Overview
ISO 22570:2020 - "Dentistry - Spoons and bone curettes" specifies design, test and marking requirements for hand‑guided spoons and bone curettes used in oral surgical procedures. The standard defines shapes (Hemingway spoon, Lucas curette), dimensional limits (maximum overall length 173 mm; minimum 17 mm from spoon tip to first bend), material guidance, surface finish, hardness, reprocessing resistance and labelling/marking expectations for safe, reprocessable dental surgical instruments.
Key topics and technical requirements
- Classification: Four size types by working‑end width - Type 1 (S), Type 2 (M), Type 3 (L), Type 4 (XL).
- Dimensions:
- Sharp spoon (Hemingway) working‑end dimensions (mm):
- S: breadth 2.0, length 3.5, height 1.5
- M: 2.5, 4.5, 2.0
- L: 3.0, 5.0, 2.2
- XL: 3.5, 5.5, 2.4
- Bone curette (Lucas) breadth (b1) (mm): S 2.0, M 2.5, L 3.0, XL 3.5
- Maximum overall length: 173 mm; minimum tip‑to‑first‑bend for Hemingway spoon: 17 mm.
- Tolerances per ISO 2768‑1 and geometric tolerances per ISO 1101.
- Shapes:
- Hemingway: sharp, double‑ended oval spoons with 180° lateral inverse orientation.
- Lucas: sharp, double‑ended pear‑shaped curettes with 180° lateral inverse orientation.
- Materials: Manufacturer’s choice; if stainless steel is used it should comply with ISO 7153‑1 or ISO 21850‑1.
- Working‑end hardness: 42–58 HRC (Rockwell C) test per ISO 6508‑1; Vickers (ISO 6507‑1) may be converted to HRC.
- Surface finish: Working ends and shafts polished, free of defects/residues; handle surface should facilitate reprocessing.
- Resistance to reprocessing: Instruments must withstand 100 reprocessing cycles (cleaning, disinfection, sterilization per ISO 17664) without corrosion, distortion or hardness loss unless manufacturer specifies a lower limit.
- Measurement & inspection: Visual inspection without magnification; dimensional measurement using vernier calipers/micrometres accurate to 1/10 of tolerance (see ISO 3611).
- Marking & labelling: Instrument marking must include manufacturer name, model/reference, lot number and UDI (if required); package labelling should follow ISO 15223‑1. Instructions for reprocessing must align with ISO 17664.
Applications and users
ISO 22570:2020 is used by:
- Dental instrument designers and manufacturers for product design, quality control and compliance.
- Regulatory and procurement teams evaluating technical conformity.
- Sterile processing departments and dental clinics to validate reprocessing instructions and expected service life.
- Test laboratories performing hardness, dimensional and reprocessing tests.
Keywords: ISO 22570:2020, dentistry, spoons and bone curettes, surgical instruments, Hemingway spoon, Lucas curette, hardness 42–58 HRC, reprocessing, sterilization, instrument marking.
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