In-Office Fabrication of Indirect Restorations

Sefira Fialkoff

More than 35 years ago, Dentsply Sirona introduced the first CEREC system, revolutionizing chairside milling. Since then, significant advancements have been made in chairside mills; however, according to internal Inside Dentistry survey data, adoption has plateaued in recent years, prompting a closer examination of this technology's role in contemporary dentistry.

Milling indirect restorations chairside offers several compelling benefits for dental practices. One of the most significant advantages is the speed and convenience it provides. In-house milling allows practices to offer same-day restorations, significantly reducing the time between diagnosis and the completion of treatment and eliminating the need for temporary crowns and multiple appointments-major advantages for both practitioners and patients. This not only improves practice efficiency but also enhances the experience for patients, who benefit from reduced chair time, fewer temporary restorations, and a quicker return to normal oral function. In turn, these factors are likely to increase patient satisfaction and acceptance of treatment plans.^1-4 "One of the major benefits for our practice is the ability to perform more conservative dentistry without the need for provisional restorations," notes Anthony Mennito, DMD, a cosmetic dentist in Charleston, South Carolina. "This has positively impacted patient satisfaction by providing convenience and efficiency."

The integration of expanded digital platforms is further broadening the scope of treatments that can be accomplished within a single visit, leveraging advanced technology to streamline the restorative process. "What we're seeing now is a shift toward the increased application of expanded digital platforms," explains Dennis Fasbinder, DDS, a clinical professor at the University of Michigan School of Dentistry. "Practices are increasingly leveraging these platforms and cloud computing to expand the range of in-office treatments, including restorations. This digital integration could allow for seamless file transfer and real-time collaboration between offices and laboratories, so although everything may not be done on-site, it could still be completed within a single visit to the office."

Another benefit of in-office milling is cost-efficiency. In-office milling can reduce reliance on external laboratories, lowering overhead costs and improving profitability over time. In addition, having full control over the fabrication process allows for meticulous quality assurance, enabling dentists to ensure that each restoration meets their exact standards. The applications for in-office milling systems have increased, and there is now a wide variety of materials available for them. These techniques and materials allow for the precise customization of restorations to patients' anatomy, which results in improved fit, function, and esthetics.⁵ Other advantages to milling restorations in house include a reduced risk of errors related to laboratory miscommunications and the ability to store the design data for easier remakes.

For many practices, it isn't about choosing between in-office fabrication and sending cases to a laboratory-it's about strategically leveraging both approaches. "Our in-office mills are not a replacement for our partner laboratories; we continue to collaborate closely with them," emphasizes Robert Ritter, DMD, a cosmetic dentist in Jupiter, Florida. "The mills serve a specific purpose within the practice. For instance, if a patient is leaving the area, we can sometimes bypass the provisional and directly provide a long-term restoration on site. However, for larger or mixed-medium cases, as well as for situations in which additional healing time is needed before placing a final restoration, we still rely on our trusted laboratories." By leveraging the advantages of both workflows, practices can offer a higher level of service while optimizing both clinical outcomes and business operations.

The initial capital investment for CAD/CAM systems can be substantial, which may not be feasible for all practices. Then, additional investment is required for ongoing operation. Many systems come with recurring fees for subscription-based licensing and cloud-based data storage. Additional costs include those for tech support, software updates, staff training, and equipment maintenance. "Dental offices are accustomed to maintaining schedules and equipment, with manufacturers providing annual maintenance, and the shift to digital is not much different," says Fasbinder. "The training required for the different aspects of digital dentistry can range from minimal to extensive. For example, digital imaging-whether for bite splints, diagnostic models, or restorations-often requires only brief training to learn the basics of operating the camera. However, achieving proficiency takes a little more time. One can learn to use the technology in half a day, but it requires repetition before it becomes second nature and an effortless part of your routine."

According to Mennito, when integrating in-office milling, it's essential that the entire team is on board with learning and utilizing the technology. "Having a ‘superuser' within the practice can be invaluable for training others and troubleshooting any issues that arise," he says.

In-office milling machines also still have some limitations regarding the range of materials available and the complexity of restorations that they can produce.⁶ Traditional 3- or 4-axis chairside machines may not achieve the precision of 5-axis laboratory systems. The geometry of a restoration is dependent on the number of axes used to mill it; the greater the number of axes, the finer and more detailed the morphology of the restoration.⁷ Therefore, typical in-office milling machines can be restrictive when it comes to the variety and customization of restorations when compared with specialized laboratory machines. "Several companies offer robust mills that are capable of milling thinner restorations with more detail," explains Jason Olitsky, DMD a private practitioner in Ponte Vedra Beach, Florida, who has an in-house laboratory. "These machines are more costly than typical chairside dental mills and often require dental offices to use CAD software. Although the initial cost of investment is higher, dentists can realize enormous benefits with the ability to use these programs, especially when transitioning to an in-house laboratory."

