endo don tics

ENDODONTICS LEGEND

Major Topic AbbreviationDiagnostic MethodslTests Diag MethIndividual Teeth Ind TthInstruments/MaterialslTechniques InstlMatlTechMiscellaneous Misc.Pulp PulpReplantation (Intentional and Replant

Avulsed Teeth)Resorption ResorpTerms/Conditions Terms/Cond

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Inst/MatlTechENDODONTICSWhich of the following is the procedure of choice when a broken endodontic instru-ment protrudes past the apex of a tooth?

Extract the tooth The broken instrument is surgically removed, and then the entire canal is filled with

gutta-percha Fill the tooth with gutta-percha and observe None of the above

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The broken instrument is surgically removed, and then the entire canal is filledwith gutta-percha

As a general rule, when a broken instrument protrudes past the apex , surgery shouldbe performed to remove the constant irritation.

When an instrument breaks off anywhere in the canal and a periapica l radiolucencyis present and minimal canal enlargement has been performed before the accident ,surgery is indicated since the periapical tissues have had little opportunity forhealing to be stimulated. You would prepare and obturate to the point of blockage andthen perform apicoectomy and retrofilling.

However, when an instrument is broken off in the apical third and is lodged tightly withno periapical radiolucency evident , the canal can be filled in the remaining root canalspace. The patient should be informed of this and placed on a 3-6 month recall.

The prognosis of a tooth with a broken instrument is best if the tooth had a vital pulpand no periapical lesion.

ENDODONTICSWhich tooth below will almost always have two canals?

Maxillary first premolar Maxillary second premolar Mandibular first premolar Mandibular second premolar


Ind Tth

Maxillary first premolar

Approximately 60% have two roots, one buccal and the other palatal , each with a singlecanal. The two roots may be completely separate or merely twin projections rising from the mid-dle third of the root to the apex (this is more common). The two roots are usually equal in lengthfrom apex to cusp. However, the palatal root and canal may be wider.

In approximately 40% of maxillary first premolars, only one root is present, usually withtwo separate canals. A cross section at the cervical line shows a canal shaped like a figure eight(ellipse). The access opening is a thin oval. Be careful not to perforate on the mesial (the con-cavity on the mesial makes perforation vel)' common).

Maxillary second premolars : The most common configuration in this tooth is a single root,occurring approximately 85% of the time. Approximately 15% of the time, two separate roots arepresent, each with a single canal. The access opening is exactly the same as that for maxil-lary first bicuspids (thin oval).

Notes : When only one canal is present (first or second premolars), it is usually found in the center

of the access preparation. If only one canal is found, but it is not in the center of the tooth, itis probable that another cana l is presen t.

Overfill ing either tooth may force materials directly into the maxillary sinus.

Ind TthENDODONTICSWhich tooth listed below may have a pulp chamber that is somewhat triangular asopposed to oval?

Maxillary central incisor Mandibular central incisor Maxillary lateral incisor Mandibular lateral incisor


Maxillary central incisor

The base of the triangle will be the facial. The apex will be the lingual. If it is not tri-angular, then it will be oval.

The cervical cross sections below of theanterior teeth show the relationship of the

crown outline to the pulp chamber and the root canal

Max 00(@Central Lateral Canine

Mand. @ @ 0Central Lateral Canine

Ind TthENDODONTICSWhich of the following will have a pulp chamber that will be triangular?

Permanent mandibu lar second premolars Permanent mandibular molars Permanent maxillary molars Permanent maxillary lateral incisors


Permanent maxillary molars

- Base is formed by buccal canals and apex by palatal canal.- The line connecting the mesial with palatal canal is the longest.- Remember: The fourth canal, if present , is usually found lingual to the orifice

of the mesiobuccal canal (It is located in the mesiobuccal root).

Mandibular molars Trapezoidal outline, formed by the two canals in the mesial root and the oval canal

in the distal root.

Remember: The distal root has a second canal approximately 30% of the time.

L

Ind TthENDODONTICSWhich of the following canals in a maxillary first molar is usually the most difficultto locate?

Palatal Distobuccal Mesiobuccal All of the canals are relatively easy to find

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Mesiobuccal

Canal orifices of a maxillary fi rst molar are arranged in the shape of a triangle. The orifice tothe mesiobuccal canal is usually the most difficult to locate, since it is under themesiobuccal cusp and must be entered from a distolingual position. This canal is the small-est canal and often splits into two canals. It maybe calcified and difficult to instrument. Thepalatal canal is the straightest, widest and most tapering canal. The most common curvature ofthe palatal root is to the facial. The distobuccal canal is also small and tapering. The orifice tothis canal has no direct relation to its cusp. The distobuccal orifice is usually located by meansof its relation to the mesiobuccal orifice, with the distobuccal found approximately 2 to 3 mm tothe distal and slightly to the palatal aspect of the mesiobuccal orifice.

Note: In approximately 59% of maxillary first molar teeth, a fourth canal is present with its ori-fice being just lingual to orifice to the mesiobuccal canal. The canal is located in themesiobuccal root and may join the mesiobuccal canal or exit through a separate foramen. If alesion is present on the mesiobuccal root prior to root canal therapy and doesn't heal in the usualamount of time (6-12 months) following treatment, it is most likely due to a missed canal (mesio-lingual).Remember : The U-shaped radiopacity commonly seen overlying the apex of the palatal rootof the maxillary first molar is most likely the zygomatic process of the maxilla.

ENDODONTICSThe root canal for a mandibular canine is:

Wide mesiodistally but thin labiolingually Thin mesiodistally but wide labiolingually The same width mesiodistally and labiolingually


Ind Tth

Thin mesiodistally but wide labiolingually

The root canal for a mandibular canine is thin mesiodistally but wide labiolingually.

Mandibular canines usually have only one root but in rare cases may have two sep-arate roots. The access opening is a large oval with the greatest width placedincisogingivally.

This tooth usually has a slightly labial axial inclination of the crown, therefore theaccess opening needs to be directed towards the lingual surface.

Ind TthENDODONTICSWhich mandibular premolar presents with more variations in root canal anatomy?

First premolar Second premolar


First premolar

The mandibular first premolar may cause problems during treatment because of therelatively frequent (15%) existence of a bifurcated canal dividing in the middle or apicalthird into a buccal and a lingual branch. The shape of the access opening is oval. Whendivided canals are present, the entry must be widened buccolingually.

The second premolar has fewer variations than the first premolar, usually having oneroot and one well-centered canal. The access opening is oval. Consideration must begiven to the mental foramen which lies in close proximity to the apex. Avoid over-instrumentation and overfill. When viewing an x-ray of this area, the mental foramen issometimes misdiagnosed as a premolar abscess. Therefore, before performing rootcanal therapy, make sure all diagnostic tests confirm your finding.

Note: If a straight-on preoperative radiograph of a mandibular first premolar shows thepulp canal disappearing in mid-root, this is an important indication that two canalsare present.

ENDODONTICSMisc.

Which of the following is the most commonly used bleaching agent for endodonti-cally treated teeth?

Ether Superoxol Chloroform Sodium hypochlor ite

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Superoxol

Superoxol is a 30% aqueous solution by weight of hydrogen peroxide in distilled water.It is a potent oxidizing agent whose bleaching effect results from direct oxidation ofstain-producing substances.

Chairside technique: Application of heat to Superoxol-saturated cotton pellets in thetooth chamber. Repeat until tooth is lighter.

Note: The heat liberates the oxygen in the bleaching agent.

Important: The most probable postoperative complication of bleaching a tooth that has not

been adequately obturated is an acute apical periodontitis. Tooth bleaching causes a color change in both enamel and dentin.

Walking bleach technique: Place a thick paste consisting of sodium perborate and2-3 drops of Superoxol in the tooth chamber with a temporary restoration. Severalrepetitions of this procedure can work quite well.

ENDODONTICSWhich tooth below is most likely to have a curved root?

