ISO 24395:2023

Overview

ISO 24395:2023, "Dentistry - Classification of tooth restorations preparation", establishes a standardized system for classifying the location and depth of human tooth restoration preparations. The standard provides a concise terminology and coding scheme to describe where a preparation is located on the tooth and how deep it extends into enamel, dentine or pulp. This classification supports consistent documentation, comparison of restorative materials and the development of decision‑support tools for clinical use.

Key topics and requirements

• Scope: Applies to preparations made prior to placement of restorations (including preparations for preventive treatments such as resin infiltration).
• 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 incisal edge
  • Class 5: gingival sites on facial or lingual/palatal surfaces
  • Class 6: cusp tips
  • Class 7: core (core build‑up)
• Depth classification (E/D/P categories): Seven depth levels based on the deepest penetration into tooth structures:
  • E1: outer half of enamel
  • E2: inner half of enamel
  • D1: outer third of dentine
  • D2: middle third of dentine
  • D3: inner third of dentine
  • P1: pulp chamber
  • P2: pulp chamber and coronal access sections of root canal(s)
• Normative references: Aligns terminology with ISO 1942 (Dentistry - Vocabulary) and ISO 3950 (Designation system for teeth and areas of the oral cavity).
• Recommendations: Encourages use of the classification in manufacturers’ instructions for use, product catalogues and other documentation to specify intended application of restorative materials.

Applications

• Standardizing product labeling and intended use for restorative materials (adhesives, composites, amalgams, liners, core materials).
• Supporting clinical decision support systems and electronic health records by offering unambiguous codes for preparation site and depth.
• Enabling consistent reporting in clinical studies, comparative testing and registries of dental restorations.
• Guiding dental education and communication between clinicians, laboratories and manufacturers.

Who should use this standard

• Dental product manufacturers (instructions for use, marketing, regulatory submissions)
• Clinicians and dental laboratories (treatment planning, documentation)
• Researchers conducting restorative materials or clinical outcome studies
• Regulatory bodies and professional organizations standardizing care pathways or device labeling
• Health IT vendors integrating dental terminology into EHRs

Related standards

• ISO 1942 - Dentistry: Vocabulary
• ISO 3950 - Dentistry: Designation system for teeth and areas of the oral cavity

Keywords: ISO 24395:2023, tooth restorations classification, dental restoration classification, depth of preparations, location of preparation, dentistry standard, restorative materials