Wet and dry milling are two fundamental techniques used in digital dental manufacturing to mill restorations such as crowns, bridges, inlays, onlays, and implant components. Both processes are performed using dental milling machines and are integral parts of CAD/CAM workflows. The choice between wet and dry milling depends on the material being processed, desired surface quality, speed, and final restoration type.
Dental milling refers to the subtractive manufacturing process of creating dental restorations by cutting and shaping blocks or discs of materials such as zirconia, glass-ceramics, PMMA, or composite resins. These restorations are digitally designed in CAD software and then fabricated via CAM-controlled dental milling machines.
Dry milling involves cutting the material without any coolant or lubricating fluid. It is typically used for:
• Pre-sintered zirconia
• PMMA (polymethyl methacrylate)
• Wax
• Composite resins
• No contamination risk from fluids
• Cleaner workflow—no drying needed post-milling
• Faster setup and changeover
• Ideal for soft, pre-sintered materials
• Generates more dust, requiring strong suction and filtration
• May produce more heat, which can affect material integrity if unmanaged
• Limited to certain materials (e.g., not recommended for glass-ceramics)
Wet milling uses a stream of water mixed with a coolant (usually oil or glycol-based) to reduce heat and friction during the milling process. It is primarily used for:
• Glass-ceramics (e.g., IPS e.max CAD)
• Zirconia (fully sintered)
• Metal alloys
• Hybrid ceramics
• Composites requiring smooth surface finishes
• Superior surface quality
• Reduced tool wear
• Minimized micro-cracks or chipping, especially in brittle materials
• Enables milling of harder and fully-sintered materials
• Requires drying time after milling
• More maintenance due to coolant handling
• Higher operational cost due to fluid systems and filtration
Feature | Dry Milling | Wet Milling |
|---|---|---|
| Materials | Zirconia (pre-sintered), PMMA, Wax | Glass-ceramics, Hybrid ceramics, Metals |
| Coolant | No | Yes (Water + lubricant) |
| Surface Finish | Moderate | High |
| Tool Wear | Higher | Lower |
| Post-processing | Minimal | Requires drying |
| Dust/Fluid Handling | Requires vacuum system | Requires fluid management system |
| Machine Cost | Lower | Slightly higher |
Dry milling is ideal for:
• Pre-sintered zirconia frameworks
• Temporary restorations made from PMMA or composite
• Wax-ups for diagnostic purposes
• High-volume production labs with streamlined dry workflows
Wet milling is recommended for:
• Glass-ceramic restorations requiring high esthetics
• Final restorations where surface integrity is critical
• Implant-supported components made of hybrid materials
• Polychromatic or multilayered ceramics
Many modern dental milling machines support both wet and dry modes, offering flexibility and efficiency:
• imes-icore CORiTEC 250i
• Roland DWX-52DCi
• Amann Girrbach Ceramill Motion 2
• vhf R5
These systems are equipped with automatic tool changers, intelligent suction systems, and self-cleaning features, making them suitable for multi-material, high-precision milling.
Clean and calibrate machines regularly to avoid cross-contamination.
• Use dedicated burs for wet and dry materials.
• Monitor spindle temperature and coolant quality.
• Keep dry milling areas dust-free with efficient filtration.
The choice between wet and dry milling in dental CAD/CAM workflows is critical for ensuring the best results in terms of material integrity, surface quality, and operational efficiency. Each technique has its ideal use cases, and many dental labs benefit from using both depending on the material and restoration type. Understanding the strengths and limitations of each approach helps dental professionals and technicians achieve optimal clinical outcomes and maximize productivity.