Maxillary central incisor Maxillary lateral incisor Maxillary canine Mandibular central incisor


Ind Tth

Maxillary lateral incisor

The maxillary lateral incisor always has one root with one canal. The root is more slender thanthe maxillary central incisor, and frequently (55%) has a distal and/or lingual curvature or dilac-eration. The access opening is oval.Maxilla ry cent ral inc isor: The maxillary central incisor always has one root and one canal.The root is bulky with a slight distal axial inclination, but rarely has a dilaceration. The accessopening is oval-triangular.Maxilla ry canine: The maxillary canine always has one root and one canal. This tooth is thelongest in the arch. The access opening is oval.Note: The maxillary central, lateral and canine roots and, hence, canals all have a distal axialinclination. This means in penetrating along the long axis of the tooth, the bur must be slightlyangled toward the distal surface. Failure to do this may lead to perforation of the mesial por-tion of the root.Mandibular central incisor : The mandibular incisors (laterals and centra ls) have only one rootwhich is narrow mesiodistally but relatively wide labiolingually and may have a distal and/orlingual curvature. Two canals may be present. When there are two canals, the labial canal isthe stra ighter one. The access opening for a mandibular central or lateral is a long oval , withthe greatest width placed inciosogingivally and the incisal extent very close to the incisal edge.

Ind TthENDODONTICSWhich of the following teeth most often refer pain to the tempo ral region?

Mandibular molars Maxillary incisors Maxillary second premolars Maxillary molars

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Maxillary second premolars

If carefu l diagnosis does not reveal the affected tooth, other teeth and relatedanatomic structures become suspect. Pulpitus in one tooth may cause pain in otherareas. The pain is referred.

Site of Pain Referral Tooth PUlp Causing Pain

Forehead region Maxillary incisorsNasolabial area Maxillary canines, premolarsTemporal region Maxillary second premolarsEar Mandibular molarsMental region of mandible Mandibular incisors, canines, and premolars

Important: The nerve endings of cranial nerves VII, IX, and X are widely distributedwithin the subnucleus caudalis of the trigeminal (V) nerve. A profuse intermingling ofthese nerve fibers creates the potential for the referral of dental pain to manysites.

Ind TthENDODONTICSWhich tooth listed below requires endodontic treatment most frequently?

Maxillary second molar Mandibular first molar Mandibular second bicuspid Maxillary first bicuspid

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Mandibular first molar

The most common morphology for the access opening in mandibular first molars is a trape-zoid formed by the two canals in the mesial root and the oval canal in the distal root. Both themesial and distal canals lie in the mesial two-thirds of the crown. The mesiolingual canal liesbeneath the mesiolingual cusp. The mesiobuccal canal Is the most difficult to locate but isusually found on a straight line to the buccal from the mesiolingual orifice and is tucked deeplybeneath the mesiobuccal cusp. The distal canal is the largest and easiest to find. Therefore,it should be located first, lying slightly distal to the buccal groove, closer to the buccal than thelingual wall.

Note: If the distal canal is more buccal (not in center of tooth), there will usually be a fourth canal(towards the lingual). This occurs in approximately 30% of mandibular first molars.

The lingual wall of mandibular molars is most easily perforated when preparing the accessopening (compared to maxillary molars). Perforations into furcation areas have the poorestprognosis. When instrumenting the mesial canals of mandibular molars, be careful not tostrip-perforate the distal surface of the root (this can happen if you are too aggress ive).

Remember: The mesiobuccal roots of maxillary molars and the mesial and distal roots ofmandibular molars often have two root canals. Make sure you look for them.

ENDODONTICSDiag Meth

Which of the following are con tra indications to the use of the electric pulp tester?

Inability to dry the tooth Teeth that have crowns or are heavily restored Tooth traumatized recently Anesthetized teeth Patient in severe pain All of the above

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All of the above

Note: The EPT (also called vitalometer) is the most popular and most debated diag-nostic method.

The clinician dries off the tooth to be tested. Normally the tooth in question, the toothadjacent to it and the contralateral tooth are tested. On a dry enamel surface, oneplaces some toothpaste (conductive medium) on the tip of the tester, which is thenapplied to sound tooth structure. The operator then delivers various electrical currentsto the tooth and the patient will respond to these. This indicates to some peoplewhether there is pulp vitality or not. To others, the degree of response can be correlat-ed to a different pupal state of health. Not all clinicians agree about this, but everyoneseems to be in agreement that the EPT is not always reliable.

Note: The EPT should be applied first to at least one tooth other than the tooth in ques-tion. This will determine a normal response for the patient.


According to the buccal object rule, when the x-ray tube is repositioned either at amore mesialor at a more distal angulation and a film is exposed, the root or canal far-ther from the film (the buccal) will:

Move in the opposite direction that the cone is directed Move in the direction that the cone is directed Not move at all


Move in the direction that the cone is directed

Therefore, when the cone is aimed to the distal (angled from the medial direction)the buccal root or canal moves to the distal and appears distal to the lingual orpalatal root (or canal).

Note: In order to apply this rule, you must have a reference object.

When treating multicanaled bicuspids and molars, it is often difficult to ascertain onthe radiograph which canal is more toward the buccal. When a straight on exposure istaken of a bicanaled tooth, the canals become superimposed on the film and visuali-zation of each canal is impossible. If the x-ray cone is moved to give an angled expo-sure, the roots will be separate on the film.

By applying the buccal object rule you will be able to determine which canal is thebuccal and which is the lingual.


What diagnostic tests are indicated for teeth that have recently been traumatized?


The dental examination should include: Soft tissue exam - observe the lips, face, tongue , etc. Hard tissue exam - visually look and then palpate the injured tooth and alveolus to

reveal the extent of tooth mobility as well as alveolar fractures and area of inflammation.Check for occlusal disharmonies to help detect tooth displacements and jaw fractures.

Radiographic examination - x-rays reveal tooth displacement and root fracturesas well as other important facts (previous root canal, periapical radiolucencies, etc.).

Other diagnostic tests - pulp vitality testing is contraindicated because thetraumatized pulp undergoes a temporary paresthesia and would give a false read-ing. The percussion test is not usually performed, since it is painful.

Observe the adjacent and opposing teeth for injury.Teeth that have been traumatized may be fine for a long time , however, many willdevelop radiolucencies. Do not indiscriminately do root canals without first check-ing pulp vitality and perform root canal therapy only in those teeth that do not respondto pulp testing. Example: Trauma to maxillary anterior teeth. A few years later x-raysreveal radiolucencies around the region of the apices of the incisors . Check the pulpvitality of all anterior teeth before performing root canals . Note: Trauma (causing deepintrusion) to a permanent tooth will most likely result in necrosis of the pulp and con-ventional root canal therapy will be necessary.


Wearing gloves when using the electric pulp tester to test the vitality of a tooth maylead to a:

False-positive response False-negative response


False-negative response

False-negative responses can also be caused by the following: Saliva on tooth Secondary dentin obliterating the pulp chamber or multiple canals presenting vari-

ous stages of pulpal pathosis Recently traumatized teeth - these teeth may exhibit interrupted neural transmis-

sion which may be temporary Patients who have recently taken analgesics for pain Immature teeth Not using conductive toothpaste Batteries are dead in tester

ENDODONTICSDiag Math

If an electric pulp tester is used to test a hyperemic tooth, the usual response will bewhich of the following?

