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NBDE II > Endo > Flashcards

Endo Flashcards

1
Q

Mild-moderate pain, lingers for 1-2 seconds after stimulus

A

Normal pulp

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2
Q

Normal pulp testing

A

Mild to moderate pain, lingers 1-2 seconds

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3
Q

Severe pain, lingers 1-2 sec

A

Reversible pulpitis

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4
Q

Reversible pulpitis testing

A

Severe pain, 1-2 sec after stimulus

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5
Q

Moderate to severe lingering pain

A

Irreversible pulpitis

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6
Q

Irreversible pulpitis

A

Moderate to severe lingering pain

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7
Q

Necrotic pulp testing

A

Negative

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8
Q

Sensitivity to percussion

A

Acute apical abscess

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9
Q

Acute apical abscess

A

Rapid onset, spontaneous pain, tender to percussion, pus, swelling

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10
Q

Pain to biting and percussion

A

No lucency: acute apical perio; with lucency flare up of chronic

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11
Q

What to test for pulp eval

A

Tooth, neighbors, contralateral

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12
Q

Supraerupted molar with irreversible pulpitis tx

A

Rct and crown

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13
Q

Spontaneous pain at night

A

Necrotic pulp

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14
Q

What does chronic periapical abscess indicate?

A

Necrotic pulp

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15
Q

Signs of chronic periodontitis

A

None; whereas abuse pain on biting and percussion

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16
Q

Electric pulp testing

A

Pulp vitality (rule out necrosis)

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17
Q

Thermal endo tests

A

Pulp vitality

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18
Q

Sensitivity to cold

A

Reversible pulpitis

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19
Q

Sensitivity to hot

A

Irreversible pulpitis

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20
Q

Percussion checks for

A

Inflammation in pdl

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21
Q

Palpating checks for

A

Spread of inflammation from pdl to periodontium

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22
Q

Hardest to anesthetize: necrotic vs irreversible, mandibular vs maxillary

A

Irreversible on mandibular

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23
Q

Electric pulp testing on traum teeth Y N

A

No

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24
Q

Hardest to anesthetize with irreversible pulpitis

A

Md molars, md pms, mx molars and pms, md anteriors, mx anteriors

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25
Q

Lingering pain to cold and sensitivity to percussion

A

Irreversible pulpitis with acute abscess

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26
Q

Not responsive to cold or percussion, sensitive to palpation

A

Necrotic pulp, chronic abscess

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27
Q

Test to diagnose chronic periapical periodontitis

A

Percussion

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28
Q

EPT on pulpal diagnosis

A

Not informative, tests fir vitality, not vascularity (aka health)

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29
Q

Perio vs endo lesion aka periodontal vs periradicular abscess

A

Check for vitality (EPT)

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30
Q

Endo tests for crowned teeth

A

Thermal (cold)

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31
Q

Best dx for irreversible pulpitis

A

Thermal (cold)

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32
Q

EPT vs cold for necrotic teeth

A

Cold is more reliable

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33
Q

Which of the following is the least important factor in referring an endo case to specialist?
Dilacerations
Calcifications
Inability to obtain adequate anesthesia
Mesial inclination of a molar

A

Mesial inclination of molars

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34
Q

Most reliable vitality test

A

Thermal (EPT can have false readings)

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35
Q

Bacteria in chronic endo lesions

A

Anaerobes

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36
Q

Chronic vs suppurative perio:

  • EPT
  • cold test
  • percussion
A

Percussion

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37
Q

Initial tx in combined endo/perio lesion

A

RCT first, then Sc/RP

UNLESS ACUTE ABSCESS

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38
Q

Acute perio abscess with endo lesion

A

Address acute abscess first: incise and drain

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39
Q

Better prognosis: perio to endo or endo to perio?

A

Endo to perio

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40
Q

Primary perio with secondary endo

A

Perio tx

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41
Q

Which of the following conditions indicates that a periodontal, rather than an endodontic problem, exists?
A. Acute pain to percussion with no swelling
B. Pain to lateral percussion with a wide sulcular pocket
C. A deep narrow sulcular pocket to the apex with exudate
D. Pain to palpation of the buccal mucosa near the tooth apex

A

Pain to lateral percussion with a wide sulcular pocket

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42
Q

pain to lateral percussion

A

perio problem

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43
Q

tx for sinus tract for RCT’d tooth

A

none, will resolve after RCT

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44
Q

Lateral periodontal abscess is best differentiated from the acute apical abscess by?

a. pulp testing (vitality tests)
b. radiographic appearance
c. probing patterns
d. percussion
e. palpation

A

a. pulp testing (vitality tests)

