Dental Bur Shape & Number Chart: A Complete FG Reference Guide
Every operatory has the same problem. Someone asks for "the 557" and everyone knows what they mean. Someone asks for "the TR-12" and half the room reaches for the wrong drawer. Diamond burs and carbide burs use two entirely different naming systems, nobody was ever formally taught either one, and the knowledge lives in whichever assistant has been there longest.
This is the reference we wished existed. Shape codes, style numbers, head dimensions in millimetres, grit bands, shank lengths, and what each bur is actually for, with a picture of the bur beside its number. Every dimension below is the real spec from a bur we stock, not a generic table copied from a catalog.
The two naming systems, briefly
Carbide burs use numbers. A 557, a 330, a 245. These are US-standard style numbers that go back decades and are consistent across manufacturers, which is why they stuck in everyday speech. The number tells you shape and size together, but only if you already know the system. There is no logic you can derive it from.
Diamond burs use letter-plus-number shape codes. A TR-12, a BR-40, a CP-11. Here the letters do carry meaning: they describe the head geometry, and the number describes the size within that geometry. Once you know the letter prefixes, the system reads itself.
Diamond bur shape codes
| Code | Shape | Primary use |
|---|---|---|
| BR | Ball / Round | Access opening, outline form, caries removal |
| TR | Round End Taper | Axial reduction with a rounded margin |
| TF | Flat End Cone | Axial reduction with a square shoulder |
| SF | Flat End Cylinder | Parallel walls, flat floor, crown sectioning |
| CP | Ogival End Cylinder | Chamfer margins |
| FO | Bud / Flame | Interproximal and veneer access |
| TC | Pointed Cone | Interproximal separation, embrasure shaping |
| EX | Inverted cone, double cone, end cut | Occlusal reduction, end-cutting |
Grit color bands
The colored band on the shank tells you grit, and this coding is standard across the industry. The order code carries it too: the suffix at the end of a diamond code is the grit.
| Band | Grit | Code suffix | When to reach for it |
|---|---|---|---|
| Black | Super coarse | S | Zirconia and other high-strength ceramics |
| Green | Coarse | C | Bulk reduction, fast sectioning, gross removal |
| Blue | Medium | none, or M | Standard preparation, the default for most work |
| Red | Fine | F | Margin refinement, finishing |
| Yellow | Extra fine | EF | Final polish on composite and ceramic |
So a TF-13 is medium, a TF-13C is the same head in coarse, and a TF-13F is the same head in fine. Same geometry, different cut.
Diamond bur size chart
Head dimensions are diameter × length in millimetres. Where two diameters are shown, the figure in parentheses is the tip diameter of a tapered head.
Round (BR)
| Bur | Code | Head | Total length |
|---|---|---|---|
 |
BR-41 | 1.4 × 1.4 mm | 19.0 mm |
 |
BR-40 | 1.6 × 1.6 mm | 19.0 mm |
 |
BR-31 | 1.8 × 1.8 mm | 19.0 mm |
The first bur into most preps. Opens access and defines outline form. Round diamond burs
Round End Taper (TR)
| Code | Head | Total length |
|---|---|---|
| TR-11 | 1.4 (0.7) × 10.0 mm | 22.0 mm |
| TR-12 | 1.6 (0.8) × 10.0 mm | 22.0 mm |
| TR-13 | 1.8 (0.9) × 9.0 mm | 22.0 mm |
| TR-25 | 1.4 (0.8) × 8.0 mm | 22.0 mm |
The workhorse of crown and bridge: axial reduction and a rounded margin in one pass. TR-25's shorter head gives you control in a short clinical crown. Round end taper diamond burs
