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

ISRCTN	ISRCTN96737564
DOI	https://doi.org/10.1186/ISRCTN96737564
Sponsor	National University of Malaysia
Funder	Investigator initiated and funded

Submission date: 25/08/2026
Registration date: 26/08/2026
Last edited: 10/09/2026

Recruitment status: No longer recruiting
Overall study status: Ongoing
Condition category: Cancer

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Record updated in last year

Plain English summary of protocol

Not provided at time of registration

Contact information

Prof Syed Nabil Syed Omar
Principal investigator

Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz
Kuala Lumpur
50300
Malaysia

Phone	+60 (0)3-92897742
Email	syednabil@ukm.edu.my

Dr Tharmentheran Pitchaimuthu
Public, Scientific

No 18 Jalan Palma 1E, Bukit Palma Kemensah
Hulu Klang
53100
Malaysia

Phone	+60 (0)123006273
Email	P138663@siswa.ukm.edu.my

Study information

Primary study design	Interventional
Allocation	Randomized controlled trial
Masking	Blinded (masking used)
Control	Active
Assignment	Parallel
Purpose	Device feasibility, Prevention
Participant information sheet	50151_PIS.pdf
Scientific title	A randomized controlled trial of structured jaw exercises using wooden tongue depressors versus basic jaw exercises for preventing radiotherapy-induced trismus and preserving mouth opening and mandibular function in adults with head and neck cancer
Study objectives	1. To determine maximum mouth opening (MMO) and maximum interincisal distance (MID) measurements before, during, and after radiotherapy 2. To determine the effectiveness of the wooden tongue depressor exercise program in reducing radiotherapy-induced trismus (RIT) severity by comparing between intervention and control groups 3. To assess the relationship between RIT severity and quality of life using validated questionnaires 4. To explore how demographic and clinical variables affect the intervention’s success
Ethics approval(s)	Approved 14/11/2023, National University of Malaysia Research Ethics Committee (Hospital Canselor Tuanku Muhriz, Jalan Yaacob Latif Kuala lumpur, Bandar Tun Razak, Cheras, 56000, Malaysia; +60 (0)3-91455046/5048; sepukm@ukm.edu.my), ref: UKM PPI/111/8/JEP-2023-524
Health condition(s) or problem(s) studied	Adults with head and neck cancer receiving radiotherapy
Intervention	Current interventions as of 10/09/2026: 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 initiation of radiotherapy. Mandibular function was assessed at the same three timepoints, and health-related quality of life was assessed at 20 weeks after initiation of radiotherapy. Standard oncological treatment, including radiotherapy, chemotherapy, and surgery where applicable, was determined by the treating team and was not allocated by the study. _____ Previous interventions: 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.
Intervention type	Device
Phase	Not Applicable
Drug / device / biological / vaccine name(s)	Wooden tongue depressors (non-commercial exercise aid)
Primary outcome measure(s)	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 initiation of radiotherapy, and 20 weeks after initiation of radiotherapy Previous primary outcome(s): 1. 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
Key secondary outcome measure(s)	Mandibular function measured using the 17-item Mandibular Function Impairment Questionnaire (MFIQ) at baseline before radiotherapy, 10 weeks after initiation of radiotherapy, and 20 weeks after initiation of radiotherapy Previous key secondary outcome(s): 1. 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
Completion date	13/11/2026

Eligibility

Participant type(s)
Age group	Mixed
Lower age limit	18 Years
Upper age limit	80 Years
Sex	All
Target sample size at registration	36
Total final enrolment	38
Key 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
Key exclusion criteria	1. Poor general health with need of assistance or care 2. Patient is unable to perform mouth exercises independently 3. Patient refused/declined or passed away between follow-up reviews 4. Patient whose radiotherapy treatment was interrupted or placed on hold
Date of first enrolment	05/12/2023
Date of final enrolment	10/01/2026

Locations

Countries of recruitment

Malaysia

Study participating centre

Tuanku Muhriz Chancellor Hospital

Jalan Yaacob Latif Kuala lumpur, Bandar Tun Razak
Cheras
56000
Malaysia

Results and Publications

Individual participant data (IPD) Intention to share	No

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Other files			26/08/2026	No	No
Participant information sheet			26/08/2026	No	Yes

Additional files

50151_PIS.pdf: Participant information sheet
50151_ConsentForm.pdf: Other files

Editorial Notes

10/09/2026: The following changes were made to the study record:
1. The interventions were changed.
2. The primary outcome(s) were changed.
3. The key secondary outcome(s) were changed.
4. The date of final enrolment was changed from 25/09/2025 to 10/01/2026.
26/08/2026: Study's existence confirmed by the National University of Malaysia Research Ethics Committee.