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45
Q

Radiographically, the acute apical abscess

a. is generally of larger size than other lesions
b. may not be evident
c. has more diffuse margins than another lesion

A

b. may not be evident

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46
Q

When do you puncture an abscess?

a. Localized chronic fluctuant in palpation
b. Localized chronic hard in palpation

A

(if hard there is no pus), so a. Localized chronic fluctuant in palpation

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47
Q 
A patient has a non-vital tooth & a fistula that is draining around the gingival sulcus. What kind of abcess is it?
endo and perio at same time
perio and then endo
only endo
only perio
A

only endo

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48
Q

There usually is no lesion apparent radiographically in acute apical periodontitis. However, histologically bone destruction has been
noted.
a. Both statements are true
b. Both statements are false.
c. First statement is true, second is false.
d. First statement is false, second is true.

A

a. Both statements are true

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49
Q

Based solely on the sharp transient response of pulp to hot stimuli, what is the periradicular diagnosis?

a. Acute apical periodontitis
b. Cannot diagnose based on information provided.
c. Acute Apical abscess
d. Irreversible pulpitis

A

b. Cannot diagnose based on information provided.

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50
Q

What is the clinical ‘hallmark’ of a chronic periradicular abscess?

a. Large periradicular lesion
b. Sinus tract drainage
c. Granulation tissue in the periapex.
d. Cyst formation.

A

b. Sinus tract drainage

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51
Q 
A periradicular radiolucent lesion of endodontic origin on the radiograph may be any of these histological diagnoses except one.
Mark this exception.
a. A cyst
b. A granuloma
c. An abscess
d. Dentigerous cyst
A

d. Dentigerous cyst

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52
Q

What complete endodontic diagnosis could be completely asymptomatic but should require endodontic therapy?

a. Pulpal necrosis and acute periradicular periodontitis
b. Normal pulp and acute periradicular periodontitis.
c. Pulpal necrosis and chronic periradicular periodontitis.
d. Normal pulp and normal periapex

A

c. Pulpal necrosis and chronic periradicular periodontitis.

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53
Q

A lesion of non-endodontic origin remains at the apex of the suspected tooth regardless of X-ray cone angulations.

a. True
b. False

A

b. False

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54
Q

After an RCT in maxillary molar, what Tx would you for sinus tract?

A

none, will resolve

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55
Q

CASE: 5 yrs old patient, he fell down 2 months ago, and hit his #E (central) when he fell down, the tooth is now discolored, what do
you suspect?
- A. There is a red swollen lesion on the gingiva of tooth #E, what is most likely be?
- B. What do you recommend for this tooth?

A

Necrotic pulp
Sinus tract (other choices, periapical cyst, periapical
granuloma, etc.)
Exo

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56
Q

What does radiolucency at furcation of primary M1 in 5 y/o usually indicate?
erupting permanent PM1, necrotic pulp, normal
anatomy

A

necrotic pulp

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57
Q

Primary tooth got necrosis, and the inflammation went down through furcation and affects permanent tooth. What is it going to
cause to permanent tooth?

A

Can disturb ameloblastic layer of permanent successor or spread infection

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58
Q

In a primary tooth, apical infection on the radiograph is usually where?

A

In the furcation

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59
Q

Most common medication for pulpectomy/pulpotomy in kids?

A

FORMOCRESOL - bc CaOH causes resorption in primary teeth

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60
Q

Little girl has ALL, had radiolucency in furcation of primary 2nd molar. What is the treatment?
• Extraction
• Pulpotomy
• Pulpectomy

A

• Pulpectomy

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61
Q

The best method to test newly erupted primary teeth –

A

percussion (most reliable)

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62
Q

Least reliable test on newly erupted primary primary teeth

A

EPT

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63
Q

7 yr old boy has vital pulp exposure of 1st perm max molar. What do you do for treatment?

A

Pulpotomy

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64
Q

Child had caries exposure on primary 1st molar…. what to do?

A

Pulpotomy

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65
Q

A 7-year-old patient fractured the right central incisor 3 hours ago. A clinical examination reveals a 2-mm exposure of a “bleeding
pulp.” The treatment-of-choice is
A. pulpectomy and apexification.
B. pulpotomy with calcium hydroxide.
C. direct pulp cap with calcium hydroxide.
D. one-appointment root canal treatment

A

A. pulpectomy and apexification.

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66
Q

Pulpectomy in primary teeth with open apex

A

ZOE

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67
Q

Apexification

A

non-vital teeth, MTA

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68
Q

You did a pulpotomy in a 7 yr old’s pulp exposed decayed tooth #30, why?

A

To allow completion of root formation (apexogenesis)

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69
Q

During apexiogenesis, all of the above with the root except:
root lengthening, root widening, root apex closure, root
revasulcatization

A

root

revasulcatization

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70
Q

Why would you do a pulpotomy in a mandibular first molar of a 7-year-old?

