Pairaydental offers a wide variety of dental burs, shopping for the perfect bur can be overwhelming. To simplify things, we’ve written guide to dental burs, which will help you understand how burs are classified, their materials, and their clinical applications.
What is a Dental Bur?
A dental bur is a small instrument that attaches to a dental handpiece and uses a rotary motion to cut, shape, or remove hard tissues like tooth enamel and dentin, or materials like old fillings.
Burs come in a range of shapes, sizes, and grits with two or more sharp-edged blades and multiple edges for cutting. Dental burs are an essential part of everyday general dentistry, used in various procedures.
The Various Components of A Bur
ISO (International Organization for Standardization) code, a standardized classification system indicating specific dimensions and characteristics for these dental cutting tools. The ISO system, looked to define the various components of a bur encapsulated in a 15-digit number. The string specified each component within five sets of three digits:
- Material: Material influences a bur’s cutting action. A carbide bur (500) slices, cutting away small sections of tooth for reshaping, whereas a diamond bur (806/807) grind the tooth away.
- Shank Type and Bur Length: This is the longest part of a bur and is used to specify the bur to its respective handpiece (FG, RA or HP) and it’s length. For example, 314 = Standard Friction Grip, 204 = Latch Type RA.
- Head Shape: This component contains the blade, or abrasive face of the bur, which is used for cutting, grinding and polishing. For example, 001 stands for round and 010 for inverted cone. The shape is critical to clinical application.
- Grit Size: Grit is the term used to categorise the abrasive material on diamond dental burs ONLY. Other bur types cut rather than abrade and therefore receive the code 000. The higher the grade of grit, the coarser the material. Coarse grit creates a rough surface, and is used for quick, rough shaping of tough material, or bulk material removal. Fine creates a smoother surface and is less abrasive.
- Head Diameter: Expressed in hundredths of a millimetre, e.g. 016 = 1.6 mm, the diameter greatly influences precision and access required.
What are Dental Burs Made of?
Rapidly robust and of high quality, dental burs are made of steel, stainless steel, tungsten carbide, ceramic, zirconia and diamond grit.
Diamond Burs:
Composed of the hardest naturally occurring substance on earth (Mohs Scale 10), Diamond Burs are made by bonding industrial-grade small particles of diamond onto a substrate, allowing for a range of grit surface densities to be available. They don’t tend to “cut” but rather “abrade”, making them perfect for shaping enamel, creating margin detail and working on finer areas where control and smoothness are critical.
Tungsten Carbide Burs:
Sometimes referred to as ‘Carbide Burs‘, these burs are made of an extremely hard material. Tungsten Carbide Burs are a highly effective and sharp cutting tool, offering fast, smooth, vibration-free performance, delivering patient comfort and reduced operative time.
Steel Burs:
Known for being more flexible, pliable and soft when compared with carbide or diamond burs, these burs are designed to manipulate acrylic materials, such as dentures and custom trays. Steel burs have good edge retention and are resistant to abrasion, chipping, breakages and corrosion. These qualities make them suitable for more delicate dental work — often used in lower speed handpieces.
Ceramic Burs:
Ceramic burs are composed of advanced oxide ceramics, usually aluminium oxide (alumina) or zirconia dioxide (zirconia). Depending on which ceramic is used, can result in slightly different strengths, despite possessing the same ISO code (900). Overall, Ceramic Burs are designed to be durable, hard, corrosion resistant, biocompatible and of low thermal conductivity.
What are the Different Grit Sizes for Dental Burs?
Grit Size only applies to diamond burs, as they abrade, rather than cut. Like sandpaper, diamond burs come in different grades of coarseness or ‘grit size’. In essence, the abrasiveness varies to suit different jobs. The harsher the grit, the more tooth surface will be removed. Finer grits are best suited to work that requires finite detail, such as the smoothing of rough edges or around margins.
Super Coarse
With an approximate grit size of ~180 microns, super coarse burs are colour-coded with a black double band. They are ideal for rapid bulk reduction of hard materials like zirconia or metal restorations.
Coarse
These burs have a grit size of around 125–150 microns and are marked with a green band. They are commonly used for initial tooth structure removal and aggressive preparation work.
