Wts Mds Endodontics Answers

8/17/2019 Wts Mds Endodontics Answers

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IDEAS WTS MDS ENDODONTICS - 2008 ExpExpExpExplanations1

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1. D. All of the above

2. B. Chronic pulpitis

3. C. Lateral spread of caries along DE junction and

weakening of the overlying enamel.The caries forms a small area of penetration in the enamel at

the bottom of a pit or fissure and does not spread laterally to a

great extent until the DEJ is reached. Force of mastication

fracture the increasing amount of unsupported enamel as thecaries progress so choice (4) is wrong. Destructive potential is

due to acid formed by bacteria by degradation of carbohydrates

so choice (1 & 2) also wrong.

4. B. Vaseline is an ideal choice.A water-soluble lubricant applied in the area of punched holes

facilitates the proximal contacts. Rubber dam lubricant is

commercially available but other lubricants, even as Having

cream or soap slurry also satisfactory. Cocoa butter and

petroleum jelly, these two are not satisfactory rubber dam

lubricants because both are Oil based and not easily rinsed from

dam once the dam is placed.

5. C. Reversibly denatured collagen.Affected dentin is softened, demineralized dentin that is not yet

invaded by Bacterua (Zone 2 & 3) Infected dentin (Zone 4 &

5) is both softened contaminated with bacteria.

It includes the superficial, granular necrotic tissue and softened,

dry, lathery dentin. The outer layer (infected dentin) can be

selectively stained by caries detection solutions such as 1%

acid red 52 (acid rhodamine B or food red 106) in propylene

glycol. This solution stains the irreversibly denatured collagen

in the outer carious layer but not the reversibly denatured

collagen in the inner carious layer.

6. A. Maxillary first premolarApproximately 60% have two roots, one buccal and the other

palatal, each with a single canal. The two roots may becompletely separate or merely twin projections rising from the

middle third of the root to the apex (this is more common). The

two roots are usually equal in length from apex to cusp.

However, the lingual root and canal may be wider. In

approximately 40% of maxillary first premolars, only one root

is present, usually with two 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 concavity on the mesial makes

perforation very 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 are present, each with a single

canal. The access opening is exactly the same as that for

maxillary first premolars (thin oval). When only one canal is

present (first or second premolar), 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, it is probable that another

canal is present Overfilling either tooth may force materials

directly into the maxillary sinus.

7. C. MesiobuccalCanal orifices of a maxillary first molar are arranged in the

shape of a triangle. The orifice to the mesiobuccal canal is

usually the most difficult to locate, since It is under the

mesiobuccal cusp and must be entered from a dlstollngual

position. This canal is the small canal and often splits into two

canals. It maybe calcified and difficult to instrument. The

palatal canal is the straightest, widest, and most tapering canal.

The most common curvature of the palatal root is to the facial.

The distobuccal canal is also small and tapering. The orifice to

this canal has no direct relation to its cusp. The distobuccal

orifice is usually located by means of its relation to the

mesiobuccal orifice, with the distobuccal found approximately

2 to 3 mm to the distal and slightly to the palatal aspect of the

mesiobuccal orifice. In approximately 59% of maxillary firstmolar teeth, a fourth canal Is present with its orifice being just

lingual to orifice to the mesiobuccal canal. The canal is located

in the mesiobuccal root and may join the mesiobuccal canal or

exit through a separate foramen. If a lesion is present on the

mesiobuccal root prior to root canal therapy and doesn't heal in

the usual amount of time (6-12 months) following treatment, it

is most likely due to a missed canal (mesio-lingual). The U-

shaped radlopaclty commonly seen overlying the apex of the

palatal root of the maxillary first molar is most likely the

zygomatic process of the maxilla.

8. A .Maxillary central incisor

9. B. Have film thickness of 1-50 microns.Liners are relatively thin layers of material used primarily to

provide a barrier to protect the dentin from residual reactants

diffusing out of a Restoration or oral fluid.

Thin film liners (1-50 micron)

Divided into

Solution liners Suspension liners

(Varnish 2-5 micron) (20-25 micron)

Thicker liners are used for pulpal medication and thermal

protection. For moderate depth tooth preparation liners are used

for thermal protection and pulpal medication. In very deep

preparation calcium hydroxide liner are used under gloss

ionomer restoration.

10. B. Thin meslodistally but wide lablolinguallyMandibular canines usually have only one root but in rare cases

may have two separate roots. The access opening is a large oval

with the greatest width placed incisogingivally. This tooth

usually has a slightly labial axial inclination of the crown

therefore the access opening needs to be directed towards the

lingual surface.

11. C. It does not alter dentin permeability.Reduction in sensitivity may result from formation of Resin

tags and a hybrid layer when a dentin adhesive is used. The

precipitation of proteins from the dentinal fluid in the tubulesalso may account for the efficacy of desensitizing solutions. So

after excluding the three option we can have answer.

12. D. Globulomaxillary cystAn 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-vital. A

radicular cyst usually occurs in a pre-existing granuloma.

Seldom is painful. Radiolucency at apex of non-vital tooth. A

chronic dental abscess is often a result of a periapical

granuloma. Radiolucent area at apex of non-vital tooth. Fistula

is often found leading from an abscess cavity. Once drainage is

established, the tooth stops being painful.

A globulomaxillary cyst is found at the junction of the globulus


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and maxillary processes of the maxilla, between the lateral

incisor and the canine roots. It is a developmental (hssural)

cyst which arises from cells in a fissural line of bone. Teeth are

vital.

13. B. Easy to manipulateShort setting time MTA is difficult to manipulate and has a

long setting time. Despite these disadvantages, it's the material

of choice today. A retrofllllng (also called a reverse filling or

retrograde amalgam filling) is placed to seal the apical portion

of the root canal. This procedure is used when an apicoectomy

alone will not yield a good result Whenever there is any chance

whatsoever that an apical seal may be faulty, a reverse filling

material must be placed. For example, if the root canal appears

calcified, it would be impossible to obturate most of the canal

and get a seal. If just the root apex were cut off (apicoectomy),

the incompletely filled canal might act as a source of

reinfection. To prevent this after the root tip is resected, the

foramen 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 flapped

back, the buccal bone about the apex is removed, the root apex

is removed, and the area is curetted out. Indications forapicoectomy:

1. A reverse filling needs to be placed.

2. It is necessary to gain access to an area of pathosis.

3. The poorly filled apical portion of the root is to be removed

to the level of canal obliteration.

A retrograde amalgam filling should always be done after an

apicoectomy. Teeth that have posts in them and need to be

retreated are the most common reason for an apicoectomy and a

retrograde filling. Remember Periapical curettage is the same

procedure as an apicoectomy (as far as flap and removal of

buccal bone) but without removing the root apex. Removal and

examination of the diseased tissue and determination of the

extent of the lesion are the objectives of apical curettage.

14. B. Sensitivity to hot, and or, cold stimuliThermal sensitivity is the earliest and most common symptom

of an inflamed pulp. As caries enters the dentin it begins with a

lateral spread at the DEJ. This is due to the increased organic

content and the involvement of many dentinal tubules. The

Tomes fibers react, causing fatty degeneration, then later

decalcification (sclerosis). As caries progresses, destruction of

dentin is followed by the bacterial invasion of the tubules and

complete destruction of dentin. Once odontoblasts are

Involved, pulpal changes occur. Initially there is vascular

dilation and local edema. The earliest common symptom of this

edema (acute pulpitis) is thermal sensitivity (usually increased

and persistent pain on application of cold). The only reliableclinical evidence that secondary dentin has formed is decreased

tooth sensitivity (usually seen a few weeks after placement of a

filling). When dentinal tubules become completely calcified,

the dentin is insensitive.

The best method to elicit a most accurate thermal response is to

individually isolate the suspected teeth with a rubber dam and

then bathe each tooth in hot or cold water. This is done because

all other methods may stimulate the tooth at only one section of

one surface. Thermal tests may be false-negative in immature,

recently traumatized teeth or because of premedication with an

analgesic.

15. B. Nickel-Cobalt-Chromium is never used in its

fabrication.

Hand cutting instruments are manufactured from two main

material carbon steel & stainless steel In addition, some are

made with carbide inserts to provide more durable Cutting

edges. Carbon steel is harder than stainless steel, but when

unprotected, it will Corrode. Other alloys of Nickel, Cobalt &

Chromium are used in the manufacture of hand instruments but

they are usually restricted to instruments other than those used

for cutting of tooth structure.

