Transcript Endodontics. Definition. Clinical and anatomical structure of teeth’ cavities and root canals of teeth. Endodontic instruments.

Endodontics. Definition. Clinical and anatomical
structure of teeth’ cavities and root canals of teeth.
Endodontic instruments. Basic endodontic
manipulation: trepanation of tooth cavity,
amputation, extirpation of the pulp. Methods of
medical and instrumental treatment of root canals
("Step-Back", "Crown-down" technique). Medicines.
Mistakes and complications.
Lecturer: Levkiv Mariana O.
Department of Therapeutic Dentistry
TSMU
• Endodontics is the science that study anatomy, pathology,
and treatment of tooth cavity and root canals.
• Under endodontic intervention it should be understand
any interference with the purpose of treatment, carried
out through the cavity of the tooth.
• Under root canal treatment should be understood odontosurgical intervention inside the tooth in order of its
preservation with the subsequent restoration of its form
and function with the help of therapeutic or prosthetic
methods.
• In endodontic practice the knowledge of topographical
anatomy of dental cavities of different groups of teeth is
necessary.
• The root canal is divided into crown, middle and apical
parts.
• The crown part is the widest and adjacent directly to
canal orifices.
• Most canals are flattened mesio-distally, but become
more rounded in the apical 1/3. Lateral canals are
branches of the main canal and occur in 17-30% of teeth.
• In the apical part near the dentinal-cement border root
canal ends with a constriction (physiological apical hole),
which is usually placed at a distance of 0.5-1.0 mm from
the radiological apex.
• Some authors identify anatomical apical hole - a place of
transition the dentin into cement, and physiological hole the border between pulp and periodontium, placed 1 mm
away from the X-ray hole.
• The apical foramina are usually sited 0.5-0.7 mm away
from the anatomical and radiographic apex.
• The apical constriction usually occurs 0.5-0.7 mm short
of the foramina. These distances ⇑ with age due to
deposition of secondary cementum. Root-filling to the
constriction provides a natural stop to instrumentation,
thus the working length should be established 1-2 mm
from the radiographic apex.
• The dentist who conducts endodontic manipulations
before the start of treatment should identify options for
topographic and anatomical structure of the tooth.
Topographical and anatomical
features of teeth cavities of
different group of teeth.
Endodontic instruments
• According to ISO endodontic instruments are classified:
• Hand instruments: files(K and H), barbed broaches,
spreader and plugger (vertical and lateral gutta percha
condensors ).
• Rotary instruments: H-files and K-reamers for slow
handpiece, lentulo spiral filler/rotary paste filler.
• Rotary instruments: Gates Glidden drills, Peeso reamer
drills.
• Pins: gutta percha pins, silver pins.
• But its more convenient to use classification by
Curson(1996) that is based on clinical usage of
endodontic instruments.
• - diagnostic instruments: root needles(Miller needles)
• - instruments for removing the soft teeth’ tissues: barbed
broaches
• - instruments for passing and enlargement of root canals
• (K-reamers, K- files, H-files)
The main endodontic instruments and their use
Barbed broaches
• Functions and precautions
• • Finger instruments
• • Disposed of in the sharps’ container
• •Used to remove the intact pulp
• • ‘Barbs’ on the broach snag the pulp
• to facilitate removal
• • They need to be used cautiously as
• they can bind and break in the canal
• Varieties
• Available in different sizes and widths
• Gates Glidden drills
• Function, features and precautions
• •To enlarge the coronal third of the canal during endodontic treatment
• • Small flame-shaped cutting instrument used in the
conventional handpiece
• • Different sizes – coded by rings or coloured
bands on shank
• •Are slightly flexible and will follow the canal
shape but can perforate the canal if used too deeply
• • Dispose of in sharps’ container
• • Should be used only in the straight sections of
• the canal
• Peeso reamer drills
Function, features and precautions
• •To remove gutta percha during post preparation
• • Small flame-shaped cutting instrument used in the conventional handpiece
• • Different sizes – coded by rings or coloured
bands on shank
• • Peeso reamers are not flexible or adaptable,
if not used with care can perforate canal
• • Dispose of in sharps’ container
• Reamers Rarely used or indicated. Disadvantages of reamers include their
inflexibility with ⇑ size, which can result in a wider canal being cut apically.
Have now been replaced by files.
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• Files These are used either with a longitudinal rasping or a rotary action (e.g.
clockwise direction).
• The main types of file available are:
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• K-type-file Made by twisting a square metal blank.
• Hedstroem file Made by machining a continuous groove into a metal blank.
More aggressive than K-file. Must never be used with a rotary action as
liable to fracture.
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• K-flex file Similar to K-file but made by twisting a rhomboid shape blank
alternating blades with acute and obtuse angles. More flexible than K-file but
becomes blunt more quickly.
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• Flex-o-file Looks similar to a K-type-file but is made from a triangular blank
of a more flexible steel. The file also has a blunt tip, which means that it is
unlikely to create a false canal. This file is more flexible than K-types and is
now becoming a popular replacement.
• Gretaer taper (GT) Hand files made from nickel titanium (NiTi). They have
increasing tapers (0.06-0.12) with matched GP cones.