The tooth will respond to less curre nt than normal The tooth will respond immediately to any current The tooth will respond to higher current than normal The tooth will not respond to any curren t


The tooth will respond to less current than normal

To some people, the electric pulp tester (EPT) only suggests whether the tooth is vital or non-vital. To others, the degree of response can be correlated to a different pulpal state of health.Importa nt: The electric pulp tester alone is not sufficient to allow a diagnosis of the pulp andmust be combined with other tests.Other tests that need to be done for a diagnosis:o Percussion - this test is a valuable diagnostic tool. It is performed by tapping the surface of

the tooth with an instrument (mirror handle). Once the infection has extended through the api-cal oramen into th P.D pace and apica tissue Rai ts localized wi the percussio ts t.

o Palpation - isolation of an inflamed or swollen area. It is performed by manipulating the tis-sue or applying pressure on an area with the fingers or hand.Radiograph - the most important diagnosis aid. X-rays can reveal deviations from the nor-mal that cannot be detected by any other method.

o Hot and cold tests - how tooth responds is a clue to the status of the pulp.Response to EPT:

Hy remi oot - tooth will respond to less current than normalo A ul i ' - tooth will respond to even less current than hyperemia

C I "s - tooth will respond to higher current than normalo P. ros ' - tooth will not respond to any current

ENDODONTICSDiag Math

Which of the following are useful diagnostic aids that can be used to determine if atooth has a vertical crown-root fracture?

Fiberoptic light for transillumination Wedging the tooth in question and then taking an x-ray Persistent periodontal defects in an otherwise healthy tooth Having a patient bite forcefu lly on a bite stick All of the above


All of the above

Important: Radiographs (without first wedging the tooth) rarely will show vertical frac-tures.

Notes :1. A tooth with a vertical fracture through root structure has a poor prognosis.2. Studies have indicated that most vertical root fractures are caused by too much

condensation force during obturation with gutta-percha.

Therapy for horizontal fractures of the root always involves considerable difficulty.Root canal treatment is not indicated if the fracture sites remain in close proximity andif the pulp retains its vitality. However, if clinical symptoms develop or the segmentsappear to be separating according to the x-ray, some treatment is necessary.

ENDODONTICSThe chronic apical abscess (CAA) is generally:

Very painful Asymptomatic Mildly painful


Terms/Cond

Asymptomatic

The chronic apical abscess (also called suppurative apical periodontitis) is sometimes so painless thatit may go undetected for years until revealed by an x-ray. It is a long-standing, low-grade infection of theperiapical bone with the root canal being the source of the infection. This condition may follow an acutealveolar abscess or unsatisfactory root canal therapy. RadlograRh will ell a diffuse radiplucency andeo hickening. The tooth may e lightly loose ontender t percussion. The chronic abscess may bedifferentiated from cysts and granulomas by the fact that both cysts and granulomas have well-definedradiolucencies associated with them. The treatment is conventional root canal treatment.Remember : 3 0 0 to 500 0 bona calcium must be altered befor ra diographic idence of periapicalbraakdo (this alteration takes place at the junction between the cortical and cancellous bone).The acute apical abscess (MA) is a localized collection of pus in the alveolar bone at the root apex fol-lowing death of the pulp with extension of the infection into the periapical tissue. The first symptom maybe a slight tenderness of the tooth. This later develops into a severe throbbing pain to percussion withswelling of the overlying mucosa. The tooth becomes more painful, elongated and loose. At times thepain may decrease or disappear completely. The patient may appear weakened, irritable and present witha fever. The diagnosis is based on the history, exam, and radiographs. The tooth will not respond tothe EPT or cold test but may respond to heat. Treatment of an acute alveolar abscess includesestablishing drainage and debriding the canal system of necrotic tissue which will relieve theacute symptoms. This is followed at a later date by conventional root canal therapy.Note: if the abscess ruptures through the periosteum into the salt tissue, the patient's symptoms will sub-side.

Terms/CondENDODONTICSIn which of the following conditions are the pulps of the involved teeth likely to be non-vital?

Apical scar Cementoma Radicular cyst Traumatic bone cyst Chronic dental abscess . Globulomaxillary cyst Chronic periapical granuloma


Apical scar Radicular cyst

Chronic dental abscess Chronic periapical granuloma

An apical scar is represented by a periapical granuloma. cyst. or abscess that heals with scar tissue.Well-circumscribed radiolucency resembling a granuloma. Tooth is non-vita l.A radicular cyst usually occurs in a preexisting granuloma. Seldom is painful. Radiolucency at apexof non-vital tooth.A chronic dental abscess is often a result of a periapical granuloma. Radiolucent area at apex ofnon-vital too th . Fistula is often found leading from an abscess cavity. Once drainage is established,the tooth stops being painful. A chronic periapical abscess is often the cause of a sinus tract inthe gingival tissues of children.A chron ic periap ical granuloma is the most common sequelae of pulpitis. It is asymptomatic andassociatedwith a non-vital too th .A cementoma occurs most frequently in the anterior region of the mandible. Starts as radiolu-cent lesion and then calcifies. The cementoma does not affect pulp vitality. Also called periapicalcemental dysplasia.A traumatic bone cys t is not a true cyst since there is no epithelial lining. Found mostly in youngpeople, asymptomatic. Radiolucency which appears to scallop around the roots of teeth. Teeth areusually vital.A globulomaxillary cyst is found at the junction of the globulus and maxillary processes of the max-illa, between the lateral incisor and the cuspid roots. It is a developmental (fissural) cyst which arisesfrom cells in a fissural line of bone. Teeth are vital.

ENDODONTICSThe most widely used material for apexif ication procedures is:

Gutta-percha Calcium hydroxide Zinc oxide Eugenol


Terms/Cond

Calcium hydroxide

Apex if ication is a technique whose goal is to induce further root development in a pulplesstooth by stimulating the formation of a hard substance at the apex, so as to allow obturation ofthe root canal space.The technique consists of isolation of the field with a rubber dam, making an access cavity andremoving all pulpal tissue by the use of reamers and files. A premixed syringe of a calciumhydroxide-methylcellulose paste (for example, a Pulpdent syringe) is injected into the canaluntil it is filled to the cervical level. The paste must reach the apical portion of the caOSll1Q...tirn:ulate the tissues to form a calcific barrier. A double seal of cement is made to close off the accesscavity. The patient is recalled after three months to see if apexification has taken place. If not, afresh supply of paste is placed. If apexification has occurred, convent ional root canal therapy isinstituted.The action of calcium hydroxide in promoting formation of a hard substance at the apex isbest explained by the fact that calcium hydroxide creates an alkaline environment that promotes~rd tissue depositionNote: If a permanent tooth fractures and has a fully formed root and the pulp is exposed (largeexposure), the treatment of choice is complete root canal therapy. Apexification is not need-ed because the root is fully formed. If the exposure is small and the length of time is short (1/2hour to 1 hour) , then a direct pulp cap with CaOH followed by a restoratioD is the treatment ofchoice. --

ENDODONTICSThe most common cause of acute osteomyelitis of the jaws is:

Unknown Iatrogenic Dental infection Radiation


Terms/Cond

Denta l infect ion

It is not a particularly common disease. It is a serious sequela of periapical infection that oftenresults in a diffuse spread of infection throughout the medullary spaces, with subsequent necro-sis of a variable amount of bone.

Acute or subacute osteo myelitis may involve either the maxilla or the mandible. In the max-illa, the disease usually remains fairly we ll- localized to the area of initial infection. In themandible, bone involvement tends to be more diffuse and widespread.

Clin icall y, the person afflicted with acute osteomyelitis is usually in rather severe pain and man-ifests an elevation of temperature with regional lymphadenopathy. The teeth in the area ofinvolvement are loose and sore so that eating is difficult, if not impossible.

Radiographi cally, acute osteomyelitis progresses rapidly and demonstrates little radiographicevidence of its presence until the disease has developed for at least one to two weeks. At thattime, diffuse lytic changes in the bone begin to appear. A "moth-eaten" radiolucent appearanceis evident.

The general principles of treatment demand that drainage be established and maintained andthat the infection be treated with antibiotics to prevent further spread and complications.

Terms/CondENDODONTICSWhich material listed below has histor ically been the retrofilling material of choice?

