Reader Question
Therapist Answer
Trismus, or difficulty with the controlled opening and closing of the jaw, is frequently seen after oral cancer resection and/or radiation treatments. Radiation can cause fibrosis: an abnormal thickening or scarring of tissue that progressively limits jaw opening if not actively addressed. To treat it, we use a combination of the Bite Block Hierarchy and the Bite Tube Hierarchy to increase mobility and maintain opening of the jaw.
The Jaw Grading Bite Blocks work on static jaw opening. The blocks are placed between the teeth and held for a period of time to stretch the restricted tissues and maintain the opened position, an isometric approach to preserving and building jaw range of motion.
The Bite Tube Hierarchy works on dynamic jaw mobility, the smooth, controlled opening and closing needed for speech co-articulation and safe chewing during feeding. This dynamic movement is most disrupted by fibrosis following radiation or surgery.
Together, these two tools address both the static stretch and the dynamic control needed for functional jaw use. High-compliance home practice is essential for best outcomes: assigned activities should be repeated multiple times daily to build mobility and prevent the progressive tightening that fibrosis can cause.
Sara Rosenfeld-Johnson, MS, CCC-SLP, Founder, TalkToolsStatic vs. Dynamic: Understanding the Dual Approach
Trismus treatment must address two distinct movement deficits. Static jaw opening capacity (how wide the jaw can open and hold) requires different tools and techniques than dynamic jaw mobility (the graded, smooth movement used in speech and chewing). The table below summarizes how each tool addresses each need.
| Tool | Movement Type | Clinical Target | Mechanism |
|---|---|---|---|
| Jaw Grading Bite Blocks | Static | Jaw range of motion, tissue stretch | Isometric hold between molars to stretch restricted fibrotic tissue |
| Bite Tube Hierarchy | Dynamic | Speech co-articulation, safe chewing | Controlled up-and-down jaw grading movement across 4-tube hierarchy |
A Protocol for Treating Trismus with TalkTools
This step-by-step progression addresses both the static and dynamic components of jaw mobility in trismus:
- Assess the degree of trismus, measuring the client's maximum inter-incisal mouth opening to establish a baseline.
- Jaw Grading Bite Blocks: introduce for static stretching, placing between the back molars and holding for a designated duration at the smallest comfortable size.
- Progress through the Bite Block sizes as opening increases, working toward functional jaw range of motion.
- Bite Tube Hierarchy: introduce for dynamic jaw movement, controlled up-and-down grading for speech and feeding movements.
- Assign home practice at a high frequency, multiple times daily, for best outcomes and to counteract fibrosis.
- Reassess jaw opening regularly and progress through tools, tracking gains against the baseline measurement.