3. Introduction
The removal and shaping of tooth structure is
an essential part of restorative and prosthetic
dentistry
Initially this was a difficult process
accomplished entirely by the use of hand
instruments.
The introduction of rotary equipments, is one
of the truly major advances in dentistry.
4. Evolution of rotary cutting
instruments
1800’s (300-1000 rpm)
Foot engine
Hand rotated drills
Electric engine
Straight hand drill
for direct access
Angle hand drill
for indirect
access
Foot engine
5. 1900’s (5000-300000 rpm)
Dental unit
Diamond cutting instruments
Tungsten carbide burs
Ball bearing handpiece
Water turbine handpiece
Belt driven handpiece
Air turbine straight and angled handpiece
a.Belt driven straight
handpiece.b.gear-driven
straight c.gear-driven angle
handpiece
Page-chayes handpiece
10. Low speed :
Uses:
Cleaning
Occasional caries excavation
Finishing and polishing procedure
Advantages:
High tactile sense
Less chances of overheating cut surfaces
11. Disadvantages:
Less effective
Time consuming
More heat and vibrations
More run-out of burs
Carbide burs break at low speed
Attachments:
Straight-long shank laboratory burs
Prophylaxis angle
Angle –latch –type rotary burs
Mandrels
12. High speed:
Uses:
Removal of decay
Removal of old restorations
Tooth preparations
Finishing and polishing
13. Advantages :
Faster with less pressure,vibration and heat
production
Greater control and ease of operation for operator
More longetivity of burs
Less comprehension by the patients
Several tooth can be prepared at 1 apointment
14. Electric handpiece:
Components:
A controller
An electric motor
Attachments : that connect to the motor and
accept burs/diamonds and other cutting
instruments.
Speed:They spin at speeds ranging from 1500
rpm to 40,000 rpm.
15. Two types:
brush motors :
This is typically a brief and straightforward in-
office procedure.
require an annual brush change.
brushless motors. :
operate without brushes, this eliminates the need
for brush changes and allows the entire motor to
be sterilized
16. Electric handpiece:
Advantages Disadvantages
More power and torque than air
turbine
Heavier than air turbine
Better bur concentricity Expensive
Less vibrations and noise Learning curve required
Broad controllable speed range Larger attachment head
Forward/reverse action
With proper attachments can be
used for several purpose
Produces smoother surface
17. Air turbine handpiece:
They employ compressed air to drive the turbines
inside.
The movement of the turbines creates the rotary action
at the end of the handpiece.
Head:
The head, or working end, of the high-speed handpiece
is where the burs and other cutting or polishing
attachments are connected.
Chuck:
The chuck is the part of the head that holds the burs
18. Shank:
The shank, or handle, is located between the
head and the connection end of the high-speed
handpiece. The shank is often contra-angled (at
an angle with) the head.
Connection End
The connection end of the high speed handpiece
is attached to the shank on one end and to
flexible hoses and cords on the other. These
hoses and cords enclose the wires from the
power source
20. Hybrid air-electric
handpiece(ATC):
ATC refers to Adaptive Torque Control
Uses a sensor in the air tubing to regulate a valve
which regulates the air pressure running through
the turbine
Advantages:
Power of electric handpiece but weight of air
turbine
Disadvantage:
Compatible only with ATC units
21. Recent advances in air –driven
handpiece:
Head size and angulation:
3 head sizes :miniature;mid –size;full-size
22. Handpiece angle:
A typical handpiece angle is 22.5o
Newer design include angles with increase
posterior visibility and patient comfort
23. Sound level:
A normal high-speed handpiece can make noise upto
71-92db
Newer handpiece with sound levels in range of 58 to
71 db have become available
Ergonomics:
Flared body shape towards the end of handpiece
Autoclavability:
Materials like titanium are used for outer shell/body to
protect the external finish of the handpiece
24. Turbine design:
Improvements in impeller design help in maintaining
constant speed and avoid stalling under load
New sensors tell the handpiece electronic “brain”
when to increase power to maintain speed under load
Anti-suck technology:
Manufacturers built this system in order to prevent
blood and aerosols from entering the water line.
