The new article pays special attention to the matters related to electromagnetic compatibility, as well as non-clinical performance testing the products covered by the scope of the guidance should undergo in order to demonstrate compliance with the relevant regulatory requirements in terms of safety and effectiveness.
Table of content
The Food and Drug Administration (FDA or the Agency), the US regulating authority in the sphere of healthcare products, has published a draft guidance document dedicated to the regulatory requirements for dental curing lights. Once finalized, the document will provide an overview of the applicable rules and regulations, as well as additional clarifications and recommendations to be taken into consideration by the parties involved in order to ensure compliance.
At the same time, provisions of the guidance are non-binding in their legal nature, nor are they intended to introduce new rules or impose new obligations. Moreover, the authority explicitly states that an alternative approach could be applied, provided such an approach is in line with the existing legal framework and has been agreed with the authority in advance.
The scope of the guidance covers certain specific aspects to be considered by the parties involved in order to ensure the completeness of the relevant applications.
Electrical Safety and Electromagnetic Compatibility (EMC)
Under the general rule, dental curing lights are medical electrical equipment that may expose the operator and patient to hazards associated with electrical energy or may fail to operate properly in the presence of electromagnetic disturbances. Thus, dental curing lights should be tested to demonstrate they perform as anticipated in their intended use environment.
The parties responsible for such products should perform the relevant testing according to the currently FDA-recognized versions of the following standards for medical electrical equipment safety and electromagnetic compatibility:
- IEC 60601-1: Medical electrical equipment – Part 1: General requirements for basic safety and essential performance
- IEC 80601-2-60: Medical electrical equipment – Part 2-60: Particular requirements for the basic safety and essential performance of dental equipment
- IEC 60601-1-2: Medical electrical equipment – Part 1-2: General requirements for basic safety and essential performance – Collateral standard: Electromagnetic disturbances – Requirements and tests
If submitting a Declaration of Conformity to these standards, the applicant is expected to provide appropriate supplemental documentation, such as an assessment of the results and how conformity was determined, and also to provide information on the test methods used, as these standards include general methods with multiple options and, in some cases, do not include specific acceptance criteria or address assessment of results. For additional information on providing electromagnetic compatibility information in a premarket submission, the authority refers to its guidance “Electromagnetic Compatibility (EMC) of Medical Devices”.
Wireless Technology
Another important matter addressed in the guidance relates to the use of wireless technologies. The authority emphasizes that in the design, testing, and use of wireless medical devices, the correct, timely, and secure transmission of medical data and information is essential for the safe and effective use of medical devices and systems.
If a dental curing light incorporates radiofrequency wireless technology such as Bluetooth, IEEE 802.11 (Wi-Fi), or RFID (radio frequency identification) technology, additional testing beyond what is specified in the IEC 60601 standards is recommended to demonstrate that the wireless device functions will perform as intended in environments with other wireless products. The applicant should take into consideration the FDA guidance “Radio Frequency Wireless Technology in Medical Devices” for additional recommendations.
Non-Clinical Performance Testing
According to the guidance, non-clinical performance testing is recommended for dental curing lights to fully characterize the device. Descriptive characteristics alone are not sufficient to ensure the devices can perform as intended for the end user.
For information on the recommended content and format of test reports for the testing described in this section, the document refers to the FDA guidance “Recommended Content and Format of Non-Clinical Bench Performance Testing Information in Premarket Submissions”.
Radiant Power Output
Radiant power output (radiant flux) measures the ability of dental curing lights to photopolymerize dental restorative resins. Inadequate radiant power output can result in incomplete curing of resins, leading to premature failure.
Excessive output can result in thermal hazards. Testing ensures the dental curing light provides appropriate energy for its intended purpose.
The parties responsible for such devices should characterize the radiant power output delivered by the dental curing light source using test methods conforming to the currently FDA-recognized consensus standard, ISO 10650 Dentistry — Powered Polymerization Activators; and also to provide test results characterizing the radiant power output, including:
- Total radiant power output (or radiant flux) (mW) throughout the total exposure cycle
- Maximum light intensity (or irradiance) (mW/cm²) at 2 mm from the distal end of the device light guide
- Total spectral irradiance (mW/cm²-nm) plot at maximum irradiance output versus wavelength at 2 mm from the distal end of the light guide
- Radiant exposure (or optical radiation dose) output range (J/cm²) calculated by multiplying irradiance outputs of the various curing modes by recommended curing times
- Irradiance attenuation plot showing irradiance versus vertical distance from the device light guide tip
- Thermal image or beam profiler of cross section of light guide tip showing relative “hot” and “cold” spots.
Heat Generation
Heat generation measures the ability of dental curing lights to accumulate heat during operation. Excessive heat can present thermal hazards to both the patient and the practitioner.
Testing ensures the device remains safe under normal and single fault conditions. To address these risks, the applicants should provide data demonstrating that the device remains safe under normal and single fault conditions.
They are also expected to identify the maximum temperature (°C) of the device body and at 2 mm from the distal end under worst-case scenarios.
Depth of Cure
Depth of cure measures the thickness of a dental restorative resin that can be cured by a dental curing light. Inadequate depth of cure can result in incomplete curing and premature failure.
Testing ensures sufficient energy to harden the resin within the recommended curing time. In this context, the applicants should provide the depth of cure on a representative, legally marketed dental restorative resin sample after a clinically relevant curing time; and also to identify the dental restorative resin tested in the submission.
Modifications
According to 21 CFR 807.81(a)(3), a device change or modification that could significantly affect the safety or effectiveness of the device or represents a major change or modification in the intended use requires a new 510(k). For additional details, the document refers to the FDA guidances “Deciding When to Submit a 510(k) for a Change to an Existing Device” and “Deciding When to Submit a 510(k) for a Software Change to an Existing Device”.
Section 3308 of the Food and Drug Omnibus Reform Act of 2022 (FDORA), enacted as part of the Consolidated Appropriations Act, 2023, added section 515C “Predetermined Change Control Plans for Devices” to the FD&C Act (Pub. L. No. 117-328). Section 515C provides the FDA with the authority to approve or clear PCCPs for devices requiring premarket approval or premarket notification.
If interested in proposing a PCCP in a marketing submission, the interested party should submit a Pre-Submission to engage in further discussion with CDRH. See FDA’s guidance “Requests for Feedback and Meetings for Medical Device Submissions: The Q-Submission Program”.
Conclusion
In summary, the present draft guidance issued by the FDA provides a comprehensive overview of the regulatory requirements applicable to dental curing lights as a special category of medical devices, considering their specifics and risks associated.
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