Mastering Dental Milling: Wet vs. Dry Milling for Optimal Results

September 17, 2024

Investing in milling technology can significantly enhance your lab's capabilities and efficiency as a dental lab owner. However, understanding the differences between wet and dry milling is crucial to making the right choice for your lab. This blog will explore when to use wet vs. dry milling, the materials best suited for each method, and the pivotal role of milling tools in the process. It will also highlight some of Zahn's top milling machines from Amann Girrbach, Roland, and XTCERA.

Wet Milling vs. Dry Milling: What's the Difference?

Wet Milling:

• Process: Uses a liquid coolant to reduce friction and heat during milling.
• Advantages: Wet milling provides highly precise and smooth surface finishes, instilling confidence in its use for esthetic restorations like crowns, veneers, and bridges.
• Materials: Best for milling glass ceramics (e.g., lithium disilicate), composite resins, and other materials that require a cooler environment to prevent heat damage.

Dry Milling:

• Process: Operates without liquid coolants, using pressurized air or a vacuum to remove debris.
• Advantages: Faster and more efficient, particularly for materials that do not require cooling.
• Materials: Suitable for zirconia, wax, PMMA (polymethyl methacrylate), and other polymers.

When to Use Wet vs. Dry Milling

• Wet Milling: Choose wet milling when working with materials that are sensitive to heat, such as glass ceramics and composite resins. The liquid coolant helps maintain the integrity of these materials, ensuring high-quality, esthetic results.
• Dry Milling: Opt for dry milling when speed and efficiency are paramount, especially for materials like zirconia and PMMA. Dry milling is ideal for full arch or mouth restorations where strength and durability are critical.

Understanding the Milling Process: Step-by-Step

1. Digital Impressions: The process begins with capturing digital impressions of the patient's teeth using an intraoral scanner. This step eliminates the need for traditional impression materials and provides a precise digital model of the patient's dentition.
2. CAD Design: Using CAD (Computer-Aided Design) software, dental professionals design the restoration based on the digital impression. This design phase allows for customization and optimization of the restoration's fit, function, and aesthetics.
3. CAM Processing: The CAD design is then transferred to CAM (Computer-Aided Manufacturing) software, which generates the toolpaths for the milling machine and calculates the precise movements required to mill the restoration from the chosen material.
4. Milling: The milling machine, equipped with various cutting tools, executes the toolpaths to carve the restoration from a solid block of material. Depending on the complexity and material, this process can take a few minutes to several hours.
5. Finishing and Polishing: After milling, the restoration may undergo additional finishing processes, such as polishing, staining, and glazing, to achieve the desired esthetic and functional properties.

Milling Tools for Wet vs. Dry Milling

Wet Milling Tools:

• Diamond-Coated Burs: These are used for milling glass ceramics and composite resins. The diamond coating provides durability and precision, ensuring smooth and accurate cuts.
• Carbide Burs: Often used for milling metals and other hard materials, carbide burs are durable and can withstand the cooling process without degrading.

Dry Milling Tools:

• Zirconia Burs: Specifically designed for milling zirconia, these burs are made from materials that can handle the hardness and brittleness of zirconia without breaking.
• PMMA Burs: Used for milling PMMA and wax, these burs are designed to efficiently remove material without generating excessive heat.

Zahn's Featured Milling Machines for Your Needs

Amann Girrbach Mills:

• Ceramill Motion 3: The Ceramill Motion 3 is an advanced 5-axis hybrid machine that combines wet and dry processing in a single unit. It supports a wide range of materials including zirconia, PMMA, wax, and composites. The machine features an intuitive user interface, automatic calibration, and RFID tool tracking, ensuring high precision and ease of use.
• Ceramill Matron: The Ceramill Matron is a high-performance milling machine designed for both wet and dry milling. It features an innovative Vmax arm for maximum strength and precision, a retractable Performance Blank Changer, and RFID-supported tool and blank management.

Roland Mills:

• DWX-42W: The DWX-42W is designed specifically for wet milling, making it perfect for glass ceramics and composite resins. It offers high-speed production with a 4-axis system and is known for its ease of use and reliable performance.
• DWX-53DC: The DWX-53DC is a state-of-the-art 5-axis dry milling machine with an automatic disc changer. It has a redesigned, robust spindle with 3x gripping power for efficient PMMA milling, a 4mm roughing tool for faster milling times, and a fully integrated webcam for real-time monitoring. The mill also includes an automated eco-system with a dedicated extraction unit, promoting cleaner milling and less maintenance.
• DWX-52D: This mill is optimized for dry milling, suitable for materials like zirconia and wax. It features a 5-axis system and an automatic tool changer, providing efficient and precise milling for dental labs.

XTCERA Mills:

• XTCERA X-Mill 500: The X-Mill 500 is a high-performance dry milling machine with 5-axis simultaneous processing. It is designed for fast and accurate milling of hard materials like zirconia, making it a reliable choice for dental labs looking for precision and efficiency.
• XTCERA X-Mill 580 DC: This machine features an automatic 12-disc changer for continuous 24-hour processing. It is equipped with intelligent monitoring and self-diagnosis tools, ensuring high precision and minimal downtime.

Conclusion

Choosing between wet and dry milling for your dental lab hinges on the unique requirements of your materials and operations. Each method offers distinct benefits, and understanding their applications can significantly enhance your lab's efficiency and output quality. Zahn's comprehensive line of milling machines, featuring suppliers like Amann Girrbach, Roland, and XTCERA, provides reliable and versatile solutions tailored to your specific milling needs. By investing in cutting-edge milling technology, you can elevate your dental lab to new heights of productivity and precision.