Dental burs guide: introduction to Shapes, Shanks and Grits

A dental bur is a rotary cutting instrument that fits into a dental handpiece and is used to cut, shape and polish tooth structure, restorations and bone. Among all the tools in the profession, burs are definitely high on the list - and there are a lot of them. The good news is that every bur, from any manufacturer, is defined by the same four parameters: shank, head shape, grit or blade count, and size. Once you can read those four, you can read any catalogue and any ISO code.

In this guide we break each one down, with the sizing tables we get asked about most. Bookmark it - it's the reference we use ourselves.

Anatomy of a Dental Bur

Every bur has three parts: the shank, which fits into the handpiece; the neck, the narrow section that carries the head; and the head, the working end that touches the tooth. Think of it this way - the shank decides which handpiece and speed you're working at, the head shape and size decide what the bur does, and the grit (diamond) or blade count (carbide) decides how aggressively it does it.

Shank Types: FG, RA, HP, Long and Short Shank

The shank is the longest part of the bur and the part that goes into the handpiece, so it's chosen by handpiece, not by procedure. Get this one wrong and the bur simply won't seat - or worse, it seats and runs out of true. Here are the ones you'll meet:

Shank	Full name	Shank diameter	Handpiece	Speed	Typical use
FG	Friction grip	1.6 mm	High-speed air turbine or electric	200,000–400,000 rpm	Cavity and crown preparation, enamel and ceramic cutting, finishing. The most common shank.
FG long shank	FG surgical / extra long	1.6 mm, 21–25 mm total length	High-speed	High	Endodontic access, posterior molars, surgical sites, deep cavities. Longer reach, same head.
FG short shank	FG mini / pediatric	1.6 mm, 16 mm total length	High-speed, mini heads	High	Children, limited mouth opening, posterior access with small handpiece heads.
RA	Right angle (latch type, CA)	2.35 mm with latch groove	Slow-speed contra-angle	Up to 40,000 rpm	Caries removal, polishing, finishing, endodontics, surgical bone work.
HP	Handpiece (straight)	2.35 mm, 44.5 mm total length	Straight slow-speed	Up to 40,000 rpm	Laboratory work, denture and acrylic adjustment, some surgical procedures.

The ISO shank codes you will see in catalogues: 313 = FG standard (19 mm), 314 = FG long (21 mm), 315 = FG short (16 mm), 316 = FG extra long (25 mm), 204 = RA (22.5 mm), 205 = RA long, 104 = HP.

Materials: Diamond, Carbide, Steel, Gold

Dental burs are made from different materials, and every material has its own advantages - so most of us keep more than one kind in the tray.

Diamond burs grind rather than cut. Diamond grit is electroplated or sintered onto a steel blank, and the bur abrades its way through enamel, ceramic and zirconia that a blade simply cannot bite into. They're the instrument for crown preparation, veneer preparation, adjusting ceramics and any enamel work.

Carbide burs cut with blades machined from tungsten carbide. They leave a smoother surface than diamond on dentin, amalgam and composite, and are the choice for cavity preparation, caries removal, finishing composite and trimming acrylic. Blade count matters: 6–8 flutes cut, 12–20 finish, 30 polishes.

Steel burs are the cost-efficient option. They're more flexible than diamond or carbide, so they're less likely to snap, but they dull quickly and are prone to corrosion. Mostly slow-speed caries removal and lab use.

Finally, gold-plated diamonds. Less common, but they run cooler and leave a finer surface finish, which is why some clinicians won't prepare a veneer with anything else. For the full diamond-versus-carbide argument, we wrote it up separately: diamond vs carbide burs.

Head Shapes and ISO Shape Numbers

If the shank is about the handpiece, the head shape is about the job. There are dozens of shapes, and each one exists because a specific preparation needed it. These are the ones a general practice reaches for every day, with the ISO shape number you'll see in every manufacturer's code.

Shape	ISO shape no.	Common sizes	Use
Round	001	Carbide ¼–8; diamond 010–023	Caries removal, cavity opening, endodontic access
Inverted cone	010	Carbide 33½–39; diamond 010–016	Undercuts, retention grooves, flattening cavity floors
Pear	237 / 238	Carbide 330 (short), 245 (long)	Cavity preparation - the 330 and 245 are the standard prep burs
Cylinder, flat end	107–110	Diamond 010–018	Shoulder margins, axial walls, occlusal reduction
Cylinder, round end	141	Diamond 010–016	Chamfer margins, crown preparation
Tapered fissure	170–172 (flat), 199 (pointed)	Carbide 169–172; diamond 012–016	Crown preparation, cavity walls, crown removal
Flame / ogival	243 / 244	Diamond 010–016	Interproximal and lingual reduction, veneer preparation, finishing
Egg / football	257 / 258	Diamond 016–023	Lingual reduction of anteriors, occlusal adjustment
Needle	164 / 165	Diamond 008–012	Interproximal access, fine contouring, IPR
Wheel	042	Diamond 030–045	Lingual reduction, occlusal grooves

One question we get constantly: 330 or 245? Both are pear carbides with a 0.8 mm diameter. The 330 head is about 1.6 mm long, the 245 about 3 mm - so the 245 reaches deeper in the same preparation, and that's the whole difference.

