US No. 704 Bur – Busch Tapered Fissure Carbide & Steel, Made in Germany

The US No. 704 is the American number for a tapered fissure bur with a 2.3 mm head (ISO size 023): a cone that narrows toward the tip, so the walls it cuts diverge toward the occlusal: the geometry crown and inlay preparations depend on. Busch & Co. manufactures it in Germany as Busch No. 33 023 and Busch No. 38 023. Every US No. 704 on this page is a genuine Busch instrument and ships from our US warehouse.

Which US No. 704 Do You Need?

US No.	Busch No.	Material	Cut	Shank	Best for	Pack
704	33 023	Carbide	Crosscut	HP	Straight handpiece: laboratory and denture work	6
704	38 023	Steel	Crosscut	HP	Economical laboratory cutting of acrylics and plaster	6

HP (2.35 mm shank, straight handpiece). See the Busch Bur Size Chart for head and shank dimensions.

Clinical Uses of the US No. 704

Crown preparation: axial reduction with built-in taper for full-coverage crowns and bridge abutments.
Inlay and onlay preparation: cavity walls that diverge toward the occlusal for a path of insertion.
Cavity preparation: extending and shaping preparations where a flat floor and tapered walls are wanted.
Sectioning and laboratory work: the surgical-length versions section teeth and roots; the HP carbide and steel versions cut acrylic and plaster in the straight handpiece.

At 2.3 mm the No. 704 is a wide cone for bulk reduction and laboratory cutting.

Speed and Technique

Keep the bur parallel to the intended path of insertion so the taper of the head becomes the taper of the wall; use water spray with the FG versions and laboratory speed for HP. 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-certified quality management and guaranteed to arrive free of manufacturing defects under our Busch arrival guarantee.

Dental Instruments, Tools, Burs, Diamonds and Polishers Made In Germany

FAQ

What is the Busch number for a US 704 bur? Busch No. 33 023 in carbide (HP); Busch No. 38 023 in steel (HP).

What size is a No. 704 bur? The No. 704 has a 2.3 mm head diameter (ISO size 023) on a tapered fissure bur head, ISO shape 168 (cone, flat end).

Carbide or steel? Tungsten carbide for enamel, dentin, composite and amalgam in the clinic; the steel No. 704 is the economical choice for acrylics, plaster and other soft materials in the laboratory.

Are Busch No. 704 burs reusable? Yes. Carbide and steel burs are cleaned, disinfected and sterilized between patients and replaced when they dull; the Bur Sterilization Guide gives the validated steps.

Related resources: US Bur Number Finder · Bur Comparison Chart · Speed Chart · Bur Glossary · Nearby sizes: US No. 702, US No. 703, US No. 705, US No. 706