Remodeling dental anatomy vs sham therapy for chronic temporomandibular disorders: A placebo-controlled randomized clinical trial

Background
Evidence regarding the etiology or effective treatments for chronic orofacial pain, the majority diagnosed as temporomandibular disorder (TMD), is limited.

Purpose
To investigate whether occlusal equilibration therapy (ET) and decreasing the (higher) angle of the lateral guidance on the nonworking-side leads to a reduction in chronic TMDs intensity.

Methods
It was conducted a randomized, explanatory, single blind with blinded assessment, placebo-controlled trial with strong protection against bias involving patients with chronic TMDs. Participants were randomly assigned to receive equilibration therapy or sham therapy. ET in this study consisted of minimal invasive occlusal remodeling to obtain balanced occlusion with reduction of the steeper angle of lateral mandibular movement with respect to the Frankfort plane. The primary outcome was a change in the pain intensity score (on a 0–10 point scale, with 0 indicating no pain and 10 the worst possible pain) at month 6. Secondary outcomes include maximum unassisted mouth opening and psychological distress.

Results
A total of 77 participants underwent randomization, 39 of whom received ET and 38 sham therapy. The trial was stopped early for efficacy, according to preestablished rules when 67 participants (n = 34, n = 33, respectively) had completed the analysis. At month 6, the mean unadjusted pain intensity score was 2.1 in the ET and 3.6 in the sham therapy group (adjusted mean difference, −1.54; 95% confidence interval [CI] −0.5 to −2.6; P = 0.004; ANCOVA model). The mean increase in maximum unassisted mouth opening (main secondary outcome) was significantly higher in the real therapy group (adjusted mean difference 3.1 mm, 95% CI 0.5–5.7, p = 0.02).

Conclusion
ET significantly reduced the intensity of facial pain associated with chronic TMDs and increased maximum unassisted mouth opening, as compared with sham therapy, over the course of 6 months. There were no serious adverse events.
Methods
Pain-intensity of the affected side will be measured by self-administered questionnaire using a validated visual analogue scale (VAS; 0–10 (0 = no pain, 10 = worst possible pain) (Huskisson, 1974). Time frame: baseline, 3-month and 6-month follow-up. The primary outcome was reduction in the mean intensity of jaw pain from baseline at the 6-month assessment; clinical important differences 1.5 points.

Maximum unassisted jaw opening, using a Boley gauge (including overbite) units mm. Defined as limited if ≤38 mm (females) or ≤40 mm (males)

Chewing function (alternate vs. one habitual chewing side): Clinically observed habitual chewing side: if at least 7/10 almonds are chewed on the same side (Paphangkorakit  et al., 2006); (or) the side where the chewing-gum are placed first cicle and at 15, 20, 25, 30, 35, 40 ane 45 s (if at least 6 of the 8 is placed on the same side). Interview: actual and retrospective chewing function (Diernberger et al., 2008): Do (and did) you prefer one side for chewing?; answers: No—yes, the left side—yes, the right side—I do not know.

Improvement in the psychological distress using the Symptoms Check List -90- Revised, and the risk of changing the habitual chewing side. Data collection periods: baseline, 3 months and 6 months (primary time for all variables) after therapy.

Parasagittal plane condylar path tracings were recorded using a kinematic Gerber’s face-bow (Kit Registier Ausrustung ‘C;’ Condylator service, Zurich, Switzerland).

Frontal plane lateral guidance recordings were conducted using a jaw-tracking device (K7 electrodiagnostic system; Myotronics Inc., Kent, WA, US).