January 2018
Volume 9, Issue 1

Questions Answered

Clearing up confusion over the FDA's position on laboratory-based CAD/CAM manufacturing

By Tim Torbenson

What is the FDA now requiring of CAD/CAM dental laboratories? This topic can be confusing due to the misinformation that has been disseminated over the past couple of years. This article breaks it out into a few parts to make it easier to understand.

What Is a Manufacturer, as Classified by the FDA?

According to FDA Definition 21 CFR 820.3 (o), a manufacturer means any person who designs, manufactures, fabricates, assembles, or processes a finished device. The definition of manufacturer includes, but is not limited to, those who perform the functions of contract sterilization, installation, relabeling, re-manufacturing, repacking, or specification development, as well as initial distributors of foreign entities performing these functions.

With regard to custom implant-related devices, dental laboratories that assemble Ti bases to CAD/CAM-processed zirconia abutments fall under the FDA definition of a "manufacturer."  Laboratories are also involved in the processing and re-manufacturing of cleared 510(k) components that are purchased from suppliers. Dental laboratories are last in the line of manufacturers before the device is delivered to the patient and as such are considered Class II medical device manufacturers.

The FDA requires that a Class II medical device manufacturer have a Quality Management System (QMS) in place, implemented, and maintained. The CAD/CAM dental laboratory/manufacturer of Class II devices must also register with the FDA.

What Is a Class II Medical Device as It Relates to the Dental Laboratory?

Implant abutments are considered Class II medical devices requiring 510(k) clearance. In the past, the pre-manufactured (stock) implant abutments or factory components, which laboratories used to hand-manufacture custom abutments, were the only components receiving the 510(k) clearance. Hand manufacturing has been the basis for laboratories' exemption from registering with the FDA as listed in 21 CFR 807.65(i). The introduction of CAD/CAM processes to produce customized implant abutments was the trigger for the FDA's increased interest in dental laboratories' activities.

A CAD/CAM abutment is any CAD/CAM-designed and -produced custom titanium-zirconia hybrid or all-titanium abutment. This includes screw-retained crowns—such as a full-contour crown cemented to a single titanium base—or screw-retained multiple-unit frameworks or full-contour bridges cemented to titanium bases. It appears the FDA is presently reviewing all products processed through CAD/CAM technology, but it is the above-listed products they are focusing on currently.

What Is Required to Manufacture Class II Devices such as Implant Abutments?

If a laboratory is manufacturing hybrid custom abutments using materials such as zirconia, IPS e.max, Juvora, Pekkton, or a similar material bonded to Ti bases in a digital CAD/CAM workflow, there must be a 510(k) for these abutments. The same applies to all titanium custom abutments. As a medical device manufacturer, a laboratory must operate under a Quality Management System and register with the FDA. The laboratory may pursue the 510(k) itself or choose to work as a contract manufacturer for another company with an appropriate 510(k) for the CAD/CAM abutments.

If your laboratory outsources custom implant abutments, it should go through a process to validate and document that the milling or production center you are working with is registered with the FDA and has their own 510(k) or is working as a validated milling center (contract manufacturer) for a 510(k)-cleared abutment system. This will save you significant grief if the FDA contacts your laboratory asking about the abutments you are marketing to your clients.

What Is a Quality Management System?

A Quality Management System (QMS) refers to the organizational structure, responsibilities, procedures, processes, and resources for implementing a system of quality management. All CAD/CAM dental laboratories producing devices in-house are required to have a QMS in place. It should be developed commensurate with the risk presented by the device, the complexity of the device and the manufacturing process, the extent of the activities carried out, and the size and complexity of the CAD/CAM dental laboratory. In terms of implant-related products, a QMS is a documented procedure for purchasing, manufacturing, and implementing inspection processes that presently relate to CAD/CAM-produced products.

It is the responsibility of the CAD/CAM dental laboratory to only use 510(k)-cleared materials and components in their manufacturing processes and to validate and document those processes. This is validated by: having controls that demonstrate that your laboratory is only ordering from a company providing 510(k)-cleared components;  and that you are a validated milling center for the 510(k) holder and have a supplier agreement with them, which is common practice among contract manufacturers and 510(k) holders.

Being a contract manufacturer is a less sophisticated manufacturing process and allows the CAD/CAM dental laboratory to have a more streamlined QMS than the implant companies or other Class II medical device manufacturers that make hundreds of parts at a time to very detailed engineering drawings. Essentially, a contract manufacturer creates a patient-specific device one at a time and under strict conditions guided by the process.

A Quality System (QS) has seven subsystems:

• Management
• Production and Process Controls
• Equipment and Facility Controls
• Records, Document, and Change Controls
• Material Controls
• Design Controls
• Corrective and Preventative Actions

Of these seven subsystems, the CAD/CAM dental laboratory is not involved in Change Controls or Design Controls. Those are managed by the original 510(k) holders or the original device manufacturer. Since it is now the responsibility of the CAD/CAM dental laboratory to only use 510(k)-cleared materials and components in their manufacturing processes and document those processes, this satisfies the Material Controls section of the QMS.

The Corrective and Preventative Actions section of the QM requires that a CAD/CAM dental laboratory act as the eyes and ears for the original 510(k) holder. If the laboratory finds a product failure or trending problems, they must be documented and reported back to the manufacturer or original 510(k) holder so the latter can perform an investigation and provide the results back to the laboratory and the clinician. The manufacturer will determine if it is a reportable issue with the FDA.

Will I Need to Modify Existing Procedures?

Many of these QMS processes already exist in the dental laboratory or milling center. Dental laboratories use case tracking software that provides data required in a Quality Manual (QM).  Information or reports regarding specific implant components used in a case can be generated and placed in the QM to document device traceability. Laboratories also have “in-process” inspections to ensure that the components the laboratory is designing to or milling are correct. Using 510(k)-cleared CAD software provides adequate coverage for the FDA. A final Quality Check confirms that all parts and components are present prior to shipping the case. This process needs to be documented and placed in the QM as a part of Process Controls. Now, with the implementation of a QMS, the laboratory needs to provide better documentation that these tasks are being completed and store them together in one single location. When calibrating the CAD software and properly maintaining mills to ensure consistent quality in your product, the laboratory needs to log these activities to satisfy another portion of the Production and Process Controls section of the QMS. The lot numbers that are tracked and provided to the dentist are also part of the QMS and satisfy the Records and Document Control section by providing traceability. Learning what is required by the FDA can help the laboratory manager modify practices to better document what they are now doing to satisfy Title 21 CFR 820 Current Good Manufacturing Practices (CGMP).

Yes, there are some areas of QMS that will require new processes in the laboratory, but they are not so intrusive as to disrupt operations. In some cases, the implementation of a Quality Management System will provide a better view of the efficiency of your CAD/CAM dental laboratory when the documents are reviewed in management meetings.

At What Level Is the FDA Considering Dental Laboratories?

While the FDA is looking at dental laboratories and milling centers with increased scrutiny, they aren't looking to shut them down. Dental laboratories play a very vital and important role in the dental health arena. The FDA is strictly viewing laboratories as producers and marketers of legitimate medical devices, and they require dental laboratories to fulfill their duties and responsibilities as such in our healthcare system.


About the Author

Tim Torbenson is the President of EVO820.

Ceramill by Amann Girbach!
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