Ultimate Dentists’ Guide to Dental Implant Components

Ultimate Dentists’ Guide to Dental Implant Components image

Dental implant manufacturing is undergoing significant regulatory changes in the US. This is changing how dental practitioners and dental labs are approaching the design and manufacture of dental implant components –  particularly in regard to mechanical tolerances, loading parameters, material selection, and impression techniques. 

Professor Neil Meredith, Specialist Prosthodontist and Dean of the Post Graduate Institute of Dental Surgery, explains that these significant regulatory changes in the US are affecting the production of milled abutments, frameworks, and components that directly interface with dental implants

“In short, the US Food and Drug Administration (FDA) now recognises dental laboratories, milling centres – and potentially dental clinics – as subcontract manufacturers for Class II medical devices,” says Professor Meredith. “That means they have to follow specific quality assurance (QA) and regulatory processes outlined by the FDA.” 

This regulatory change signifies a heightened level of oversight and accountability for entities involved in the production of implant components in the US. Regulatory compliance is now essential for US dental laboratories, milling centres, and potentially dental clinics that want to continue their operations and maintain market access for their products in the US.

It also has potential implications for dental laboratories operating in Australia. Regulatory changes in major markets like the US often influence global standards and practices in the dental industry and can prompt similar discussions and potential adjustments to local regulations.

“There is no doubt that this level of scrutiny will come to Australia very shortly,” Professor Meredith explains. “Compliance with these regulations is very onerous and will be difficult for small to medium-sized laboratories in Australia to achieve. Therefore, the proper selection and design of implant components is very important for laboratories to achieve the very highest level of success.”

Dentists in Australia already play a critical role in the proper selection and design of implant components. However, this role will only gain greater importance if the regulatory environment in Australia changes to reflect the US developments. 

That’s why it’s so important for dentists to understand the intricacies of mechanical tolerances, material selection, and impression techniques as applied to implant dentistry. 

To achieve excellence in implant design and manufacturing, precision accuracy and trueness are fundamental, as is an understanding of mechanical tolerances and how they apply particularly to dental implants components and prosthetic frameworks,” Professor Meredith adds. 

Professor Meredith explains that it’s also important for dentists to take into consideration the precision and accuracy of implant manufacturers’ (Original Equipment Manufacturers) components – particularly abutment screws.

“These may have sophisticated coatings to control friction, preload and maximise screw retention. The use of inexpensive third-party copy components can lead to significant maintenance issues with screw loosening and fracture. This especially applies to axial and screw channel connections,” he says.

“Overall, accuracy and precision should be maintained throughout the design and production pathway by the use of the best quality components with the best design and the most accurate tolerances. This will lead to minimal maintenance and complications in the near and long term.”

Understanding mechanical tolerances 

If regulatory changes similar to the US are adopted in Australia, dentists may also need to become more aware of the importance of mechanical tolerances in dental prosthetics and engage more closely with dental laboratories to ensure that prosthetic components meet required mechanical tolerances and regulatory standards.

Mechanical tolerances refer to the permissible deviation or variation in the dimensions and alignment of dental implant components. These components include the implant fixture (the part that is surgically placed into the jawbone), the abutment (the connector that attaches to the implant fixture and supports the prosthetic tooth or restoration), and any auxiliary parts like screws or prosthetic components.

Matching tolerances precisely is crucial for ensuring the proper fit, function, and longevity of dental implant components. Even slight deviations from the specified tolerances can affect the seating, stability, and biomechanical behaviour of the components within the implant system. This can present a significant challenge for dental labs. 

“Dental implant manufacturers specify the tolerances of the components that they use, but these are not made available to third-party companies and laboratories,” Professor Meredith explains. “So laboratories and milling centres must therefore rely on reverse engineering to define tolerances and measurements. This is typically undertaken using a few original parts and a coordinate measuring machine or scanner to reconstruct the parts.”

While reverse engineering allows laboratories to approximate the dimensions of original components, it’s not a perfect solution. Reverse-engineered tolerances may not precisely match those specified by the manufacturer, which may lead to potential discrepancies in fit and performance. This lack of exact matching can compromise the integrity and stability of the final restoration.