Tapered Fissure / Flat End Cone (TF)
| Code | Head | Total length |
|---|---|---|
| TF-21 | 1.6 (0.8) × 6.5 mm | 21.0 mm |
| TF-12 | 1.6 (0.8) × 10.0 mm | 22.0 mm |
| TF-13 | 1.8 (0.9) × 10.0 mm | 22.0 mm |
Flat tip cuts a defined shoulder, the margin most all-ceramic restorations want. Tapered fissure diamond burs
Straight Cylinder (SF)
| Code | Head | Total length |
|---|---|---|
| SF-12 | 1.4 × 8.0 mm | 22.0 mm |
| SF-13 | 1.6 × 8.0 mm | 22.0 mm |
Parallel walls and a flat floor. Crown sectioning and parallel-wall preparation. Straight cylinder diamond burs
Flame / Bud (FO)
| Code | Head | Total length |
|---|---|---|
| FO-32 | 1.8 × 3.6 mm | 19.0 mm |
Narrow profile for interproximal work and veneer margins. Flame diamond burs
Chamfer (CP)
| Code | Head | Total length |
|---|---|---|
| CP-11 | 1.2 × 8.0 mm | 22.0 mm |
| CP-12 | 1.4 × 8.0 mm | 22.0 mm |
| CP-13 | 1.6 × 8.0 mm | 22.0 mm |
The ogival tip cuts an even margin depth in a single pass, giving the lab a chamfer it can actually read on the die.
Needle / Pointed Cone (TC)
| Code | Head | Total length |
|---|---|---|
| TC-10 | 1.4 × 10.0 mm | 22.0 mm |
| TC-11 | 1.6 × 10.0 mm | 22.0 mm |
Tapers to a point for interproximal separation. The 10.0 mm head keeps the shank clear of the adjacent tooth.
Round End Inverted Cone and End Cut (EX)
| Code | Shape | Head | Total length |
|---|---|---|---|
| EX-21 | Round End Inverted Cone | 2.1 (1.6) × 5.0 mm | 19.0 mm |
| EX-18 | End Cut | 1.2 × 0.2 mm | 21.0 mm |
The EX-21's rounded end and inverted taper follow cusp and fossa anatomy for occlusal reduction without gouging a flat spot. The end cut carries diamond on the tip face only, with smooth non-cutting sides, so it deepens a shoulder or box without touching the wall you just finished.
Carbide bur numbers
Carbide style numbers group loosely by shape. Round burs run 2, 4, 6, 8 in ascending size. Pear-shaped burs sit in the 200s and 300s. Straight fissures run 56 through 63 plain and 556 through 563 crosscut, the same eight head sizes in both. Dome-end fissures follow the same logic: 1156 through 1161 plain, 1556 through 1561 crosscut. Finishing burs use four-digit numbers in the 7000s.
| Bur | Style | Shape | Head | Best for |
|---|---|---|---|---|
 |
2 | Round | 1.0 × 1.0 mm | Small caries excavation, conservative access, refining internal line angles |
 |
4 | Round | 1.4 × 1.4 mm | Routine caries removal, Class I access, retention grooves |
 |
6 | Round | 1.8 × 1.8 mm | Larger carious lesions, gross dentin removal, wide access |
 |
8 | Round | 2.3 × 2.3 mm | Bulk dentin removal, deep caries excavation |
 |
245 | Pear | 0.9 × 2.5 mm | Conservative Class I access, shallow occlusal preps |
 |
330 | Pear | 0.8 × 1.9 mm | Class I/II access, intracoronal cavity form |
 |
556 | Straight fissure crosscut | 0.8 × 3.8 mm | Narrow sectioning, fine flat-floor cavity form |
 |
557 | Straight fissure crosscut | 1.0 × 4.2 mm | Initial access, crown prep, flat-floor cavity form |
 |
1157 | Dome fissure | 1.0 × 4.2 mm | Cavity form with a rounded floor, reduced line-angle stress |
 |
1158 | Dome fissure | 1.2 × 4.2 mm | Wider cavity form, Class II box preparation |
All ten styles above run 19.0 mm total length on an FG shank. Carbide burs
Trimming and finishing carbides
Finishing burs are identified by a 7000-series style number. Blade count is not encoded in that number, it lives in the ISO toothing code, so a supplier spec sheet is the only reliable place to read it. More blades means smaller bites and a smoother surface straight off the bur.
