Overview
EN ISO 4823:2025 (ISO 4823:2025, corrected version 2025-08) is the CEN-adopted international standard that specifies requirements and test methods for elastomeric impression and bite registration materials used in dentistry. The document replaces EN ISO 4823:2021 and was prepared by ISO/TC 106 in collaboration with CEN/TC 55. It defines how manufacturers, testing laboratories and regulators should evaluate performance characteristics that affect clinical accuracy and handling.
Key topics and technical requirements
The standard covers classification, pre-test planning and a comprehensive suite of requirements and test methods, including:
- Component colours (where applicable) and labelling checks
- Mixing and working times for hand- and machine-mixed materials
- Consistency and handling characteristics during impression taking
- Detail reproduction - ability to capture fine dental anatomy
- Linear dimensional change and dimensional stability after setting
- Compatibility with gypsum (important for casts and models)
- Elastic recovery and strain in compression - elastic properties that affect fit and accuracy
- Bite registration criteria: minimum intraoral time, compression set and hardness
- Pre-test procedures: sampling, laboratory conditions, specimen preparation, timing and pass/fail determination
- Standardized test methods for each requirement (mixing time, consistency, working time, detail reproduction, dimensional change, gypsum compatibility, elastic recovery, etc.)
Note: the standard provides test apparatus descriptions, specimen preparation steps and expressions of results - users should consult the full text for procedural detail and acceptance criteria.
Practical applications and users
EN ISO 4823:2025 is essential for:
- Manufacturers developing and validating elastomeric impression and bite registration materials to demonstrate conformity and support product claims.
- Dental materials testing laboratories performing standardized performance and quality tests.
- Regulatory bodies and notified bodies assessing conformity for market access across CEN member countries.
- Dental laboratories and clinicians who need to understand material properties (dimensional stability, tear resistance, detail reproduction) when selecting materials for crowns, bridges, prosthetics and bite records.
- Procurement and quality assurance teams in dental supply and healthcare organizations.
Related standards and notes
- Supersedes EN ISO 4823:2021; identical adoption by CEN as EN ISO 4823:2025.
- Prepared by ISO/TC 106 (Dentistry) with input from CEN/TC 55.
- Users should be aware of possible patent considerations and follow national implementation timelines (national adoption expected by December 2025 for CEN members).
Keywords: EN ISO 4823, ISO 4823:2025, elastomeric impression materials, bite registration materials, dental materials standard, dimensional stability, detail reproduction, elastic recovery, compatibility with gypsum.