Treatment of Temporomandibular Joint Disorders With a Stabilizing Occlusal Splint in Somatosensory Tinnitus: a Randomized Double-blind Placebo-controlled Clinical Trial

The clinical variables of somatosensory tinnitus (ZS) will be assessed by a researcher blinded to the treatment type, using the Tinnitus Handicap Inventory (THI) and Visual Analogue Scale (VAS) at time points T1, T2, T3, T4, and T5, with 30 days interval. The THI, validated and adapted to Portuguese, is the most frequently used questionnaire in clinical trials for tinnitus patients, quantifying the subjective impact of tinnitus on quality of life across three main domains: functional, emotional, and catastrophic. THI classifies tinnitus into five grades: (a) I - negligible (0-16); (b) II - mild (18-36); (c) III - moderate (38-56); (d) IV - severe (58-76); (e) V - catastrophic (78-100). Audiometry and psychoacoustic measures of tinnitus (pitch, loudness, minimum masking level) will be performed at T1 and T5 by an audiologist blind to the treatment group.

The clinical variables of temporomandibular dysfunction (TMD) will also be assessed by a researcher blinded to the treatment type, using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and VAS at the same time points. The DC/TMD is a validated tool, adapted to Portuguese, used in clinical trials that provides a systematic assessment, including a standardized clinical examination and questionnaires. This classification system, based on the biopsychosocial model of pain, includes a physical assessment through Axis I, using reliable and well-operationalized diagnostic criteria, and an assessment of the psychosocial status and pain-related disability through Axis II.

Both assessments will be conducted at T1, T2, T3, T4, and T5.