Overview
EN ISO 24395:2023 - Dentistry - Classification of tooth restorations preparation (ISO 24395:2023) establishes a standardized system for describing the location and depth of human tooth preparation prior to placement of restorations. Published in 2023 and endorsed by CEN as a European Standard, this document provides consistent terminology to support product labeling, clinical decision-making and comparison of restorative materials.
Key topics and requirements
- Scope: Classifies preparations by anatomical location on the tooth and by the deepest tissue structure penetrated.
- Location classification (Classes 1–7):
- Class 1: single-surface occlusal, facial or lingual/palatal and posterior proximal without occlusal extension
- Class 2: posterior proximal with occlusal extension
- Class 3: anterior proximal without incisal involvement
- Class 4: anterior proximal including an incisal edge
- Class 5: gingival sites on facial or lingual/palatal surface
- Class 6: cusp tips
- Class 7: core (main central tooth structure)
- Depth classification (E, D, P codes):
- E1 / E2: outer/inner halves of enamel
- D1 / D2 / D3: outer, middle, inner thirds of dentine
- P1 / P2: pulp chamber; pulp chamber plus coronal root canal access
- Normative references: Builds on ISO 1942 (vocabulary) and ISO 3950 (tooth/designation system).
- Recommendations for use: The classification is recommended for manufacturer’s instructions for use, product catalogues and other documentation to specify intended application of restorative materials.
Applications and who should use this standard
- Dental manufacturers and product managers - to label intended uses of restorative materials consistently and to specify clinical indications in instructions for use.
- Clinicians and dental teams - to document preparation type and depth in patient records, treatment planning and communication across care settings.
- Researchers and clinical trial authors - to define inclusion criteria and to compare outcomes across studies using a standardized lesion/preparation taxonomy.
- Regulatory bodies and procurement specialists - to evaluate conformity of restorative products against specified intended uses.
- Dental educators - to teach a modern, internationally accepted system that complements or updates historical cavity classifications.
Related standards and value
- Related: ISO 1942 (Dentistry - Vocabulary) and ISO 3950 (Designation system for teeth).
- Value: Harmonized terminology improves interoperability, enables direct comparison of restorative materials, supports decision-support tools and enhances clarity in product documentation - promoting better clinical outcomes and streamlined regulatory/market communications.
Keywords: ISO 24395, dentistry standard, tooth restoration classification, tooth preparation depth, restorative materials, dental manufacturers, clinical documentation.
