Speed in dentistry /prosthodontic courses

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Education

INTRODUCTION
DEFINATIONS OF SPEED
HISTORY OF ROTARY CUTTING
CLASSIFICATIONS OF SPEED
LOW SPEED
HIGH SPEED
ULTRA HIGH SPEED
HANDPIECES
DEVELOPMENT
CLASIFICATIONS
AIR ABRASION
LASERS
ULTRASONIC DEVICES
STERLIZATION & DISINFECTION
REFERENCES
CONCLUSION

o RATE OF MOTION WITHOUT SPECIFYING ANY DIRECTION
o MAGNITUDE OF VELOCITY WITHOUT REGARD TO DIRECTION.
o RATE OF CHANGE OF POSITION WITH TIME WITHOUT
REFERENCE TO DIRECTION.

Bur drill-300rpm
1838-Egg beaters drill-300rpm
1858-Finger ring(drill socket)-300rpm
1868-Merrys drill stock-300rpm

1871 FOOT ENGINE 700rpm
1874 ELECTRIC ENGINE 1000rpm
1914 DENTAL UNIT 5000rpm
1942 DIAMOND CUTTING INSTRUMENT 5000rpm
1946 OLD UNITS CONVERTED 10,000rpm
1947 TUNGSTEN CARBIDE BURS 12,000rpm
1945-55 AIR ABRASION UNITS
NON CUTTING DEVICES
ULTRA SONIC DEVICES

1953 BALL BEARING HANDPIECE 25,000rpm
1955 WATER TURBINE HANDPIECE 50,000rpm
1955 BELT DRIVEN HAND PIECE 1,50,000rpm
1957 AIR TURBINE HANDPIECE 2,50,000rpm
1961 AIR TURBINE ST.HANDPIECE 2,50,000rpm
1994 CONTEMPORARY AIR TURBINE 3,00,000rpm

• STURDUVENT
• MARZOUK
• CHARBAENAU
• DCNA1971

TYPES OF SPEED
1. FREE RUNNING SPEED
2. CUTTING OPERATIONAL SPEED
3. COAST SPEED
4. VARIABLEOPTIMAL SPEED

LOW SPEED
<6,000rpm
NO LONGER USED FOR CAVITY PREPATION
USES
DISADVANTAGES

HIGH SPEED
6,000-1,00,000rpm
CAN BE USED FOR CAVITY PREPARATION
MOST OF FINISHING PROCEDURES DONE
ADVANTAGES
DISADVANTAGES

ULTRA HIGH SPEED
>1,00,000rpm
MORE VERSATILE CUTTING
USES
SOME CAVITY PREPARATIONS
MAY BE COMPLETED.

BASED ON SPEED
BASED ON DESIGN
BASED ON POWER
MECNANISM
DEVICE USED FOR HOLDING ROTATING INSTRUMENTS, TRANSMITING
POWER TO THEM& FOR POSITONING THEM INTRAORALLY

ROTARY POWER GENERATED BY BELT
PULLEYS & E-CORD
GEARS & SHAFTS
5000 rpm
FUNCTIONS BEST AT LOW SPEED
BECAUSE OF MANY MOVABLE PARTS
WITH METAL TO METAL CONTACT

Hydrualic Driven Handpiece(1953)-60,000 rpm
Turbojet(1955)-1,00,000 rpm
(CO-AXIAL TUBING)
Small tube Large tube

PAGE CHEYANS HANDPIECE – 1955 – 1,00,000 rpm
Worked with gears, also had cords – 10,000 rpm

INDEPENDENT OF TURBINE
DESIGN.
RELATED TO ACTUAL TURBINE
DESIGN.
Multiple coupling connectors with
rotatable joints
Fibre optic illumination
Push button &lever chuck system
Ability to withstand routine
autoclaving.
Larger diameter rotors
Smaller rotors
Improved bearings
Modified rotor blade design.