Water delivery:
Multi-port spray emanating water from the face of
handpiece which causes equal distribution of coolant
25. Cellular optics:
One solid glass rod instead of optic fibres
Improves operator visibilty with 25%
Handpiece with LED’s which are more brighter
26. Sterilization and care of
handpiece
Do not exceed 275 0F /1350 C while autoclaving
Do not autoclave with bur attached
Use bags with 1 paper side to absorb excess
moisture
Do not leave overnight or store in autoclave
Before removing flush water for 30 seconds
Do not use any chemical solution for cleaning
Lubricate the handpiece
Run the handpiece for 20 seconds after oiling
Alcohol can be used to wipe excess oil form the
fiber optics
29. Shank:
Fits into the handpiece
Controls the alignment and concentricity of the
instrument
Acc to ADA no.23:
a. straight handpiece
b. latch-angle handpiece
c. friction-grip handpiece type
Slow and medium speeds
High speeds
30. Neck :
Connects head to shank
Transmits rotational and translation forces to the head
A neck to small will result in a weak instrument
A neck to large will hamper the visibility and restrict
access for coolants
31. Head:
Working part of the instrument
Varies in size ,shape , materials used ,according
to intended use
32. Dental burs
The term ‘bur’ is applied to all rotary cutting
instruments that have bladed cutting heads
Can be used for:
Finishing metal restorations
Bone cutting
Tooth preparation
Cavity preparation
33. Classification of burs
Steel burs:
Earliest burs made
Perform well while cutting dentine at low speed
Dull rapidly while cutting enamel
Mainly used for finishing purpose now
34. Carbide burs:
Introduced in 1947
Heads of carbide cemented on steel shanks
Particle of tungsten carbide embedded in matrix
of cobalt or nickel
Attached to steel necks by brazing or welding
35. They are stiffer and stronger than steel
They breaks on a sudden blow or shock unlike
steel burs which bend
Perform best at high speeds for tooth preparation
36. Mechanism of action of burs:
Cuts by “cutting operation”
Regularly arranged blades remove small shaving
of the substrate as the bur rotates
Regular pattern of tooth
removal by blades
37. Bur numbering systems
In united states:
Arbitrary numerical code is given for head size
and shape:
Example:
57=1mm diameter straight fissure
34=0.8mm diameter inverted cone
2=1mm diameter round bur
38. According to FDI and ISO:
The bur name include separate designation for
shape(name) and size (number)and giving the
head diameter in 10th of mm
Example :round010
straight fissure plain 010
Inverted cone 080
41. Bur shapes:
Round :
Spherical
Initial entry
Caries removal
Preparation of retentive features
Inverted cone:
Rapidly tapered cone with apex towards the
shank
For undercuts in tooth preparations
42. Pear –shaped bur:
Slightly tapered cone with apex towards shank
The edges are curved or rounded
Class1 preparations for amalgams and gold
Straight fissure bur:
Elongated cylinder
Retentive grooves
Tooth preparation
43. Tapered fissure bur:
Slightly tapered bur
Small end of cone away from shank
Used for :
Occlusal guiding grooves
Additional retentive features in complete and
partial cast crowns
Finishing
Proximal boxes,bevels,occlusal reduction in class
II inlays and MODs
44. Head design features:
Spiral angle:
Less on high speed burs
Larger spiral angle smoother preparation
Smaller spiral angle more efficient cutting
Crosscuts:
Notches along the blades
Increase cutting at low and medium speeds
Produces rougher surface at high speeds
45. Blade number:
Number of blades is always even
Areas between the blade is called flutes
Excavating bur:6 to 8-10 blades
Finishing burs:12 to 40 blades
46. Blade design:
blade/cutting edge: part that contacts the
horizontal line of work/tooth
Two sides of blade:
Rake face
Clearance face
47.
48. Rake angle: angle between the radial line and
the rake face
Negative rake angle: when the rake face is
ahead of the radial line
Zero rake angle: when the radial line and the
rake face coincide
Positive rake angle: when the rake face is
behind the radial line
49. Clearance angle:
The angle between the clearance face and the
tooth surface
It eliminates the friction of clearance face
Provides a stop and prevents edge digging in
tooth structure
Provides clearance space to wash out chips
ahead of the following face
50. Land: the plane surface immediately following the
cutting edge
primary clearance angle: angle between the
land and tooth
Secondary clearance angle: angle between
clearance face and work
51. Edge angle :angle between two faces of the
edge
Greater the edge angle stronger is the blade
Positive rake angle:
1. Thinner and sharper teeth
2. More temperature rise
3. Less life
4. Used for cutting soft & weak
materials.