| Bur | Style | Shape | Head | Best for |
|---|---|---|---|---|
 |
7104 | Flame | 1.4 × 3.3 mm | Anterior composite finishing, line angle refinement |
 |
7404 | Egg | 1.4 × 2.7 mm | Occlusal composite, lingual surfaces, concave anatomy |
 |
7901 | Needle | 0.8 × 4.0 mm | Tight embrasures, gingival margin finishing |
Surgical and endodontic carbides
| Bur | Style | Shape | Head | Total length | Best for |
|---|---|---|---|---|---|
 |
Endo-Z 152 | Tapered, safe-ended | 1.6 × 9.0 mm | 21.0 mm FG L | Access refinement and pulp chamber roof removal without gouging the floor |
 |
Zekrya 151 | Surgical taper | 1.6 × 11.0 mm | 21.0 mm | Third molar sectioning, crown and root separation |
 |
4 Surgical | Round | 1.4 × 1.4 mm | 25.0 mm | Deep posterior caries access, bone removal |
Shank types and lengths
Shank designation and total instrument length are two different numbers. The designation below is the shank standard; the total length of a finished bur depends on the head.
| Shank | ISO | Designation | Notes |
|---|---|---|---|
| FG | 314 | 19 mm | Standard friction grip. Fits every standard high-speed handpiece in US practice. Finished burs run 19.0 to 24.0 mm total depending on head length. |
| FG L | 315 | 21 mm | Slightly extended. Common on endodontic and surgical shapes. |
| FG XL | 316 | 25 mm | Surgical length. Keeps the handpiece head clear of the cheek on deep posterior access. |
| RA | 204 | 22.5 mm | Latch-type for slow-speed contra-angle. 2.35 mm shank diameter. |
Picking a bur by procedure
- Crown prep, chamfer margin: TR-12 or TR-13 for axial reduction, CP-11 to define the margin, then a fine-grit TR to refine.
- Crown prep, shoulder margin: TF-12 or TF-13 through the axial walls and shoulder in one instrument.
- Class I access: carbide 330 or 245, or a BR-41 diamond to open.
- Class II box: carbide 1158 for a rounded internal floor, or 557 for a flat one.
- Crown sectioning: coarse SF-12 or SF-13, or a carbide 557 where you want tactile feedback rather than a slurry.
- Veneer prep: FO-32 flame for interproximal margins, fine grit to finish.
- Third molar sectioning: Zekrya 151 on a surgical-length shank.
- Endodontic access: carbide 4 to open, then Endo-Z 152 to flare the walls without touching the floor.
- Composite finishing: 7104 flame on line angles, 7404 egg on occlusal anatomy, 7901 needle in the embrasures.
One thing the chart can't tell you
Numbers and dimensions tell you which bur to pick up. They don't tell you when to put one down.
Burs almost never fail outright. They drift. A diamond's bonded layer wears unevenly, the head loses true, and it stops cutting and starts scraping. A carbide's blades round over until it's burnishing dentin instead of shearing it. It happens across three or four cases, slowly enough that you compensate without ever deciding to: a little more pressure, one more pass, longer at the margin. Your hand adjusts before your brain does.
The practical test is simple: if you're pushing harder than you did on the first case in the pack, the bur is finished, whatever it looks like. We go deeper on that in how long dental burs last and when to replace one, and on choosing between materials in diamond vs carbide burs.
Browse the full bur catalog. Diamonds and carbides, direct to your practice, no distributor markup. Or start with a prep kit and get a full sequence in one box.
Head dimensions listed are for Taft Dental Supply burs. Dimensions for a given style number vary slightly between manufacturers, so check your supplier's specs if you're matching an existing bur exactly.