesia after treatment (30 days) for the cluster of women with moderate anxiety, salivary cortisol above 10 ng/ml, and without contraceptive use.


Low-level laser therapy Myofascial pain syndromes Pain measurement Placebo Temporomandibular joint disorders 



This study was financially supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).

Compliance with ethical standards

All procedures were performed in accordance with the guidelines of the Brazilian Ethics Committee on Human Research. This study was conducted after approval by the Ethics Committee of the School of Dentistry of Ribeirão Preto (under protocol 33658114.7.0000.5419). All subjects were informed about the study and signed a consent form. Patients who composed the placebo group and did not have pain reduction after the study completion were invited to receive treatment with LLLT, in the same parameters of the active laser group.

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer-Verlag London Ltd., part of Springer Nature 2017

Authors and Affiliations

  • Laís Valencise Magri
    • 1
    • 2
  • Vinícius Almeida Carvalho
    • 3
  • Flávia Cássia Cabral Rodrigues
    • 2
  • César Bataglion
    • 2
  • Christie Ramos Andrade Leite-Panissi
    • 1
    • 3
    • 4
    Email author
  1. 1.Psychobiology Graduate Program, School of Philosophy, Science and Literature of Ribeirão PretoUniversity of São PauloRibeirão PretoBrazil
  2. 2.Departament of Restorative Dentistry of Dentistry School of Ribeirão PretoUniversity of São PauloRibeirão PretoBrazil
  3. 3.Departament of Morphology, Physiology and Basic Pathology of Dentistry School of Ribeirão PretoUniversity of São PauloRibeirão PretoBrazil
  4. 4.Faculdade de Odontologia de Ribeirão PretoUniversidade de São PauloRibeirão PretoBrazil

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