16. B. AsymptomaticThe chronic apical abscess (also called suppurative apical

periodontitis) is sometimes so painless that it may go

undetected for years until revealed by an x-ray. It is a long-

standing, low-grade infection of the periapical bone with the

root canal being the source of the infection. This condition may

follow an acute alveolar abscess or unsatisfactory root canal

therapy. Radiographs will reveal a diffuse radiolucency and

PDL thickening. The tooth may be slightly loose or tender to

percussion. The chronic abscess may be differentiated from

cysts and granulomas by the fact that both cysts and

granulomas have well-defined radiolucencies associated with

them. The treatment is conventional root canal treatment. 30%

to 50% of bone calcium must be altered before radiographicevidence of periapical breakdown occurs (this alteration takes

place at the junction between the cortical and cancellous bone).

The acute apical abscess (AAA) is a localized collection of pus

in the alveolar bone at the root apex following death of the pulp

with extension of the infection into the periapical tissue. The

first symptom may be a slight tenderness of the tooth. This later

develops into a severe throbbing pain to percussion with

swelling of the overlying mucosa. The tooth becomes more

painful, elongated and loose. At times the pain may decrease or

disappear completely. The patient may appear weakened,

irritable and present with a fever. The diagnosis is based on the

history, exam, and radiographs. The tooth will not respond to

the EPT or cold test but may respond to heat Treatment of anacute alveolar abscess Includes establishing drainage and

debrldlng the canal system of necrotic tissue which will relieve

the acute symptoms. This Is followed at a later date by

conventional root canal therapy. If the abscess ruptures

through the periosteum into the soft tissue, the patient's

symptoms will subside.

17. C. Dental InfectionIt is not a particularly common disease. It is a serious sequela

of periapical infection that often results in a diffuse spread of

infection throughout the medullary spaces, with subsequent

necrosis of a variable amount of bone. Acute or subacute

osteomyelitis may involved either the maxilla or the mandible.

In the maxilla, the disease usually remains fairly well-localizedto the area of initial infection. In the mandible, bone

involvement tends to be more diffuse and widespread.

Clinically, the person afflicted with acute osteomyelitis is

usually in rather severe pain and manifests an elevation of

temperature with regional lymphadenopathy. The teeth in the

area of involvement are loose and sore so that eating is

difficult, if not impossible. Radiographically, acute

osteomyelitis progresses rapidly and demonstrates little

radiographic evidence of its presence until the disease has

developed for at least one to two weeks. At that time, diffuse

lytic changes in the bone begin to appear. A "moth-eaten"

radiolucent appearance is evident.

The general principles of treatment demand that drainage be


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established and maintained and that the infection be treated

with antibiotics to prevent further spread and complications.

18. C. Periapical abscessOf all the dental abscesses, the periapical is the most common

type. It is a localized collection of pus in the alveolar bone at

the root apex following death of the pulp with extension of the

infection into the periapical tissue. The first symptom may be a

slight tenderness of the tooth. This later develops into a severe

throbbing pain (acute abscess) with swelling of the overlying

mucosa. The tooth will not respond to the EPT or cold tests but

may respond to heat. Emergency treatment includes

establishing drainage (ideally through the canal) and

prescribing antibiotics and analgesics. This will relieve the

acute symptoms followed by conventional endodontic therapy

at a later date. For endodontic infections that do not respond to

penicillin, clindamycin is often recommended. It produces high

bone levels and is effective against anaerobic bacteria but must

be used with caution because of the potential for

pseudomembranous colitis. The periodontal abscess is an acute

abscess that develops through the periodontal pocket. Alveolar

bone loss, pocket formation and periodontal pathologic

conditions are suggestive of the periodontal abscess. The toothwill usually be palpation and percussion positive. It will

respond to the electric pulp tester (unlike the pehapical

abscess). Bacteria associated with this abscess include gram-

negative rods such as Capnocytophaga species, Vibrio-

corroding organisms and Fusobacterium species. The gingival

abscess is a relative rarity mat occurs when the bacteria invade

through some break in the gingival surface. Such abrasions may

be the result of mastication, oral hygiene procedures, or dental

treatment.

19. B. Irreversible pulpitisThe severity of the clinical symptoms will vary as the

inflammatory response increases. Pain will vary from a mild

and readily tolerated discomfort to a severe, throbbing andexcruciating pain. The pain is spontaneous and is intermittent in

nature. The pain lingers after the removal of the 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 overall increase in cephalic

blood pressure is relayed to the confined pulp tissue. The tooth

may be tender to percussion, heat may intensify the pain

response while cold may relieve it (in advanced stages).

Usually they both will cause severe and lasting pain. The

radiographs will usually disclose no periapical pathology.

Treatment is root canal therapy.

Reversible pulpitis (hyperemia) -» the pain associated with

hyperemia does not occur spontaneously. It requires an externalirritant to evoke a painful response (i.e., cold, sweets). The

pains are sharp and of brief duration, ceasing when the irritant

is removed. Radiographs appear normal (may show deep caries

or cavity preparation). The tooth is usually percussion negative.

In thermal tests, the pulp responds more readily to cold stimuli

than to hot (the response leaves shortly after removal of the

stimulus). Treatment usually Is a sedative filling or new

restoration with a base. Pulpal Inflammation (hyperemia) is

most commonly caused by bacteria.

20. D. None of the aboveApexification Is a technique whose goal is to induce further

root development in a pulpless tooth by stimulating the

formation of a hard substance at the apex, so as to allow

obturation of the root canal space. Apexification may be

required after pulpectomy as at seven years of age the apex of

this tooth must be open. Remember: Apex closes 2-3 years

after eruption. The technique consists of isolation of the field

with a rubber dam, making an access cavity and removing all

pulpal tissue by the use of reamers and files. A premixed

syringe of a calcium hydroxlde-methylcellulose paste (for

example, a Pulpdent syringe) is injected into the canal until it is

filled to the cervical level. The paste must reach the apicalportion of the canal to stimulate the tissues to form a calcific

barrier. A double seal of cement is made to close off the access

cavity. The patient is recalled after three months to see if

apexification has taken place. If not, a fresh supply of paste is

placed. If apexification has occurred, conventional root canal

therapy is instituted. The action of calcium hydroxide in

promoting formation of a hard substance at the apex is best

explained by the fact that calcium hydroxide creates an alkaline

environment that promotes hard tissue deposition. If a

permanent tooth fractures and has a fully formed root and the

pulp is exposed (large exposure), the treatment of choice is

complete root canal therapy. Apexification is not needed

because the root is fully formed. If the exposure is small andthe length of time is short (1/2 hour to 1 hour), then a direct

pulp cap with CaOH followed by a restoration is the treatment

of choice.

21. C. Perform the amputation at a more apical levelUncontrolled bleeding is a sign of inflamed pulp tissue. The

radicular pulp must be uninflamed for the success of this

procedure. It is not uncommon to find uninflamed pulp at a

more apical level, especially in cariously exposed teeth. If

bleeding does not stop even after more apical amputation,

hemostatic agents are used as a compromise treatment. These

are closely monitored and if vitality is lost, apexification

(pulpectomy) procedures should be instituted. Pulpotomy is

removal of a portion of the pulp. The common Indicationsinclude: Cariously exposed deciduous teeth -> with healthy

radicular pulps. Traumatic or carious exposure of permanent

teeth with undeveloped roots. •An alternative to extraction

when endodontic treatment is not available. Emergency

treatment in permanent teeth with acute pulpitis. Unfortunately,

pulpotomy procedures performed in fully developed permanent

teeth are not found to be successful. For this reason it is

regarded as a temporary procedure in these teeth.

22. A. Accidental exposure of the pulpPulp of a young child Pulp capping is the placing of a sedative

and antiseptic dressing on an exposed healthy pulp in order to

allow it to recover and maintain normal function and vitality.

The dressing most commonly used is CaOH2 (Dycal). Pulpcapping is overused in dentistry today. In reality it has only

very few indications for its use. Young pulps are more

vascularized and, therefore, more amenable 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 be pinpoint to expect success. Repair

is accomplished by the formation of a dentin bridge at the site

of exposure. Even a small carious exposure should have root

canal therapy for the best long-term prognosis. A tooth may

stay asymptomatic for several weeks after pulp capping has

been performed. However, this may be only temporary.

