The Ultimate Guide to the #170 Dental Bur: Tapered Precision for Crown Preparations and Restorations

Published July 27, 2026 by Deutsche Dental Technologien

In restorative dentistry and dental technology, tapered fissure carbide burs are indispensable for achieving ideal tooth reduction, smooth axial walls, and precise margins. The #170 Dental Bur and its longer #170L counterpart stand out as versatile, high-performance instruments trusted by clinicians and technicians worldwide. Manufactured by Busch & Co., these carbide cone fissure and flat cutter burs deliver controlled cutting with exceptional durability.

This comprehensive guide explores the #170 Dental Bur and #170L in detail: design specifications, historical background, clinical and laboratory applications, best practices, comparisons, and direct links to premium Busch packs from Deutsche Dental Technologien. Whether preparing for crowns, refining cavities, or performing lab adjustments, these burs elevate procedural outcomes.

Tapered Fissure Burs Explained: The Role of #170 and #170L

Tapered fissure burs feature a narrow tip that gradually widens, creating the slight divergence (typically 6–10 degrees total convergence) essential for the path of insertion in indirect restorations like crowns, bridges, inlays, and onlays. The #170 Dental Bur provides standard length for most operative work, while the #170L (long head) offers extended reach for deeper preparations or posterior teeth — and both are available in FG and HP shank versions to suit clinical and laboratory handpieces alike.

Carbide construction ensures efficient cutting, reduced vibration, and smoother surfaces compared to diamonds in many reduction phases. For a deeper look at when each material shines, see our Carbide vs. Diamond Burs: A Clinical Selection Guide.

The #170 is part of a family of tapered fissure instruments — if you work with its slimmer sibling, don’t miss our companion article, The Ultimate Guide to the #169 Dental Bur.

Specifications: The Four Busch #170 and #170L Variants

The #170 series is available in four configurations — standard and long head lengths, each in FG and HP shanks — so there’s a version for every clinical and laboratory setup.

Busch 23 010 FG (US #170):

• Shape: Carbide cone fissure / tapered
• Head Diameter: 010 (1.0 mm)
• Shank: FG for high-speed handpieces
• Key Features: Precise taper, efficient flutes for debris removal
• Pack: 6 burs

Busch 23L 010 FG Long (US #170L):

• Shape: Carbide cone fissure, extended head length
• Head Diameter: 010 (1.0 mm)
• Shank: FG for high-speed handpieces
• Applications: Deeper preparations and posterior access at chairside
• Pack: 6 burs

Busch 23 010 HP (US #170):

• Shape: Carbide cone flat cutter
• Head Diameter: 010 (1.0 mm)
• Shank: HP for straight/low-speed handpieces
• Applications: Laboratory work and slow-speed adjustments
• Pack: 6 burs

Busch 23L 010 HP (US #170L):

• Shape: Cone flat cutter, extended length
• Head Length: Longer for increased cutting depth
• Shank: HP for straight/low-speed handpieces
• Applications: Deeper access and extended laboratory reach
• Pack: 6 burs

All four are Made in Germany with fine-grain tungsten carbide for longevity, high concentricity, and compliance with ISO standards. (Curious how the ISO code on the packaging decodes to shape, size, and cut? Our post Dental Bur ISO Numbering Explained breaks down the full 5-block system.) They resist wear even during demanding crown preparations.

Historical Development of Tapered Burs

The evolution of dental burs accelerated with carbide introductions in the 1940s. Busch & Co. GmbH, established in 1905, has refined these designs over generations, producing instruments that meet the demands of high-speed dentistry and modern prosthodontics. The #170 Dental Bur and #170L embody this legacy of precision engineering. For a broader look at how dental instruments evolved, explore The History and Evolution of Dental Surgical Instruments.

Clinical Applications of the #170 Dental Bur

The #170 Dental Bur excels in:

• Crown and Bridge Preparations: Axial wall reduction with ideal taper for retention and resistance form. Browse our full Crown Preparation collection for complementary instruments.
• Proximal Surfaces: Creating smooth, divergent walls in Class II restorations — see the complete Cavity Preparation bur collection.
• Occlusal and Functional Reduction: Controlled depth while preserving cusp anatomy.
• Margin Definition: Refining chamfer or shoulder margins before finishing.