Grits: What the Colour Bands Mean

Every diamond bur carries a coloured band on the shank, and that band is the grit. Coarse grit removes material fast and leaves a rough surface; fine grit is for finishing. In a typical crown preparation you'd run green or blue for the bulk reduction, red for the margins and refinement, then yellow or white to finish. Once you know the colours you never need to read the label.

Band colour	Grit	Particle size (approx.)	Use
Black	Super coarse	180 μm	Rapid bulk reduction, crown removal, zirconia sectioning
Green	Coarse	125–150 μm	Bulk reduction, crown and bridge preparation
Blue	Medium / standard	100 μm	General preparation - the default grit when no band is shown
Red	Fine	50 μm	Margins, finishing preparations, composite finishing
Yellow	Super fine	25–30 μm	Final finishing, polishing enamel and ceramic
White	Ultra fine	15 μm	High-gloss finishing of composite and porcelain

Carbide burs use blade count instead of grit, sometimes marked with the same colours: no band or green for cutting (6–8 blades), red for finishing (12 blades), yellow for fine finishing (16–20), white for ultra-fine (30).

Sizes: Reading Head Diameter

Diamond burs make this easy: the last three digits of the ISO code are the head diameter in tenths of a millimetre. 010 is 1.0 mm, 012 is 1.2 mm, 014 is 1.4 mm, and so on up through 016, 018, 021 and 023. Carbide burs are less kind - they use the older US numbering, where one number identifies shape and size together. Here are the two families you'll look up most:

Round carbide no.	Head diameter	Inverted cone carbide no.	Head diameter
Round ¼	0.5 mm	Inverted cone 33½	0.6 mm
Round ½	0.6 mm	Inverted cone 34	0.8 mm
Round 1	0.8 mm	Inverted cone 35	1.0 mm
Round 2	1.0 mm	Inverted cone 36	1.2 mm
Round 4	1.4 mm	Inverted cone 37	1.4 mm
Round 6	1.8 mm	Inverted cone 39	1.8 mm
Round 8	2.3 mm	-	-

How to Read a Dental Bur ISO Number

ISO 6360 gives every bur a 15-digit code in five groups. It looks intimidating on the box, but it's the same five groups every time. Take a typical FG round diamond, 806 314 001 524 014:

• 806 - head material: diamond (500 = tungsten carbide, 330 = steel)
• 314 - shank: FG, 21 mm long (313 = FG 19 mm, 204 = RA, 104 = HP)
• 001 - head shape: round
• 524 - grit: medium (534 = coarse, 514 = fine, 504 = super fine; the middle digit identifies the grit)
• 014 - head diameter: 1.4 mm

Read the same way, 500 314 237 006 012 is a carbide FG pear with a 1.2 mm head - the 245. Once you can decode the five groups, every manufacturer's catalogue reads the same, which is exactly why the search box at the top of our site takes ISO numbers.

Choosing Dental Burs: A Short Checklist

1. Match the shank to the handpiece - FG for the turbine, RA for the contra-angle, HP for the straight handpiece.
2. Choose material by what you are cutting - diamond for enamel, ceramic and zirconia; carbide for dentin, amalgam, composite and acrylic.
3. Choose shape by the preparation - round for access, pear and inverted cone for cavity form, cylinders and tapers for crowns, flames and needles for interproximal work.
4. Sequence the grits - coarse to reduce, fine to finish. One bur rarely does both well.
5. Buy ISO-coded burs from a manufacturer you can trace. A bur that runs out of true or dulls after two preparations costs you far more in chair time than it saved at the checkout. Ours are made in Israel, ISO 6360 coded, and every product page shows the code - that's how we'd want to buy them too.

Where to Go Next

That's the four parameters. For an overview of bur categories by procedure, read types of burs in dentistry. For the diamond-versus-carbide decision in detail, diamond vs carbide burs. For how many uses a diamond bur gives before replacement, diamond bur lifespan. And when you know the code you need, browse diamond burs or search by ISO number in the box at the top of the page.