The learning curve associated with in-office milling presents another challenge because mastering the technology and integrating it into daily workflows demands training and time. Practices must also navigate the choice between closed systems, which limit the use of third-party materials and can increase costs, and open systems, which offer better compatibility but may demand more technical expertise to integrate them. Furthermore, practices must assess their available space and workflows to accommodate the equipment and ensure that it does not disrupt existing operations. The most basic dental milling machines are compact tabletop units that take up minimal physical space in dental offices. Benchtop milling units are the next size up, and they offer a variety of advantages over tabletop milling, such as spindles that are more robust. The largest milling machines, which are floor models, provide higher production capacities, but take up significantly more physical space in practices.⁸

With the ongoing advancements in 3D printing resins, it has more recently become possible to fabricate indirect restorations using additive manufacturing. The use of 3D printing technology offers several advantages for the in-office fabrication of indirect restorations, especially in its ability to produce complex geometries that milling units may struggle with. Moreover, 3D printing reduces material waste by using only the necessary amount for each restoration, which results in cost savings. In addition, 3D printing equipment is generally less expensive than milling equipment, and the modality provides faster production times, making it an attractive option for many practices.

Nonetheless, there are notable drawbacks to 3D printing indirect restorations, particularly regarding the strength and durability of crowns. Cary Goldstein, DDS, a private practitioner in Atlanta, Georgia, notes concerns about the longevity of resin-based materials. "Although we explored 3D printing, its current capabilities did not meet our needs for prosthodontic work," he says. "Previous resin-based crowns have failed due to fracture, so we will not use these materials until their long-term durability is proven." Although 3D printing excels in the creation of inlays and temporary restorations, higher-strength ceramics are still preferred for final crowns because of the current limitations of the available 3D printing resins.

The future of in-office restoration fabrication is poised to bring significant advancements that will be driven by, among other factors, ongoing improvements in both milling technologies and materials. "It's an exciting time in dentistry because cutting-edge technology from other fields is being adapted for our use, enabling us to advance rapidly in the delivery of expedient, high-quality in-office restorations," says Ritter.

Innovations in milling processes, such as enhanced precision and faster production times, coupled with the development of stronger, more versatile materials, could revitalize interest in chairside milling systems, potentially reversing the recent plateau in their adoption. At the same time, the evolution of 3D printing technology is likely to play a pivotal role in shaping the landscape of in-office restoration fabrication. "We're looking forward to the day when 3D-printed restorations can confidently be used as definitive solutions," explains Olitsky. "For example, designing, producing, finishing, and delivering ten veneers is much simpler with 3D printing than with traditional fabrication methods for high-strength ceramics. Printing allows for thinner restorations that facilitate faster fitting times and require fewer contact adjustments. Although the esthetics of 3D printed restorations currently fall short of those of glass ceramic or porcelain restorations, these materials are evolving, and the potential for 3D printing in in-house laboratories looks very promising."

As 3D printing resins continue to improve in strength and durability, making the fabrication of final restorations increasingly viable, the lower cost of entry and relative ease of use when compared with traditional milling could encourage more practices to integrate 3D printing as a core component of their restorative workflows. In addition, emerging innovations, such as hybrid systems that combine the strengths of both milling and 3D printing and advancements in AI-driven design and fabrication processes, promise to further enhance the efficiency and quality of fabricating restorations in house. "With an increasing number of group practices being formed, I believe that many groups who practice in a geographic cluster will utilize these technologies to internalize a majority of their laboratory costs," predicts Mennito. "I am aware of some larger group practices who have already hired laboratory technicians and set up physical spaces to take advantage of the economic benefits of milling zirconia pucks and 3D printing. This not only has cost benefits for dental support organizations (DSOs) but also makes quality control and turnaround times much more predictable."

In the future, the interplay between traditional milling and emerging 3D printing innovations will redefine how dental practices approach the fabrication of indirect restorations, offering a range of cost-effective, high-quality options to accommodate diverse clinical needs. "When it comes to predicting the future, I believe it will be less about the dentistry itself and more about the advancements in technology," reflects Fasbinder. "After more than 30 years in the field, I've realized that discussions about the future often center around the evolution of technology rather than purely dental innovations. Consider the telephone as an analogy. Who would have imagined 25 years ago that we'd be carrying it in our pockets and using it as a camera and a computer? This highlights the challenge of anticipating what's coming next in our field because increasingly, developments in dentistry intersect with technological progress." The rapid pace of the recent advances in fabrication technologies and materials suggests a future in which dental practices will have even more versatile, cost-effective, and high-quality options at their disposal, allowing for even greater customization and patient satisfaction.

The current state of the technology for the in-office fabrication of indirect restorations represents a significant milestone in modern dentistry. Clinicians now have the tools to create high-quality restorations with increased efficiency, accuracy, and control. Although the benefits of being able to offer same-day restorations, improve the patient experience, reduce costs, and enhance customization are compelling, the challenges associated with the large initial and ongoing investment, material limitations, learning curves for dentists and their teams, and factors related to a practice's physical space and workflow must be carefully considered. Balancing the benefits with the drawbacks is critical in determining the viability of integrating current and future technologies into your practice.

For those who are interested in offering same-day restorations but are far from ready to cut the cord with their laboratories, a hybrid approach may offer the best of both worlds. Leveraging in-office systems for simpler restorations while relying on external laboratories for more complex cases can help practices ease into the technology without compromising on quality or efficiency. "Ask a lot of questions, do the math to ensure that it works financially for your office, and don't be afraid to make the technological jump," Ritter advises. "As with the adoption of any new technology, there's always a learning curve. However, you shouldn't let that hinder you from implementing it and providing the best care for your patients."

The evolution of both milling and 3D printing technologies will continue to redefine the landscape of restorative dentistry. Practices that remain vigilant and flexible will be able to navigate the complexities of these technologies, and when appropriate, leverage their strengths to enhance patient care and operational efficiency.