A

To continue physiologic root development

apexogenesis

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71
Q

Indications for apicoectomy:

A

failed existing RCT that can’t be re-treated
persistent periradicular pathosis after endo
periradicular pathosis that enlarged after endo
uncleanable apical portion
overextension of obturation material

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72
Q

Periapical lesion biopsied after apicoectomy of RCT treated tooth, tooth still sensitive tooth, with neutrophils, plasma cells,
nonkeratanized stratified epithelium (islands of), and fibrous connective tissue → abscess, granuloma, cyst

A

granuloma

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73
Q

There is a study that shows there is extraradicular plaque in an infected tooth. What does this mean that the dentist might need to
do: mechanochemical irrigation and debridement of the canal vs doing surgical endo (apicoectomy)

A

mechanochemical irrigation and debridement of the canal

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74
Q

Extraradicular biofilm theory recommends endo with:

A

Crown down, debridement, Ca(OH)2 therapy? (irrigate and debride)

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75
Q

Patient (6 yo), the treatment of choice for a necrotic pulp on permanent first molar would be:

  1. Apexification
  2. Apexogenesis
  3. Root Canal Treatment
A
  1. Apexification
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76
Q

Why you perform apexification

A

(non-vital)

When you have necrosis on an open apex tooth

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77
Q

Definition of apexification:

A

The process of induced root development or apical closure of the root by hard tissue deposition
(NONVITAL)

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78
Q

Tx for traumatic pulp exposure on max incisor that root has not completed formation?

A

Apexogenesis

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79
Q

Irreversible pulpitis with open apex –

A

apexification

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80
Q

Six months ago you did a RCT on central with an open apex (young pt). You place calcium hydroxide in canal and waited the 6
months. You open the canal but can still pass #70 file through the apex. What would you do?
Calcium hydroxide
Zinc oxide eugenol
Gutta percha

A

Calcium hydroxide

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81
Q 
Pt is 13 years old and has a non-vital maxillary central. The apex is still open what do you do?
A. Apexogenesis
B. Apexification
C. Pulpectomy
D. Nothing
A

Apexification

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82
Q 
Pulp is vital, pt’s a 8 year old. Apex is open. What do you do?
A. Apexification
B. Apicoectomy
C. Pulpectomy
D. calcium hydroxide pulpotomy.
A

D. calcium hydroxide pulpotomy.

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83
Q

Why are traumatized primary incisors discolored?

A

Pulpal Necrosis & Pulpal Bleeding

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84
Q

Reason for failure of replantation of avulsed tooth: external resorption or internal resorption

A

external resorption

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85
Q

Splinting in avulsion, hz root fractures, extrusion

A

Avulsion: 7-10 days, flexible
Hz root frx: rigid splint
Extrusion: 2-3 weeks

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86
Q

Splints are for

A

patient comfort

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87
Q

Main factor in success of replantation

A

time

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88
Q

Why would an implanted avulsed tooth fail?

a) the dentist curettage the socket
b) too much extra oral time
c) the dentist clean the root surface
d) failure to place the tooth in the solution

A

b) too much extra oral time

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89
Q

Before 15 min, what is success rate of avulsed tooth? At 30 min?

A

90% success rate, by 30 minè success rate decreases to 50%

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90
Q

If tooth is taken out, rinse with water Y or N

A

No!

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91
Q

How long do you splint after tooth has been avulsed?

A

7-10 days

1-2 weeks

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92
Q

Splinting avulsed teeth for how many days?

A

7-10 days

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93
Q

What is best storage media for avulsed tooth?

A

HANK (HBSS: Hank’s balanced salt solution, Na, K, Ca + glucose)

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94
Q

If tooth has a closed apex, immerse tooth in

A

2.4% sodium fluoride solution with what pH & for how many minutes? pH of 5.5 for 20
min

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95
Q

Avulsed tooth, extraoral time was less than 60 mins, primary tooth, what you do?

A

Don’t put it back.

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96
Q

tooth has open apex, and it gets avulsed, how you close it?

A

You use MTA.

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97
Q

CaOH tx for an avulsed tooth?

A

no

98
Q

Intrusion tx of permanent teeth?

A

Reposition and splint

99
Q

Which is more damaging to the PDL? Extrusion, intrusion, lateral luxation, avulsion

A

intrusion

100
Q

Patient intrudes mature maxillary incisor. Permanent tooth trauma due to deep intrusion causes

A

PULP NECROSIS & conventional

RCT is necessary.

101
Q

Intrusive trauma/ pulp necrosis, what percent is rate of pulp necrosis?

