Overview
EN ISO 22254:2005 (ISO 22254:2005) specifies a standardized test method for determining the resistance of the tufted portion of manual toothbrushes to deflection. It applies to toothbrushes with a conventional, flat-trim design and provides reproducible laboratory procedures to measure tuft resistance (and-optionally-derive tufted-area-based stiffness). The standard clarifies that measured resistance may not match consumer perceptions of bristle stiffness.
Key topics and technical requirements
- Scope: Test method for the tufted portion of manual toothbrushes with conventional flat trim; may not apply to other head designs.
- Sampling: Test five as‑manufactured brush heads (handle removed).
- Conditioning: Cut off head at the neck, weigh to 0.5 g, immerse in water (grade 3 per ISO 3696) at (37 ± 2) °C for 90 s, shake off excess water and mount.
- Test machine:
- Brushing table with five rods (3.2 ± 0.1 mm diameter) spaced with centres at (8.2 ± 0.1) mm.
- Gripping block holding brush head with a preload of (5 ± 0.05) N.
- Load cell 0–20 N accurate to 0.05 N.
- Driving unit to slide the table at 10–50 mm/s for at least the length of the brush head.
- Procedure: Start sliding within (3 ± 0.25) min after immersion; perform five cycles, record the maximum force from the load cell in each direction, take the mean of the two directions as the resistance to deflection for each brush; report mean and standard deviation for five brushes.
- Optional stiffness calculation (Annex A): After testing, remove tufts, measure tufted area A (planimeter on photograph/tracing), then compute stiffness S = F / A (N/cm²), where F is resistance to deflection.
Applications and users
EN ISO 22254 is practical for:
- Toothbrush manufacturers - product development, design comparison, and quality control.
- Independent testing laboratories - repeatable lab verification of tuft resistance.
- Regulatory and procurement bodies - specification and compliance checks for oral care equipment.
- R&D and material scientists - comparing filament arrangements, tuft density and head designs.
Practical uses include product specification, batch verification, comparative testing between designs, and supporting marketing claims when combined with consumer perception studies.
Related standards
- ISO 1942 (Dentistry - Vocabulary) - terms and definitions used.
- ISO 3696 (Water for analytical laboratory use) - water quality for conditioning.
- EN 28627:1990 - earlier European standard superseded by EN ISO 22254:2005.
Keywords: ISO 22254, EN ISO 22254:2005, manual toothbrush testing, resistance to deflection, tufted area, toothbrush stiffness, brushing table, load cell, toothbrush standards.