FG 557 Straight Fissure Crosscut Carbide Bur

Q: What is the difference between 556, 557, and 558?

They are the same crosscut straight-fissure shape with different head diameters: 556 is 0.8 mm, 557 is 1.0 mm, and 558 is 1.2 mm. The 557 is the most commonly used size.

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Product Details

The FG 557 is a crosscut straight fissure tungsten carbide bur used for cutting cavity walls, slicing through enamel, and forming flat cavity floors. Its flat-end cylinder shape creates clean, parallel walls, and the crosscut serrations remove material fast with minimal vibration — making it one of the most-reached-for burs in everyday restorative dentistry.

Specifications

US / ADA Number	557
Shape	Straight fissure, flat-end cylinder
Cut	Crosscut (transverse serrations for fast, efficient cutting)
Head Diameter	1.0 mm (ISO size 010)
Head Length	4.1 mm
Overall Length	19 mm (FG standard)
Shank	FG (Friction Grip), 1.6 mm diameter
Material	Tungsten carbide
ISO Specification	500 314 107 007 010
Handpiece	High-speed (air-driven or electric)
Pack Sizes	10 or 100

Common Applications

Creating cavity walls with parallel sides
Cutting through enamel and initial tooth entry
Forming flat cavity floors in restorative preps
Amalgam removal and outline form
Sectioning crowns and bridges (with adequate water spray)

557 vs 556 vs 558 — Which Size?

The 55x crosscut straight-fissure family shares the same flat-end shape and differs only in head diameter:

556	Head 0.8 mm — smaller, more conservative preps
557	Head 1.0 mm — the everyday workhorse size
558	Head 1.2 mm — larger outline, faster bulk cutting

Usage Tips

Speed: Run at high speed with light, intermittent pressure — let the bur cut, don't force it.
Water: Always use adequate water spray to prevent heat buildup.
Replacement: Carbide burs typically stay efficient for several uses; replace when you notice slower cutting, chatter, or visible wear.

Frequently Asked Questions

What is a 557 bur used for?
The 557 straight fissure carbide bur is used to cut cavity walls, slice through enamel, form flat cavity floors, and remove old amalgam. Its flat-end cylinder shape produces clean, parallel walls.

Is the FG 557 crosscut?
Yes. The FG 557 is a crosscut straight fissure bur. The transverse serrations across its blades remove tooth structure and old restorations faster than a plain-cut bur, with less clogging.

What handpiece does the FG 557 fit?
The FG (Friction Grip) shank fits any standard high-speed handpiece — air-driven or electric — with a 1.6 mm chuck.

How many times can I use a carbide 557 bur?
With proper sterilization and technique, a quality carbide 557 stays sharp for several procedures. Replace it once cutting slows, you feel vibration, or the blades show wear.

What's the difference between 556, 557, and 558?
They're the same crosscut straight-fissure shape with different head diameters: 556 is 0.8 mm, 557 is 1.0 mm, and 558 is 1.2 mm. The 557 is the most commonly used size.

Why Choose Koyo Dental?

Koyo Dental burs ship factory-direct from our US warehouse in Irvine, CA — no distributor markups. Every bur is held to strict quality standards for consistent cutting across the whole pack.