Treatment responses in chronic temporomandibular patients depending on the treatment modalities and frequency of parafunctional behaviour.

Objectives: (i) To evaluate the effect of three different interventions on treatment outcomes and (ii) to determine how the frequency of oral parafunction influences the effectiveness of the different therapeutic modalities.

Methods: Forty-five participants were randomly assigned into three treatment groups [physical therapy (PT), stabilisation splint (SS) and control therapy (CT)]. According to Oral Behavior Checklist score, participants were divided into "high-frequency parafunction" (HFP) and low-frequency parafunction" (LFP) group. Primary (spontaneous pain and characteristic pain intensity) and secondary outcomes (range of mouth opening, anxiety symptoms, quality of life, perceived stress and global functional limitation) were evaluated during six-month treatment period.

Results: Participants in PT group showed a significant reduction in characteristic pain intensity (p = .047, η  = 0.243) when compared to SS and CT group, but significant improvement in spontaneous pain was found in all treatment groups. Patients treated with PT and SS exhibited significantly stronger improvement in pain-free mouth opening than patients in CT group (3rd month: p=.037, η2=0.258; 6th month: p = .005, η  = 0.383). Within-group analyses showed significant decrease of perceived stress, anxiety symptoms and global functional limitation only in PT group over a six-month treatment period. Participants with HFP presented significantly greater levels of anxiety (3rd month: p = .009, η  = 0.275; 6th month: p = .041, η  = 0.176) than participants with LFP. Within-group analyses, however, showed significant improvement of anxiety, but also the decrease of perceived stress and improvement of global limitation for the HFP group but not for the LFP group.

Conclusion: Although no treatment can be marked as superior in terms of spontaneous pain relief, PT was more effective when observing relief of characteristic pain intensity. In HFP group the reduction of anxiety, stress and functional limitation was present regardless of the applied therapy.

Trial Registration: ClinicalTrials.gov NCT04694274. Registered on 01/04/2021.