Responsibilities of manufacturers of 3D resins for medical uses

The responsibilities of 3D resin suppliers are multiple, the most important being that:

  • the safety and purity of the raw materials used in the formulation of 3D resins and their health hazards and risks as supplied before printing
  • the raw materials used to formulate 3D resins should be as safe as possible to reduce any potential health hazards and risks to consumers in the event of quality problems occurring during the manufacture of printed medical devices
  • the safety data sheets reflect the health hazards and risks of 3D resins in liquid state as supplied before curing
  • technical sheets reflect the basic physical properties of the 3D resins as supplied before curing
  • technical data sheets reflect the attainable physical-mechanical and safety properties of the resins once cured in two possible scenarios:
    • printed, post-cured and tested under specific conditions and with specific equipment and protocols, or
    • printed, post-cured and tested in a wide range of conditions, with different equipment and protocols to determine approximate ranges of the obtainable values of each property tested
  • 3D resin production is carried out with quality and cross-contamination risk with unsafe raw materials is prevented

On the other hand, printer users, are responsible for the quality of their 3D printed medical devices since they are the real medical device manufacturers.

Medical device manufacturers (printer users) are responsible for:

  • choosing safe and compliant 3D resins for the intended medical application since most commercial biocompatible 3D resins contain monomers, except for 3Dresyns monomer-free resins. Since monomers and resins are thermo and photo-reactive, depending on their safety and degree of curing during 3D printing and post-curing and subsequent cleansing, they may have a higher or lower percentage of uncured monomers, in addition to other leachables and extractables which may be absorbed by the body unless previously removed before medical devices are used. Consequently, medical device manufacturers are also responsible for;
  • the percentage of uncured monomers, and other leachables and extractables and their potential health hazards and risks to consumers depend on how 3D printed medical devices are manufactured under the responsibility of printer users, the medical device manufacturers
  • the light source used and the specifications and conditions used to print the 3D resins such as:
    • wavelength
    • power
    • curing time per layer
    • layer thickness
    • positioning
    • orientation
    • uniformity since at the ends of the print area most printers have significant lower light output (down up to 20-30% or even higher)
    • non variability since light power decays upon time
  • the light source used and the specifications and conditions used to post-cure the 3D resins such as:
    • wavelength
    • power
    • Post-curing time
    • positioning
    • orientation
    • uniformity as most post-curing units have different light output in different zones with power difference of up to 20-30% or higher
    • non variability since light power decays upon time
    1. the calibration and maintenance of the used equipment, since all the light sources used to print and post-cure the resins suffer a power decay with the use after certain working hours
      • prevention of decay is necessary to ensure constant printing and post-curing conditions over time
      • control of the uncured monomer is necessary to avoid its extraction and health risks
    2. the cleaning process as it is necessary to remove as much as possible uncured monomers, as well as other types of leachable and extractables, trapped in the printed resin before being marketed and used by consumers.
    3. validation and quality control of the production system and medical devices produced to ensure the quality of production of 3D printed medical devices by the printer or manufacturer of medical devices including:
      • safety control, including control of leachables and extractables and ensurance that their content is lower than required in the specifications for each type of medical application to prevent any associated hazards and risks to consumer health
      • control that the physical-mechanical properties meet the requirements for each type and design of 3D printed medical device

    Conclusions

    3D resins are raw materials, not medical devices, that depending on how they are printed and processed can be transformed into safe medical devices or not, since safety and quality depend on the manufacturing quality of 3D printed medical devices.

    To avoid public health risks 3Dresyns has developed as safe as possible monomer-free resins, as well as monomer-based resins, to prevent as much as possible potential human health problems in the event that medical devices printed by manufacturers of 3D printed medical devices had a low safety and quality.

    Medical device manufacturers, include dental and orthodontic printer users since they are legally liable for the safety and quality of their sold devices, independently on the specific scenario, since they use of compliant or certified 3D resins does not guarantee nor replace their legal liability for the quality of their in house 3D printed medical devices.