This study evaluates the effects of exercise therapy combined with a jaw-mobilizing device on enhancing quality of life in head and neck cancer patients undergoing radiotherapy.

This study investigates the efficacy of exercise therapy combined with a jaw-mobilizing device (ET-JMD) in improving maximal mouth opening (MMO), preventing trismus, enhancing quality of life (QoL), and alleviating trismus-related symptoms in head and neck cancer (HNC) patients undergoing radiotherapy.

Inclusion Criteria:

• Age ≥ 20 years.
• Ability to communicate in Mandarin or Taiwanese, without significant reading, hearing, or writing impairments, and capable of completing questionnaires independently or with researcher assistance.
• Diagnosed with head and neck cancer and scheduled for initial radiotherapy to the head and neck region.
• Clear consciousness without severe cognitive or psychiatric disorders.
• Presence of intact central incisors (#11, #41) on the right side or (#21, #31) on the left side of both the upper and lower jaws.
• Baseline maximal mouth opening (MMO) ≥ 25 mm.
• Willingness to participate in the study with signed informed consent.

Exclusion Criteria:

• Known temporomandibular joint disorders.
• Postoperative wound healing complications diagnosed by a physician that prevent participation in mouth-opening rehabilitation exercises.

Participants are unaware of their group allocation (experimental or control) to minimize bias in self-reported outcomes and adherence to the intervention. However, investigators and outcome assessors are not masked due to the nature of the intervention.