BORDEN HANDPIECE – 1957 – 3,00,000 rpm
SPEED DROPS FROM 3,00,000rpm TO
1,60,000 rpm WITH LATERAL WORK LOAD
OF 13/4 OUNCE

ROTARY CUTTING INSTRUMENT WITH
CUTTING HEADS OF VARIOUS SHAPES &
TWO OR MORE SHARP EDGED BLADES
USED AS ROTARY GRINDER.
STEEL TUNGSTEN CARBIDE
•STEEL BLANK T.C POWDER+CO/Ni(VACUUM)
•V.H.N= 800 V.H.N= 1650-1700
•WELL AT LOW SPEEDS WELL AT ALL SPEEDS
DULL AT HIGH SPEEDS.

MODIFICATIONS IN BUR DESIGN
1. Reduced use of cross cuts
2. Extended heads on fissure burs
3. Rounding of sharp triangles

FACTORS INFLUENCING CUTTING EFFECTIVINESS
& EFFICIANCY OF BUR
•RAKE ANGLE,CLEARENCE ANGLE & BLADE ANGLE
POSITIVE RAKE ANGLE SHOULD NOT BE GIVEN IN STEEL BURS

NUMBER OF BLADES & THEIR DISTRIBUTION
DECRESING NO OF BLADES- INCREASE FORCE ON ONE BLADE
-INCREASE SIZE OF CHIP REMOVED
-LESS CLOGING TENDENCY
STRAIGHT FLUTES V/S SPIRAL FLUTES

RUN OUT
DEFINITION
CLINICALLY ACCEPTABLE RUN OUT

LOAD IS FORCE EXERTED BY OPERATOR ON THE BLADE DURING CUTTING
INFLUENCE OF LOAD
LOW SPEEDS– 1000-1500 gms
HIGH SPEEDS– 60-120gms
INFLUENCE OF SPEED
30,000-1,50,000rpm

1940- - DR.ROBERT BLACK
1951- - S.S. WHITE TECHNOLOGY-
AIR DENT
1990- - ADVANCED AIR ABRASION
UNITS

SYSTEMS & FEATURES
•AIR –FLOW PREP K1 ALUMINIUM OXIDE POWDER STREAM IN
WATER SPRAY.
•PROPHY JET FINE PARTICLES OF NaHCO3 THRU A
STREAM OF AIR SURROUNDED BY WATER
ABRASIVE PARTICLES
•ALUMINIUM OXIDE -
•POLY CARBONATE RESIN ALUMINA- HA MIXTURES

VARIABLES
1. PRESSURE- 40-140psi
2. TIP SIZE- 0.015”-0.027”
3. TIP ANGLE- 40-140
4. TIP DISTANCE- 2mm
5. DWELL TIME- >EXPOSURE=>PREPARATION
6. PARTICLE SIZE- 27m-50m

MAINMAN- RUBY LASER in 1960
STERN&SOAGNNAES- DENTAL TISSUES 1964
CO2 LASER - JEFFERY et al 1990
wavelength of 10.6um
power of 2-10 W
time 0.5-25S
ND-YAG LASER-
wave length of 1.06um
power of 0.3-3W

EXCIMER LASER- ULTRA VOILET RAYS
wave length of –193-351nm
time-15-300ns
ARGON LASER- ARGON GAS
wave length of 514-488nm

CAVITRON ENDO PIEZO ELECTRIC

TECHNICAL DATA:
WORK AIR PRESSURE: .3-0.6MPA
AIR CONSUME: 60 L/MIN
WORKING PROCEDURE:

• THE ORIGIN OF THE AIR TURBINE DENTAL HANDPIECE
BRITISH JOURNAL 1974 469-473
•DENTAL HANDPIECES AND ROTARY CUTTING INSTRUMENTS
DCNA 1971 (15) 219-245
•STATUS REPORT ON DENTAL OPERATING HANDPIECES
J AM DENT ASSOC 1974 (89) 1163-69
•DENTAL HANDPIECE- A HISTORY OF ITS DEVELOPMENT
AUSTRALIAN DENT JOUR 1986 31(3)
•HIGH SPEED CAVITY PREPARATION TECHNIQUES WITH DIFFERENT
WATER FLOWS,
JO OF PROS DENT 87(2) 158-162
•WATER FLOW IN HIGH SPEED HAND PIECES
QI 2005 36(6) 361-65
REFERENCES

Speed in dentistry /prosthodontic courses

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