4 Endodontics. Definition.methods of Medical and Instrumental Treatment of Root Canals

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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

("tep!Bac", "Cro#n!do#n" techni$ue%. Medicines.

Mistaes and complications.

Lecturer: Levkiv Mariana O.

Department of Therapeutic Dentistry

TSMU


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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 odonto-

surgical intervention inside the tooth in order of itspreservation with the subsequent restoration of its form

and function with the help of therapeutic or prosthetic

methods.


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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 adacent directly to canal

orifices.

!ost canals are flattened mesio-distally, but become more

rounded in the apical "#$. %ateral canals are branches of

the main canal and occur in "&-$'( of teeth.

In the apical part near the dentinal-cement border rootcanal ends with a constriction )physiological apical hole*,

which is usually placed at a distance of '.+-".' mm from

the radiological ape.


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ome authors identify anatomical apical hole - a place of

transition the dentin into cement, and physiological hole -

the border between pulp and periodontium, placed " mmaway from the -ray hole.

The apical foramina are usually sited '.+-'.& mm away

from the anatomical and radiographic ape.

The apical constriction usually occurs '.+-'.& mm short ofthe foramina. These distances with age due to deposition

of secondary cementum. /oot-filling to the constriction

provides a natural stop to instrumentation, thus the working

length should be established "-0 mm from the radiographic

ape. The dentist who conducts endodontic manipulations before

the start of treatment should identify options for

topographic and anatomical structure of the tooth.


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Topographical and anatomical

features of teeth cavities ofdifferent group of teeth.


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Endodontic instruments 1ccording to I2 endodontic instruments are classified3

4and instruments3 files)5 and 4*, barbed broaches,

spreader and plugger )vertical and lateral gutta percha

condensors *.

/otary instruments3 4-files and 5-reamers for slow

handpiece, lentulo spiral 6ller#rotary paste 6ller.

/otary instruments3 7ates 7lidden drills, 8eeso reamer

drills.

8ins3 gutta percha pins, silver pins.


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9ut its more convenient to use classification by

:urson)";;


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The main endodontic instruments and their use

Bared roachesFunctions and precautions

> ?inger instruments

> @isposed of in the sharps= container

>Used to remove the intact pulp

> A9arbs= on the broach snag the pulp

to facilitate removal

> They need to be used cautiously as

they can bind and break in the canal

Varieties1vailable in different siBes and widths


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!ates !lidden drills Function, features and precautions

>To enlarge the coronal third of the canal during endodontic treatment

> mall Came-shaped cutting instrument used in the

conventional handpiece

> @ifferent siBes D coded by rings or colouredbands on shank

>1re slightly Ceible and will follow the canal

shape but can perforate the canal if used too deeply

> @ispose of in sharps= container

> hould be used only in the straight sections of

the canal


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"eeso reamer drillsFunction, features and precautions

>To remove gutta percha during post preparation

> mall Came-shaped cutting instrument used in the conventional handpiece

> @ifferent siBes D coded by rings or coloured

bands on shank

> 8eeso reamers are not Ceible or adaptable,

if not used with care can perforate canal

> @ispose of in sharps= container


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#eamers/arely used or indicated. @isadvantages of reamers include theirinfleibility with siBe, which can result in a wider canal being cut apically.

4ave now been replaced by files.

$iles These are used either with a longitudinal rasping or a rotary action )e.g.clockwise direction*.

The main types of file available are3

%&type-file !ade by twisting a square metal blank.

'edstroem file!ade by machining a continuous groove into a metal blank.!ore aggressive than 5-file. !ust never be used with a rotary action asliable to fracture.

%&fle(file imilar to 5-file but made by twisting a rhomboid shape blankalternating blades with acute and obtuse angles. !ore fleible than 5-filebut becomes blunt more quickly.


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$le(&o&file%ooks similar to a 5-type-file but is made from a triangular blankof a more fleible steel. The file also has a blunt tip, which means that it is

unlikely to create a false canal. This file is more fleible than 5-types and isnow becoming a popular replacement.

!retaer taper)7T* 4and files made from nickel titanium )iTi*. They haveincreasing tapers )'.'


