1. fixed prosthodontics
Dental Rotary Instruments

2. Instruments used for tooth preparation
The dental instruments used for tooth praeparation are a rotary cutting or abrading instrument .
Rotary instrument are tools held and operated by a hand piece (air turbine) or by electric motor (micromotor)
Air turbine is :
- A high speed rotation ,000 – 100,000 r.p.m
-Ulra – high speed rotation ,000 – 500,000 r.p.m
and micromotor is low speed rotation – 4000 r.p.m

3. Air turbine

4. micromotor

5. Dental units

6. Dental instrument
It’s the tool or device used for a specific type of dental work or procedure in prosthodontics
These instruments used for cutting and reducing the hard tissue of tooth
Dental instruments divided to types :
1- diagnostic ( probe , twisser , mirror)
2- cutting (hand , rotary )
3- restoring ( ammalgam condensor , excavator , …..etc.)

7. Hand instrument made from stainless steel and consist of three part :
Cutting instruments
Rotary instruments
Hand instrument ( chisel , hatchet , hoes excavator , angle former , gingival trimmer .
Hand instrument made from stainless steel and consist of three part :
1- handle ,
2-shank
3- blade

8. Blade (cutting edge)
Shank
Handle (shaft)

9. Rotary instruments divided to :
Cutting
abrasive
Carbide burs
1-Diamond burs
2- Discs
3- stones
4- rubber wheels
Made from
1- tungsten carbide
2- steel carbide

10. Rotray instruments consist of three parts :
1- shank
2- neck (shaft)
3- head
Shank design
1 – long shank – used for straight hand piece (low speed)
shaft
Shank
head

11. 2- short latch shank – used for contra-angle (low speed)
3- friction grip shank - used for high speed hand piece
head
shank
shaft

12. Dental burs According shank According to shape
According to composition
friction grip short shank
long shank
short latch
Round
Flat
Fissure
Wheel
Football
Pear
Bud
Diamonds
Tungsten
Steel carbide

13. Carbide burs
Burs possess blades that shear (cut) tooth structure . They are used for making precise intracoronal preparation features such as placing groove ,and boxes .
And they are used for smoothing surface in enamel and dentin
They are not used for bulk reduction because to producing undulations on the tooth surface
1- Twelve-fluted carbide bur
Its used for highly smoothing of prepared surfaces of tooth
Because of its blades in a diagonal to the instrument shaft
Its have a torpedo shape

14. Twelve-fluted carbide bur

15. 2- Plain fissure bur
Its tapered and cylinder shape its used for palcing groove and boxes and they also used for finishing of preparation (smoothing)
Groove seating

16. Diamond durs
These are made from diamond chips bonded to blanks (heads) . Diamond burs used for griding enamel and dentin surfaces
Diamond burs may divided according to :
1- coarseness ( medium grit - fine grit )
2- shape
Medium grit
Fine grit

17. 1- Tapered round-ended bur
Use ;
For axial reduction (buccal –lingual – mesial – distal ) with 6 grades taper
And for chamfer finish line 0.5mm
Indication :
1- full metal crown
2- palatal surface of full ceramic crown

18. Depth marking
Axial reduction
Chamfer forming

19. 2- Tapered flat-ended bur
Use :
Axial reduction with their surfaces anf form shoulder finish line
Indications
1- full ceramic crown facial surface of metal ceramic crown

20. 3- Long needle bur
Use :
For interproximal initial access without causing injury to adjacent tooth and to form knife – edge (chisel) finish line )

21. 4 – torpedo bur
Used for formating the bevel shoulder finish line in full ceramic and netal-ceramic crowns

22. 5 – wheel-shaped bur
Used for reduction of occlusal surface , for reduction incisal edge reduction and also used for reduction of palatal fossa of anterior teeth

23. 6 – football-shaped bur
Used for occlusal reduction and for reduction of palatal fossa of anterior teeth

24. 7- depth marking burs
Depth marker
Round bur o.16 , o.15

25. Burs kit of tooth preparation

26. Discs and rubber wheels

27. Plaster (stone) cuters
Fine fissue bur

28. Diamond disc
Wheel stone
Felt wheel
Stones

29. Thanks