Composite Zinc-free amalgam Gutta-percha Methyl methacrylate

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Zinc-free amalgam

"The best argument for the use of zinc-free amalgam is the lack of expansion found when con-taminated with moisture.A retrofilling (also called a reverse filling or retrograde amalgam filling) is placed to seal the apicalportion of the root canal. This procedure is used when an apicoectom y alone will not y ield a goodresult. Whenever there is any chance whatsoever that an apical seal may be faulty, a reverse fillingmaterial must be placed. For example, if the root canal appears calcified, it would be impossible toobturate most of the canal and get a seal. If just the root apex were cut off (apicoectomy), the incom-pletely filled canal might act as a source of reinfection. To prevent this after the root tip is resected, theforamen is found, enlarged, and filled with a zinc-free amalgam to create a seal.An apicoectomy (root resection, root amputation) is a procedure where the buccal tissue is flappedback, the buccal bone about the apex is removed, the root apex is remo ved , and the area is curet-

I ted out. Indications for apicoectomy: 1) A reverse fil ling needs to be placed. 2) It Is necessary togain access to an area of pathosis. 3) The poorly filled apical port ion of the root is to be removed tothe level of canal obliteration. Note: A retrograde amalgam filling should always be done after an api-coectomy. Teeth that have posts in them and need to be retreated are the most common reason foran apicoectomy and a retrograde filling.Remember: Periapical curettage is the same procedure as an apicoectomy (as far as flap andremoval of buccal bone), but without removing the root apex. Removal and examination of the dis-eased tissue and determination of the extent of the lesion are the objectives of apical curettage.

Terms/CondENDODONTICSWhich condition listed below is characterized by pain that is spontaneous and hasperiods of cessation (intermittent in nature)?

Reversible pulpitis Irreversible pulpitis


Irreversible pulpitis

The severity of the clinical symptoms will vary as the inflammatory response increases. Pain willvary from a mild and readily tolerated discomfort to a severe, throbbing and excruciating pain.The pain is spontaneous and is intermittent In nature. The pain lingers after the removal ofthe irritant. The pain is usually not readily localized by the patient but is diffuse in character.Lying down or bending over intensifies the pain of irreversible pulpitis because the overallincrease in cephalic blood pressure is relayed to the confined pulp tissue. The tooth may be ten-der to percussion, heat may intensify the pain response while cold may relieve it (in advancedstages). Usually they both will cause severe and lasting pain. The radiographs will usually dis-close~riaplcal pathologY..Treatment is root canal therapy.

Reversible pul pit is (hyperemia): The pain associated with hyperemia does not occur spon-taneously. It requires an external irritant to evoke a painful response (i.e., cold, sweets). Thepains are sharp and of brief duration, ceas ing whe n the irri tant Is removed. Radiographsappear normal (may show deep caries or cavity preparation). The tooth is usually percussionnegative. In thermal tests, the pulp responds more readily to cold stimuli than to hot (theresponse leaves shortly after removal of stimulus). Treatment usually is a sedative fillingor new restoration with a base.

Note: Pulpal Inflammation (hyperemia) is most commonly caused by bacteria.

Terms/CondENDODONTICSWhich condition below is an apical lesion that develops as an acute exacerbation of achronic apical abscess (also called a suppurative apical periodontitis)?

Cyst Phoenix abscess Granuloma None of the above


Phoenix abscess

It is also known as a recrudescent abscess. It develops as the granulomatous zone becomescontaminated or infected by elements from the root canal. Diagnosis is based on the acute symp-toms (pain to percussion) plus radiographic examination, which reveals a large periapical radi-olucency.A granuloma is defined as a growth of granulomatous tissue continuous with the periodontal lig-ament resulting from pulpal death with diffusion of toxic products into the periapical area. In mostcases a granuloma is symptomless. Radiographically, one sees a well-defined area of rar-efaction with some irregularities, while clinically the tooth is not sensitive. A massive Invasionof pulpal contaminants will result In the formation of an acute abscess (Phoenix abscess) .A cyst is an inflammatory response of the periapex, which develops from preexisting granu-lomatous tissue (granuloma ). It is characterized by a central, fluid-filled, epithelium-linedcavity , surrounded by granulomatous tissue and peripheral fibrous encapsulation. It is oftenassociated with a chronically infected tooth. The tooth may be mobile. On radiographs, one willsee a well -defined area of rarefaction (radiolucency), which is limited by a continuousradiopaque, sclerotic border of bone. It is usually asymptomatic .Remember: A granuloma or a cyst can only be differentially diagnosed by histologicalexamination .

ENDODONTICSThe earliest and most common symptom of an acute pulpltls is:

A dull throbbing sensation Pain upon chewing Thermal sensitivity Discomfort, particularly on palpation

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Terms/Cond

Thermal sensitivity

As caries enters the dentin it begins with a lateral spread at the DEJ. This is due tothe increased organic content and the involvement of many dentinal tubules. TheTomes fibers react, causing fatty degeneration, then later decalcification (sclerosis). Ascaries progresses, destruction of dentin is followed by bacterial invasion of the tubulesand complete destruction of dentin. Once odontoblasts are involved, pulpalchanges occur. Initially there is vascular dilation and local edema. The earliest com-mon symptom of this edema (acute pulpitis) is thermal sensitivity (usually increasedand persistent pain on application of cold).

Remember: The only reliable clinical evidence that secondary dentin has formed isdecreased tooth sensitivity (usually seen a few weeks after placement of a filling).When dentinal tubules become completely calcified, the dentin is insensitive.

Terms/CondENDODONTICSWhich condition listed below is the result of a pulpal infection that extends throughthe apical foramen to the periapical tissues?

Periodontal abscess Gingival abscess Periapical abscess


Periapical abscess

Of all the dental abscesses, the periapical is the most common type. It is a localized collec-tion of pus in the alveolar bone at the root apex following death of the pulp with extension of theinfection into the periapical tissue. The first symptom may be a slight tenderness of the tooth.This later develops into severe throbbing pain (acute abscess) with swelling of the overlyingmucosa. The tooth will not respond to the EPT or cold test but may respond to heat.Emergency treatment includes establishing drainage (ideally through the canal) and prescribingantibiotics and analgesics. This will relieve the acute symptoms followed by conventionalendodontic therapy at a later date. For dodo tic iote ti s tha 0 not respon 1 Renici in,c1 iodamycin i of en recomm nded. It produce igb bone e)/els an 's ettacH e gains aer-obic bacteria bu must be used with caution because of th pote ti I f ~ s udo e branous coli-tis.The periodontal abscess is an acute abscess that develops through the periodontal pocket.Alveolar bone loss, Rocket formation and lJ,eriodontal pathologic conditions are suggestive of theperiodontal abscess: The tooth will usually be palpation and percussion positive. It will respond1

Misc.ENDODONTICSAll of the following cells would be found in a hyperemic pulp after an exposure duringcaries removal, except

Plasma cells Lymphocytes Goblet cells Mast cells Neutrophils (PMN's)


Goblet cells

Plasma cells, lymphocytes, mast cells and neutrophils (PMN 's) are all chronicinflammatory cells.

The increased blood volume associated with hyperemia ("reversible pulpitis") alsoincreases the intrapulpal pressure in the involved area, which may be limited to a pulphorn or include the entire coronal chamber. Histologically, the tissue is likely to showsigns of acute inflammation near the site of exposure and a band of chronic inflamma-tory cells (plasma cells, Iympocytes, PMN 's and mast cells) between the acute inflam-mation and the underlying normal pulp.

Remember: Most clinicians agree that carious exposure of a permanent tooth gen-erally requires root canal treatment. Bacterial invasion of the pulp has already takenplace. An exception would be a carious exposure in a tooth with an immature apex.Performing a partial pulpotomy and pulp capping may have a higher chance of suc-cess.

Misc.ENDODONTICSIn most cases where there is endodontic-periodontic therapy indicated on a tooth,which is performed first?

