How Do 4-Axis and 5-Axis Dental Milling Machines Differ?

You already know the basics of dental milling machines. But when it comes to 4-axis and 5-axis models, how much do you really know about their differences? Which one can handle the restorations you want to produce and match your dental lab’s future plans? Let’s break it down so you can make the right choice with confidence.

How Does Each Axis Shape the Milling Process?

To understand the difference between 4-axis and 5-axis milling machines, it helps to start with the basics. Every dental milling machine moves along three main axes:

• X-axis controls horizontal movement.
• Y-axis manages depth positioning.
• Z-axis handles vertical movement.

With only these three, the tool can cut from the top and sides, but reaching steep angles or deep contours is limited.

A 4-axis machine adds the A-axis, which rotates the material around the X-axis—typically up to about 200°. This wider range allows more cutting angles, ideal for many bridge designs or angled crown preparations, but rotation is in one primary direction. Very steep angles or deep undercuts still require repositioning or cannot be reached.

A 5-axis machine adds both the A-axis and the B-axis. While the A-axis rotates around X (up to a full 360°), the B-axis tilts around Y, typically ±25° to ±65°. Together, they let the tool approach from almost any angle, making it possible to mill complex shapes, deep undercuts, and angled screw channels without stopping to reposition the workpiece.

Why Does the B-Axis Matter for Milling Performance?

High-Precision Milling

By adding tilt to the A-axis rotation, the B-axis lets the cutting tool reach the workpiece from nearly any angle. That means fewer repositioning steps, smoother tool paths, and consistent accuracy within 0.02–0.04 mm. Margins seat with precision, and complex geometries like angled screw channels or deep undercuts are milled without manual intervention.

Faster Milling Cycles

In terms of speed, a 5-axis machine can mill up to 60% faster than a 4-axis model. In tests, producing an inner crown in glass ceramics took about 40 minutes on a 4-axis machine, compared with roughly 25 minutes on a 5-axis system.

With greater accuracy, faster cycles, and the ability to mill from almost any angle, the impact of the B-axis becomes clear when you look at what each system can actually produce in the lab.

What Can You Mill with 5-Axis and 4-Axis?

Now that we’ve covered the movement capabilities, let’s see how these differences translate into real-world milling applications. The table below outlines common restorative cases, showing which can be handled efficiently by each system and where additional axis movement provides a clear advantage.

Restoration Type / Case	4-Axis Milling Machine	5-Axis Milling Machine
Single crowns (Zirconia)/PMMA	✅ Cost-effective, efficient	✅ Same capability
Copings, inlays, standard bridges	✅ Efficient for high volume	✅ Same capability
Temporary restorations, diagnostic wax-ups	✅ Suitable	✅ Greater flexibility for complex shapes
Full-arch implant bridges	❌ Not supported efficiently	✅ Essential for angulation and undercuts
Custom abutments	❌ Limited capability	✅ Fully supported
Angled screw channels	❌ Not supported	✅ Fully supported
Hybrid implant bars	❌ Not supported	✅ Fully supported
Cases with deep undercuts	❌ Not supported	✅ Fully supported

A 4-axis system can complete most daily lab work with ease. When cases involve steep angulation, deep undercuts, or multi-surface milling in a single setup such as custom abutments or full-arch implant bars, a 5-axis system provides the precision and flexibility needed to handle them effectively.

Pros & Cons

Beyond case capability, other factors such as cost, learning curve, and maintenance requirements can influence the choice.

Feature	4-Axis Advantages	4-Axis Considerations	5-Axis Advantages	5-Axis Considerations
Cost	Lower investment	Limited upgrade path	Broad indications	Higher cost
Learning Curve	Easier for new users	Less versatile	More adaptable	Requires more training
Maintenance	Fewer moving parts, simpler	May require upgrades sooner	Advanced, future-proof	More complex and costly to maintain
Throughput	Efficient for simple cases	Slower for complex cases	Handles both simple and complex cases	Slightly slower for basic cases
Material Utilization	Ideal for standard blocks	Limited for angled abutments	Excellent for complex shapes	May require advanced CAM

What to Evaluate Before Choosing?

When choosing between a 4-axis and 5-axis dental milling machine, keep these key considerations in mind:

• Restoration Mix: What types of cases are most common in your lab?
• Complexity: Are you planning to expand into advanced, implant-supported, or full-arch cases?
• Service Expansion: Will your services evolve in the near future?
• Volume Needs: What’s your current monthly restoration volume, and how do you expect it to grow?
• Technical Expertise: Does your team have experience with 5-axis workflows, or would additional training be needed?
• Budget: Are you prioritizing a lower upfront cost or long-term capabilities?
• Support & Maintenance: How much maintenance can your team manage on-site?
• Client Demands: Are your clients increasingly requesting complex cases or digital solutions?

Recommendation & Summary

Current Trend:
The dental industry is increasingly moving toward more complex restorations, digital implantology, and highly customized solutions. For labs focused on single-unit work with quick ROI in mind, a 4-axis machine is still a cost-effective choice. However, if your lab or dealership plans to expand, attract high-value clients, or stay ahead with evolving digital workflows, investing in a 5-axis milling machine offers greater flexibility and enhances competitiveness.

In short, here’s what to consider:

• Go for 4-axis if your case mix is straightforward, you’re looking for a quick ROI, and you’re not planning to handle advanced restorations just yet.
• Choose 5-axis if you want to tackle a wider range of cases—including full-arch restorations, custom abutments, and complex implants—or if you’re looking to future-proof your lab.

Looking to optimize your dental lab workflow? Contact us today. Our experts can help you compare milling machine specifications, evaluate robust spindle performance, and choose the right model for your materials—be it zirconia, wax, PMMA, or metal. If you’re evaluating new equipment, our team can walk you through real case examples and performance data, helping you choose the right system for your workflow.