5. Possesses greater efficiency
6. Has lesser edge strength.
Negative rake angle:
1. Broader teeth
2. Less temperature rise
3. More life
4. For hard brittle materials.
5. Possesses lesser efficiency
6. Has greater edge strength
52. Concentricity:
Direct measurement of symmetry of bur head
Indication whether one blade is shorter than the other
Run-out:
Measures whether the centre of rotation passes
through the centre of rotation of the head
Primary cause of vibration during cutting
Run-out occurs when the -bur head is off the centre
- bur neck is bent
- bur isn’t held straight in
handpiece
53. Diamond abrasive
instruments:
Abrasive instruments are based on small, angular
particles of hard substance held in matrix of softer
material
Cutting occurs at large number of points where
theses hard particles abrade rather than along
continuous blade edges
54. Mechanism of abrasion:
It works by grinding operation
When cutting a ductile material
like dentine
When cutting brittle material
55. Parts:
Metal blank
Powdered diamond abrasive
Metallic bonding material
The diamonds are attached to blank by
electroplating a layer of metal over diamond
particles
57. According to their shapes and
sizes they can be classified as:
Flat end tapered diamond cylinder:
used for :
Bulk axial
Occlusal reduction
Shoulder finish line in tooth preparation
58. Straight cylinder diamond with a tapered
point:
Used for chamfer placement
Also called Tinker diamond
creates a chamfer with greater control than
the round-end tapered diamond. It is usually
indicated for molars.
59. Round-ended tapered diamond cylinders:
used for :Axial and occlusal reduction and
developing chamfer margins.
Less than half the diameter of the tip is used
for chamfer margins.
60. Round diamonds:
Used for:
Depth grooves before reduction.
To establish rest seats
Reduce lingual surfaces of anterior teeth.
They vary in size and are measured to
determine the cut depth.
They are numbered from ¼, ½, 1, 2 to 10.
62. Thin tapered diamond cones (needle):
used for:
proximal cutting to isolate teeth from adjacent teeth.
They tend to lose their sharpness sooner than coarse
diamonds and are replaced frequently.
66. End cutting burs:
They are cylindrical in shape with just the end
carrying abrasive particles
Used for: extending preparations apically without
axial reduction.
They are numbered from 900 to 904
67. According to particle size of diamond
abrasives: Particle
size(µm)
Super coarse -coarse 142
Coarse –regular 122
Coarse-regular 86
Fine 60
Fine 52
Fine-superfine-coarse-
finishing
40
Superfine-medium-
finishing
14
Ultrafine-fine finishing 8
Milling pastes 6
Polishing pastes 2-5
Particle
size(µm)
Coarse 125-150
Medium 88-125
Fine 60-74
Finishing 10-38
70. Other rotary instruments:
Laboratory burs:
They have longer shank and bigger heads
Used in slow speed handpiece
Most commonly used burs :acrylic burs
Used for cutting and polishing of acrylic
71. Mandrels:
Rods of various lengths used in low speed
handpiece
Abrasives can be permanently attached or
separate
Shanks: latch; friction grip; straight
Attachments: snap-on;screw;pin-design
72. Attachments:
1.sandpaper discs:
Used to polish and finish restorations
Abrasives like garnet, sand,emery and cuttlefish are
used
2.carborandum disc:
Also called separating disc or Jo-dandy disc
Double sided
Green-gray or dark colors
Fast cutting of metal castings, cast gold, porcelains,
acrylics, and tooth structure.
73. 3.diamond disc:
Diamond particles bonded to metal structure
Used to trim porcelain
74. Stones:
Used for cutting,polishing metal ,amalgam
,gold,porcelain restorations in laboratory
The abrasive material include garnet,aluminium
oxide,silicon carbide
Used at slow speeds
White stones have finer grit than green
75. Rubber wheels and discs:
The matrix can be phenolic resins or rubber
Abrasive can be sintered or resin bonded
Softer and less wear-resistant
Used for finishing and polishing for metal
restorations
Conforms to the surfaces like grooves and cusps
76. Robinson’s brushes:
Robinson brushes (stiff, medium, soft) are
used with pumice or tripoli.
