Occlusal Equilibration vs. Sham Therapies for TMDs: Post-Trial Follow-up (OEST)

Official title

OEST Protocol: Physiologically Oriented Occlusal Equilibration Versus Sham Therapy for Chronic Temporomandibular Disorders (TMDs): 10 Years Post-trial Follow-up

Overview

Chronic temporomandibular disorders (TMDs) affect the masticatory muscles, the temporomandibular joints (TMJs), and associated structures. Except in cases of trauma, their etiology remains uncertain, debated, and multifactorial. Conservative therapies-including no active intervention-often alleviate symptoms; however, approximately 3% of the population develops persistent forms associated with substantial individual suffering and significant social and economic burden. At the Unit of Occlusion and Prosthodontics of the University of Santiago de Compostela (USC), Physiologically Oriented Occlusal Equilibration (POOE) has been used for chronic painful TMDs since 1985. POOE aims to correct unilateral mastication patterns and to establish appropriate non-working side contacts in order to protect the temporomandibular joints from mechanical overload. Singh (Cochrane, 2024) emphasized that occlusal interventions should be evaluated with long-term follow-up of at least 3-5 years. This is a single-blind study: the evaluator remains blinded to treatment allocation during outcome assessment. The aim of this observational study is to assess the long-term effectiveness of POOE treatments for chronic TMDs from 1985 to the present. Treatment effectiveness will be confirmed if the reduction in pain achieved with POOE is statistically significant and clinically meaningful (≥1.5/10 on a 0-10 visual analog scale) compared with sham therapy at ≥3 years post-intervention relative to baseline. Additionally, effectiveness will be supported if the proportion of individuals meeting criteria for chronic TMD ("affected") is lower in the POOE-treated group than in those receiving alternative therapies.

Detailed description

Chronic TMDs constitute a complex syndrome that is currently understood as comprising more than 30 distinct nosological entities. The underlying cause of their pathophysiology has not been fully elucidated. Consequently, treatments are typically empirical and applied simultaneously, including pharmacotherapy, counseling, physiotherapy, occlusal splints (perhaps the most widely used), physical modalities, and other minimally invasive procedures such as arthrocentesis or arthroscopy, extending even to total TMJ replacement. None of these interventions has demonstrated superior efficacy compared with placebo or no treatment. Globally, these patients often consult multiple specialists and undergo numerous treatment modalities, with an unpredictable prognosis.

Physiologically oriented occlusal equilibration (POOE) was shown to be more effective than placebo at 6 months post-treatment. The 2024 Cochrane review indicated that assessing the efficacy of occlusal therapies requires evaluation at least 3 to 5 years after treatment. The treatments performed at USC since 1985 for chronic TMDs represent a valuable source of long-term clinical experience that may clarify whether POOE remains effective many years after treatment (from 1985 to the present), rather than only at 6 months.

Scientific Objectives To evaluate the effect of occlusal adjustment on pain intensity in patients with chronic TMDs during long-term follow-up over several years.

To disseminate the findings-whether positive, negative, or inconclusive-in peer-reviewed scientific journals.

Methods This is an observational study, as no intervention will be applied to participants. It will be open-label or single-blind (outcome assessors will be blinded to the treatment previously received, but participants will not be). The study is cross-sectional, as it will be conducted at a single time point and in a single visit. The study will consist of diagnosing any current TMDs potentially affecting individuals who were previously treated at USC for chronic TMDs. All participating individuals are familiar with the diagnostic procedures, which include extra- and intraoral examination, dynamic recording of mandibular and condylar movements, and the tests recommended in the DC/TMD criteria.

If the participant provides authorization, clinically relevant information from their medical record regarding TMD history will be used to determine the degree of improvement or deterioration relative to the pretreatment baseline.

Primary outcome measures

• Group differences in change in pain intensity at 10 years follow-up in respect pretreatment scores. [Time frame: Pretreatment, and 10 years follow-up]
• Group differences in the change in maximum unassisted mouth opening [Time frame: pretreatment, 10 years follow-up]
• Odds of "success" in pain reduction of POOE compared with sham therapy [Time frame: Pretreatmen, 10 years follow-up]

Secondary outcome measures (2)

• Psychological distress (GSI from SCL-90-R test) [Time frame: Pretreatment, 10 years follow-up]
• Change in condylar path angles [Time frame: Pretreatment, 10 years follow-up]

Eligibility criteria

Inclusion criteria

• Previous occlusal equilibration for TMD pain at the University of Santiago.
• Be diagnosed with joint and/or muscle TMD pain according to DC/TMD.
• Be aged 18-85 years.
• Be completely dentate with normal or adequately restored occlusion (fixed crowns/bridges allowed).
• Report pretreatment significant TMD pain (VAS/NRS 4-9 on a 0-10 scale).
• Have actively sought treatment and been referred to the University/Hospital service.
• Have undergone ≥6 months of prior conservative therapy.

Exclusion criteria

• Psychosis, major depression, substance abuse, or cognitive impairment.
• Opioid (morphine-derivative) addiction.
• Ongoing litigation or disability claims related to chronic pain.
• Dental professional background.
• Orthodontic treatment within the last 2 years.
• Severe tooth mobility (grade 3).
• Other pain conditions indistinguishable from or more severe than TMD pain.
• Additionally, patients will be excluded if minimally invasive occlusal adjustment cannot achieve equilibration, defined by: 2 mm discrepancy between maximal intercuspation and centric occlusion, and/or 4 mm total interarch discrepancy (≥2 mm on one side) in defined premolar/molars reference points, measured intraorally using a Boley gauge.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Observational model

Cohort

Study locations

Spain · 2 centers

• Universidad de Santiago de Compostela — Santiago de Compostela
• Urbano Santana Penín — Santiago de Compostela

Publications

• Santana-Mora U, Lopez-Cedrun J, Mora MJ, Otero XL, Santana-Penin U. Temporomandibular disorders: the habitual chewing side syndrome. PLoS One. 2013 Apr 8;8(4):e59980. doi: 10.1371/journal.pone.0059980. Print 2013. PMID 23593156
• Santana-Mora U, Lopez-Cedrun J, Suarez-Quintanilla J, Varela-Centelles P, Mora MJ, Da Silva JL, Figueiredo-Costa F, Santana-Penin U. Asymmetry of dental or joint anatomy or impaired chewing function contribute to chronic temporomandibular joint disorders. Ann Anat. 2021 Nov;238:151793. doi: 10.1016/j.aanat.2021.151793. Epub 2021 Jun 26. PMID 34186201
• Santana-Penin U, Santana-Mora U, Lopez-Solache A, Mora MJ, Collier T, Pocock SJ, Lorenzo-Franco F, Varela-Centelles P, Lopez-Cedrun JL. Remodeling dental anatomy vs sham therapy for chronic temporomandibular disorders. A placebo-controlled randomized clinical trial. Ann Anat. 2023 Oct;250:152117. doi: 10.1016/j.aanat.2023.152117. Epub 2023 Jun 9. PMID 37302432

Identifiers

NCT: NCT07445516 · USC 124/2025 · USC 124/2025

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