Dental Bur Shapes Guide: Flame, Football, Pear, Round, Fissure and Inverted Cone Explained

Selecting the correct dental bur shape is the single biggest factor separating a clean, efficient preparation from a frustrating one, whether you are chairside or at the lab bench.

Revised on October 1, 2026

Among the six shapes covered here, the inverted cone bur stands out for its inverted taper — wider at the working tip than at the neck — which lets it cut undercuts and retention features that no straight-sided bur can reach.

This reference guide compares flame, football, pear, round, fissure, and inverted cone geometries side by side, with links to the inverted cone bur collection and a specific pattern for each shape.

Why Bur Shape Drives Clinical Outcome

Bur shape determines contact geometry: which surfaces the blades or grit engage, how much clearance the tip needs, and whether the instrument can undercut a margin or only cut in a straight line. Flame and football shapes taper or bulge to follow external contours; round and pear shapes excavate spherically; fissure shapes cut flat, parallel walls; and the inverted cone reverses the taper entirely to create mechanical retention. Matching shape to task reduces the number of bur changes per procedure and produces more predictable margins across the full Busch Dental Burs catalog.

Flame, Football, and Pear: Contouring and Finishing Shapes

The flame shape narrows to a rounded point, making it well suited to occlusal fissure refinement, interproximal contouring, and fine finishing where access is tight. Best for: the Busch Steel Finishing Flame Bur (48 010) handles composite and acrylic finishing without gouging adjacent contours, while the Busch Diamond Flame Bur (862 012) is the diamond-grit choice for contouring enamel, ceramic, and porcelain in the same tight embrasure spaces.

The football (also called egg) shape is widest at its center and rounds off at both ends, giving broad, even contact across cuspal and occlusal anatomy. Best for: the Busch Carbide Finishing Football (Egg) Bur (44E 018) smooths cusp reduction and occlusal morphology in one pass.

Pear-shaped burs combine a bulbous head with a narrower neck, letting the tip open into undercut areas that a straight bur cannot access — useful for Class II box preparation and caries removal near the pulpal wall. Best for: the Busch Steel Pear Cutter (77 060) in prosthetic and lab settings.

Round, Fissure, and Inverted Cone: Preparation and Retention Shapes

Round burs remain the workhorse for caries excavation, pulp access, and rounding internal line angles; a round diamond such as the Busch Diamond Round Bur (801 010) is a common choice for opening enamel and refining cavosurface margins. Every steel, carbide and diamond round bur size is listed in the Round Dental Burs collection.

Fissure (cylinder) burs cut straight, parallel-sided walls and flat floors, which makes them the standard for crown preparation walls and box forms; the Busch Steel Straight Fissure Bur (36 006) is representative of this pattern.

The inverted cone bur is the outlier of the group: its cutting head is wider at the tip than at the shank, so it removes material laterally as it withdraws rather than as it advances. That geometry makes it the tool of choice for retention grooves, dovetail preparations in amalgam and cast restorations, and undercut removal in prosthetic work where mechanical retention — not adhesion alone — needs to hold a restoration in place. Chamfer margins prepared with a tapered diamond are a different task entirely and should not be confused with the inverted cone's retentive function.

Flame Burs: Busch Figure Numbers, Grits and Shanks

A flame bur is sold at DeutscheDT.com in three materials, and the Busch figure number tells you which one you are holding. Flame diamond burs carry figure numbers 860, 861, 862, 863, 864 and 889 (plus the micro-prep MI 8889 for minimal-access work), all in FG shanks for the high-speed handpiece. A prefix sets the grit: 5862 and 5863 are super coarse (black ring); 6862, 6863 and 6889 are coarse (green ring); a plain 862, 863 or 889 is medium; 8860, 8862, 8863 and 8889 are fine (red ring); and 860EF, 862EF and 863EF are extra fine (yellow ring). A typical sequence on an enamel or ceramic margin runs Busch 6862 014 for reduction, 862 012 for contouring, then 8862 012 and 862EF 012 to finish.

