Crown Prep Bur Sequence: Anterior vs Molar, Step by Step
An anterior crown prep and a molar crown prep use a lot of the same burs. They are not the same sequence.
On an anterior, the job is esthetics and control: a labial face that has to be reduced in two planes, a lingual concavity a straight bur cannot follow, and a margin that ends up on display. On a molar, the job is bulk and access: more occlusal reduction, functional cusps that take a bevel, and a second molar you are reaching with a cheek and a tongue in the way.
Here is the bur sequence for each, step by step, with the shape for every step and where the two preps split.
The shared backbone
Both preps follow the same order, and it is worth keeping the order fixed, because each step sets up the next:
- Depth orientation grooves
- Incisal or occlusal reduction
- Facial and lingual reduction
- Proximal reduction
- Margin and axial refinement
- Finishing
The round end taper does most of the work in both. What changes is the diameter you pick, which supporting shapes join it, and how much structure each step removes. Our round end taper guide covers that bur in depth, and the two main supporting shapes each have their own guide: the football diamond and the needle diamond.
Reduction values below are common ranges. The restoration material and your lab's guidelines set the actual numbers, so check both before you cut.
Anterior crown prep sequence
Diameter: a smaller round end taper, around 1.4 to 1.6 mm (Taft TR-11 or TR-12). Anterior teeth are narrow faciolingually, and a large bur over-reduces fast.
1. Depth grooves on the incisal edge and labial face
Cut incisal depth grooves, then labial grooves in two sets: one following the cervical third, one following the incisal two-thirds. The labial face of an anterior is not flat, and a single plane of reduction either leaves the incisal third thick or over-reduces the cervical third toward the pulp.
2. Incisal reduction
Connect the incisal grooves. Common guidance is in the range of 1.5 to 2.0 mm for all-ceramic, angled slightly toward the lingual on maxillary teeth so the incisal edge is not undermined.
3. Labial reduction in two planes
Reduce the cervical plane, then the incisal plane, with the round end taper held parallel to each set of grooves in turn. This is the single step that most decides whether the final crown looks natural or bulky.
4. Lingual reduction: the step that needs a different shape
The lingual surface of an anterior is concave. A straight bur flattens it and removes structure you need. A football diamond follows the concavity. Then use the round end taper for the short lingual axial wall above the cingulum, which provides much of the prep's retention. Do not over-taper it.
5. Proximal reduction
Anterior contacts are tight and the adjacent tooth is esthetic. Break through with a narrow instrument first, such as a needle diamond or flame diamond, leaving a thin sliver of enamel between the bur and the neighbor. Then follow with the round end taper.
6. Margin and finishing
Establish the margin with the round end taper tip, or a chamfer bur for a defined chamfer, or a tapered fissure if the material calls for a shoulder. Refine with the same shape in fine grit (red band), and round any sharp incisal line angles.
Molar crown prep sequence
Diameter: a larger round end taper, around 1.8 mm (Taft TR-13). More bulk to remove, and ceramics on molars usually want a heavier chamfer.
1. Depth grooves on the occlusal and axial surfaces
Cut occlusal depth grooves along the cusp ridges and central groove, and axial depth grooves on the buccal and lingual. Sink the bur tip to half its diameter and you know the groove depth, roughly 0.9 mm with a 1.8 mm bur.
2. Occlusal reduction that follows the anatomy
Reduce following the cusp inclines rather than flattening the occlusal table. A flat occlusal surface removes more tooth than needed at the cusp tips and leaves too little room in the grooves. Common guidance is in the range of 1.5 to 2.0 mm, depending on material. A football diamond follows cusp and fossa curvature naturally.
3. Functional cusp bevel: the molar-only step
Place a bevel on the functional cusps: the lingual cusps of maxillary molars and the buccal cusps of mandibular molars. Without it, the restoration is thin exactly where occlusal load is highest. Hold the round end taper at roughly the angle of the opposing cusp inclines.
4. Buccal and lingual axial reduction
Keep the shank parallel to the path of draw and use the full head length for one smooth plane. On long clinical crowns, a longer head avoids steps in the axial wall.
5. Proximal reduction
Same principle as anterior: open the contact with a narrow bur first, protecting the adjacent tooth, then bring the round end taper through. On second molars, check your angle from the occlusal view. Access tempts you to tilt, and a tilted bur means an over-tapered distal wall.
6. Margin and finishing
Carry the chamfer around at consistent depth. Molar margins most often thin out on the distal and lingual, where visibility is worst. Refine with fine grit in the same shape, and round the occlusal line angles so the lab has nothing sharp to design around.
Anterior vs molar: where the sequences split
| Step | Anterior | Molar |
|---|---|---|
| Round end taper size | Smaller, about 1.4 to 1.6 mm | Larger, about 1.8 mm |
| Facial reduction | Two planes, following labial contour | Single plane, parallel to path of draw |
| Lingual | Football for the concavity, then a short axial wall | Axial reduction, same as buccal |
| Occlusal or incisal | Incisal reduction, angled lingually | Follows cusp anatomy, plus a functional cusp bevel |
| Main risk | Over-reducing toward the pulp and esthetic margin errors | Access, tilted walls, and thin distal margins |
The one bur that ruins both
The round end taper does most of the cutting on every crown prep, which means it is also the bur most likely to be worn. A worn bur cuts slower, gets pushed harder, and pressure is exactly what causes over-reduction on anteriors and lipped margins on molars. Your hand compensates before you notice, which we call Bur Drift. The signs are in signs your dental bur is dull.
Keep a fresh round end taper for the margin, even if an older one finishes the gross reduction.
The sequence in one box
Taft Crown Prep Anterior (FG-101) and Crown Prep Molar (FG-102) kits are built around these sequences, so every shape in the box gets used. $39.95 per kit, dual-layer diamond bonding on every bur, FG shank. Subscribe & Save on the product page sends them on a schedule you pick.
One verified buyer's review sums it up: "Great every day bur for price ours gets sent every 90 days. We use in all crown preps."
Prefer to build your own block? Every shape in this post is sold individually at $19.95 for a 5-pack. Browse the bur catalog, or call 513-580-8414.
Common questions
What burs do I need for a crown prep?
Most crown preps can be done with a round end taper as the main bur, plus a narrow bur such as a needle or flame for proximal break-through, a football for occlusal anatomy or anterior lingual concavities, and the same main shape in fine grit to refine the margin. A chamfer or tapered fissure bur is added when the margin design calls for it.
What is the difference between an anterior and a posterior crown prep?
Anterior preps reduce the labial face in two planes, use a football diamond for the lingual concavity, and prioritize esthetics at the margin. Posterior preps remove more occlusal structure following cusp anatomy, add a functional cusp bevel, and are more limited by access.
How much reduction does a crown prep need?
It depends on the restoration material and your lab's guidelines. Common ranges are roughly 1.5 to 2.0 mm incisally or occlusally for all-ceramic, with axial and margin depths set by the material. Always confirm against the material manufacturer and your lab.
What bur is used for the lingual of an anterior crown prep?
A football-shaped diamond is the standard choice for the lingual concavity, because it follows the curve instead of flattening it. The short lingual axial wall above the cingulum is then prepared with a round end taper.
What is a functional cusp bevel?
A bevel placed on the functional cusps, the lingual cusps of maxillary molars and the buccal cusps of mandibular molars, to give the restoration enough thickness where occlusal load is highest.
Professional Use Only. Licensed Dental Professionals. General information only. Preparation dimensions vary by material, manufacturer, and case. Follow manufacturer instructions, your lab's prescription guidelines, and your clinical judgment.