Therefore, it’s essential for dental labs to have access to accurate tolerance specifications to achieve optimal results. Dentists can assist this process by precisely calculating tolerance specifications based on a combination of factors, including the dimensions of the implant system, the intended prosthetic design, and the specific clinical requirements of the patient. 

Dentists should also consider clinical factors that may affect tolerance specifications, such as the type of restoration, the location of the implant in the dental arch, the presence of parafunctional habits, and the patient’s occlusal scheme.

For example, factors such as occlusal stability, centric relation, and occlusal clearance must be considered to determine the appropriate tolerances for achieving balanced occlusion and functional harmony.

The importance of loading parameters 

Understanding the importance of loading parameters and how they relate to determining mechanical tolerances is another critical factor dentists must understand to enable their lab to design and manufacture precise implant components that are up to the job.   

“Dental implants and components manufacturing is regulated to a very high accuracy with clearly defined tolerances so that they will perform within the regulated and tested loading parameters,” Professor Meredith explains. 

Loading parameters refer to the forces exerted on dental implants and their supporting structures during normal oral functions, such as chewing and speaking. 

Here’s how dentists use loading parameters to determine mechanical tolerances:

The role of material selection

Material selection also plays a crucial role in mechanical tolerances for dental prosthetics and components.  

Different materials have varying degrees of dimensional stability and accuracy during fabrication. Some materials, such as high-performance ceramics or high-precision metals, may exhibit tighter tolerances and greater accuracy in maintaining specified dimensions during manufacturing processes like milling or casting. 

So dentists need to select materials that can meet the required mechanical tolerances for the specific prosthetic components being fabricated.

For example, materials with higher strength properties, such as titanium and cobalt-chromium alloys, may be better suited for applications where tight tolerances are critical, such as implant-supported frameworks or abutments. 

Professor Meredith explains that “materials used in dentistry today for prosthetic reconstruction comprise three main families: polymers, ceramics, and metals and their subsets including alloys and blends.”  

Optimising the geometry of the implant ensures stress is distributed evenly to minimise the risk of fatigue failure. Surface treatments, such as coatings or modifications, may also be applied to enhance osseointegration and reduce bacterial adhesion. 

Critical impression and scanning considerations 

The final piece of the puzzle to helping your lab design and manufacture precise implant components is associated with potential discrepancies between the accuracy and precision of physical impressions versus digital intraoral scans.

“Metrology, or the science of measurement, is now more essential in dentistry than it ever has been,” says Professor Meredith. “In everyday practice, clinicians are relying on the use of sophisticated instrumentation to process three-dimensional data in order to be able to assist in the design and production of dentures, crowns and bridgework. 

“However, when we review methods for making dental records, studies have shown that impression techniques can have an acceptable level of accuracy – as little as 25 µm in all directions. It is essential, therefore, that any digital technology such as intraoral scanners maintain or better this precision.”

Professor Meredith points out that this is posing something of a challenge in full arch records. He believes there is some confusion between accurate data capture, precision, and accuracy in the final framework.  

“Flags, gauges and modified scan bodies can be used to enhance the trackability of intraoral scanners,” he explains. “As an alternative, stereophotogrammetry works in a different way albeit at high cost to record the implant position. 

“However, whichever method is used to record implant locations for full arch restorations, verification is a key to the successful fabrication of the final implant prosthesis and to ensure certainty of clinical fit.” 

The final word

In conclusion, recent regulatory changes in the US have significantly altered the landscape for the production of dental implant components. The potential ripple effects of these changes may extend beyond US borders, with potential implications for dental clinics and labs in Australia. 

As regulatory environments evolve, the dental industry must adapt. This adaptation will no doubt emphasise the need for precision, accuracy, and adherence to mechanical tolerances in the design and manufacturing of implant components.

Dentists play a pivotal role in ensuring the success of implant prosthetics by understanding and guiding the intricacies of mechanical tolerances, material selection, and impression techniques. 

As custodians of patient care, dentists must collaborate closely with dental laboratories to uphold the highest standards of quality and reliability in implant dentistry. By prioritising precision in design, manufacturing, and clinical practice, dental professionals can navigate regulatory changes effectively, and deliver implant solutions that meet the stringent demands of modern dentistry while ensuring optimal patient outcomes.

Avant Dental is a full-service dental laboratory. To find out more about working with us, please email contact@avantdental.com.au or phone 1800 287 336.

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