Endodontic therapy Periodontic therapy


Endodontic therapy

Combined endodontic-periodontal therapy is widely used because the anatomicand clinical connections between the pulp and periodontal structures are close andnumerous. In most cases of this nature, endodontic procedures are performed firstand,when necessary, are followed by periodontal measures.In these cases, the value of precise pocket probing and correct appraisal of the vitali-ty of the pulp is crucial. In some doubtful cases, the better part of wisdom is to waituntil after the completion of the root canal therapy to see whether spontaneous resolu-tion (pocket closure and osseous fill-in) will occur before surgical periodontal proce-dures are begun.Periodontal therapy should be initiated first only in the case of a primary periodon-tal lesion with subsequent secondary endodontic involvement.Remember: A perioendo abscess is a combined lesion. The lesion usually demon-strates radiographic involvement of the periodontium and apex of the involved tooth.There is significant probing depths, percussion sensitivity, and pulpal sensitivity.Note: A common clinical finding of a periodontal problem Is pain to lateral per-cussion on a tooth with a wide sulcular pocket.

Misc.ENDODONTICSWhich of the following are the two basic reasons for the use of a post when restoringan endodontically treated tooth?

To strengthen the root To retain the restoration To protect the remaining tooth structure To help in the fabrication of a crown


To retain the restoration To protect the remaining tooth structure

Important : Posts do not strengthen the rootOptions available when restoring endodontically treated posterior teeth:

Resto ration of occlusal opening only - in rare instances the access opening and cariesdestruction do not encroach on the cusps and marginal ridges. These teeth may be restored withan occlusal amalgam; however, a cuspal coverage restoration would provide protection fromfracture.Onlay resto ration - in most cases it is imperative that root canal treated teeth be protectedfrom fracture by a cusp-coverage type of restoration. The minimum (most conservative) prepa-ration should be for an onlay covering the cusps and marginal ridges.

Crown - a full-coverage crown is preferred when the remaining coronal tooth structure does notafford sufficient tooth structure for an onlay.Crown with post and core - to reinforce the treated tooth and provide suitable coronal tooth struc-ture for an optimum crown preparation, the use of a post and core is often indicated. Be very care-ful when placing posts. Perforations and vertical root fractures can occur.

Notes:1. If you are performing a pulp chamber-retained amalgam. you need to place amalgam 3mm into

each canal for retention.2. Endodontically treated posterior teeth are more prone to fracture than untreated posterior teeth

due mainly to the destruction of the coronal tooth structure (they have reduced structural integrity).

ENDODONTICSWhich of the following are contraindications to endodontic therapy?

A non-restorable tooth A tooth with insuffi cient periodontal support A tooth with a vertical root fracture All of the above


Misc.

All of the above

Other contraindications include: A non-strategic tooth (a tooth not in occlusion) A tooth with massive internal or external resorption A tooth that has a canal unsuitable for instrumentation or for surgery (i.e., bro-

ken instruments, dentinal sclerosis, sharp dilacera tions, etc.)A medical condition such as hemoph ilia is not a contraind ication to conventionalendodontic therapy. However, it is strong ly recommended that a dentist obtain clear-ance from the patient's physic ian prior to treatment.

Any teeth not contraindicated are excel lent candidates for successful endodontictherapy.

Note: Example of a special case: A previously traumati zed tooth may show completeobliteration of the pulp chamber and canal. The periodontal ligament may appear nor-mal. The patient wil l be asymptomatic and the tooth will not respond to pulp vitality test-ing. The treatment of choice is to observe as long as the tooth remains asymp-tomatic and no periapical changes are evident.

ENDODONTICS .An apicoectomy is a resection:

Of the most coronal portion of the root Of the coronal portion of the pulp horn Of the most apical portion of the root Of the entire pulp horn


Misc.

Of the most apical portion of the root

" ' An apicoectomy is best accomplished by obliquely resecting the most apicalportion of the involved root.

If a tooth has had previous endodontic therapy and becomes reinfected , it is usu-ally best to try and retreat it conventionally (remove filling material, debride the canalsand refill). However, if the tooth has been restored with a post, core and crown thenapical curettage, apicoectomy and a retrofill should be performed.

Indications for apicoectomy:o A reverse filling needs to be placed.o It is necessary to gain access to an area of pathosis.o The poorly filled apical portion of the root is to be removed to the level of canal oblit-

eration.

Misc.ENDODONTICSWhen symptoms and clinical tests show the presence of pulpal pathosis in a posteriortooth and the radiograph shows no decay or restoration in any proximity to the pulp, thisis virtually path ognomon ic of :

Condensing osteitis A vertical fracture of the tooth Periodontal abscess Secondary occlusal trauma

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A vertical fracture of the tooth

Radiographic examination seldom reveals the fracture because the crack is usually parallel tothe x-ray film. One of the most puzzling and frustrating dental conditions involving the possibleneed for endodontic treatment is the cracked tooth syndrome. Symptoms from this condi-tion usually are characterized by a sharp but brief pain occurring unexpectedly only whenthe patient is chewing. Having a patient bite forcefully on a bite stick and noticing the cusps thatocclude when the pain occurs will aid in the location of the offending tooth.

Vertical fractures through root structure, however, have an almost hopeless prognosis. If thefractured segment can be removed and gingivoplasty and alveoloplasty performed, treatmentcan be successful. However, unrealistic or overambitious case selection leads to a high degreeof failure.

When an anterior tooth fractures, it generally occurs in a more horizontal plane and may showup on the x-ray. The cause is usually accidental trauma such as a blow to the jaw or teeth. If thefracture line is not too far down the root of the tooth, it may be able to be saved with a root canaland a crown.

Inlays have been shown to be a cause of fractures. If a patient complains of pain on mastica-tion since the placement of an inlay, suspect a fractured cusp (using a bite stick will help deter-mine which cusp may be fractured).

Misc.ENDODONTICSWhich of the following flap designs is preferred when performing endodontic surgeryin the maxillary anterior region?

Vertical (single or double) flap Scalloped (Leubke-Ochsenbein) flap Curved (semilunar flap) Palatal flap


Scalloped (Luebke.-Ochsenbein) flap

This flap is a modified double vertical flap. It has the advantage of being able to besutured into the dense attached gingiva, thus causing less scarring.

Verti cal flaps Single - allows for visualization of the complete length of the root, the option of per-

forming periodontal surgery, incisions to be made over sound bone, and retaining anexcellent blood supply.

Double - allows for greater visualization and access to the surgical site than doesthe single vertical flap. However, there is increased hemorrhage and flap shrinkage.

The curved (semilunar) flap was at one time the most commonly used flap, however,it is not used much today due to excessive shrinkage and the formation of anobv ious, uns ightly collagen scar.

The palatal flap is used around the gingival margins of maxillary bicuspids and molarsto expose the palatal roots.

.ENDODONTICSReplant

Which of the following appears to be the ideal storage media for a tooth that has beentraumatically avulsed and will be out of its socket for more than an hour?

Soda Sodium hypochlorite Milk Hydroge n peroxide

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Milk

Five factors that are critical to the management of traumatic avulsion injuries to teeth:1. Time: The time interval from injury to replacement of the tooth is a rnalor factor in the main-

tenance of ligament viability and subsequent root resorption. Teeth replanted within 30 min-utes have been reported to exhibit very little resorption, whereas most of the teeth replantedafter 2 hours show a lot of external root resorption (which is the main cause of failure ofreplanted teeth).

2. Storage media : If the tooth cannot be immediately replanted, proper storage of the toothcan favorably influence periodontal ligament viability. The preferred storage mediaseems to be saliva, physiologic saline or milk. The root that is allowed to dry will show themaximum amount of resorption. If the footH will e 0 t 0 tfi e soc et for mor t an an our,milk appear to be th Ideal storage mellia.

3. Tooth socket: Should not be damaged by curettage or forceful replantation4. Splint stabilization: A splint that allows the physiologic movement is placed for a maximum

of 2 weeks. This time period allows for the initial reattachment of the periodontal ligamentfibers.

5. Root surface: Should not be scraped, dried or manipulated with caustic chemicals.Note: The above information changes when a tooth has been out of the mouth for morethan 2 hours (mainly the treatment of the tooth socket and root surfaces as well as the time forsplint stabilization).