• Files have traditionally been made from steel, but newer varieties made of
NiTi are gaining popularity as they are much more flexible. Larger-sized
files can be sterilized and re-used more than the smaller sizes. All
instruments should be examined regularly, and discarded if there are any
signs of damage. It is good practice to dispose of smaller files after one use.
In future files may all be single use (disposable).
• NiTi rotary instruments (Profile) reduce creation of blocks, ledges,
transportations and perforations by remaining centred within the natural path
of the canal. Useful for curved canals but ⇑ risk of fracture. Prior to use
check for patency/ glide-path up to the full working length with a size 10
file.
• Endodontic K files. Also called: Root canal hand files
• Function, features and precaution
• • Finger instrument
• • Colour coded by size. The 6 colours used most often are: size 15 (white);
20 (yellow); 25 (red); 30 (blue); 35 (green); 40 (black). Also available in size
6 (pink), 8 (grey) and 10 (purple)
• • Operator gradually increases the size of the
• file to smooth, shape and enlarge canal
• • The larger the number of the file, the larger
• the diameter of the working end
• • Disposed of in the sharps’ container
• Varieties
• • Different lengths: 21mm, 25mm and 30mm
• • Hedstrцm files, Flexofiles®
• NiTi (Nickel titanium) rotary instruments
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Function, features and directions for use
• Used to clean and shape the canals
• Used with endodontic handpiece and motor
• NiTi is flexible and instruments follow the
canal outline very well
• Several varieties of systems with different
sequences of instruments are used
• Important to follow the manufacturer’s
recommended speeds and instructions for use
Varieties
Different lengths: 21mm and 25mm
• Lentulo spiral filler/rotary paste filler
• Function and features
• • Small flexible instrument used to place materials into
the canal
• • Fits into the conventional handpiece
• • Use with caution as it can be easily broken
• • Different sizes available
Geometric symbols of endodontic
instruments
Access to cavity preparations
• The main purpose of root canal treatment is:
• removal of pulp;
• removal of infected dentine from the inner wall of the
root canal;
• expansion and forming a root canal for its adequate
filling.
This procedure of root canal treatment consists of such
stages:
• -disclosure of the tooth cavity;
• - disclosure of the root canal orifices;
• - the root canal passing;
• - the root canal enlargement;
• - the root canal shaping.
Manipulations of root canal treatment(RCT) are carried out
manually or with the help of rotary instruments by several
treatment methods, the most widespread among them are:
• apical-crown - envisage treatment from the apical hole to
canal orifices with gradually increasing of instrument
diameter( e.g. from №10 -№ 40)
• crown-apical - envisage root canal
treatment that starts from canal orifices
to apical hole with a gradual decrease
in instrument diameter(e.g. from №40 –
№ 10)
• Combined method of treatment:
 Step-back technique The apical part of the root canal is prepared
first and the canal is then flared from apex to crown. Blockage of
canals may occur using this technique, and irrigation can be difficult.
 Crown-down technique This (along with several others) prepares
the coronal part of the canal before the apical part. This has
advantages and is the preferred technique.
 Balanced force technique This involves using blunt-tipped files with an
anticlockwise rotation whilst applying an apically directed force. It requires
practise to master but is particularly useful when preparing the apical part of
severely curved canals.
 Anticurvature filing This was developed to minimize the possibility of
creating a 'strip' perforation on the inner walls of curved root canals. It is
used in conjunction with other techniques or preparation, and the essential
principle is the direction of most force away from the curvature.
• Advantages of orifice enlargement
• • Effectively, ⇓ the curvature in the coronal part of the root canal,
allowing straighter access for files to the apical region. It therefore
reduces the likelihood of apical transportation (zipping).
• • It allows improved access for the flow
of irrigant solution within the canal.
• • It reduces the likelihood of apical extrusion
of infected material as most of the canal
debris is removed before apical instrumentation
takes place. This is particularly important
because the majority of bacteria in an infected
root canal are located in the coronal region.
• Passing and enlargment of root canal (especially narrow
and sclerosed) is not always possible to implement using
only endodontic instruments. In such cases, additional
chemical expansion is conducted .Such technique
involves the use of different types of acids for
decalcification of dentin.
• In root canal treatment is often used products based on
EDTA.
• For chemical enlargement of a root canal a small amount
of gel product is applied to endodontic instruments and
mechanical treatment of root canal is performed. The
procedure is repeated several times. After obtaining the
required result, canal is washed with solution of sodium
hypochlorite or distilled water.
Drugs for chemical enlargement of root
canals
Type of active ingredient
The product, the manufacturing
company
A solution of EDTA
Largal ultra (“Septodont”)
Edetat solution (“Pierre Roland”)
Endofree (“Dencare”)
A solution of citric acid and
propionic acid
Verifix (“Spad”)
Gels based on EDTA
Canal+ (“Septodont”)
HPU15 (“Spad”)
RC-prep (“Premier”)
Канал Глайд («Радуга-Р»)
Root canal treatment should include thorough mechanical
debridement and medication treatment as well (antiseptic
solutions), these two procedures should go together.
