A coarse diamond bur is a friction-grip rotary instrument with coarse-graded electroplated diamond particles, engineered for the fastest stage of tooth preparation — bulk enamel reduction and crown cutting. The WR-13C runs the green ISO band that signals coarse grit, on head sizes 4.2/1.8mm and a 19mm total length. The specification matters because coarse grit clears material at the highest rate in the sequence, which is why clinicians reach for it first on full crown cases. Five burs per box, evenly coated under ISO 13485, with CE and FDA registration. Factory direct from a 40-plus country exporter.
A coarse diamond bur is the first instrument in the tooth-preparation sequence — the green-banded, coarse-grit tool that removes the bulk of enamel and dentin before finer burs define the margins. The WR-13C is our coarse variant of the diamond bur line, running head sizes 4.2/1.8mm on a 19mm total length and the standard FG 1.6mm friction-grip shank.
The specification matters because coarse grit is where preparation speed is won or lost. Coarse diamond particles cut at the highest material-removal rate in the sequence, clearing cusps and occlusal surfaces fast while generating less heat than a fine grit pushed to do the same job. That is the clinical difference: a coarse bur doing bulk reduction stays cooler and faster than a medium bur forced into heavy cutting.
Based on the material science behind our coating process, the WR-13C's coarse particles are electroplated in an even layer so the cutting surface wears predictably across its full working life — no hot spots, no sudden dullness halfway through a case. The green ISO band on the shank is the instant, visual confirmation of grit, so there is no second-guessing at chairside.
Coarse grit (C/Green) with ISO color coding
Here's what that means clinically: the green band tells you this is the fast-cutting grade. In a busy clinic or hospital, the assistant restocks by color, the clinician confirms by color — green means bulk reduction, no reading required. This is the first bur you reach for on a full crown case.
Why this grade matters: coarse diamond particles maximize material removal per pass, which shortens prep time and keeps the bur cooler than a finer grit forced into heavy cutting. (Z6: every pack carries the Ai Oral anti-counterfeit label and batch code)
Head size 4.2/1.8mm, total length 19mm — matched to crown geometry
The practical impact on your prep workflow is straightforward: the 4.2mm head clears broad occlusal and axial surfaces fast, the 1.8mm head reaches interproximal spaces and tight contours. One model covers the rough-cutting stage end to end.
FG 1.6mm standard shank with controlled concentricity
The reason this specification matters: at high-speed RPM, any shank eccentricity becomes vibration, and vibration means rough walls and patient discomfort. Our shank tolerance is held under ISO 13485 so the WR-13C runs true every time. (Z2: our diamond instrument coating provides stable cutting efficiency in clinical use)
Even electroplated coarse diamond coating
What the cheap spec sheets don't tell you: uneven diamond distribution is why cheap burs dull in patches and skip mid-cut. Our even coating wears uniformly, so the cutting feel on prep one is the same as prep fifty — the kind of consistency a multi-chair hospital depends on for predictable scheduling.
Five burs per box, ISO 13485 batch traceability
For institutional procurement, the paperwork matters as much as the product. Each box carries a traceable code back to the diamond grade, coating process, and tolerance check — the documentation your compliance team and EU distributors expect.
Full crown preparation — the WR-13C's coarse grit handles bulk enamel and dentin reduction as the first step in the sequence.
Old restoration and adhesive removal — failed composites and cements come off fast with coarse cutting.
Core buildup reduction — rapid reduction of core material to contour before finer finishing.
Cavity opening and access — clears carious tissue and opens access efficiently.
Zirconia and lithium disilicate bulk shaping — coarse grit is the efficient first pass on high-hardness materials before medium and fine grit refine.
Let us talk about what the cheap quote does not include.
When a hospital or clinic network compares coarse diamond burs, the unit price is the smallest part of the decision. The real cost hides in three places. First, cutting efficiency — a coarse bur with sloppy diamond grading cuts at a fraction of the rate, adding minutes to every prep and burning through the bur faster. Second, coating evenness — cheap burs dull in patches, which means the bur skips mid-cut and the clinician compensates with pressure and heat. Third, batch consistency — a bur that cuts well in box one and dies in three preps in box two is a procurement problem that shows up as chair-time overruns and staff frustration.
Our coarse series is built to remove those hidden costs. The diamond particles are graded to spec, the electroplating is even, and the shank tolerance is controlled under ISO 13485 — batch after batch, with a traceable code on every box. We ship to over 40 countries with CE and FDA registration, and the clinics that run our coarse burs reorder on consistency, not on price.
One thing to be clear about: coarse grit is the bulk-reduction tool, not the finishing tool. If you try to define a margin with a coarse bur, you leave a rough surface that needs rework. The sequence matters — coarse for bulk, medium for definition, fine for finish. For a hospital standardizing its instrument trays, we recommend stocking the full sequence so each bur does the job it is built for. Send us your typical case mix and we will spec the right tray setup.
For institutional buyers comparing suppliers: send us your monthly volume, case mix, and compliance checklist. We will return a full quotation with certification documents within 48 hours. Standard specs available from factory stock, FOB Shanghai.
Q: What does the green band on the WR-13C mean?
A: Green is the ISO standard color for coarse grit — the fast-cutting grade. It signals the bur for bulk enamel and dentin reduction, the first step in tooth preparation. The color coding lets you confirm the grit at a glance, no reading required, which matters when you are mid-procedure.
Q: When should I use the WR-13C coarse bur versus a medium bur?
A: Use coarse for bulk reduction — the initial removal of large amounts of enamel, dentin, or old restoration material. Use medium for shaping and margin definition once the bulk is cleared. Pushing a medium bur into heavy cutting wears it faster and generates unnecessary heat; using a coarse bur on margins leaves a rough surface. The sequence, not any single bur, is what produces a clean prep.
Q: Is the WR-13C suitable for zirconia crown preparation?
A: Yes, as the bulk-shaping pass. Coarse grit is the efficient first step on high-hardness materials like zirconia and lithium disilicate, but you will step down to medium and fine grit for margin definition and surface refinement. The key is matching the grit to the stage — coarse for bulk, fine for finish.
Have more questions about the WR-13C, bulk procurement, or OEM options? Send us a message and we will get back to you within one working day.
Written by Dr. Mark Wu, Co-founder & Technical Director, Sichuan Ai Oral Co., Ltd. 15 years manufacturing dental instruments for clinics and distributors in 40+ countries.
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