ReplantENDODONTICSWhich of the following factors are important to the success of intent ional replantat ion?

A short extraoral time period (to maintain the viability of the periodontal ligament) A healthy periodontium A skillful extraction technique All of the above


All of the above

Intentional replantation implies that a tooth requiring endodontic therapy is purpose-ly removed from its socket, some type of canal or apical preparation and/or filling is per-formed and the tooth is returned to its original socket.

Indications for intentional replantation (also called replant surgery): When routine endodontic therapy of a tooth is impractical or impossible When an obstruction of a canal is present, such as a broken instrument or a cal-

cification, and periapical surgery is impractical (a lower molar with the mandibularcanal in close proximity).

When perforating internal or external resorption is present , yet surgery isimpractical

When a previous treatment has failed but nonsurgical treatment or surgery isimpractical.

Note: Intentional replantation should be considered when it is the only alternativeto extraction.

ENDODONTICSPrimary avulsed teeth:

Replant

Should be cleaned very well and replanted if within five hours of the injury Are usually not replanted Should be replanted immediately Should have a pulpotomy performed on them prior to replantation


Are usually not replanted

"Most clinicians advise against replantation of primary avulsed teeth unless ideal conditions exist to pre-vent trauma to the permanent succedaneous tooth.Proper management of an avulsed permanent tooth that has been rep lanted with in two hours of theacci dent:

Ten days to two weeks after replantation, the root canal is prepared (cleaned and shaped) and a calci-um hydroxide pas te is placed into the canalsThis paste is rep laced every three months for one yearIf after one year , it appears that resorption has reversed or stopped, a permanent gutta-percha filling canbe placed

Important: If a tooth Is out of the mouth for more than two hours:Anky losis and external root resorption will probably result within two years. Ankylosis resulting fromreplacement would give a better prognosis than external resorption, which would lead to failure.Root canal therapy is performed in its entirety pr ior to replantati on.The tooth is soaked In a 2.4% fluoride so lution acidulated at pH 5.5 for 20 minutes or more. (The flu-oride will slow the resorptive process .)Gently curette blood clot out of the alveolar socket and irrigate with saline.Rinse tooth with saline, replant into socket and splint for 4-6 weeks.

Note: Resorption is the most frequent sequela to replantation. Three different types of resorption have been iden-tified: surface, inflammatory and replacement (ankylotic resorption). Replacement resorption refers to resorptionof the root surfaceand its substitution by bone, resulting In ankylosis.

ResorpENDODONTICSWhich of the following is generally believed to be the cause of internal resorption ofa tooth?

Orthodontic treatment Tooth fracture The presence of a chronic pulpitis Periodontal disease


The presence of a chronic pulpitis

>This condition is frequently precipitated by traumatic injury to the tooth. Undifferentiatedreserve connective tissue cells of the pulp are activated to form dentinoclasts, which resorb thetooth structure in contact with the pulp.Internal (inflammatory) resorption is usually asymptomatic and is discovered on routine radi-ographic evaluation. The anatomic configuration of the root canal is altered and increases in sizewith internal resorption. It will appear as an irregular radiolucency anywhere along the canalspace. The tooth involved may respond to pulp vitality tests.

When internal resorption is detected, a pulpectomy should be performed. Once the pulp tissueresponsible is removed, all resorption ceases. To "wait and see" may result in sufficient destruc-tion of the tooth to create a perforation of the root.

Typical radiographic appearance of internal resorption

ENDODONTICSResorp

Which type of external root resorption listed below may occur from combined injuryto the POL and cementum complicated by bacteria from an infected root canal space?

Surface resorption Inflammatory resorption Replacement resorption


Inflammatory resorption

80 I-shaped areas f resorption involving cementum and dentin characterize exter-nal inflammatory root resorption. This type of resorption is rapidly progressive and illcontinue i treatment is not institute . Sif.1ee bot eereti I d th pr~sen e ofbacteria are necessary components ato resorption t R 0 S ca bearrested by immediate roo nal tr atme . The tooth is opened and the canal iscleaned and shaped. .A calcium hydroxide paste is placed in the canal. This isreplaced every three months for one year. If after one year, it appears that the resorp-tion has stopped, a permanent root canal filling (gutta-percha) can be placed. A calci-um hydroxide-based root canal sealer Is strongly recommended.

Surface resorption is caused by acute injury to the periodontal ligament and root sur-face. If injury is not repeated, healing takes place with new cementum and PDL.

Replacement resorption refers to resorption of the root surface and its substitution bybone, resulting in ankylosis. Remember: This is often seen in unsuccessful replantcases.

PulpENDODONTICSAnatomically, the dental pulp is divided into two portions, the coronal and radicularpulp. Which portion is located in the pulp chamber and pulp horns?

Coronal pulp Radicular pulp


Coronal pulp

Portions of pulp1. Coronal pulp - located in the pulp chamber and pulp horns (crown portion of tooth).2. Radicular pulp - located in the pulp canals (root portion of tooth)..Accessory canals extend from the pulp canals through the root dentin to the PDL. An abruptchange in the radiolucent appearance of a canal in the middle third of the root is most likelydue to a bifurcation of the cana l.The central zone or pu lp proper contains large nerves and blood vessels. This area is linedperipherally by a specialized odontogenic area which has three layers (from innermost to out-ermost):1. Cell-rich zone which contains fibroblasts.2. Cell-free zone or zone of Weil which is rich in both capillaries and nerve networks. The

nerve plexus of Rashkow is located in this zone.3. Odontoblastic layer which contains odontoblasts and lies next to the predentin and mature

dentin.Cells found in the denta l pulp include fibroblasts (the principal cell), odontoblasts, histiocytes(macrophages), and lymphocytes.Note: In a diseased pulp, the following cells are present: PMN's, plasma cells, basophils,eosinophils, lymphocytes and mast cells (contain histamin e and heparin).

ENDODONTICSWhich of the following is the main function of the dental pulp?

Nutritive Sensory Protective Formative


Pulp

Formative

' --The primary function of the dental pulp is to form dentin (by the odontoblasts)

Other functions include: Nutritive - the pulp keeps the organic components of the surrounding mineralized

tissue supplied with moisture and nutrients . Sensory - extremes in temperature, pressure , or trauma to the dentin or pulp are

perceived as pain. Protective - the formation of reparative or secondary dentin (by the odontoblasts).

Note: The primary response of the pulp to tissue destruction is inflammation.

Composition of the pulp:Loose connective tissue (collagen and reticulin fibers)

Fibroblasts (principal cell), odontob lasts, reserve cells and undifferentiated mes-enchymal cells (histiocytes and macrophages)

Blood vessels (arteries and veins),nerves , and a lymphatic system Ground substance

ENDODONTICSWhich two of the following decrease with age in the dental pulp?

Number of collagen fibers Number of reticulin fibers The size of the pulp Calcifications within the pulp

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Pulp

Number of reticulin fibers The size of the pulp

As the pulp ages there is a decrease in reticulin fibers (the pulp becomes less cel-lular and more fibrous). The size of the pulp also decreases because of the contin-ued deposition of dentin. r ~\ 612o LJ S Put-(='As the pulp ages there is an increase in the number of collagen fibers and calci-fications within the pulp (called denticles or pulp stones).The pulp contains both myelinated and unmyelinated nerve fibers. They are affer-ent and sympathetic. The myelinated fibers are sensory and the unmyelinated fibersare motor (they playa role in the regulation of the lumen size of the blood vessels).Note: Proprioceptors (which respond to stimuli regarding movement) are not foundin the pulp.The only type of nerve ending found in the pulp is the free nerve ending, which is aspecific receptor for pain. Regardless of the source of stimulation (heat, cold, pres-sure), the only response will be pain.Note: Pulp stones are associated with chronic pulpal disease (from advanced cariouslesions or large restorations).

Inst/Mat/TechENDODONTICSWhich of the following methods for using endodontic instruments involves no rotationof the instrument whatsoever and relies on hard tissue removal on the outstrokeonly?

