Overview
ISO 1797:2017 - "Dentistry - Shanks for rotary and oscillating instruments" specifies dimensional and material requirements, marking and measurement methods for shanks that fit into dental handpieces. It covers metal, tungsten‑carbide, ceramic and plastic shanks for rotary and oscillating instruments, describes verification tests (diameter, cylindricity, surface roughness, hardness, tensile strength, heat‑ and chemical‑resistance) and includes an informative Annex A on quality control. The standard is not applicable to tips fixed to the handpiece with a screw (e.g., scaler tips).
Key topics and technical requirements
- Classification: Four shank types with defined diameters and forms - Type 1 (RA/CA, 2.35 mm), Type 2 (HP, 2.35 mm), Type 3 (FG, 1.6 mm), Type 4 (HP, 3 mm). Fitting‑lengths are specified (see Table 1).
- Dimensions & tolerances: Detailed geometry, groove and flat‑area limits (including permitted flattening for plastic shanks), and fitting lengths for miniature/standard/extra‑long designs.
- Surface roughness (Ra):
- Metal/tungsten‑carbide/ceramic: Type 1, 2, 4 ≤ 1 µm; Type 3 ≤ 0.5 µm.
- Polymeric shanks: Ra ≤ 6 µm.
- Material properties:
- Metal/tungsten‑carbide shanks: hardness ≥ 250 HV5.
- Ceramic shanks: hardness ≥ 1 400 HV0,5.
- Plastic shanks: tensile strength ≥ 130 MPa; heat resistance, colour stability and swelling/chemical stability tests apply for reusable plastics (not for single‑use instruments).
- Marking & colour: Marking is recommended outside the fitting length; if inside it must not increase effective diameter. Plastic shanks should follow instrument colour‑coding.
- Measurement & test methods: Test clauses cover shank diameter, other dimensions, cylindricity (per ISO 1101), surface roughness (profile methods), Vickers hardness, tensile tests (ISO 527‑2 cited), and heat/swelling procedures.
Applications and users
ISO 1797:2017 is intended for:
- Dental instrument manufacturers designing shanks and working heads to ensure interchangeability with handpieces.
- Handpiece and motor manufacturers verifying compatible shank geometry.
- Dental laboratories and CAD/CAM vendors producing instrument components.
- Quality assurance and regulatory teams performing acceptance testing, supplier audits and conformity checks.
- Procurement specialists specifying shank standards in purchase documents.
Practical benefits include improved interchangeability, reduced risk of instrument slippage, reliable sterilization/reprocessing performance for reusable plastics, and a clear basis for product testing and supplier quality control.
Related standards
Normative references cited in ISO 1797:2017 include ISO 1101 (geometrical tolerancing), ISO 6507‑1 (Vickers hardness), ISO 527‑2 (tensile testing for plastics), ISO 3274 / ISO 4288 (surface texture methods), ISO 14457 (handpieces and motors) and ISO 8325 (test methods for rotary instruments). These are commonly used together when implementing ISO 1797:2017.