Slow speed with pressure produces greater
cutting potential;
high speed with light pressure produces a
high-lustre finish
77. Chamois wheels :
Chamois wheel are used only with dental rouge and
give a luster to the casting and dentures
79. Cleaning
After each use, clean the diamond bur by running
it against a wet diamond cleaning stone.
Manual Cleaning: Presoak in cleaner to loosen
debris (5 min.). Brush away remaining debris.
Rinse (2 min.), dry with absorbent towel.
Ultrasonic Cleaning: Burs may be ultrasonically
cleaned after inserting them in bur holders (or
blocks) to prevent damage. A cycle of 10 minutes
is recommended, using a enzymatic cleaner,
followed by a cold water rinse (2 min.)
80. Autoclave:
A wrapped bur should be steam sterilized at 132
oC for a minimum of 10 minutes or at 121oC for a
minimum of 50 minutes.
An unwrapped bur should be steam sterilized at
132o C for a minimum of 8 minutes or at 121oC
for a minimum of 30 minutes.
Do not exceed 135oC
81. Never
Dry heat sterilize
Expose bur to chemical disinfection or cold
sterilization
Surface wipes
Hand soap or detergents
Surface sprays
Sterilization bags containing disinfectants
83. Gates –glidden burs:
Long thin shaft ending in a flame shaped head
Used for coronal flaring of post space
Available in set of 6 (0.5-1.5mm)
Number is indicated by number of rings on the
shank
Speed 750-1500rpm
Flexogates –gates made with NiTi and non-
cutting tips
84. Peeso reamers:
Long ,sharp flutes connected to thick shaft
Used for gutta-percha removal in post space
preparation
Safe ended
Tip diameter 0.7-1.7mm
Caution:
Do not follow root curvature ,can cause lateral
perforation and iatrogenic errors
86. Many inventories are used for surgical and
prosthodontic phase of implant
Although most implant systems present
approximately similar surgical and prosthetic
components,most of them remain system specific
Implant motor which is not system specific is
required for osteotomy and other procedures
87. Inventories used to practise basic
implant procedure:
1. Dental implant surgical kit
2. Implant motor(physiodispensor)
3. Rotary reduction handpiece
4. Basic oral surgery instruments
5. Cleaning and sterilization instruments
88. 1.Dental implant
surgical kit:• Large carbide bur:
• Remove bony irregularities before
osteotomy
:
• Small round carbide burs
• Mark implant site
• To make entry through cortex
• Pilot drill:
• 1st drill;to make entry
• Should be used till full depth of implant
size
• Generally 2 mm
• Width increasing /widening drills
• Sequentially increase in diameter to
widen osteotomy
• Have depth markings
89. :
Parallel /depth guide/force indicators
Accurate measure of depth in radiograph after
pilot drill (depth guide)
To visualize parallelism during multiple
implants(parallel guide)
To visualize direction of occlusal force in future
(force indicators)
To access precise spacing in multiple implants
(spacing guide)
90. Drill stoppers:
To prevent over-drilling
Bone tap/thread former:
Used with non-cutting/non self-tapping implants
(to reduce pressure necrosis of bone){eg:mastero
implant from bio-horizon}
Used at 20 -40 rpm
91. Countersink drill:
After sequential drilling before implant insertion
To widen crestal bone to submerge wider platform
of implant
Used at 1500-2000rpm
92. Drill extender:
Fitted to any drill to extend its length
Implant depth probe:
For depth evaluation of prepared osteotomy
Tactile examination of bone and sinus membrane
or any perforations
93. Implant insertion tool/driver:
To drive implant during its insertion
Rotary handpiece driven or hand ratchet driven
Ratchet:
A.ratchet wrench:
Ratchet without torque measurement
b.Torque ratchet:
Torque level can be adjusted (0-45N) to check
primary stability
94. Screw driver/Hex driver:
To drive connection screw,cover screw,gingival
former
Hand driven /rotary handpiece driven
95. 2.Implant motor:
(physiodispensor)
Surgical motor for implant insertion
Features:
A. torque control:
Should have torque from 0-50 N (recommended 25
-35N)
B.speed control:
While using a 20:1 reduction handpiece
20 rpm (implant insertion)
2500 rpm(drilling hard bone)(normal 800-1200 rpm)
C.saline irrigation control:
Controlled saline flow to reduce heat production
96. D.hand-piece selection:
1:1 handpiece for osteoplasty.bone
harvesting,sinus window preparation
20:1 reduction handpiece for osteotomy
preparation
E.programmes:programmes for particular implant
procedure
97. F.forward and reverse function:
Helps in taking drills/implants out
Removing cover screw,gingival former
G.foot control:
Foot control with forward/reverse speed funtions
H.autoclavable implant motor cord:
To maintain surgical aspesis
98. Rotary handpiece:
A.1:1 straight or contra-angle handpiece:
Used for osteoplasty,autogeneous bone
harvesting,sinus window preparation
B.20:1 reduction handpiece:
Used for osteotomy,bone tapping,implant
insertion
Other 16:1 30:1 reduction handpieces
C.newer fiberoptic handpiece:
Better visibility
99. 4.Basic oral surgery
instruments:
Lips /cheek retractors
Diagnostic instruments
Bone measuring calliper
Bone rongeur
Periosteal elevators
B.P handles and blades
Needle holders,scissors,artery forceps etc
100. 5.sterilization:
A.ultrasonic cleaner:
To remove blood clots/debries before autoclaving
B.fumigator:
Implant chamber should be fumigated with
formalin
C.autoclave:
With dry cycles to sterilize implant kit and
instruments
101. References:
Sturdevants’s art and science of operative dentistry 4th
edition
Phillips’s science of dental materials11th edition
Clinical implantology :ajay vikram singh
Grossman’s Endodontic Practice 12th edition
Prashtanth katta Shridhar et al Handpieces in dentistry-
Review ;Journel of dental science and research:5(1);1-9
Sharon Crane Siegel Dental Burs-What Bur for Which
Application? A Survey of Dental Schools J Prosthod
1999;8:258-26
Sangamshewar ,Durga Hugaret al Decontamination
Methods Used for Dental Burs – A Comparative Study J
Clin Diagn Res. 2014 Jun; 8(6)
Alessandro Geminiani et al Influence of oscillating and
rotary cutting instruments with electric and turbine
handpieces on tooth preparation surfaces JPD 112(1) ;51-
Editor's Notes
Back end of the bur shank fits in the finger ring ,while the front end is rotated with fore finger and thumb
The bur is activated by spring loaded handle
First belt driven handpiece to operate at 100000rpm speed
Laboratory handpiece have greater torque than handpiece used intraorally
speed of 200000 rpm is used
A typical controller connects to a 4-hole, 5-hole, or 6-pin hose from the dental unit. The controller also comes with a transformer that plugs into a standard wall outlet.
Smaller head size gives more visibility in posteriors and lighter weight
Greater head size gives more power that means more rate of tooth cutting requiring reduced operative time.
So that cutting instruments remains in sight of operators line of sight
But this might decrese posterior visibility
This reduces the pinching force of the operator thus reducing hand and wrist fatigue
An impeller is a rotating component of a centrifugal pump, usually made of iron, steel, bronze, brass, aluminum or plastic, which transfers energy from the motor that drives the pump to the fluid being pumped by accelerating the fluid outwards from the center of rotation.
To remove potential contaminants from internal water line
Bending of steel burs causes excessive run out which cause more heat and vibrations and undue cutting
They grouped burs by 9 shapes and 11 sizes
½ and ¼ sizes were added later
Later crosscut burs were introduced for low speed a prefix 500 was added to the original head number eg 57 became 557
Similarly,prfix 900 was used for end cutting burs eg.957.all have the same head dimensions.
Certain amount of pressure is required to engage the tooth structure by the blade.longer the length of the bur more the pressure,crosscuts reduce this length thus reducing the pressure required to cut
Primary and secondary clearance angle are incorporated to increase the effeciency and decrease the clogging
Some material is removed as chips,but much material is left as lateral ridge of deformed material .this material by repeated work harden and becomes brittle and chips off.
Brittle:the abrasive particles cause subsurface cracks underminng small pieces which are easily removed by other particels
2.8;3.2;4;4.5;5
So that handpiece does not stop rotating while drilling in dense bone
Should have option of selecting handpiece
To remove irregular bone and harvest cancellous bone