Filing Reaming Circumferential filing All of the above


Filing

Filing is a push-pull action with emphasis on the withdrawal stroke. Its efficiency isgreater with files than with reamers for removing dentin because of the greater num-ber of flutes in contact with the canal walls during the rasping motion of removing theinstrument. The appearance of the canal is irregular and for this reason a canal pre-pared with this action must be filled with gutta-percha in a condensation procedure.

Reaming is defined as repeated clockwise rotation of the instrument, particularlyduring insertion. The appearance of the canal is approximately round (this method isrecommended if using a silver cone to fill canal). Reamers are usually most efficient forthis function.

Circumferential filing is a push-pull action with emphasis on scraping the canalwalls to create a smooth, tapered preparation. It is a method of filing whereby theinstrument is moved first towards the buccal side of the canal, then reinserted andmoved slightly mesially. This is done all the way around the tooth until all the dentinwalls have been planed. This technique enhances preparation when a flaringmethod is used.

ENDODONTICSA reaming action produces a canal that is relatively:

Square in shape Irregular in shape Round in shape Triangular in shape


Inst/MatlTech

Round In shape

Studies have shown that the action of using the instrument, rather than the instrumentused, determines the general shape of the canal preparation. Therefore, a reamingaction produces a canal that is relatively round in shape while a filing action pro-duces a canal that is irregular in shape.

Important: A canal should be instrumented and shaped so that it has a continuouslytapering funnel shape. The widest diameter would be at the canal opening and thenarrowest at the d nti oeem I j cti n (0.5 to .0 mm from the radiograpbi(;apex). ij:hi i here II ee h sho Id b fil d to and filled to (ideally).

Inst/MatlTechENDODONTICSWhen fitting the master cone in a properly prepared canal, the cone must :

Be 2 mm from the apex Be within 1 mm of the working length and have a slight resistance to dislodgement Fit to the exact apex Be at least 1 mm past the apex


Be within 1 mm of the working length and have a slight resistance to dis-lodgement

This slight resistance to dislodgement is referred to as "tugback". The cone should also havea definite apical seat (it should not be able to be pushed further apically).If the preparation is properly flared , fitting the master cone is not a time-consuming proce-dure. A gutta-percha cone the same size as the file used last during preparation (MAF) is select-ed and placed as far as possible into the canal, but not beyond the working length. Once satis-factory tugback and apical positioning appear to be obtained, a radiograph is taken to verify conepositioning. If an accurate determination and careful enlargement have been performed, the x-ray will show that the master cone reaches the most apical position of the preparation orextends to a point just short of that (1 mm). When the cone is slightly short, the pressure ofcondensation plus the lubricating action of the sealer will be sufficient to produce complete seat-ing of the cone.

If the cone is more than 1 mm from the radiographic apex, discard the cone and fit a smaller oneor instrument more in the apical third.

Remember: The main reason for recapitulation (using your MAF after each increase in file size)during instrumentation of the canal is to clean the apical segment of the canal of any dentinfilings that were not removed by irrigation.

Inst/MatlTechENDODONTICSThe primary function of root canal sealers is:

To act as a lubricant. facilitating placement of the gutta-percha To form a bond between the filling material and the dentin walls To fill in the discrepancies between the filling material and the dentin walls To exert antibacterial activity

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To fill in discrepancies between the filling material and the dentin walls

Other purposes or functions of a root canal sealer include : To act as a lubricant , facilitating placement of the gutta-percha To form a bond between the filling material and the dentin walls To exert antibacterial activity (some exert more than others). This activity is the

highest in the period of time immediately after its placement

Most root canal sealers are some type of zinc oxide-eugenol cement and are capa-ble of producing a seal while being well-tolerated by periapical tissues.

All sealers display some degree of radiopacity (caused by metallic salts in the sealer) ;therefore their presence can be demonstrated on a radiograph. This is an importantproperty, since it may disclose the presence of accessory canals. resorptive areas, rootfractures. and the shape of the apical foramen and other structures of interest.

Note: After filling a tooth with gutta-percha, if you see a horizontal line of material(gutta-percha or sealer) extending both mesially and distally from the canal to theperiodontal ligament space, this is indicative of a root fracture.

Inst/Mat/TechENDODONTICSWhich of the following intracanal instruments is designed for the removal of pulp tis-sue, cotton pellet absorbent points and other soft materials, but not for canal enlarge-ment?

Files Reamers Broaches None of the above


BroachesThe barbs are notched out of the instrument shaft and represent a weakened point. If thebroach is not used with the utmost of care or if it is forced apically, the barbs will be bentand will engage the walls, making removal difficult.

K-type instruments: Files are the most useful instruments in endodontics for the removal of hard tissue in canal

enlargement. They are manufactured by twisting a blank, which is a square rod, producing aseries of cutting flutes. The action used for placing this type of file into a canal should resem-ble a clockwise-counterclockwise motion with pressure directed apically (can be a filing orreaming action). Note: These files are the strongest of all files and cut the least aggres-sively. A modification to this type of file is the K-f1ex file.

Reamers are manufactured in a manner similar to files, only they have fewer flutes. They areused in canal preparations to shave dentin with a reaming action only. They remove intra-canal debris with clockwise reaming action. They are also used to place materials into the api-cal portion of the canal by using a counterclockwise rotation.

H-type instruments: Hedstrom files are manufactured by using a sharp, rotating cutter to gauge triangular seg-

ments out of a round blank shaft. This produces a very sharp edge and therefore an effectivecutting instrument. If used carefully, with a filing action only, it will successfully plane thedentin walls much faster than K-type files or reamers. A modification of this file is the S-file.t Note: All of the above are made of stainless steel.

InstiMatITechENDODONTICSWhich two of the following situations offer better success for pulp capping?

Accidental exposure of the pulp Pulp of a middle-aged person Carious exposure of the pulp Pulp of a young child


Accidental exposure of the pulp Pulp of a young child

Pulp capping is the placing of a sedative and antiseptic dressing on an exposed healt!}}' pulpin order to allow it to recover and maintain normal function and vitality. The dressing most com-monly used is CaOH2 (Oyca~ . Pulp capping is overused in dentistry today. In reality it has onlyvery few indications for its use. Young pulps are more vascularized and, therefore, moreamenable to repair. Pulp cappings are more successful if the exposure was accidental(trauma or with a dental bur) as opposed to carious. In addition, the exposure should only bepinpoint to expect success. Repair is accomplished by the formation of a dentin bridge at thesite of exposure. Even a small carious exposure should have root canal therapy for the bestlong-term prognosis.A tooth may stay asymptomatic for several weeks after pulpcapping has been performed.However, this may be only temporary. Unfortunately, if pulp capping fails and the toothbecomes symptomatic, it may be difficult, if not impossible, to treat with routine endodonticsbecauseof the severe calcifications in the root canal. Perforations may occur during attempts tofollow the obliterated canal to gain patency to the apex. Perforations into furcations of multi-root-ed teeth have the poorest prognosis.Traumatic blows to teeth are also a cause for calcification of the pulp space sometimes to apoint where locating the canal is very difficult. With primary teeth, trauma may cause calcifica-tions in the pulp chamber, which in turn cause a yellowish discoloration of the tooth.

ENDODONTICSWhich of the following are chelating agents?

