1846- hand drill replaces hand instruments for removal of tooth structure

1910- motorized belt driven handpiece introduced still used by lab technicians because of high torque

1945- introduction of air abrasive using aluminum oxide driven CO2

1954- modern air turbine handpiece

1965- modern electric slow speed

low speed - up to 20,000 rpm

ultra speed - above 150,000 rpm

• excavating decay
• polishing restoration and or teeth
• smoothing and finishing prep
• lab procedures for cutting , smoothing and polishing metals and acrylics and other lab materials

screw type

latch

friction grip

straight head

motor

contra angle head( friction grip)

electric motor

red strip

orientation post

(3 angles are found )

initial penetration of tooth structure

preparation of teeth

high speed : friction only, air/water spray , fiber optic lights

electric : friction grip only

head

neck

shank

handpiece

latch

friction grip

round

inverted cone

straight

tapered

pear

used for retention and cavity definition, make smooth pulpal walls, convergent vertical walls and create sharp internal line angles ,used in both high and low speed

• short head with broad flat end and narrower at neck ( trapezoid shape)
• size range from 33.5 to 39

• crosscut blades, sides of burs are parallel to each other
• plain 55-58 , and crosscut(little notches perpendicular to length of blade)  555-558
• 1155-1158-plain straight with rounded end
• 1555-1558 crosscut straight with rounded end

cross cut , head(neck)  is wider than at the tip, used to create divergent walls in cavity prep, can be plain or crosscut

-#699 -#703 crosscut

-#169-172 plain

#271-272 round nose tapered fissure , mainly for inlays

245 larger than 331, similar to inverted cone bur

much rounder and without crosscut

shorter head come with a length of 1.5mm (330-331)

elongated head comes with length of 3 mm ( 245)

used for all tooth prep that receive direct filling

can be used for initial penetration of enamel , all other aspects of cavity prep 

7002 7004 7303 7901 7802

-polishes amalgam restoration

 have from 12-40 flutes

burs and abrasives with red stripes denote fine or smooth cutting

not made of carbide or steel  but still are diamond bus

made of three parts : metal blank, powdered diamond abrasive, and metallic bonding material

-abrade large area

used to extensive tooth reduction like crown prep

coarse diamonds used for rapid reduction

finer diamonds - for finishing

• finger rest
• air and water must always be used weith high speed to counter act generation of heat
• alway use either a hand instrument or slow speed to conserve tooth structure and protect pulp
• rubber dam helps proctect soft tissue while using rotary
• wedges placed in interdental space protect the tissue and rubber dam
• driangles ,rolls , gauze keep field dry and protect soft tissue
• metal matrix placed btw teeth during cavity prep to protect adj tooth