Unfortunately, if pulp capping fails and the tooth becomes

symptomatic, it may be difficult, If not Impossible, to treat with


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routine because of the severe calcifications in the root canal.

Perforations may occur during attempts to follow the

obliterated canal to gain patency to the apex. Note: Perforations

into furcations of multi-rooted teeth have the poorest prognosis.

Traumatic blows to teeth are also a cause for calcification of the

pulp space sometimes to a point where locating the canal is

very difficult. With primary teeth, trauma may cause

calcifications in the pulp chamber, which in turn cause a

yellowish discoloration of the tooth.

23. A. "Tugback" within 1 mm of working lengthSince studies show that solvent softening does not ultimately

result in a better apical seal, this time consuming procedure can

be reserved for the other indications listed on the front of the

card. This slight resistance to dislodgement is referred to as

"tugback." The cone should also have a 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 procedure. A gutta-percha cone the same size

as the file used last during preparation (MAF) is selected and

placed as far as possible into the canal, but not beyond the

working length. Once satisfactory tugback and apical

positioning appear to be obtained, a radiograph is taken toverify cone positioning. 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 or extends to a point just short of that (1 mm).

When the cone is slightly short, the pressure of condensation

plus the lubricating action of the sealer wilt be sufficient to

produce complete seating of the cone. If the cone is more than 1

mm from the radiographic apex, discard the cone and fit a

smaller one or instrument more in the apical third. 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 dentin filings that were not

removed by irrigation.

24. D. The tooth responds to thermal testsThis indicates inadequate debridement as a pulpless tooth

should not respond to any stimuli. 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 have entered the

periapical tissues from the canal are eliminated by the natural

defenses of the body. Objectives of root canal obturation: 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 healing In endodontic

treatment the importance of canal obliteration (filling) is second

only to canal debridement. Approximately 40% of failures arebelieved to be caused by incomplete obliteration of the root

canal. If the canal is not filled, tissue fluid and microorganisms

from the periapical tissues are able to enter the voids, with

failure as the ultimate result. However, if an accessory canal is

not totally filled during obturation, the appropriate treatment is

to observe the tooth and evaluate every three months. After

endodontic therapy is completed on a tooth with a periapical

radiolucency, it usually takes 6-12 months before marked

reduction in the size of the radiolucency is evident on an x-ray.

Desired periapical tissue changes include regeneration of

alveolar bone, deposition of apical cementum, and re-

establishment of the PDL

25. A. Pseudomonas.

The microorganisms identified in periradicular infections of

endodontic origin are similar to bacteria isolated and identified

from within the root canal. Gram negative anaerobic micro

organisms are the main causative agent of endodontic

infections while pseudomonas is aerobic. Among aerobes alpha

hemolytic streptococci were the most commonly recovered

microorganism.

26. A. Eucalyptol is the reagent of choice to dissolve gutta-

perchagutta-percha is slightly soluble in Eucalyptol.

Highly concentrated chloroform is very effective but should be

used with caution. Its vapor is potentially hazardous so it is

dripped directly in the canal avoiding excessive flooding. Other

chemicals which can dissolve gutta-percha to a varying degree

include: xylol, halothane, benzene, carbon disulfide, essential

oils, methyl chloroform and white rectified turpentine. If a

gutta-percha cone has passed beyond the apex then a file must

be used beyond the apex in order to avoid breakage of the cone.

A broken cone in the periapical area may result in an

orthograde re-treatment failure. Techniques to remove gutta-

percha include: Rotary removal, Ultrasonic removal, Heat

removal, Heat and instrument, removal, File and chemicalremoval. Gutta-percha points may be disinfected by placing

them in a 5.25% NaOCI solution for one minute. A glass bead

sterilizer can sterilize endodontic files in 15 seconds at 220° C

(428° F).

27. D. It is also an excellent Irrigation solutionit has a limited value as irrigation solution. The decalcifying

process induced by EDTA is self-limiting and stops as soon as

the chelator is used up. Chelating agents are used to aid and

simplify preparation for very sclerotic canals after the apex has

already been reached with a fine instrument. These agents act

on calcified tissues only and have little effect on periapical

tissue. Their action is to substitute sodium ions, which combine

with the dentin to give soluble salts for the calcium ions that arebound in less soluble combination. 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 completion of the appointment the canal must be

irrigated with a sodium hypochlorite (NaOCI) containing

solution. EDTAC is EDTA with the addition of Cetavlon, a

quaternary ammonium compound. It has greater antimicrobial

action than EDTA. However, it has greater inflammatory

potential to tissue as well. The inactivator for EDTAC is

NaOCI. RC-PREP combines the functions of EDTA plus urea

peroxide to provide both chelation and irrigation. The foamy

solution has a natural effervescence that is increased by

irrigation with NaOCI to aid in the removal of debris.

28. C. To achieve glassy smooth walls of the canalClean shavings are difficult to see on a file. The attainment of a

clean irrigating solution is considered an inaccurate way to

determine the end point of debridement. Debridement is

defined as the removal of foreign material and contaminated or

devitalized tissue 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 root canal treatment. Complete debridement of the canal is

the most effective means to reduce root canal microorganisms.

It can be carried out in various ways as the case demands, and

may include instrumentation of the canal, placement of

medicaments and irrigants and / or surgery. The most common


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cause of root canal failure is incompletely and inadequately

disinfected root canal systems. The second most common cause

of failures of root canals is leakage from a poorly filled canal.

This is common even after apical curettage. Example: Root

canal treatment performed on a tooth with apical curettage of a

lesion that was found to be a cyst. Three years later the lesion is

even bigger than it was before. The most likely cause of this

failure is leakage from a poorly filled canal. When a canal is

properly prepared, any of the accepted methods of filling willalmost certainly produce a successful result (as long as the

canal is completely filled).

29. B. Permits restoration to withstand occlusal forces.

30. D. All of the aboveThe engine driven instruments, however, use only the reaming

motion. Nickel titanium instruments can be bom hand operated

and engine-driven. Generally, hand instrumentation is done by

either filing (push and pull) or reaming (repeated rotations).

Filing is a push-pull action with emphasis on the withdrawal

stroke. Its efficiency is greater with files than with reamers for

removing dentin because of the greater number of flutes in

contact with the canal walls during the rasping motion ofremoving the instrument. The appearance of the canal is

irregular and for this reason a canal prepared with this action

must be filled with gutta-percha in a condensation procedure.

Reaming is defined as the repeated clockwise rotation of the

instrument, particularly during Insertion. The appearance of the

canal is approximately round (this method is recommended if

using a silver cone to fill canal). Reamers are usually most

efficient for this function. Circumferential filing is a push-pull

action with emphasis on scraping the canal walls to create a

smooth, tapered preparation. It is a method of filing whereby

the instrument is moved first towards the buccal side of the

canal, then reinserted, and removed slightly mesially. This is

done all the way around the tooth until all the dentin walls have

been planed. This technique enhances preparation when aflaring method is used.

31. D. Long history of successful usageThis alone outweighs its disadvantages of staining, slow setting

time, non-adhesion and solubility. The primary function of a

root canal sealer is to fill in the discrepancies between the core-

filling material and the dentin wall. In fact it is said that it is

more important than the core filling material. 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

oxlde-eugenol cement and are capable of producing a seal

while being well-tolerated by periapical tissues. All sealers

display some degree of radiopaclty (caused by metallic salts in

the sealer); therefore their presence can be demonstrated on a

radiograph. This is an important property, since it may disclose

the presence of accessory canals, resorptive areas, root

fractures, and the shape of the apical foramen and other

structures of interest. After filling a tooth with gutta-percha, if

you see a horizontal line of material (gutta-percha or sealer)

extending both mesial ly and dlstally from the canal to the

periodontal ligament space, this is Indicative of a root fracture.

32. D. Its absorption is faster than the plain gut sutures.

Chromic gut sutures consist of plain gut treated with chromium

trioxide this result in delayed absorption rate. Evidence indicate

that plain gut is more biocompatible with oral soft tissues than

is chromic gut. Collagen is basic component of plain gut suture

material. The collagen is treated with diluted formaldehyde to

increase in strength.