Irrigants. These are required to flush out debris and
lubricate instruments. Dilute sodium hypochlorite is
generally considered to be the best irrigant as it is
bacteriocidal and dissolves organic debris. The normal
concentration is 2.5% available chlorine. Chelating agents
which soften dentine by their demineralizing action are
particularly helpful when trying to negotiate sclerosed or
blocked canals.
Prepared root canal for sealing, regardless of the method
of instrumental treatment, must fulfill the following
criteria as:
To be sufficiently enlarged;
To have a conical shape;
To have formed apical ledge;
Do not contain a necrotic dentin;
Do not have typical smell;
To be clean and dry;
Do not have a painful reaction to percussion.
• Common errors in canal preparation
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• Incomplete debridement : working length short, missed canals.
• Lateral perforation : often occurs as a result of poor access.
• Apical perforation : makes filling difficult.
• Ledge formation : can be very difficult to bypass.
Apical transportation (zipping) A file will tend to straighten out
when used in a curved canal and straightening can transport the
apical part of the preparation away from the curvature. The use of
flexible files reduces the likelihood of this happening.
• Elbow formation When apical zipping happens, a narrowing often
occurs coronal to this in the canal such that the canal is hourglass in
shape. This narrowing is termed an elbow.
• Strip perforation A perforation occurring in the inner or furcal wall
of a curved root canal, usually towards the coronal end.
SOME ENDODONTIC PROBLEMS AND THEIR MANAGEMENT
• Fractured instruments. Sometimes it is possible to get hold of the
fractured portion with a pair of fine mosquitos. If not, insertion of a fine
file beside the instrument may dislodge it. Should the fractured piece be
lodged in the apical portion of the canal it may be better to fill the canal
below it and keep it under observation, resorting to an apicectomy as a lastditch solution.
• Fractured instrument removal. Ultrasonic vibration may be used to
facilitate fractured instrument removal.The clinician must take care to
ascertain the type of metalic obstruction because nickel-titanium (NiTi) and
stainless steel respond differently to ultrasonic vibration. Direct ultrasonic
vibration causes NiTi to fragment, so the clinician must work carefully
around the fragment. Stainless steel is more resistant to vibration and
responds to it by subsequently loosening.
• Ultrasonic vibration is applied directly to stainless steel files. Fine inserts
can be used to work counter-clockwise around broken instruments. This
technique often results in an “unscrewing” action that assists in removal.
• Recurrent symptoms/intractable infection If thorough cleaning
and repeated dressing of the canal with calcium hydroxide are
unsuccessful, it may be necessary to do an apicectomy. Do not
routinely turn to surgery for failed cases consider retreatment in the
first instance.
• If careful exploration with a small file is unsuccessful,
investigation of the expected position of the canal entrance with a
small round bur may help. Once the canal is found, a No. 8 or 10 file
should be used to try and negotiate it, using EDTA, File Eze, or RC
Prep as a lubricant, and the canal prepared and filled conventionally.
Success rates of 80% have been reported for canals that were hairline
or undetectable on radiographs.28 Occasionally, a total blockage of
the canal is encountered, in which case the filling is placed to this
level and/or an apicectomy done.
• Pulp stones in the pulp chamber can usually be flicked out. If they
occur in the canal use EDTA and a small file to try and dislodge
them.
• Pain following instrumentation. This is usually due to instruments or
irrigants, or to debris being forced into the apical tissues. Placement of a small
amount of Ledermix(Antibiotic/steroid paste ) in the canal may provide
symptomatic relief, but care is required not to breach the apex. Occasionally, an
acute flare-up of a previously asymptomatic tooth occurs following initial
instrumentation this is called a phoenix abscess. Loss of face is saved by
warning patients that this can happen. Affected teeth should be opened and
irrigated and if possible resealed. This may need to be repeated after 24-48 h.
• Perforations can be iatrogenic or caused by resorption
In the latter case, dressing with non-setting calcium hydroxide may help to arrest
the resorption and promote formation of a calcific barrier. Increasingly MTA is
being used for the repair of perforations and in surgical endodontics as a
retrograde filling material with excellent results. Management of traumatic
perforations depends upon their size and position:
• Pulp chamber floor If small perfortion, one can cover with calcium
hydroxide and fill with GP or GI, but if large, hemisection or extraction may be
necessary.
• Lateral perforation If this occurs near the gingival margin it can be
incorporated in the final restoration of the crown, e.g. a diaphragm
post and core crown. If in the middle 1/3, the remainder of the canal
may be cleaned by passing instruments down the side of the wall
opposite the perforation. Then the canal can be filled with GP, using a
lateral condensation technique to try and occlude the perforation as
well. Larger perforations may require a surgical approach and in
multirooted teeth hemisection or extraction may be unavoidable.
• Apical 1/3 It is usually worth trying a vertical condensation
technique to attempt to fill both the perforation and the remainder of
the canal. If this is unsuccessful an apicectomy will be required.
• Ledge formation If this occurs, return to a small file curved at the
apex to the working length and use this to try and file away the ledge,
using EDTA or RC- Prep as lubricants.
Thank you for your attention