Overview
EN ISO 5139:2023 (ISO 5139:2023) - Dentistry: Polymer-based composite machinable blanks - specifies characteristics and test methods for polymer-based composite machinable blanks used to fabricate permanent dental restorative appliances (for example single crowns and inlays) by milling (CAD/CAM) processes. It covers clinical issues specific to these materials, packaging and labelling requirements, and information to be included in instructions for use. Large-sized multi-unit discs and materials intended for temporary restorations are excluded.
Key topics and technical requirements
- Scope and definitions: Clarifies what constitutes a polymer-based composite machinable blank and related terms (Clauses 1–3).
- Dimensional tolerances: Sampling and measurement procedures for blank size (Clause 4.1 and 6.2). Blanks shall meet specified size tolerances relative to the declared dimensions (see Clause 8 d)).
- Machining-related tests:
- Machining damage: Methods to evaluate surface and subsurface damage caused by milling (Clause 6.3). Test specimen preparation, apparatus and result expression are defined.
- Machinability: Recommended evaluation using established methods (reference to merlon fracture test in ISO 18675:2022).
- Bonding to holding jig: Procedures and recommended test method for bonding between blank and jig; Annex C provides guidance.
- Sampling and test methods: Sampling rules (Clause 5) and detailed test procedures (Clause 6) covering size, machining damage and related properties.
- Packaging, labelling and instructions: Mandatory and recommended information for outer pack and individual blanks (Clause 7) and required content for instructions for use (Clause 8).
- Informative annexes: Annex A (flexural strength specimen prep), Annex B (milling design for test specimen), Annex C (bonding test method).
- Exclusions and cross-references: Material property requirements are deferred to future editions of ISO 10477; biological hazard assessment is referenced to ISO 10993‑1 and ISO 7405.
Practical applications
- Ensures consistent quality and safe clinical performance of CAD/CAM polymer composite blanks used for permanent restorations.
- Provides standardized test methods for manufacturers to validate milling behavior, packaging and instructions.
- Enables dental laboratories and clinics to evaluate and compare machinable block products for milling workflows.
Who should use this standard
- Dental materials manufacturers and R&D teams creating polymer-based machinable blanks.
- Quality assurance and regulatory personnel responsible for product compliance.
- Dental laboratories and CAD/CAM service providers selecting blanks for milling restorations.
- Standards bodies, testing laboratories and clinicians involved in material evaluation.
Related standards
Keywords: EN ISO 5139:2023, ISO 5139:2023, polymer-based composite machinable blanks, dental CAD/CAM, milling, machinability, machining damage, dental materials, packaging and labelling.