33. C. Round In shapeStudies have shown that the action of using the instrument,

rather than the instrument used, determines the general shape of

the canal preparation. Therefore, a reaming action produces a

canal that is relatively round In shape while a filing action

produces a canal that is irregular In shape. A canal should be

instrumented and shaped so that it has a continuously tapering

funnel shape. The widest diameter would be at the canal

opening and the narrowest at the dentinocemental junction (.5

to 1.0 mm from the radiographic apex). This is where all teeth

should be filed to and filled to (ideally).

34. C. BroachesThe barbs are notched out of the instrument shaft and represent

a weakened point If the broach is not used with the utmost of

care or if it is forced apically, the barbs wilt be bent and willengage the walls, making removal difficult.

K-type instruments: Flies are the most useful instruments in

for the removal of hard tissue in canal enlargements. They are

manufactured by twisting a blank, which is a square rod,

producing a series of cutting flutes. The action used for placing

this type of file into a canal should resemble a clockwise-

counterclockwise motion with pressure directed apically (can

be a filing or reaming action). These files are the strongest of

all files and cut the least aggressively. A modifcation to this

type of file is the K-flex file. Reamers are manufactured in a

manner similar to files, only they have fewer flutes. They are

used in canal preparations to shave dentin with a reaming

action only. They remove intracanal debris with clockwise

reaming action. They are also used to place materials into theapical potion of the canal by using a counterclockwise rotation.

H-type Instruments: Hedstrom flies are manufactured by using

a sharp, rotating cutter to gauge triangular segments out of a

round blank shaft. This produces a very sharp edge and

therefore an effective cutting instrument. If used carefully, with

filing action only, it will successfully plane the dentin walls

much faster than K-type files or reamers. A modification of this

file is the S-file. All of the above are made of stainless steel.

35. D. Polymorphonuclear (PMN) LeucocytesThe onset of pulpal inflammation is an insiduous process and is

characterized by a chronic cellular response (plasma cells,

macrophages and lymphocytes). There is no direct exposure of

the pulp to dental caries and the response, therefore, is not

acute. After pulp exposure, the acute inflammatory cells

(mainly PMN cells) are chemotactically attracted to the area.

Histologically, the tissue is likely to show signs of acute

inflammation near the site of the exposure and a band of

chronic inflammatory cells between the acute inflammation and

the underlying normal pulp. The response of vital pulp to

microbial Invasion is very resistant. You can have an idea

about its resistance from the observation that even after two

weeks of traumatic exposure of the pulp, only 2 mm of the

coronal pulp may "give in* to microorganisms. Non-vital pulp,

incontrast, is a "fertile ground" for the growth of

microorganisms. Carious exposures in permanent teeth

generally require root canal treatment. Immature (open apex)


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permanent teeth with carious exposures can be treated by pulp

capping or pulpotomy procedures. Pulp capping is not

recommended in primary teeth with carious exposures due to

its high failure rate and because pulpotomy, having similar time

requirements, has shown to be very successful. Pulp capping

can be done, however, in mechanical exposures.

36. B. A vertical fracture of the toothRadiographic examination seldom reveals the fracture because

the crack is usually parallel to the x-ray film. One of the most

puzzling and frustrating dental conditions involving the

possible need for endodontic treatment is the cracked tooth

syndrome. Symptoms from this condition usually are

characterized by a sharp but brief pain occurring unexpectedly

only when the patient is chewing. Having a patient bite

forcefully on a bite stick and noticing the cusps that occlude

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 the fractured segment can be

removed and gingivoplasty and alveoloplasty performed,

treatment can be successful. However, unrealistic or

overambitious case selection leads to a high degree of failure.

When an anterior tooth fractures, it generally occurs in a morehorizontal plane and may show up on the x-ray. The cause is

usually accidental trauma such as a blow to the jaw or teeth. If

the fracture line is not too far down the root of the tooth, it may

be able to be saved with a root canal and a crown. Inlays have

been shown to be a cause of fractures. If a patient complains of

pain on mastication since the placement of an inlay, suspect a

fractured cusp (using a bite stick wilt help determine which

cusp may be fractured).

37. D. 0.005 – 0.01 microns.Nano fillers are about 7 mm range and used in modern

composite as they penetrate the typical key hole etch pattern of

enamel as well as smallest dentin channels. Microdentristry

uses A12O3 particles of 27 micron range.New composites are being developed with nanofillers that

ranges in size from 0.005 – 0.01 micron which is below the

wavelength range for visible light (0.02 – 2 µm) Because these

particles do not interact with visible light they do not produce

scattering or significant absorption.

38. A. A submarginal curved flapA submarginal curved flap also called semilunar flap

This half-moon shaped flap is raised with a curved horizontal

incision in the mucosa or attached gingival with the concavity

towards the apex. Although it's simple and does not impinge on

the surrounding tissue, the disadvantages outweigh its

advantages. These include: 1) Limited access and visibility 2)Tearing of comers of the incisions when an attempt is made to

improve accessibility by stretching the flap 3) If somehow a

lesion is found to be bigger than anticipated, the incisions come

to lie over the bony defect. Healing occurs by scarring 4) Its

extent is also limited by attachments (e.g., frenum, muscles

etc.) Submarginal triangular and rectangular flap (Ochsenbein-

Leubke) requires at least 4 mm of attached gingiva and a

healthy peridontium. It is raised by a scalloped incision in the

attached gingiva with one or two vertical incisions. Less risk of

incising over bony defects and no post-surgical recession of

gingiva. Its disadvantages include hemorrhage from the cut

margins and scarring. Access and visibility is better (and

acceptable) than semilunar flap but not as good as full

mucoperiosteal flap. Full mucoperiosteal flap allows maximal

access and visibility. It is raised from the gingival sulcus

(elevating gingival crest and interdental gingiva). This wide

outline of the flap precludes any incisions over bony defects

and allows various periodontal procedures including curettage,

root planing and bone re-shaping. A large flap may be difficult

to reposition, suture and make alterations. Post surgical

gingival recession is also a possibility.

39. A. Tooth socket

40. A. A conical shaped probingIn "blow-out type" and "sinus tract type" probings, another clue

for diagnosis is a non-vital (necrosed) pulp -» these two lesions

can completely heal after root canal treatment. Acute or blow-

out lesions -» a tooth with this type of lesion will show normal

sulcus depth all the way around the tooth until the area of the

swelling is probed. At this point, the probe drops suddenly, to a

level near the apex. The probing depths in all other areas are

within normal limits. Periodontal lesions characteristically

show bone loss which begins at the crestal bone level and

progresses apically. Hence probing defect would be conical in

shape. This type of lesion may not be amenable to root canaltreatment alone even if it is associated with a pulpless tooth.

However, endodontic treatment must be completed prior to

tackling the periodontal problem.

A narrow sinus tract type lesion --> the probing reveals normal

depths all around the tooth except at one very narrow area.

Here, the probe can pass down the root surface to some

distance and sometimes even to the apex. The tooth is pulpless

(non-vital). Once the root canal treatment is completed, the

lesion heals within one week. A perio-endo abscess is a

combined lesion. The lesion usually demonstrates radiographic

involvement of the periodontium and the apex of the involved

tooth. A common clinical finding of a periodontal problem is

pain to lateral percussion on a tooth with a wide sulcular

pocket.

41. D. Threaded screw posts are preferred over parallel

sided and tapered postsThese may actually increase the chance of fracture. The

parallel-sided posts are preferred. Options available when

restoring endodontically treated posterior teeth: Restoration of

occlusal opening only -» in rare Instances the access opening

and caries destruction do not encroach on the cusps and

marginal ridges. These teeth may be restored with an occlusal

amalgam; however, a cuspal coverage restoration would

provide protection from fracture.

Onlay restoration -> In most cases it is Imperative that root

canal treated teeth be protected from fracture by a cusp-

coverage type of restoration. The minimum (most conservative)

preparation 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 not afford sufficient

tooth structure for an onlay.

Crown with post and core -» to reinforce the treated tooth and

provide suitable coronal tooth structure for an optimum crown

preparation, the use of a post and core is often indicated. Be

very careful when placing posts. Perforations and vertical root

fractures can occur. If you are performing a pulp chamber-

retained amalgam, you need to place amalgam 3 mm Into each

canal for retention. Endodontically treated posterior teeth are

more prone to fracture than untreated posterior teeth due mainly


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to the destruction of the coronal tooth structure -* they have

reduced structural integrity.

