Controlled-release essential oil hydrogels (geranium, lavender and combination) for pain management in temporomandibular joint dysfunction: a randomized, double-blind, placebo-controlled clinical trial
Temporomandibular joint dysfunction (TMJD) associated with chronic orofacial pain
Current interventions as of 06/03/2026: Participants were randomly assigned to four groups: a hydrogel containing geranium essential oil (H-GEO), a hydrogel containing lavender essential oil (H-LEO), a combined geranium-lavender hydrogel (H-GEO/LEO), and a placebo hydrogel without active ingredients. The formulations were applied topically once daily to the TMJ region for 3 months. Participants will be randomised in a 1:1:1:1 ratio to four arms (H-GEO/LEO, H-GEO, H-LEO, placebo). The allocation sequence will be computer-generated by an independent statistician using permuted blocks of variable sizes (e.g., 4 and 8), stratified by sex (male/female) and baseline TMJ pain intensity (VAS <5 vs ≥5). Allocation concealment will be ensured via sequentially numbered, opaque, sealed envelopes (SNOSE) prepared off-site by the statistician/pharmacist. After eligibility confirmation and written consent, the investigator enrols the participant; the pharmacist assigns the next code and dispenses identically packaged interventions. The trial will be double-blind (participants, investigators, outcome assessors). The randomisation list will be stored securely and only accessible to the independent pharmacist/statistician. Emergency unblinding will follow a predefined SOP and will occur only when knowledge of the assignment is essential for participant safety. Analyses will follow the intention-to-treat principle. All participants received standardized background analgesic care consisting of a diclofenac sodium transdermal patch administered uniformly across all study groups. This was implemented for ethical pain management and was not a variable under investigation. Previous interventions: Participants were randomly assigned to four groups: a hydrogel containing geranium essential oil (H-GEO), a hydrogel containing lavender essential oil (H-LEO), a combined geranium-lavender hydrogel (H-GEO/LEO), and a placebo hydrogel without active ingredients. The formulations were applie
Current key inclusion criteria as of 06/03/2026: 1. Diagnosed temporomandibular joint dysfunction (TMJD) according to Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) criteria 2. Aged between 18 and 65 years 3. Chronic TMJ-related pain lasting more than 3 months 4. Baseline pain intensity ≥3 on the Visual Analog Scale (VAS). 5. Ability to comply with treatment and follow-up visits 6. Signed informed consent Previous key inclusion criteria: 1. Diagnosed temporomandibular joint dysfunction (TMJD) according to Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) criteria 2. Aged between 18 and 65 years 3. Chronic TMJ-related pain lasting more than 3 months 4. Baseline visual analogue scale (VAS) pain score ≥4/10 5. Ability to comply with treatment and follow-up visits 6. Signed informed consent
1. Previous TMJ surgery 2. Acute infection or trauma of the TMJ area 3. Systemic rheumatologic or autoimmune disorders in active phase 4. Pregnancy or breastfeeding 5. Known allergy to essential oils or hydrogel components 6. Concurrent use of systemic corticosteroids or NSAIDs during trial period 7. Psychiatric or neurological conditions impairing protocol adherence