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,ndodontic % -les. lso called: #oot canal hand -les Function, features and precaution

> ?inger instrument

> :olour coded by siBe. The < colours used most often are3 siBe "+ )white*F0' )yellow*F 0+ )red*F $' )blue*F $+ )green*F G' )black*. 1lso available in siBe< )pink*, H )grey* and "' )purple*

> 2perator gradually increases the siBe of the

6le to smooth, shape and enlarge canal

> The larger the number of the 6le, the larger

the diameter of the working end

> @isposed of in the sharps= container

Varieties > @ifferent lengths3 0"mm, 0+mm and $'mm

> 4edstrm 6les, ?leo6lesJ


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)iTi *)ickel titanium+ rotary instruments Function, features and directions for use

> Used to clean and shape the canals

> Used with endodontic handpiece and motor

> iTi is Ceible and instruments follow the

canal outline very well > everal varieties of systems with different

sequences of instruments are used

> Important to follow the manufacturer=s

recommended speeds and instructions for use

Varieties

@ifferent lengths3 0"mm and 0+mm


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Lentulo spiral -ller/rotary paste -ller

Function and features

> mall Ceible instrument used to place materials intothe canal

> ?its into the conventional handpiece

> Use with caution as it can be easily broken

> @ifferent siBes available


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!eometric symols of endodontic

instruments


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The main purpose of root canal treatment is3

removal of pulpF

removal of infected dentine from the inner wall of theroot canalF

epansion and forming a root canal for its adequatefilling.

This procedure of root canal treatment consists of suchstages3

-disclosure of the tooth cavityF

- disclosure of the root canal orificesF

- the root canal passingF

- the root canal enlargementF

- the root canal shaping.


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!anipulations of root canal treatment)/:T* are carried outmanually or with the help of rotary instruments by severaltreatment methods, the most widespread among them are3

apical-crown- envisage treatment from the apical hole tocanal orifices with gradually increasing of instrumentdiameter) e.g. from K"' -K G'*

crown-apical -envisage root canal

treatment that starts from canal orifices

to apical hole with a gradual decrease

in instrument diameter)e.g. from KG' D

K "'*

:ombined method of treatment3


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Step&ack techni0ueThe apical part of the root canal is preparedfirst and the canal is then flared from ape to crown. 9lockage of

canals may occur using this technique, and irrigation can be difficult.

1ro2n&do2n techni0ueThis )along with several others* preparesthe coronal part of the canal before the apical part. This hasadvantages and is the preferred technique.

Balanced force techni0ue This involves using blunt-tipped files with ananticlockwise rotation whilst applying an apically directed force. It requirespractise to master but is particularly useful when preparing the apical part ofseverely curved canals.

nticurvature filing This was developed to minimiBe the possibility ofcreating a LstripL perforation on the inner walls of curved root canals. It isused in conunction with other techniques or preparation, and the essentialprinciple is the direction of most force away from the curvature.


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dvantages of orifice enlargement

> Effectively, the curvature in the coronal part of the root canal,allowing straighter access for files to the apical region. It thereforereduces the likelihood of apical transportation )Bipping*.

> It allows improved access for the flow

of irrigant solution within the canal.

> It reduces the likelihood of apical etrusionof infected material as most of the canal

debris is removed before apical instrumentation

takes place. This is particularly important

because the maority of bacteria in an infected

root canal are located in the coronal region.


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8assing and enlargment of root canal )especially narrowand sclerosed* is not always possible to implement usingonly endodontic instruments. In such cases, additionalchemical epansion is conducted .uch techniqueinvolves the use of different types of acids fordecalcification of dentin.

In root canal treatment is often used products based onE@T1.

?or chemical enlargement of a root canal a small amountof gel product is applied to endodontic instruments and

mechanical treatment of root canal is performed. Theprocedure is repeated several times. 1fter obtaining therequired result, canal is washed with solution of sodiumhypochlorite or distilled water.


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Drugs for chemical enlargement of rootcanals

Type of active ingredient The product3 the manufacturingcompany

1 solution of E@T1 %argal ultra )MeptodontN*

Edetat solution )M8ierre /olandN*Endofree )M@encareN*

1 solution of citric acid andpropionic acid

Oerifi )MpadN*

7els based on E@T1 :analP )MeptodontN*

48U"+ )MpadN*/:-prep )M8remierN*QRSR RVW )XYRWZ[R-Y\*


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/oot canal treatment should include thorough mechanicaldebridement and medication treatmentas well )antisepticsolutions*, these two procedures should go together.

4rrigants. These are required to flush out debris andlubricate instruments. @ilute sodium hypochlorite is

generally considered to be the best irrigant as it isbacteriocidal and dissolves organic debris. The normalconcentration is 0.+( available chlorine. :helating agentswhich soften dentine by their demineraliBing action are

particularly helpful when trying to negotiate sclerosed or

blocked canals.


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Prepared root canal for sealing, regardless of the method

of instrumental treatment, must fulfill the followingcriteria as:

To be sufficiently enlargedF

To have a conical shapeF

To have formed apical ledgeF

@o not contain a necrotic dentinF

@o not have typical smellF

To be clean and dryF

@o not have a painful reaction to percussion.