42. C. Of the most apical portion of the rootAn apicoectomy is best accomplished by obliquely resecting

the most apical portion of the involved root. If a tooth has had

previous endodontic therapy and becomes reinfected, it is

usually best to try and retreat it conventionally -> remove

filling material, debride the canals, and refill. However, if the

tooth has been restored with a post, core, and crown then apical

curettage, apicoectomy, and a retrofill should be performed.

Indications for apicoectomy: A reverse filling needs to be

placed. It is necessary to gain access to an area of pathosis. The

poorly filled apical portion of the root is to be removed to the

level of canal obliteration. Indications of peiiradicular surgery:

Non negotiable canal, blockage or severe root curvature in

which non-surgical treatment is impossible. Complications

arising from procedural accidents (e.g., separation of

instruments, ledging and/ or perforations) which cannot be

handled without surgical exposure of the site. Failed

treatment due to irretrievable posts or root fillings. Horizontal

apical fractures in which apical end of the pulp becomes

necrotic. Biopsy -> to diagnose non-odontogenic causes ofsymptoms, (e.g., patient with a history of previous malignancy,

lip parsthesia or anesthesia).

43. C.The size of the pulpAs the pulp ages there is a decrease in reticulln fibers (the pulp

becomes less cellular and more fibrous). The size of the pulp

also decreases because of the continued deposition of dentin.

As the pulp ages there is an increase in the number of collagen

fibers and calcifications within the pulp (called denticles or

pulp stones). The pulp contains both myelinated and

unmyelinated nerve fibers. They are afferent and sympathetic.

The myelinated fibers are sensory and the unmyelinated fibers

are motor -» they play a role in the regulation of the lumen size

of the blood vessels. Proprioceptors (which respond to stimuli

regarding movement) are not found in the pulp. The only type

of nerve ending found in the pulp is the free nerve ending,

which is a specific receptor for pain. Regardless of the source

of stimulation (heat, cold, pressure), the only response will be

pain. Pulp stones are associated with chronic pulpal disease -

»from advanced carious lesions or large restorations.

44. C. PredentinImmediately adjacent to the odontoblast layer in the pulp, 10-

47 iim of the dentin matrix remain unmineralized. If this

unmineralized layer of dentin is lost (e.g., due to trauma or

infectious process) it predisposes the dentin to internal

resorption by odontoclasts.Mantle dentin -> is first-formed dentin which is laid before

odontoblast layer gets organized. Hence the pattern of

deposition and size of collagen fibers is different from

circumpulpal dentin.

Clrcumpulpal dentin -> represents most of the dentin which is

formed.

Secondary dentin -» forms after eruption of a tooth and

throughout life resulting in a gradual but asymmetric reduction

in pulp size.

Tertiary dentin or reparative dentin -» is an irregular and

disorganized layer of dentin laid down in response to any

injurious / irritant stimuli. Dentin formation is the primary

function of pulp. Other functions include:

Induction -» forms dentin which in turn induces enamel

formation

Nutrition -» dentinal tubules are linked to the pulp which

maintains its hydration and formation of peritubular dentin.

45. D.Digital Fibre optic trans-illumination

46. C. Saliva can allow storage of the tooth up to 6 hours'This is false; saliva is hypotonic and can therefore allow

storage up to 2 hours. Maximum storage time of 6 hours isreported for milk. Note: All of the other statements on the front

of the card are true and must be remembered. Five factors that

are critical to the management of traumatic avulsion injuries to

teeth: Time -> the time interval from injury to replacement of

the tooth is a major factor in the maintenance of ligament

viability and subsequent root resorption. Teeth replanted within

30 minutes have been reported to exhibit very little resorption,

whereas most of the teeth replanted after 2 hours show a lot of

external root resorption (which is the main cause of failure of

replanted teeth).

Storage media -» if the tooth cannot be immediately replanted,

the proper storage of the tooth can favorably influence the

viability of PDL cells. Milk is considered best for this purposebecause of its near neutral pH (6.5-6.8) and osmolality,

conducive for the survival of cells. Other storage media are

physiologic saline and saliva.

Tooth socket -» should not be damaged by curettage or forceful

replantation.

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

ligament fibers.

Root surface -» should not be scraped, dried, or manipulated

with caustic chemicals. The above information changes when a

tooth has been out of the mouth for more than 2 hours -*

mainly the treatment of the tooth socket and root surfaces as

well as the time for splint stabilization.

47. D. Curettage of the socket to remove periapical pathoslsThis is probably unnecessary. In fact, socket wall should be

minimally manipulated. Intentional replantation implies that a

tooth requiring endodontic therapy is purposely removed from

its socket, some type of canal or apical preparation and / or

filling is performed, 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 calcification, and

periapical surgery is impractical (a lower molar with the

mandibular canal 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 is impractical. Intentional

replantation should be considered only when there's no other

alternative treatment to maintain a "strategic" tooth. Long term

follow up is required to monitor for complications including

periodontal defects and ankylosis with replacement resorption.

48. C. Leave the tooth and come to the office ImmediatelyReplantation of a primary tooth is not recommended because of

the potential danger to the permanent successor from sequels of

trauma (e.g., infection, ankylosis, or damage due to

manipulation during procedure itself). Proper management of

an avulsed permanent tooth that has been replanted within two

hours of the accident: Ten days to two weeks after replantation,


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the root canal is prepared (cleaned and shaped) and a calcium

hydroxide paste is placed into the canals. This paste is replaced

every three months for one year. If after one year, it appears

that resorption has reversed or stopped, a permanent gutta-

percha filling can be placed. Important: If a tooth is out of the

mouth for more than two hours : Ankylosis and external root

resorption will probably result within two years. Ankylosis

resulting from replacement would give a better prognosis than

external resorption, which lead to failure. Root canal therapy isperformed in its entirety prior to replantation. The tooth is

soaked In a 2.4% fluoride solution acidulated at pH 5.5 for 20

minutes or more. The fluoride 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. Resorption is the most frequent sequela to

replantation. Three different types of resorption have been

identified: surface, inflammatory and replacement (ankylotic

resorption). Replacement resorption refers to resorption of the

root surface and its substitution by bone, resulting In ankylosis.

49. C. Inflammation due to an infected coronal pulpThis condition is frequently precipitated by traumatic injury to

the tooth. Undifferentiated reserve connective tissue cells of thepulp are activated to form dentinoclasts, which resorb the tooth

structure in contact with the pulp. Internal (inflammatory)

resorption is usually asymptomatic and is discovered on

routine radiographic evaluation. The anatomic configuration of

the root canal is altered and increases in size with internal

resorption. It will appear as an irregular radiolucency anywhere

along the canal space. The tooth involved may respond to pulp

vitality tests.When internal resorption is detected, a pulpectomy

should be performed. Once the pulp tissue responsible is

removed, all resorption ceases. To "wait and see" may result in

sufficient destruction of the tooth to create a perforation of the

root. Typical radiographic appearance of internal resorption

Although, internal resorption can occur only when some of thepulp tissue is still vital, a negative sensibility test does not rule

out this etiology. Also remember that sometimes on a

radiograph, an external resorptive lesion can superimpose the

canal space to mimic internal resorption. In such cases, another

radiograph should be exposed at an angle to the tooth. The

radiolucent lesion inside the canal space will not shift.

50. B. Inflammatory resorptionBowl-shaped areas of resorption involving cementum and

dentin characterize external inflammatory root resorption. This

type of resorption is rapidly progressive and will continue if

treatment is not instituted. Since both a necrotic pulp and the

presence of bacteria are necessary components of inflammatory

resorption, the process can be arrested by immediate root canaltreatment. The tooth is opened and the canal is cleaned and

shaped. A calcium hydroxide paste is placed in the canal. This

is replaced every three months for one year. If after one year, it

appears that the resorption has stopped, a permanent root canal

filling (gutta-percha) can be placed. A calcium hydroxide-based

root canal sealer is strongly recommended. Surface resorption

is caused by acute injury to the periodontal ligament and root

surface. 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 by bone,

resulting in ankylosis. This is often seen in unsuccessful replant

cases. The etiology of external and Internal resorption:

External resorption -* periradicular inflammation, dental

trauma (resulting in damage to attachment apparatus),

excessive orthodontic forces, impacted teeth, bleaching of non-

vital teeth. Internal resorption -» dental trauma (resulting in

loss of vitality and subsequent infection), dental caries, pulp

capping with calcium hydroxide, cracked tooth.