EDTA RC-Prep EDTAC All of the above


Inst/Mat/Tech

rovide both chelation andirn ation with

All of the above

"'Important: These agents all contain ethylene diam ine tetra-acetic acid as the active ingre-dient.Chelat ing agents are used to aid and simplify preparation for very sclerotic canals after the apexhas already been reached with a fine instrument. These agents act on calcified tissues onlyand have little effect on periapical tissue. Their action is to substitute sodium ions, which com-bine with the dentin to give soluble salts for the calcium ions that are bound in less soluble com-bination. The edges of the canal are thus softer, and canal enlargement is facilitated.EDTA will remain active in the canal for 5 days if not inactivated. For this reason, at the com-pletion of the appointment, the canal must be irrigated with a sodium hypochlorite (NaOe L)-containing solution.EDTAC is EDTA with the addition of Cetavlon, a quaternary ammonium compound. It hasgreater antimicrobial action than EDTA. However, it has greater inflammatory potential to tissueas well. The inactivator for EDTAC Is NaOCL.@C.~R~mbines the functions of EDTA Ius urea

~nga Ion. The foam solution has a natural efferveNaDeL to aid in the removal of debrig:

Inst/MatlTechENDODONTICSNo endodontic cases lend themselves to successful treatment without some degreeof:

Irrigation Debridement Obturation Medication


Debridement

Debridement is defined as the removal of foreign material and contaminated or devitalized tis-sue from or adjacent to a traumatic infected lesion until surrounded healthy tissue is exposed.Chemomechanical debridement of the root canal system is the most crucial aspect of rootcanal treatment.

Complete debridement of the cana l is the most effective means to reduce root canal microor-ganisms. It can be carried out in various ways as the case demands, and may include instru-mentation of the canal, placement of medicaments and irrigants andlor surgery.

Remember: The most common cause of root canal failure is incompletely and inadequately disinfec-

ted root canal systems.The second most common cauOse of failures of root canals is leakage from a poorly filledcanal. This is common even after apical curettage. Example: Root canal treatment performedon a tooth with apical curettage of a lesion that was found to be a cyst. Three years later thelesion is even bigger than it was before. The most likely cause of this failure is leakage froma poorly filled canal .

When a canal is properly prepared, any of the accepted methods of filling will almost cer-tainly produce a successful result (as long as canal is completely filled).

InstlMatlTechENDODONTICSGutta-percha is freely soluble in which two solvents listed below?

Alcohol Chloroform Xylol Eugenol


Chloroform (most effective) Xylol

It is slightly soluble in eucalyptol. Gutta-percha is pliable at room temperature andbecomes plastic at 60 C (140 F).

The simplest method of removing gutta-percha from a root canal is by softening thegutta-percha with a solvent , such as chloroform, xylol, or eucalyptol. Once the orifice ofthe canal has been uncovered , the access cavity is filled with solvent. After 1 to 2 min-utes, the solvent in the pulp chamber will dissolve the gutta-percha to the extent that asmall file will easily negotiate the canal. Be careful not to use any solvent at or nearthe apical foramen. Passage of these chemicals past the end of the root may result insevere postoperative discomfort.

Notes:1. Gutta-percha points may be disinfected by placing them in 5.25% NaOCl (sodi-

um hypochlorite) solution for one minute .2. Endodontic files should be immersed in a bead sterilizer at 220 C (428 F) for

15 seconds for sterilization.

Inst/MatlTechENDODONTICSWhich of the following are indi cations for performing a pulpotomy?

Treatment of pulp exposures in deciduous teeth Treatment of pulp exposures in permanent teeth with undeveloped root apices An alternative to extraction when endodontic therapy is unavailable Temporary emergency treatment for an acute pulpitis All of the above


All of the above

A pulpotomy is the removal of a portion of the pulp. Usually the injured or infectedcoronal pulp is removed in an attempt to preserve the health of the radicular pulp. Note:If there is a radiolucency, draining sinus tract present, internal resorption, or painin percussion, a pulpectomy is the treatment of choice.

Unfortunately, pUlpotomy procedures performed in permanent teeth often result inhaving their entire root canal systems calcified. This is a result of degenerativechanges. The canals of these teeth may be inoperable when the presence of periapi-cal pathosis makes root canal therapy necessary. For this reason, a pulpotomy isregarded as a temporary treatment.

Important: The success of a pulpotomy for a primary tooth is dependent upon vitalpulp tissue in the root.

Inst/MatlTechENDODONTICSWhich of the following irrigants is the most widely used in endodontics?

Sodium hypochlorite Urea peroxide Hydrogen peroxide Saline


Sodium hypochlorite (NaGeL)It is the most widely used irrigant and has effectively aided canal preparation for many years.A .25% soltitian p vides e cellen germicidal Iven action, ut is dilute enough to causeonly mild irritation when contacting periapical tissue. NaOCl is a good tissue solvent as well ashaving some antimicrobial effect. It also acts as a lubricant for root canal instrumentation. Note:It is toxic to vital tissue; always use rubber dam.Hydrogen peroxide 30 soJution)a is also widely used in endodontics with two modes of action.The bubbling of the solution when in contact with tissue and certain chemicals physically foamsdebris from the canal (effervescent effect). In addition, the libecatio f oxyge(l will destroy strict-Iy anaerobic icroorganis . The solve t action of hydrogen peroxide is much les b that ofNaeC . However, many clinicians use the solutions alternately during treatment.

[ r ide is available in an anhydrous glycerol base, as y,. to prevent decompo-sition and is a useful irrigant. It is better tolerated by periapical tissue than NaOCl, yet hasgreater solvent action and is more germicidal than hydrogen peroxide. Therefore, it is an excel-lent irrigant for treating canals with normal periapical tissue and wide apices. The best use forGly-Oxide is in nan w an L r c c , utilizing the Iippery ff of the lv.ce I.Note: Irrigants perform the important biologic function of destroying bacteria during endodontictherapy. Their action is unquestionably more significant than that supplied by the use ofintracanal medicaments. Irrigants should be used copiously throughout the instrumentationphase of root canal procedures.

Inst/MatlTechENDODONTICSWhich of the following are cons idered to be the two object ives of the access opening?

To provide patient comfort To provide direct access to the apical portion of the canal To facilitate visualizati on (location ) of the canal To remove all old restorative materials from the tooth


To provide direct access to the apical portion of the canal. Important: This isthe primary function of access openings.

To facilitate visualization (location) of the canal.

Access to the root canal is the initial step in canal preparation. It is necessary toestablish straight-line access to the apical foramen to ensure free movement of theinstrument during debridement and preparation of the canal. All the treatment that fol-lows hinges on the correctness of the access preparation. All access cavities aremade through the lingual on anterior teeth and through the occlusal on posteriorteeth (see note below).

Remember:..Mandibular incisors and maxillary first premolars are the easiest teethto perforate during preparation of the access opening due to the limited access mesio-distally. Therefore care must be taken when initiating treatment on these teeth.

~o~e: A facial appraaQ.!.1 is recommended for. an access opening on maxillary p.nmarymmsors,

Inst/MatlTechENDODONTICSWhich of the following criteria must be met before a canal is considered ready to fillwith gutta-percha?

The canal must be prepared in a manner that ensures optimum debridement andaccess to the apical area so that the filling material can be condensed to obliteratethe entire preparation

The tooth must be asymptomatic At the time of fill, the canal must be dry If a bacteriologic culture test is being used, a negative culture must be obtained All of the above


All of the above

The most important consideration before filling a root canal is proper cleaning (debridement)and shaping (instrumenting) of the canal. Once the canal is obturated, any organisms that haveentered the periapical tissues from the canal are eliminated by the natural defenses of the body.Objectives of root canal obturatio n:

To develop a fluid-tight seal at the apical foramen Complete filling of the root canal space To create a favorable biologic environment for the process of tissue healingIn endodontic treatment the importance of canal obliteration (filling) is second only to canaldebridement. A proximately 40% of failures ar belie ed to be caused b incom lete a Iitera-tio 0 h to ca al. If the canal is not filled, tissue fluid and microorganisms from the periapi-cal tissues are able to enter the voids, with failure as the ultimate result. However, if an acces-sory canal is not totally fill ed during obturation, the appropriate treatment is to observethe tooth and ~va luate every three months.Note: Atter endodontic therapy is completed on a tooth with a periapical radiolucency, it usuallytakes 2 a a con e ize ut radioltJcency ' evident on an x-ray. ir a i 9 e n 'on 0 bo , deposition ofapical cementum and re-establishment of the PDL.

endo don tics

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