ROTARY CUTTING INSTRUMENTS Dr.linda Maher

ROTARY CUTTING INSTRUMENTS A group of instruments operated with a power source and used for cutting, finishing & polishing tooth structure.

the rotary cutting instruments are classified in to : 1. Hand pieces: these are power devices. 2. Burs: these are the cutting tools.

HANDPIECE FUNCTIONS OF HANDPIECE: a small drill used during dental procedures. FUNCTIONS OF HANDPIECE: 1.holds rotating instrument (bur) and transmits power to it. 2. helps to position and control the rotating instrument (bur) intra orally.

1.slow speed handpiece Hand pieces are operated by 1\air pressure that is supplied by a compressed air transmitted through a compressor.(AIROTOR HANDPIECE) 2\directly by an electric micromotor (MICROMOTOR HANDPIECE) TYPES OF HAND PIECE: 1.slow speed handpiece 2.high speed handpiece

SLOW SPEED HANDPIECE Operated by: Has two shapes: Usually composed of two peaces Operated by: either a compressed air or directly by an electric motor. The speed of the handpiece: ranges from 0 to 40 000 rpm.(round per minute) Has two shapes: 1-straight handpiece,this is difficult to use in the mouth and is therefore restricted to extra oral use, such as laboratory work . 2-contra-angle handpiece is used intra orally for the removal of caries, polishing and finishing

HIGH SPEED HANDPIECE Operated by: Speed: It is used for: It is one piece and contra angled This design helps to stabilize the hand piece and improve access and visibility while it is in use. Operated by: compressed air ( air-turbine or Airotor. handpiece) Speed: 250 000–500 000 rpm and It is used for: cutting through enamel and dentin and removing previous restorations.

is directed at the cutting part of the bur to keep it cool . water spray is directed at the cutting part of the bur to keep it cool . A fibreoptic light in the head of the handpiece aids visibility.

DEDNTAL BURS A bur is a rotary cutting instrument supplied with cutting head of various shapes

parts of a dental bur: Shank : is the part of the bur which fits into the handpiece. Neck: the neck serves to connect the shank to the head of the bur. Head: this is the working end of the bur and is available in various sizes, shapes and materials.

Burs materials: stainless steel or tungsten carbide. Burs sizes: the number representing the bur size has been used as a code for the diameter of the head. Burs shape: burs are available in several shapes. There shapes correspond to the function.

RETENTION OF BURS TO THE HANDPIECE: 1\ Latch grip for slow speed. 2\ Friction grip for high speed.

Types of dental burs: 1- cavity preparation burs are : Round, inverted cone, pear shape, straight fissure & tapered fissure.

Rubber cup and coated discs 2- finishing & polishing burs: Rubber cup and coated discs

THANK YOU