51. B. periodontal cyst

52. C. Intentional replantation Is a viable alternative to

endodontic surgeryIntentional replantation is not a substitute for endodontic

surgery if it can be undertaken. All of the other statements on

the front of the card are true and must be remembered.

Transplantation is the transfer of a tooth from one alveolar

socket to another either in the same person or in another person

Orthodontic extrusion is defined as force-controlled vertical

tooth movement occlusally in the socket. Indications include

unbeatable subgingival pathoses e.g., cervical caries, cervial

fracture, periodontal defects, resorptive lesions and perforations

in the cervical area. Crown lengthening is a procedure used to

apically position the gingival margin and / or to reduce the

cervical bone. It is employed during the treatment of

subgingival caries perforations and resorptions. Rootsubmersion involves resection of tooth roots 3 mm below the

alveolar crest and then cover with a mucoperiosteal flap.

Indications include rampant caries, adverse periodontal

conditions and in cases that have had repeated prosthetic

failures. The submerged roots will prevent alveolar resorption

and maintain better proprioception. This is especially useful in

medically compromised or handicapped patients requiring

better denture control. Sometimes, this is also done to avoid

formation of an esthetic defect that may result after extraction.

53. C. Stieglitz forceps

54. D. "Pink" tooth Is considered to be pathognomonic of

replacement resorption

Traditionally pink tooth has been considered pathognomonic ofinternal resorption but it is not an uncommon feature of cervica

root resorption as well. It is characterized by a pinkish

appearance of the tooth due to growth of granulation

undermining the coronal dentin. Replacement resorption, which

accompanies dento- alveolar ankylosis resulting from extensive

trauma to the attachment apparatus of the tooth is characterized

by progressive replacement of the root by the bone.

Histologically, it shows direct contact between dentin and bone

with no intervening PDL or cemental layer. This condition's

pathognomonic signs are: Lack of mobility Metallic sound to

percussion Infra-occlusion of the involved tooth in the

developing dentition

55. C. Endodontic treatment followed by periodontic

treatmenttn a combined perio-endo lesion, endodontic treatment

generally takes precedence over periodontal management.

Combined endodomtic-periodontal therapy is widely used

because the anatomic and clinical connections between the pulp

and periodontal structures are close and numerous. In most

cases of this nature, endodontic procedures are preformed first

and, when necessary, are followed by periodontal measures. In

these cases, the value of precise pocket probing and correc

appraisal of the vitality of the pulp is crucial. In some doubtfu

cases, the better part of wisdom is to wait until after the

completion of the root canal therapy to see whether

spontaneous resolution (pocket closure and osseous fill-in) wil


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occur before surgical periodontal procedures are begun.

Periodontal therapy should be initiated first only in the case of

a primary periodontal lesion with subsequent secondary

endodontic involvement. A common clinical finding of a

periodontal problem is pain to lateral percussion on a tooth with

a wide sulcular pocket.

56. B. Chemical solutionsThe method of choice for sterilization of gutta percha is

chemical solutions. Gutta percha cones may be kept sterile in

screw-capped vials containing alcohol. To sterilize a gutta-

Percha cone freshly removed from the manufacturer’s box, one

should immerse it in 5.2% sodium hypochlorite for 1 min, then

rinse the cone with hydrogen peroxide and dry it between 2

layers of sterile gauze. It has been demostrated that 5.2%

sodium hypochlorite is more effective than sporicidin and as

effective as activated dialdehyde (cidex) for sterilizing guta-

percha cones.

57. B. The numbers of flutes on the blade are more in files

than in reamers.

58. C. Pulp & supporting tissue59. B. Establish drainageAn acute apical abscess is accompained by a severe local

reaction and, at times, a general reaction of systemic toxicity

such as elevated temperature, gastrointestinal disturbance,

malaise, nausea, dizziness and other symptoms related to

continuous pain and lack of sleep. To relieve this constant pain

as an emergency measure, one should establish drainage

through the root canal, preferably, and through the soft tissue

and bone, if necessary. The open-drainage technique is

preferable to one in which the prepared root canals are sealed,

followed by incision of the soft tissue and artificial fistulation

of the bone to establish drainage. Open root canals permit

drainage and frequently eliminate the need for a surgicalincision as well as the routine administration of oral antibiotics

and analgesics. The prognosis for the tooth is generally

favourable, depending on the degree of local involvement and

the amount of tissue destruction.


61. C. Both a & b

62. A. Chronic open pulpitisChronic hyperplastic pulpitis or “pulp polyp” is a productive

pulpal inflammation due to an extensive carious exposure of a

young pulp. It is characterized by the development of

granulation tissue, covered at times with epithelium and

resulting from long-standing, low-grade irritation. Slow,progressive carious exposure of the pulp is the cause. A large

open cavity, a young, resistant pulp, and a chronic, low-grade

stimulus are necessary for the development of hyperplastic

pulpitis. Mechanical irritation from chewing and bacterial

infection often provide the stmulus. The condition is usually

symptomless and is generally seen only in the teeth of children

and young adults. The appearance of the polypoid tissue is

clinically characteristic; a fleshy, reddish pulpal mass pulpal

mass fills most of the pulp chamber or cavity or even extends

beyond the confines of the tooth.

63. C. Grey matter of spinal cord

64. B. Immature teeth

65. C. SuperoxolWalking bleach technique is used for bleaching a discolored,

endodontically treated tooth. Superoxol can be used alone or

mixed with sodium perborate into a paste for use in the

“walking bleach”. Superoxol is a 30% solution of hydrogen

peroxide by weight and 100% by volume in pure distilled

water. Sodium perborate is a stable, water soluble white

powder which decomposes into sodium metaborate and

hydrogen peroxide, relaeasing oxygen. When mixed into apaste with superozol, this paste decomposes into sodium

metaborate, water and oxygen. When sealed into the pulp

chamber, it oxidizes and discolors the stain slowly, continuing

its activity over a longer period of time.

66. D. Dentinal chips along with a & b

67. A. Proper instrumentation

68. A. Pain of pulpal originThermal testing involves the application of cold and heat to a

tooth, to determine sensitivity to thermal changes. A response

to cold indicates a vital pulp, regardless of whether that pulp is

normal or abnormal. When a reaction to cold occurs, the patient

can quickly point to the painful tooth. Cold can be applied inseveral different ways such as: Stream of cold air Ethyl

chloride spray/cotton pellet saturated with ethyl chloride Ice in

wet gauze/ ice pencils Carbondiozide (dry ice) snow – 780C

temperature.

69. B. Remineralization

70. B. Irrigation of root canal

71. B. Does not relate to the periodontal conditionCalcification of pulp tissue is a very common occurrence and is

unrelated to the periodontal condition of the tooth. In the

coronal pulp, calcification usually takes the form of discrete,

concentric pulp stones, whereas in the radicular pulp,

calcification tends to be diffuse. The cause of pulpalcalcification is largely unknown, Calcification may occur

around a nidus of degenerating cells, blood thrombi, or

collagen fibers. Many authors believe that this represents a

form of dystrophic calcification. Calcification may occur

around a nidus of degenerating cells, blood thrombi, or

collagen fibers. Many authors believe that this represents a

form of dystrophic calcification. Calcification replaces the

cellular components of the pulp and may possibly hinder the

blood supply. Luxation of teeth as a result of trauma may result

in calcific metamorphosis, subsequently causing partial or

complete radiographic obliteration of the pulp chamber.

72. B. It is not successful in wet field

73. D. Periphery, at the bottom

74. D. Provide straight line access to the apexThe objectives of access cavity preparation are:

1. To achieve straight or direct-line access to the apical foramen

or to the initial curvature of the canal.

2. To locate all root canal orifices

3. To conserve sound tooth structure.

A properly prepared access cavity creates a smooth, straight-

line path to the canal system and ultimately to the apex. When

prepared correctly, the access cavity allows complete irrigation

shaping and cleaning and quality obturation. Ideal access

results in straight entry into the canal orifice, with the line

angles forming a funnel that drops smoothly into the canal.


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10

Modifications of the outline form may be needed to facilitate

location of canals and to create a convenience form.