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1ommon errors in canal preparation

5 4ncomplete deridement3 working length short, missed canals. > Lateral perforation3 often occurs as a result of poor access.

> pical perforation3 makes filling difficult.

> Ledge formation3 can be very difficult to bypass.

pical transportation)Bipping* 1 file will tend to straighten out

when used in a curved canal and straightening can transport theapical part of the preparation away from the curvature. The use offleible files reduces the likelihood of this happening.

,lo2 formation]hen apical Bipping happens, a narrowing oftenoccurs coronal to this in the canal such that the canal is hourglass inshape. This narrowing is termed an elbow.

Strip perforation1 perforation occurring in the inner or furcal wallof a curved root canal, usually towards the coronal end.


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SOM, ,)DODO)T41 "#OBL,MS )D T',4# M)!,M,)T

$ractured instruments.ometimes it is possible to get hold of the fracturedportion with a pair of fine mosquitos. If not, insertion of a fine file beside theinstrument may dislodge it. hould the fractured piece be lodged in the apical

portion of the canal it may be better to fill the canal below it and keep itunder observation, resorting to an apicectomy as a last-ditch solution.

$ractured instrument removal. Ultrasonic vibration may be used tofacilitate fractured instrument removal.The clinician must take care to

ascertain the type of metalic obstruction because nickel-titanium )iTi* andstainless steel respond differently to ultrasonic vibration. @irect ultrasonicvibration causes iTi to fragment, so the clinician must work carefullyaround the fragment. tainless steel is more resistant to vibration andresponds to it by subsequently loosening.

Ultrasonic vibration is applied directly to stainless steel files. ?ine insertscan be used to work counter-clockwise around broken instruments. Thistechnique often results in an MunscrewingN action that assists in removal.


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#ecurrent symptoms/intractale infection If thorough cleaningand repeated dressing of the canal with calcium hydroide areunsuccessful, it may be necessary to do an apicectomy. @o not

routinely turn to surgery for failed cases consider retreatment in thefirst instance.

4f careful e(ploration 2ith a small fileis unsuccessful,investigation of the epected position of the canal entrance with asmall round bur may help. 2nce the canal is found, a o. H or "' file

should be used to try and negotiate it, using E@T1, ?ile EBe, or /:8rep as a lubricant, and the canal prepared and filled conventionally.uccess rates of H'( have been reported for canals that were hairlineor undetectable on radiographs.0H 2ccasionally, a total blockage ofthe canal is encountered, in which case the filling is placed to thislevel and#or an apicectomy done.

"ulp stonesin the pulp chamber can usually be flicked out. If theyoccur in the canal use E@T1 and a small file to try and dislodgethem.


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"ain follo2ing instrumentation. This is usually due to instruments orirrigants, or to debris being forced into the apical tissues. 8lacement of a smallamount of %edermi)1ntibiotic#steroid paste * in the canal may provide

symptomatic relief, but care is required not to breach the ape. 2ccasionally,an acute flare-up of a previously asymptomatic tooth occurs following initialinstrumentation this is called a phoeni abscess. %oss of face is saved bywarning patients that this can happen. 1ffected teeth should be opened andirrigated and if possible resealed. This may need to be repeated after 0G-GH h.

"erforations can eiatrogenic or caused by resorptionIn the latter case, dressing with non-setting calcium hydroide may help to arrestthe resorption and promote formation of a calcific barrier. Increasingly !T1 is

being used for the repair of perforations and in surgical endodontics as aretrograde filling material with ecellent results. !anagement of traumatic

perforations depends upon their siBe and position3

"ulp chamer floor If small perfortion, one can cover with calciumhydroide and fill with 78 or 7I, but if large, hemisection or etraction may benecessary.


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Lateral perforation If this occurs near the gingival margin it can beincorporated in the final restoration of the crown, e.g. a diaphragm

post and core crown. If in the middle "#$, the remainder of the canalmay be cleaned by passing instruments down the side of the wallopposite the perforation. Then the canal can be filled with 78, usinga lateral condensation technique to try and occlude the perforation as

well. %arger perforations may require a surgical approach and inmultirooted teeth hemisection or etraction may be unavoidable.

pical 6/7 It is usually worth trying a vertical condensationtechnique to attempt to fill both the perforation and the remainder ofthe canal. If this is unsuccessful an apicectomy will be required.

Ledge formation If this occurs, return to a small file curved at theape to the working length and use this to try and file away theledge, using E@T1 or /:- 8rep as lubricants.


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4 Endodontics. Definition.methods of Medical and Instrumental Treatment of Root Canals

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