Carbide flame finishing burs are figure 48 (US No. 242 at the 010 size), supplied in FG for chairside composite and amalgam finishing, with a 48F fine grade (yellow ring) and a 48L long-head version: see the 48 010 FG and 48F 012 FG. The same figure 48 is also made as a steel finishing flame in HP shanks for the lab bench (48 010 HP). For bulk acrylic and plaster work, HP flame cutters in carbide (figure 425, from the fine crosscut 425FX 060 to the super coarse 425SGX 060, plus the short-head Shorties S 430X 023) and steel (figure 78, 78 050) do the heavy removal. Browse all of them in the Flame Burs collection.

End-Cutting Burs (US No. 958)

An end cutting bur is a cylinder that cuts only on its flat tip; the sides are smooth, so it can deepen a floor or flatten a shoulder without touching the axial walls. The pattern DeutscheDT.com carries is the Busch 207 012 carbide end cutting cylinder bur (US No. 958), an FG bur for the high-speed handpiece, and it is the only end cutting bur in the current range; its collection page is US No. 958 Bur. Typical uses are finishing the gingival floor of a Class II box and flattening a shoulder margin on a crown preparation. When the axial wall and the shoulder are to be cut in the same pass, a diamond cylinder with rounded edges such as the Busch 837KR 012 is the usual choice instead.

Football (Egg) Burs: Diamond and Carbide Options

Busch lists football burs as "Football (Egg)" and makes them in two diamond figures and one carbide finishing figure. Diamond football burs come as figure 368 and figure 379, running from super coarse (5379 023) through coarse (6368 016) and medium (379 018) to fine (8368 023) and extra fine (379EF 023), all FG, with a few HP sizes (368 023 HP, 379 014 HP and 379 023 HP) for the lab. The large 5811 033 and 037 are super coarse eggs for fast occlusal reduction, and the Ziramant 6379Z and 8379Z are the zirconia versions. Carbide finishing football burs are figure 44E (US No. 7404, 7406 and 7408 by head size) in FG and RA shanks, with 44E-F fine (US No. 8406) and 44E-UF ultra fine (US No. 9406) grades for composite finishing. Typical uses: occlusal reduction for crowns and onlays, shaping cusp inclines, and finishing the lingual surfaces of anterior restorations. See the full Football (Egg) Burs & Diamonds collection, and the step-by-step composite sequence in Best Dental Burs for Composite.

Bur Shape Comparison

FAQs

What is an inverted cone bur used for?
It is used to cut retention grooves, dovetails, and undercut features in cavity and crown preparations, since its cutting head is wider at the tip than at the neck.

How does a flame bur differ from a football (egg) bur?
A flame bur tapers to a rounded point for fine contouring, while a football bur is widest at its center and rounds off at both ends for broader occlusal shaping.

When is a chamfer bur preferred over a round diamond bur?
A chamfer preparation calls for a tapered, rounded-end diamond that produces a smooth, curved shoulder margin, while a round diamond bur is better suited to opening access and excavating caries rather than defining a finish line.

What makes pear-shaped burs useful for Class II preparations?
Their bulbous head and narrower neck let the bur open undercuts inside the preparation without widening the external cavosurface margin.

Are inverted cone burs compatible with high-speed handpieces?
Most inverted cone burs, including Busch's steel and carbide versions, are supplied in HP (straight handpiece) shanks for lab and prosthetic use; check the specific product listing for shank type before ordering.

Which bur shape should I reach for first when prepping a crown margin?
A fissure (cylinder) bur is the standard choice for cutting straight axial walls and box forms before refining the margin with a shape-specific finishing bur.

What are the best brands for flame diamond burs?
Busch, Komet, Meisinger, Alpen, and Edenta are widely regarded as leading manufacturers of flame diamond burs, alongside Brasseler USA, SS White, NTI, and Horico. Busch’s flame diamond line spans figure numbers 862, 862EF, 863, 863EF, 6862, 8862, and 8863 across coarse through extra-fine grits, covering everything from bulk enamel and ceramic reduction to fine margin finishing.

Shop the full Inverted Cone Burs.