75. B. Compaction method

76. B. Bacterial

77. B. PacemakerElectric pulp tests are contraindicated in patients who have

cardiac pacemakers because they can interfere with the function

of the pacemaker. Attachments that reduce the amount of

surface contact necessary to conduct the electric stimulus are

available, and bridging the tip to a small area of tooth structure

with an explorer has been suggested. However, use of even this

small electric stinulus in patients with pacemakers is not

recommended; any such risk would outweigh the benefit. The

same caution holds true for electrosurgical units.

78. A. middle 1/3rd premolars

79. A. At the same appointment

80. A. 2 hoursAvulsed tooth may be stored in saliva for upto 2 hours. Storage

of avulsed teeth in saliva for 2 to 3 hours causes swelling andmembrane damage to periodontal ligament cells owing to

saliva’s nonphysiologic osmolality. The nonphysiologic

osmolality, less favorable composition and presence of

microorganisms makes saliva a less desirable storage medium

for the avulsed tooth. However, it is preferable to dry storage

for short peroids.

81. A. Root crown ratio

82. B. Chemical solutions

83. A. Sodium hypochloriteThe ultrasonic instrument consists of a piezoelectric ceramic

unit that generates ultrasonic waves, which activates a

magnetostrictive stack hand piece. The hand piece holds a K-file or a diamond file that produces movements of the shaft of

the file when activated. This oscillating movement produces the

cutting edge of the file. Sodium hypochlorite irrigant solution is

delivered alongside the file into the root canal.

84. C. H2O2 & sodium perforate bleaching

85. D. None of the above

86. B. Used to stabilize periodontally weakened teeth with a

poor ‘crown:root’ ratioAn endodontic implant is a metallic extension of the root, with

the object of increasing the root-to-crown ratio to give the tooth

better stability in the arch. Endodontic implants are useful for

treatment of- Periodontally involved teeth requiringstabilization. Transverse root fractures. Pathological resorption

of root apex (due to abscess). Pulpless teeth with short roots.

Root affected by internal resorption.

87. A. Penicillin

88. C. Culture for 48 – 96 hrs at 37°°°° C and plating of

positive findings

89. B. HermannHermann introduced Ca(OH)2 as a successful pulp capping

agent in 1930. He demonstrated the formation of secondary

dentin over the amputation sites of vital pulps capped with

Ca(OH)2.

90. C. Biting on rubber wheel

91. D. Triangular

92. B. Maxillary central incisorThe teeth most vulnerable to injury in order of frequency are-

1.Maxillary central incisors.

2. Maxillary lateral incisors.

3. Mandibular incisors.

Commonly observed dental trauma is fracture of enamel, or ofenamel and dentin, but without pulp involvement.

93. B. 0.12 to 0.38 mm

94. A. Fibrinolysin and polymorphonuclear leukocytes

95. B. Zone of irritationFish described the reaction of peri-radicular tissues to noxious

products of tissue necrosis, bacterial products, and antigenic

agents into 4 well defined zones of reaction.

ZONE CHARACTERIZED BY

Zone of infection PMNs

Zone of contamination Round cell infiltration

Zone of irritation Macrophages and osteoclasts

Zone of stimulation Fibroblasts and osteoblasts

96. C. 08 to 150

97. D. Full crown preparationsPalpal injuries may be caused by-

1. Heat generated by injudicious cutting.

2. Restorative materials having high thermal conductivity in the

absence of proper pulp protection.

3. Chemical ingredients of restorative materials.

4. Galvanic currents.

5. Ingress of microbes due to microleakege.

98. C. Post space preparation

The two popular engine-driven instruments are-1. Gates Glidden drill: It is used for initial opening of canal

orifices and deeper penetration, in both straight and curved

canals. 2. Piezo reamer: It is most often used in preparing the

coronal portion of the root canal for a post and core.

99. A. Notched

100. A. Gram positive organisms

101. D. EDTA with urea peroxideRC-Prep is a chelating agent used for removal of smear layer.

RC prep is composed of EDTA and urea peroxide in a base of

carbowax. It is not water soluble. Its popularity in combination

with sodium hypochlorite is enhanced by the interaction of urea

peroxide in RC-Prep with sodium hypochlorite, producing abubbling action thought to loosen and help float out dentinal

debris.

102. A. Cell free zone

103. B. Pulp polyp104. A. Pulp is bounded by rigid dentinThe encasement of pulp in the dentin creates an environment

that allows only small amounts of intracellular accommodation

of exudate during inflammatory reactions. This inability of the

pulp to swell creates an abnormally high pressure in an area of

Inflammation, with interruption of blood flow due to collapse

of the pulpal veins which Results in anoxia and localized

necrosis.


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106. C. Presence of inflammation in the apical portion of

the periodontal ligament

107. A. Flare the walls of root canalsHedstroem files (H – files) are manufactured from a round

stainless steel blank, machined to produce spiral flutes

resembling cones of a screw. H-files have higher cutting

efficiency than K-files. They cut in one direction only(retraction). H-files are fragile and fracture easily.

108. D. Fibroblasts

109. D. 5 seconds

110. B. Root canal treatment

Condition of the pulp Treatment indicated

Pulp exposure not over

24 hours

Pulp capping

Pulp exposure within 72

hours

Pulpotomy/Apexogenesis

Pulp exposure greater

than 72 hours

Pulpectomy/ Apexification

111. B. Penicillin or erythromycin

112. C. Since it will reduce the flora

113. A. Apical thirdThe primary gutta percha should seal the apical canal

approximately 1 mm short of the pulpoperiapical juncture.

The purpose of fitting the primary cone short of the canal apex

is to avoid inadvertent overfilling of the root canal during

condensation.Gutta perchan can also be used as a root end

filling material. At least 5 mm of gutta percha should be

retained apically in case of post space preparation.

114. D. Produce a hermetic seal when set

115. B. Removal of broken instruments

116. B. 3 mmIndications for apical resection/root end resection/apicoectomy

are- 1. Persistent symptoms and continued presence of a

periradicular lesion.

2. Interradicular posts.

3. Irretrievable root canal filling material.

4. Procedural accidents (perforations etc).

5. Apical root fracture.

Two important points to be considered while doing this

procedure are-

1. Extent of apical resection-removing 3mm of the root tip.

2. Bevelangle-root resection must be done perpendicular to thelong axis of the root.

whenever possible. Bevel greater than100 are undesirable and

structurally destructive.

117. C. Streptococci and staphylococci

118. C. Lentulo

119. C. Flutes of a Hedstroem file in reverseMc Spadden Compactor is a type of thermoplastic gutta percha

delivery system, where a large cone of gutta percha is placed

into the root canal and a special bur –the compactor-is used in a

low speed hand piece to both plasticize it and pack it against

the root canal walls. It is similar to a Reverse Hedstroem file

that drives the material back into the canal rather than removes

it. It can be best used in canals of size 50 and larger canals and

also in those that are relatively straight. Formerly, it was very

popular for filling teeth having resorptive defects. Its major

disadvantage is that it can not be used in narrow and curved

canals.

120. C. Fine argyrophillic fibers

121. C. Loss of apical seal

122. D. Carbamide peroxideNight Guard/Mouth Guard bleaching technique is widely used

as a hone bleaching technique. Carbamide peroxide is generally

used.

Intracoronal bleaching Sodium perborate

Extracoronal bleaching Hydrogen peroxide &

Carbamide peroxide

123. B. Streptokinase

124. B. Apical third of the root

125. D. Mineral Trioxide Aggregate (MTA)MTA is a root end filling material. The main molecules present

in MTA are calcium and phosphorus ions. MTA is a newmaterial developed for endodontics that appears to be a

significant improvement over other materials for procedures in

bone. It is the first restorative Material that consistently allows

for the overgrowth of cementum, and it may facilitate the

regeneration of the periodontal ligament. It is mixed with a

sterile liquid such a saline or local anaesthetic solution on a

sterile glass slab.

126. B. Fibrin and epithelial cells

127. D. Magnesium carbonate

128. A. Cemented.

129. B. 10

130. C. 6.5 and below

131. A. Periapical abscessPeriapical abscess/Dento-alveolar abscess/Alveolar abscess is

an acute or chronic suppurative process of the dental periapical

region. It usually arises as a result of infection following

carious involvement of the tooth and pulp, but it also does

occur after traumatic injury to the teeth resulting in necrosis of

the pulp and in cases of irritation of the periapical tissues either

by mechanical manipulation or by the application of chemicals

in endodontic procedures. Acute exacerbation of a chronic

periapical lesion is called a Phoenix abscess.