The #170L Dental Bur variant is particularly valuable for:

• Posterior teeth with limited access.
• Longer clinical crowns or surgical-length needs.
• Extended laboratory adjustments.

Example Workflow: Begin gross reduction with the #170 Dental Bur, verify taper, then refine margins with specialized finishing instruments for optimal fit of the final restoration. For a full sequenced approach to crown work, read our guide to the best burs for crown preparation.

Laboratory Applications (Especially #170L HP)

In dental labs:

• Die trimming and model contouring.
• Framework adjustment for crowns and bridges — see Model Casting instruments.
• Plastics and casting material processing.
• Precise finishing for excellent marginal adaptation with prosthesis carbides.

Advantages of Busch #170 and #170L Dental Burs

• Predictable Taper: Ensures proper path of insertion and seating.
• Efficiency and Comfort: Minimal vibration, reduced chair time.
• Durability: High-grade carbide maintains sharpness.
• Versatility: Effective on enamel, dentin, metals, and composites.
• Inventory Efficiency: Packs of 6 from authorized sources.

Best Practices and Techniques

• Irrigation: Always use water coolant to minimize heat.
• Pressure and Speed: Light, feathering strokes at manufacturer-recommended RPM — consult our Busch sterilization, speeds & techniques library for instrument-specific guidance.
• Sequence: Pair with round burs for initial entry and diamonds for final polishing.
• Verification: Use depth gauges or digital scans to confirm reduction.
• Maintenance: Clean, sterilize, and inspect regularly — our step-by-step post on How to Sterilize Rotary Instruments covers full reprocessing protocols, and STERI-SAFE Bur Blocks keep your rotary inventory organized through the cycle.

In minimally invasive and digital workflows, the #170 Dental Bur supports conservative preparations compatible with CAD/CAM.

Material Science and Design Excellence

Tungsten carbide’s hardness combined with optimized flute geometry delivers clean cuts and excellent surface finishes. Busch’s precision manufacturing minimizes runout for vibration-free performance in both the #170 Dental Bur and #170L.

Comparisons: #170 vs. #170L and Other Burs

• #170 vs. #170L: Standard vs. extended length for accessibility.
• Tapered vs. Straight Fissure: Superior for crown divergence.
• Carbide vs. Diamond: Better for controlled reduction and smoother walls — full breakdown in our clinical selection guide.
• Busch Quality: Outperforms generics in consistency and lifespan.

Not sure which bur family fits your procedure? Start with How to Choose Dental Burs: A Practical Guide.

Purchasing and Product Links

• FG Version (#170): Ideal for clinical high-speed use. Buy Busch Carbide Cone Fissure #170 Dental Bur Pack of 6 (FG)
• FG Long Variant (#170L): Extended reach for deep chairside preparations. Buy Busch Carbide Fissure Cone #170L Dental Bur Pack of 6 (FG Long)
• HP Version (#170): For straight/low-speed handpieces and lab work. Buy Busch Carbide Cone Flat Cutter #170 Dental Bur Pack of 6 (HP)
• HP Long Variant (#170L): Optimized for lab and extended reach. Buy Busch Carbide Cone Flat Cutter #170L Dental Bur Pack of 6 (HP)

You can also browse the complete Clinical Rotary collection or shop all Busch carbide burs.

Safety, Maintenance, and Future Trends

Follow standard sterilization protocols and safety measures. The durability of these burs supports sustainable practice by reducing replacement frequency. Ongoing innovations in coatings and designs — like Busch’s heat-reducing COOL DIAMANT instruments — will further enhance tools like the #170 series.

Conclusion: Equip Your Practice with the #170 Dental Bur Series

The #170 Dental Bur and #170L variant from Busch provide the tapered precision, cutting efficiency, and reliability needed for modern crown and bridge work, operative dentistry, and laboratory procedures. Their German engineering ensures consistent, high-quality results.

Upgrade your rotary instrument inventory today for better efficiency and superior patient outcomes.

Shop Now:

• #170 FG Pack
• #170L FG Long Pack
• #170 HP Pack
• #170L HP Pack

Related resources: Bur Comparison Chart · Speed Chart · Bur Glossary