ISO 23298:2023 PDF

Overview - What ISO 23298:2023 covers

ISO 23298:2023 specifies standardized test methods to evaluate the machining accuracy of computer‑aided milling machines used in dental CAD/CAM systems that fabricate indirect restorations (inlays, crowns and bridges). The standard defines two normative test methods - the metal die method and the software method - and sets out requirements for test specimens, measuring apparatus, data preparation, machining, evaluation and test reporting. It replaces ISO/TR 18845:2017 and is intended for use by manufacturers, laboratories and others involved in device validation and quality assurance.

Key technical topics and requirements

• Test methods (Clause 5): Two complementary approaches
  • Metal die method (5.1) - evaluates marginal adaptability of machined restorations against precision metal dies (class II inlay, crown, four‑unit bridge).
  • Software method (5.2) - compares a scanned file of a milled restoration to a master manufacturing file using reverse‑engineering software to assess margin, intaglio and external surface accuracy.
• Target restorations: class II inlay, crown, four‑unit bridge (manufacturer‑specified selections permitted).
• Metal die specifications: removable occlusal/shoulder parts, tight dimensional tolerances (removable occlusal diameter difference ≤ 10 μm), and surface roughness S_a