132. C. None of the above133. A. Prevention

134. A. The pulp is necroticApexification is defined as a method of inducing apical closure

by the formation of osteocementum or a similar hard tissue.

Treatment by apexification should be tried when the pulp has

died in a developing tooth with incomplete root formation.

Ca(OH)2 paste is used. The calcific barrier at the root apex

serves as a stop for a gutta percha filling and ensures an

adequate seal.

135. C. 2 -3 mm

136. A. Hyaline bodies


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137. B. Its antimicrobial propertyThe antiseptic action of Ca (OH)2 is probably because of its

high pH and its leaching action on necrotic pulp issue.

Ca(OH)2 causes a significant increase in pH of circumpulpal

dentin when the compound is placed in the root canal.

Ca(OH)2 paste is best used as an intracanal medicament when

one anticipates an Excessive delay between appointments,

because it is efficacious as long as it remains within the root

canal.

138. C. The blood stream

139. B. 6.6%

140. C. Enamel, Dentin and Pulp are involvedClassification of Ellis and Davey (1960) is as follows-

Class I Simple fracture of the crown involving little or no

dentin

Class II Extensive fracture of the crown involving

considerable dentin, but not the pulp

Class III Extensive fracture of the crown involving

considerable dentin and exposed dental pulp

Class IV The traumatized tooth which becomes non-vital

with or without loss of crown structure.Class V Loss of tooth

Class VI Root fracture with or without loss of crown

structure

Class VII Displacement of a tooth without fracture of crown

or root

Class

VIII

Fracture of crown enmass

Class IX Traumatic injuries of deciduous teeth

141. B. MB

142. B. 873.63

143. C. Barbed broachK file – K-file is an ISO Group I instrument traditionally made

from a square blank. H file – H-type files are made by cutting

spiraling flutes into the shaft of a piece of a round, tapered,

stainless steel wire. They cut in one direction only and are very

efficient in cutting. Barbed broach- Barbed broaches are short-

handled instruments used primarily for vital pulp extirpation.

They are also used to loosen debris in necrotic canals or to

remove paper points or cotton pellets.

Reamer – Reamers are instruments that ream. It is specificically

a sharp edged tool for enlarging or tapering holes. They cut by

reaming action.

144. D. Black

145. B. Anachoretic pulpitisAnachoresis refers to the attraction or fixation of blood-borne

bacteria in areas of inflammation. One probable cause of this

phenomenon is increased capillary permeability in the

particular area. Anachoretic pulpitis probably occurs in a

clinically insignificant number of cases of pulpitis compared

with the number of cases occurring as a result of dental caries.

146. C. 6 to 12 months


148. D. All of the aboveOther 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., broken

instalments, dentinal sclerosis, sharp dilacerations, etc.) A

medical condition such as hemophilia is not a contraindication

to conventional endodontic therapy. However, it is strongly

recommended that a dentist obtain clearance from the patient's

physician prior to treatment. Any teeth not contralndlcated are

excellent candidates for successful endodontic therapy.

Example of a special case: A previously traumatized tooth mayshow complete obliteration of the pulp chamber and canal. The

periodontal ligament may appear normal. The patient will be

asymptomatic and the tooth will not respond to pulp vitality

testing. The treatment of choice is to observe as long as the

tooth remains asymptomatic and no periapical changes are

evident.


150. A. Porphyromonas and PrevotellaThese species, which were previously classified under

bacteroids species merited a separate genus due to their distinct

characteristics. Predominant bacterial species isolated from

Infected root canals include: Eubacterium speciesPeptostreptoccus species ■ Fusobacterium species

Porphyromonas species Prevotella species Virulence factors

which play a role in periradlcular pathosis include:

Llpopolysaccharide (LPS) -> found on the surface of gram

negative bacteria Enzymes -+ neutralize antibodies and

complement components

Extracellular vesicles -»involved in bacterial adhesion,

proteolytic activities, hemagglutination and hemolysis

Fatty acids -* affect chemotaxis and phagocytosis

A vital pulp resists bacterial invasion. Even if the pulp is

exposed to microorganisms for 2 weeks, the penetration of

bacteria may extend no more than 2 mm into the pulp. In

contrast, non-vital pulp is a fertile ground for the growth of

microorganisms and leads to necrosis. RememberStreptococcus spp. may not be as important in the progress of a

carious lesion (leading to pulp exposure) as much as it is, in the

initiation of the lesion. Strict anaerobes are found to play a

significant role in periapical pathoses.

151. A. 2.0% Sodium nitriteItems sensitive to elevated temperatures can not be autoclaved.

Autoclaving tends to corrode the steel neck and shank portions

of some diamond instruments and carbide burs. For autoclave

sterilization, burs can be protected by keeping them submerged

in a small amount of 2% sodium nitrite solution.

152. D. Presence of a fistula

153. D. Submaxillary space

154. D. Mandibular lateral incisorClass-III restorations are indicated for defects located on the

proximal surface of anterior teeth that do not affect the incisal

edge. A. lingual access preparation of the distal surface of the

maxillary canine is recommended because the use of amalgam

in that location is more likely. Usually the outline form

includes only the proximal surface, however, a lingual dovetail

may be indicated if one existed previously or if additional

retention is needed for a larger restoration.

155. A. 16 mm

156. C. Phoenix abscess


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157. B. Permit chemical bonding between resin and enamelAcid –etching transforms the smooth enamel into a very

irregular surface, and also increases its surface free energy.

When a fluid resin-based material is applied to the irregular

etched surface, the resin penetrates into the surface, aided by

capillary action. Monomers in the material polymerize, and the

material becomes interlocked with the enamel surface. The

formation of resin micro tags within the enamel surface is the

fundamental mechanism of adhesion of resin to enamel.

158. D. Carious exposure

159. D. Co –Cr alloy

160. B. Barium and strontium glassesFiller compositions often are modified with other ions to

produce desirable changes in properties.

Lithium and Aluminium make the glass easier to crush to

generate small particles.

Barium, Zinc, Boron, Zirconium, Yttrium have been used to

produce radiopacity.


162. A. Sodium hypochlorite

163. B. Occlusally diverging mesial and distal wallsIn Class –I cavities for dental amalgam facial & lingual walls

are occlusally converging for retention and mesial & distal

walls are occlusally diverging. In Class-I cavities for direct

filling gold or gold inlays, facial & lingual walls as well as

mesial & distal walls are occlusally diverging.

164. A. Mesiobuccal


166. A. Calciumhydroxide cementOlder calcium hydroxide liners without Barium, Lead or Zinc

(added to lend radiopacity) appear radiolucent and may

resemble recurrent or residual caries. Despite the calciumpresent, the relatively large proportion of low atomic number

material in calcium hydroxide causes its radiodensity to be

similar to a carious lesion. Composite, plastic or silicate

restorations also may simulate carious lesions. It is often

possible however, to identify and differentiate these radiolucent

materials from caries by their well-defined and smooth outline

reflecting the preparation.

167. B. Labiolingual

168. C. Silicate

169. B. 1500This cavosurface design helps seal and protects the margins. A

cavosurface enamel angle of more than 1500 is incorrect

because it results in a less defined enamel margin and if its

angle is less than 300, the marginal cast metal alloy is too thin

and weak. Conversely, if the enamel margin is 1400 or less, the

metal is too bulky and when the angle is greater than 400, it is

difficult to burnish.

170. D. Removal of the pulp tissue

171. D. irritant

172. C. AtropineThe use of drugs to control salivation is rarely indicated in

restorative dentistry and is generally limited to the

anticholinergic drug-atropine. Atropine is contraindicated in

nursing mothers and in patients with glaucoma.

173. A. Apexification with calcium hydroxide

174. B. Apical scar

175. B. Traction principleThere are two principle methods of tooth movement-

1) Rapid/immediate tooth movement: - Wedge method

Eg: Elliot separator

Wood / plastic wedges

- Traction method

Eg. Non-interfering; true separator

Ferrier double-bow separator

2) Slow/delayed tooth movement

Separating wires, Oversized temporaries,Orthodontic

appliances.

176. B. Seepage of saliva into the canal

177. C. Both a & b

178. D

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