Solid-Core vs. Hollow: What Schools Should Know Before Buying Chew Tools
The single most important construction question for classroom chew tools is one most catalogs never answer: is the chew surface solid, or is it a hollow shell? For moderate-to-heavy chewers, the difference is a safety and hygiene issue — not a preference.
How hollow chew tools fail in classrooms
Hollow-molded silicone and plastic chew items are cheaper to produce, which is why they dominate low-cost listings. Under the sustained, forceful chewing common among students with significant oral sensory needs, thin walls fail in a predictable sequence:
- Puncture. Repeated molar pressure eventually breaks through the wall — and a punctured wall can present sharp or ragged edges to the student who is still actively chewing it.
- Bacteria trapping. Once punctured, the hollow interior takes in saliva and cannot be fully cleaned or dried — a hygiene problem no classroom sanitation routine can fix from the outside.
- Quiet failure. Punctures are easy to miss on visual inspection, so compromised units often stay in circulation.
To be fair: hollow isn’t always wrong
Honest nuance matters here, because hollow construction is a deliberate, appropriate design choice in one context: teething and light-chewing tools. A hollow tube can be filled with water and frozen for cold therapy on sore gums — our own teething straws work exactly this way, and they’re age-graded and safety-tested for that use.
The problem is not hollow construction itself. The problem is hollow tools marketed to the heavy chewers who will defeat them. Match construction to chewing intensity: freezable hollow designs for teething and light input, high-density solid cores for moderate-to-heavy sensory chewing.
Evaluating chew tools for your caseload?
Put a solid-core sample in the hands of your most avid chewer — we ship free evaluation kits to OTs, clinics, and school districts.
What to look for instead
- High-density solid-core silicone in any tool intended for moderate-to-heavy chewers — no cavity to puncture, nothing to trap bacteria.
- 100% food-grade silicone, stated explicitly, free of lead, BPA, PVC, latex, and phthalates.
- Third-party lab verification to ASTM F963-23 and CPSIA — from an accredited independent laboratory, with report numbers you can check. Self-certified factory paperwork is not the same thing. Our reports are downloadable here.
- Dishwasher-safe for realistic classroom and clinic sanitation.
- An inspect-and-replace policy. Even solid-core tools are consumables under heavy use — a good vendor says so and replaces defects free.
Our free Institutional Sensory Safety Compliance Checklist turns this into a printable line-by-line vetting sheet you can apply to any vendor.
Try before your district commits
The fastest way to evaluate construction quality is to put a sample in the hands of your OTs and your most avid chewers. We ship free evaluation sample kits to school districts and clinics for exactly this reason — durability claims should be tested, not taken on faith.
Solid-core tools, verifiable paperwork
Lull Kids chew bricks are high-density solid-core silicone, co-developed with pediatric OTs, and third-party tested to ASTM F963-23 and CPSIA — with the reports public.