ISO 21606:2022

Overview

ISO 21606:2022 - "Dentistry - Elastomeric auxiliaries for use in orthodontics" specifies requirements and test methods for elastomeric auxiliaries used with fixed and removable orthodontic appliances, both intra‑oral and extra‑oral. Covered products include orthodontic elastics, elastomeric chains, elastomeric thread, ligatures and separators. The standard enables consistent, comparable data on dimensions and mechanical performance so clinicians and manufacturers can make meaningful comparisons.

Key topics and requirements

• Scope and definitions - Clear terminology for elastomeric auxiliaries (elastic, thread, chain, ligature, separator) and test lengths.
• Sampling - All tests are type tests on 10 specimens randomly selected from the same batch; a broken specimen is considered a failure.
• Ambient conditions - Force determinations at controlled laboratory conditions (e.g., ~23 °C and 50 % RH as specified).
• Dimensions - Measurement of inner/outer diameters, link length and cross‑section thickness using accurate measuring devices.
• Mechanical properties and test methods:
  • Initial extension force (F0) - Determined after specific extension and relaxation cycles using a tensile testing machine; results must be within the manufacturer’s stated range.
  • 24 h residual force (F24) - Measured after storing specimens in an extended condition (support plate with pins) and reported as a percentage of initial force.
  • Ultimate extension (A) - Extension at break expressed as a percentage of test length; separators must meet or exceed manufacturer values.
• Apparatus and procedures - Tensile testers with specified crosshead rates, test rods/half‑rods, support plates with pins (1 mm), and procedural timing (e.g., hold and measurement intervals) are defined.
• Marking, labelling and packaging - Products must be labelled and packaged to allow identification and enable verification against manufacturer‑stated ranges.

Applications and users

ISO 21606:2022 is intended for:

• Manufacturers and suppliers of orthodontic elastomeric products - to design, test and declare dimensional and mechanical performance.
• Test laboratories and quality departments - to perform type testing, verify compliance and generate comparable specifications.
• Regulatory bodies and procurement teams - to assess product claims and conformity for clinical use.
• Orthodontists and dental clinicians - to better understand product performance (force decay, extension) when choosing elastomeric auxiliaries.

Practical benefits include standardized force data (initial and residual), reproducible test methods for product comparison, and clearer labelling for clinical decision‑making.

Related standards

• ISO 10993‑1 and ISO 7405 - for biological hazard assessment recommendations (not covered by ISO 21606).
• Other referenced documents in ISO 21606: ISO 3696, ISO 1942, ISO 8601‑1.

Keywords: ISO 21606:2022, elastomeric auxiliaries, orthodontics, orthodontic elastics, elastomeric chains, ligatures, test methods, initial extension force, 24 h residual force, ultimate extension.