Medium or Standard
With a grit size of about 100–120 microns, these burs may have no band or a blue band. They are the workhorses of restorative dentistry, suitable for general crown and veneer preparations and routine tooth reduction.
Fine
Fine-grit burs have a size range of 40–60 microns and are identified by a red band. They are excellent for finishing cavity and crown preparations, especially around margins and contact points.
Extra Fine
At around 30 microns, extra fine burs are colour-coded with a yellow band. These are used for polishing and smoothing margins, especially in cosmetic procedures.
Super Fine
The finest available, with a grit size of ~15 microns, these burs are marked with a white band. They’re typically reserved for final enamel smoothing and achieving a high-gloss finish on restorative surfaces.
What are the Different Types of Dental Burs based on Handpiece and Shank Design?
Friction Grip (FG) Burs
Also known as Turbine Dental Burs, High Speed Burs or High Rotation Burs. FG burs are used with high-speed turbine machines (300,000–450,000 rpm) and possess a shank diameter of 1.6 mm. Used for cutting hard materials—express removal of enamel, cavity preparation and crown/veneer preparation. They are usually used with Diamond Burs, Tungsten Carbide and Zirconia.
Latch-Type (RA) Burs
Otherwise known as low-speed burs, with RA standing for right-angle attachment which allow for a snap-lock into low-speed contra-angle handpieces (5,000–40,000 rpm) with a shank diameter of 2.35 mm. These are for precise, smooth and controlled movements: caries removal, polishing, finishing and endodontic access. Materials used are Steel, Tungsten Carbide and Ceramic. Common lengths: 22 mm & 26 mm.
Straight Handpiece (HP) Burs
Long Straight or Straight Handpiece (HP) burs are for slow-speed handpieces (5,000–40,000 rpm) used in lab or surgical settings, with a shank diameter of 2.35 mm. Their lower speed makes them ideal for surgery, lab work, extraoral and denture trimming. Materials: Steel & Tungsten Carbide. Common lengths: 44.5 mm & 65 mm.
How to Select the Right Dental Bur
If you want to use the perfect dental bur for your chosen procedure, you’ll improve patient safety and ensure the best clinical outcome. To help you achieve this, we’ve written a brief step-by-step process to guide you:
- Define The Clinical Objective: The right bur suits the material or tissue worked on, so depending on whether you’re removing dentine, adjusting a prosthesis or endodontic access — identify what bur type would suit your procedure.
- Match The Handpiece and Shank: If it’s a heavy-duty job, choose a friction grip (FG) bur. For rapid cutting, with careful and smooth precision, you’ll need latch type (RA) burs for caries excavation and polishing. If you’re working in the lab or on dentures, you’ll want a HP bur.
- Find The Right Bur Shape: The shape of the bur greatly determines, cutting direction, control and overall finish. Select Round or Inverted Cone for access and undercuts. Use Flame or Tapered for margin finishing and try Cylinder or Wheel Burs for flat surface preparation.
- Factor in Material: The hardness of the material you are cutting through will impact both the lifespan and the effectiveness of the bur you select. For harder materials, use a harder bur material such as Carbide of Diamond. If you’re working with a softer material, or more sensitive patient, a Ceramic or Steel bur may be more appropriate.
- Consider ISO Length & Size: Depending on your access and depth needed, a longer shank, but smaller head diameter may be necessary. Refer to the ISO code on the packaging on your bur.
How to Maintain and Sterilise Burs
To keep your dental burs functioning for as long as possible and, more importantly, keep your patients safe, reusable dental burs need strict maintenance. After use, first clean the bur manually or using an ultrasonic cleaner (dependant on manufacturers indication) to remove biological debris.
Once cleaned, sterilise your bur via autoclave so as to ensure all microbial life is eliminated. Following this, proper drying, handling and storage will help prevent corrosion and rust buildup. Sterilisation cassettes and sealed pouches will help to maintain a clean & sterile set of burs for future use. Bur blocks may be less effective at protecting your burs from contamination in the long-term, and are more of a solution for keeping your burs organised when they are about to be used.
PLEASE NOTE – We advise against sterilising single-use burs, this can increase the chances of fracturing of the bur head, degradation of its cutting ability and risk spreading infection. Unless a single-use bur specifies it should be sterilised before use, do not sterilise single-use burs.