US No. 55 Bur – Busch Straight Fissure Carbide, Made in Germany
The US No. 55 is the American number for a straight fissure bur with a 0.8 mm head (ISO size 008): a parallel-sided cylinder with a flat end, so it cuts straight walls and a flat floor in one motion. Busch & Co. manufactures it in Germany as Busch No. 21 008. Every US No. 55 on this page is a genuine Busch instrument and ships from our US warehouse.
Busch & Co. GmbH
US No. 55 Busch Carbide Straight Fissure (Cylinder) Bur | Busch No. 21 008 – FG | Pack of 6
Regular price $36.99Unit price-
Busch & Co. GmbH
US No. 55 Busch Carbide Straight Fissure (Cylinder) Bur | Busch No. 21 008 – HP | Pack of 6
Regular price $36.99Unit price
Reference pages already linked from this collection, in one place.
Which US No. 55 Do You Need?
Choose by shank first; every active product in the collection is linked once below by its Busch number.
FG (high-speed handpiece)1 items
| Busch No. | US No. | Material | Cut | Shank | Best for | Pack |
|---|---|---|---|---|---|---|
| 21 008 | 55 | Carbide | Plain-cut | FG | High-speed handpiece | 6 |
HP (straight handpiece)1 items
| Busch No. | US No. | Material | Cut | Shank | Best for | Pack |
|---|---|---|---|---|---|---|
| 21 008 | 55 | Carbide | Plain-cut | HP | Straight handpiece: laboratory and denture work | 6 |
FG (friction grip, 1.6 mm shank, high-speed handpiece). HP (2.35 mm shank, straight handpiece). See the Busch Bur Size Chart for head and shank dimensions.
Speed and Technique
Run the FG version in the high-speed handpiece with continuous water spray and light, intermittent pressure; let the blades do the work. The HP version runs at laboratory speed in the straight handpiece. Maximum recommended speeds for every Busch shape are in our Dental Bur Speed Chart, and reprocessing steps in the Bur Sterilization Guide.
Made in Germany by Busch & Co.
Busch & Co. has manufactured rotary instruments in Engelskirchen, Germany since 1905. Every instrument on this page is a genuine Busch product, precision-ground on a concentric shank under ISO 13485-certified quality management and covered by our Busch warranty.
Clinical Use
- Cavity preparation: opening through enamel and establishing the straight walls and flat floor of Class I and Class II preparations, including proximal boxes.
- Restoration removal: cutting out old amalgam and composite.
- Sectioning: dividing crowns and multi-rooted teeth.
- Laboratory and denture work: the HP carbide version trims acrylic, adjusts denture bases and reduces plaster models in the straight handpiece.
At 0.8 mm the No. 55 is a fine head for narrow fissures and conservative preparations.
The No. 55 is plain-cut; its crosscut twin in the same shape and size is the US No. 555 (Busch 31 008). Crosscut blades cut faster and clear debris; plain-cut blades leave a smoother wall.
Care and Reconditioning
Busch carbide burs are reusable: clean, disinfect and sterilize them between patients following the manufacturer instructions and replace them once they dull. Our Dental Bur Reprocessing & Sterilization Guide gives the steps for Busch rotary instruments.
Compare With
Related Busch collections: US No. 56 Bur, US No. 57 Bur, US No. 555 Bur, Straight Fissure (Cylinder) Burs, and Burs for Cavity Preparation. For bur numbering and dimensions, see the Busch Bur Size Chart and the Dental Bur Glossary.
Related resources: US Bur Number Finder · Bur Comparison Chart · Speed Chart · Bur Glossary · Nearby sizes: US No. 56, US No. 57
FAQ
What is the Busch number for a US 55 bur?
Busch No. 21 008 in carbide (FG/HP).
What size is a No. 55 bur?
The No. 55 has a 0.8 mm head diameter (ISO size 008) on a straight fissure bur head, ISO shape 107 (cylinder, flat end).
What is the difference between a No. 55 and a No. 555?
Same shape and size; one is plain-cut and the other crosscut. The No. 55 is plain-cut — crosscut cuts faster and clears debris, plain-cut leaves a smoother surface.
Are Busch No. 55 burs reusable?
Yes. Carbide burs are cleaned, disinfected and sterilized between patients and replaced when they dull; the Bur Sterilization Guide gives the validated steps.
