Can jaw exercises with wooden tongue depressors prevent restricted mouth opening after radiotherapy for head and neck cancer?

INTERVENTION: This single‐centre, parallel‐group randomised controlled trial recruited adults with head and neck cancer who were receiving radiotherapy at Hospital Canselor Tuanku Muhriz, Universiti Kebangsaan Malaysia. Participants were randomised in a 1:1 ratio using block randomisation generated by Random Allocation Software version 1.0 by a departmental statistician. The allocation sequence was concealed in sequentially numbered, opaque, sealed envelopes. The enrolling investigator opened the relevant envelope after completion of the baseline assessment. Stratified randomisation was not used. Active control group: Participants were taught basic jaw‐opening, closing, and side‐to‐side exercises. They performed the exercises twice daily for 30 seconds for 20 weeks. Intervention group: Participants completed a structured 20‐week programme using wooden tongue depressors. The 5‐5‐30 protocol consisted of five sessions each day, with five cycles per session and a 30‐second stretch in each cycle. Each session began with 10 repetitions of jaw opening and small lateral movements, followed by chin movements to the left, right, and forward held for 3 seconds each and maximal mouth opening held for 10 seconds. For passive stretching, participants inserted a tolerable stack of wooden tongue depressors, added one further depressor, and held the stretch for 30 seconds. The number of depressors was progressively increased as tolerated. Mouth opening was measured at baseline before radiotherapy and at 10 and 20 weeks after radiotherapy. Mandibular function was assessed at the same three timepoints, and health‐related quality of life was assessed at 20 weeks after radiotherapy. Standard oncological treatment, including radiotherapy, chemotherapy, and surgery where applicable, was determined by the treating team and was not allocated by the study. CONDITION: Adults with head and neck cancer receiving radiotherapy ; Cancer PRIMARY OUTCOME: Mouth opening measured using maximal interincisal distance (dentulous participants) or maximal mouth opening between the maxillary and mandibular alveolar ridges (edentulous participants), measured in millimetres using a calibrated WIHA digital calliper at baseline before radiotherapy, 10 weeks after radiotherapy, and 20 weeks after radiotherapy SECONDARY OUTCOME: Mandibular function measured using the 17‐item Mandibular Function Impairment Questionnaire (MFIQ) at baseline before radiotherapy, 10 weeks after radiotherapy, and 20 weeks after radiotherapy INCLUSION CRITERIA: 1. Aged over 18 years 2. Coherent: demonstrates the capacity to perform mouth opening exercises independently and effectively 3. Able to communicate in English, Bahasa Malaysia, or Mandarin 4. Patients diagnosed with head and neck cancer with documented tumour staging and histopathological examination 5. Having any head and neck cancer, excluding larynx 6. Underwent radiotherapy treatment either exclusively or combined with chemotherapy and/or surgical treatment