(FG)Dental Diamond Burs Classification

The dental practice utilizes various dental instruments. Each instrument has its own set of characteristics and functions. Hand instruments and rotary instruments are two main classes of dental instruments. The rotary instruments are high-speed instruments that have excellent cutting and abrasive abilities. Dental burs are the main rotary instruments widely used in dentistry.

By definition, dental burs are; rotary instruments that have cutting abilities and bladed heads used for tooth grinding and cutting purposes. Usually, the dental burs are made of carbide and diamond. Both have efficient cutting ability and strength.

Main parts of diamond burs

Diamond burs or rotary burs are divided into three main segments.

Burs’ head, burs shaft and shank.

• Shank

Shank is the part of diamond burs that makes the connection with the handpiece. the different shank design used in dental burs and each has its specific functions. The most common shank designs are;

• Long shank

A long shank of diamond burs is compatible with the straight handpiece. The handpiece for the long shank design is a slow speed rotary handpiece.

• Short Shank

The design is used for the contra-angle slow speed handpiece. It is also called Latch type design.

• Friction Grip

The most widely used diamond burs used in dentistry shank design is also denoted as FG shank design. In diamond burs, the FG shank is suitable for high-speed handpieces.

Diamond burs Classification:

Diamonds burs are abrasive burs that have diamond cutting grits. They have an efficient and fast cutting ability and long shelf life. The diamond burs have unique diamond chips or grits that bounded to the burs head. These grits perform outstanding enamel grinding and provide the smooth surface of the tooth.

The diamond burs divided on the base of

Coarseness

Shape or design.

• Coarseness.

The coarseness of diamond burs is due to the arrangement and size of diamond particles. The cutting efficacy of diamond burs mainly depends upon the grit size. The smaller the grit size less the coarseness and fast cutting. The two most common grits types of diamond burs used in dentistry.

• Diamond points

The diamond points are the diamond particles with the matrix that are bound on the head of the shaft for cutting and grinding.

• Fine grits

The fine grit diamond burs offer a smooth and excellent finishing. They can operate at high speed and rotation. The particle sizes of fine grits are smaller than coarse grits surface area is more than the course.

The sizes of fine and extra-fine diamond burs are 60-74um and 38-44um respectively.

• Coarse grits

The coarse diamond grits used for gross tooth cutting and preparation. The coarser burs used for larger tooth reduction. The grit size can change from medium-coarse to high and extra-high coarse diamond burs. Coarse grits diamond burs produce more heat so extra pulp protection is required while working with diamond burs.

The sizes of coarse burs are 125-150um and for medium diamond, grits are 88-125um.

FG diamond burs types by head shape

The dental diamond burs head design has a large variation in shapes. Each head design performs its specific function and is unique for its cutting and shaping.

The most common head designs are;

• Roundhead

The spherical head design of diamond burs is used for initial tooth entry for restoration, an extension of the cavity and retentive purpose and caries removal. the design variations are;

o   BR-Ball Round Type

o   BC-Ball Collar Type

• Inverted conehead

The inverted burs have a tapered cone with an inverted apex. Its head is equal in length and diameter. inverted burs specific for the undercuts and tooth angulation during cavity design preparation. The designs include;

o   DI-Double Inverted Cone

o   SI-Single Inverted Cone

• Pear-shaped burs

The head is pear-shaped that is slightly tapered toward the neck. Pear-shaped burs are specific for the undercuts in cavity designs for retention and resistance of filling materials. The pear-shaped can be tapered or flat.

•  Straight fissure

Straight fissure burs have an elongated cylinder and are used for amalgam cavity preparation. The Straight fissure designs include;

o   SO-Straight Ogival End 

o   SF-Straight Flat End

o   SR-Straight Round End

• Tapered Fissure burs

The tapered fissure used specifically for crown and inlay preparation. The tapered design gives an excellent shoulder to the crowns. The other designs for tapered burs are;

o   TF-Taper Flat End 

o   TR-Taper Round End  

o   TC-Taper Conical End 

• TF-Taper Flat End burs are specific for the ceramic crown preparation and additional facial preparation of the tooth.

• Taper Round End burs have the axial reduction with the 6-degree bur taper. They are used for the metal crowns and palatal finishing of ceramic crowns.

• Flame shaped burs

Flame shaped burs have their unique appearance and play an essential role in composite finishing. The flame-shaped diamond burs act as abrasive to offer a fine filling surface. The flame-shaped burs have other design of;

o   FO-Flame Ogival End

• Wheel shaped burs

The wheels shaped diamond FG burs are specific for crown cutting. It provides excellent occlusal clearance, incisal reduction and palatal fossa reduction of anterior teeth while crown cutting and preparation. The dental crown the design of wheel-shaped bur is;

• WR-Wheel Round Edge

• Most used diamond burs in dentistry carts

Factors for burs Efficacy and Effectiveness

Dental burs are essential for the cutting and grinding of the tooth during the restoration and crown preparation. Few factors play an important role in the effectiveness of dental burs.

1.Size of burs abrasive particles:

The smaller size of abrasive particles offers more efficient cutting. The tooth penetration ability is higher for the finer particles they also provide rapid cutting and saves time and effort during dental procedures.

2.Shapes of bur particles:

The irregular particles are more efficient for cutting and grinding. The round particles are usually slow at speed and take more time for cutting.

3.Hardness of particles:

The hardness of particles related to the cutting ability. The harder the abrasive more efficient and excellent cutting ability of bur.

4.Density of Particles

Density is the number of abrasive particles per unit area. The closely packed particles are denser than widely spaced abrasive particles.

5. speed and pressure on dental burs.

The high-speed handpieces are responsible for fast and rapid cutting. The burs pressure and speed are related to each other. High pressure without high speed can lead to burs failure. Similarly, high speed can cause accidental damage to the tooth and oral tissue. Heat production and pulp damage are common at high speed.

6. Clogging of particles.

The debris during the cutting can clog the abrasive dental burs. The clogging reduces the efficacy and cutting ability. The compacted particles have more clogging than widely spaced. The use of constant water spray during the cutting can reduce the clogging and increases the working life of the bur.

Care and reuse of diamond burs:

For flawless cutting and longer shelf life, the care of dental burs is essential. The dentist should remove the burs after every procedure and clean them with cotton. The Diamond burs can be reused after sterilization. The most suitable sterilization procedure for Diamond burs is Autoclave or cleaning with 2% sodium nitrate solution.