Faculty of Dentistry
Endodontic Division
Lecture : Endodontic Instruments
Dr.: Sherif AlHassan Heidar Date : 8/10/2023
Carbon steel: Stainless steel Nickel titanium Diamond tips
Highest cutting Highest corrosion Highest flexibility Unflexible
effeciency resistance
Least flexible Less controlled
Least corrosion Powered by
resistant ultrasonic
K-file H file
Manufacturing Wire pulled & twisted in Machine grinding
counter clockwise
Cross section Square Comma
cutting Lower cutting effeciency Higher cutting effeciency
Flexibility More Breaks eaisly
Canals used in: Apical & coronal Coronal only
Motion Filing & reaming Filing only
K files made of NiTi are available since 1988
NiTi files have improved flexibility than
stainless steel
Hybrid instrument
Diamond cross section instead of square
c.s.
2 acute angle: cutting effeciency
2 obtuse angle: removal of debris
Diamond Reduction in metal
mass: Flexibility
Triangular C.s.
3 acute angle: cutting effeciency
Triangle Reduction in metal mass:
Flexibility
Exactly Flex O but manufactured from NiTi
instead of st. st.
Rectangular C.s., decrease metal bulk
Accordingly higher flexibility
Non cutting tips
Rectangular cs Reduction in metal
mass: Flexibility improved
Modified H file
S shape cross section (second blade)
decrease depth of blade
(reduce breakage )
Modified H-file
Collapse in inner curve so cut less
aggressive
A file Avoid strip perforation
Modified H file
Removal of blades from one side
Safety H file design
H file design
D shaped cross section
Siff files useful in calcified canals
Non cutting tips: avoid ledge or root canal
transportation
Avoid ledge or transportation
Flex R
Flex O
NiTi Flex
RT files
A File
D Finders
Contra designed to grip st. st. hand files &
create file motions instead of hand motion
of file in manual preparations
First contra to operate endo files
Produced by W&H in 1925
Operates k files or reamers
Motion: moves file 360 degree rotation +
vertical stroke
Operates k files or reamers
Motion: moves file in vertical motion
Gear reduction handpiece 5:1 or 10:1
1964
Motion: moves file 90 degree reciprocal
(clock wise & counter clockwise) motion
First file contra with partially flexible motion
▪ Motion: move file in Vertical movment + 90
degree rotation if file is under fricition
2 common features
Gear reduction handpiece
Reciprocating motion
Many companies produce Hand file contra
1) Reciprocating motion
60 degree back & forth
2) Gear reduction
1) Reciprocating motion
30 degree back & forth
2) Gear reduction
NiTi rotary files
Introduction
• In 1988, use on NiTi alloys, it was 2-3 times
more flexible than St.St. allowing canal
preparation in rotary motion
• In mid to late 1990s, rotary Greater taper (GT)
files
NiTi rotary files
▪ Designed with latch handle to fit contra head
connected to special endo motor has:
▪ 1) speed control by rotation per minute (RPM)
▪ 2) Torque control
▪ Not used with special contra or low speed
contra
Rotary files
▪ Designed from nickel titanium (NiTi )
▪ Rotary files have non-cutting tips
▪ File design has greater taper than hand files
▪ Rotary file taper by 0.04 mm per millimeter
(mm) or 0.06 mm taper per mm
NiTi advantages
▪ Flexible preseve root canal curvature
▪ Quick
▪ Reduced number of files for preparation Due
to increased taper (no need for filing after
apical preparation as step back technique
using hand files)
NiTi disadvantages
▪ Expensive
▪ Fracture
▪ Strict number of use
NiTi fracture
▪ Rotary files require endo motors with speed control
& torque control
▪ Susceptible to unexpected fracture
▪ Return to original shape after bent in curved canal
(no curving) in some rotary files but recent rotary
files do not return to original shape
NiTi fracture
2 types of fracture
1) Torsion fracture: file tip interlocked in canal while
file remains rotating
▪ Smaller files more susceptible
2) Cyclic Fatigue : In curved canals, areas of
compression in inner curve & tension in outer curve
Rotary files generations
First generation rotary files
• Characterized by fixed taper of 0.04-0.06%
throughout the file length and passive radial
lands
• Example: profile rotary files
Second generation rotary files
• Characterized active cuttuing edges, improving
cutting efficiency so reducing files required to
completely prepare the canal.
• Example: Protaper rotary files
SEM view of rotatry files cross section
First Generation , passive radial lands Second Generation , active cutting
edges
Third generation rotary files
Heat treated NiTi files
Advantages of heat treatment
More flexible
Greater resistance to cyclic fatigue.
Fourth generation rotary files
Reciprocation, a process that may be defined as any
repetitive counter-clockwise (CCW) and clockwise
(CW) in lesser degree to progress apically.
Most popular, WaveOne and RECIPROC are single
file concepts.
Files are heat treated as third generation but
reciprocating motion is advantage
Reciprocating rotary files
▪ Motor move file in clockwise and counter
clockwise
Advantages of reciprocating
Single file for root canal preparation
Less cyclic fatigue than continuous rotation
Higher cutting efficiency
More tappered prepartion with rotary files
Hand Rotary
files
Postoperative radiographs
Enlarging instrument
shape dentin
▪ Operated manually: hand instruments
▪ Automated contra for hand files: grip hand files,
Have gear reduction and reciprocation motion
of files
▪ Operated by contra: rotary instruments
▪ Ultrasonics: Undesirable because not respect
curvature of root canal and uncontrolled cutting
Enlarging instrument
shape dentin
Enlarging instruments
Reamers: hand
K files : hand
H files : hand
Hybrid files : hand
Rotary files : rotary but operated in torque & speed control
motor
Gates Glidden : rotary operated on low speed handpiece
Pesso reamer : rotary operated on low speed handpiece
Us diamond tips : ultrasonic
