Difference Between MDR and MDD: Which Class Do Dental 3D Printing Resins Belong To?

To enhance patient safety and ensure traceability of products, the European Union (EU) replaced the Medical Device Directive (MDD) 93/42/EEC with the more stringent Medical Device Regulation (MDR) 2017/745, which came into force on May 26, 2021 (European Parliament and Council, 2017). This regulation brought new provisions, especially regarding patient safety and device traceability.

2. Key Differences Between MDR and MDD

2.1. Reasons for Transition to MDR

The key factors driving the transition to MDR can be summarized as follows:

• Patient Safety: Some medical devices released to the market were found to have undergone insufficient testing and posed risks (Rägo & Sant, 2017).
• Device Traceability: With MDR, the use of the EUDAMED database has become mandatory (European Commission, 2021).
• Uniform Regulation: Since MDD was a directive, it could be interpreted differently across countries. MDR, however, will be applied uniformly across all EU countries (Francesco et al., 2020).

3. Medical Device Classifications and 3D Printing Resins

3.1. Medical Device Classification Under MDR

MDR classifies medical devices into four main groups based on their risk level:

• Class I: Low-risk devices
• Class IIa: Medium-low risk devices
• Class IIb: Medium-high risk devices
• Class III: High-risk devices

3.2. Classification of Dental 3D Printing Resins

Dental 3D printing resins used in the dental industry are classified into different categories depending on their application:

3.2.1. Class I (Low-Risk) Dental Resins

These resins can remain in the patient’s mouth for a maximum of 24 hours. Examples include:

• Surgical guide resins (for implant surgery)
• Impression tray resins
• Trial resins (temporary trial prostheses)

3.2.2. Class IIa (Medium-Risk) Dental Resins

Class IIA (Medium-Risk Dental Resins):Resins that remain in the patient's mouth for more than 24 hours fall into this category. The conformity assessment processes for these resins are more stringent. According to the classification rules outlined in Annex VIII of the MDR, Rule 7 and Rule 8 are determined based on the application area and contact duration of the devices. Implants that remain in the body for less than 30 days fall under Rule 7, while those remaining for more than 30 days are classified under Rule 8.

• Temporary/Permanent crown and bridge resins
• Aligner resins
• Splint and night guard resins

4. Obligations for Manufacturers During the Transition to MDR

With the transition to MDR, manufacturers are now subject to stricter regulations. For Class IIa and higher products, manufacturers must obtain approval from a Notified Body. This requires the following additional processes:

· Obligation to provide clinical data: The effectiveness and biocompatibility of products must be proven (Plessis, 2021).

· Preparation of a technical file: All components of the product, the manufacturing process, and test results must be presented in detail.

· Product traceability: Registration in the EUDAMED system is required, and a unique UDI code must be assigned (Regula, 2019).

5. CE Certificate Verification

To verify whether a product has a CE certificate, the EUDAMED database provided by the European Commission can be used. You can check products with a CE certificate using the following link: EUDAMED Database.

Conclusion

The transition to MDR is a critical step, particularly for enhancing patient safety and quality standards. 3D printing resins used in the dental sector are classified as either Class I or Class IIa, depending on their application. If a resin remains in the patient’s mouth for only 24 hours or less, it is classified as Class I. However, if it is used for more than 24 hours, it falls under Class IIa and must undergo stricter regulatory processes.

These new regulations aim to ensure the release of safer and more traceable products in the industry, creating a more reliable environment for both patients and dental professionals.

References

• European Parliament and Council (2017). Regulation (EU) 2017/745.
• European Commission (2021). EUDAMED Database.
• Francesco, P. et al. (2020). "New Regulatory Framework for Medical Devices in Europe". Journal of Medical Devices, 14(3), 102-119.
• Plessis, L. (2021). "Implementation of MDR: Challenges and Solutions". Regulatory Affairs Journal, 18(4), 76-89.
• Rägo, L. & Sant, G. (2017). "Medical Device Regulations: A Global Perspective". Health Policy, 121(5), 451-462.
• Regula, J. (2019). "Understanding EU MDR: Key Changes". European Journal of Medical Research, 24(1), 12-27.