A

96%

102
Q

Luxated tooth, negative EPT, why?

A

disruption of nerves to tooth

103
Q

Pt. has dark permanent lateral incisor. What is the cause? Tetracycline, damage to primary tooth at age five, damage to permanent
lateral

A

damage to permanent

lateral

104
Q

What’s the worst thing you can do to a tooth you plan to re-implant right before you do so?

A

Scrape the tooth with a currette

105
Q

Primary purpose of sodium hypochlorite?

A

Dissolve necrotic tissue

***Sodium hypochlorite (NaOCl) is NOT a chelator, (it dissolves organic tissue)

106
Q

Sodium hypochlorite is used for everything except?

A

Chelation

- Bleach is not a chelating agent

107
Q

What is the job of Ca(OH)2 during a root canal procedure:

A

Intracanal medicament

108
Q

Which material is least cytotoxic for perforation repair?

A

MTA

109
Q

Which is a chelator/chelating agent for endo? EDTA, sodium hypochlorite, etc.

A
  • EDTA is chelator, removes SMEAR LAYER and inorganic material.
  • NaOCl (sodium hypochlorite) only dissolves organic material, only disinfects & is most common irrigant.
110
Q

Percentage of EDTA:

A

17%

111
Q

What is the function of EDTA?

A

remove inorganic material & smear layer

112
Q

Which one is correct about EDTA?

A

It’s a chelating agent.

113
Q

Contraidication for Ca(OH)2?

A

Pulp symptomatic for last month

114
Q

PARL seen on asymptomatic tooth. When opened, the canal is calcified. What do you do? do nothing, refer to endodontist, place
EDTA

A

place

EDTA

115
Q

Internal resorption left untreated can lead to?

A

Pink tooth

116
Q

What causes “Pink Tooth of Mummery”?

A

internal resorption

117
Q

Treatment for internal resorption:

A

RCT

118
Q

Internal resorption shows all BUT:
radiograph is symmetrical with the pulp space
can resorb all the way to the PDL
a treatment option is observe until resorption stops
resorbed to create pink tooth

A

a treatment option is observe until resorption stops

119
Q

When a tooth is ankylosed, what type of resorption?

A

replacement resorption

120
Q

When you replant teeth, what will happen?

A

Ankylosis (will not say that) – replacement bone formation

121
Q

The treatment-of-choice for an inflammatory external root resorption on a non-vital tooth is which of the following?
A. Extraction
B. Surgical curettage of the affected tissue
C. Pulpectomy and obturation with gutta-percha and sealer
D. Removal of the necrotic pulp and placement of calcium hydroxide
E.Observation since it is a self-limiting process

A

D. Removal of the necrotic pulp and placement of calcium hydroxide
- Do Ca(OH)2 every 3 months until PDL is healthy, then complete RCT

122
Q

When a reimplanted tooth presents external resorption, what is the treatment?:

A 
JUST OBTURATE (instrument) AND PLACE CaOH
(other options are RCT w/ gutta percha & extraction)
123
Q

Which of the following is not a property of gutta-percha? radiopacity, Biocompatibility, Antibacterial, Adaptation

A

Adaptation

- Needs sealer to adapt to tooth well

124
Q

Gutta percha has the following advantages EXCEPT:

  1. easy manipulation
  2. Adapts to tooth surface
  3. Anti- microbial
  4. Biocompatible
A
  1. Adapts to tooth surface
125
Q

What is the NOT an advantage of stainless steel files?

  1. More flexible
  2. Less chance for breaking
  3. Allows the file to be centered in canal
  4. Aids depth penetration in the canal
A
  1. Allows the file to be centered in canal
126
Q

All are advantages of using nickel titanium endo files over regular steel files except?

a. flexibility
b. bending memory
c. direction of the flutes

A

c. direction of the flutes

127
Q

What is the weakness of NiTi files vs regular SS files? strength, flexibility… and some other choices

A

strength

128
Q

Which of the following is not an advantage of Ni-Ti over stainless steel file?

a. Maintains the shape of canal,
b. flexibility,
c. resistance to fracture

A

c. resistance to fracture

129
Q

most common cause of rct failure

A

poorly debrided

130
Q

Which case has the best prognosis?
• perforation in extneral resorption
• perforation in internal resorption
• extruded gutta percha

A

• perforation in internal resorption

131
Q 
Least likely to result in endo failure?
overfilling with gutta percha
inadequate either obturation or cleaning and shaping
lateral root resorption
perforating internal resorption
A

perforating internal resorption

132
Q 
Cause of grey tooth
• Blood products in the dentinal tubules
• internal resorption
• external resorption
• calcified canal
A

• Blood products in the dentinal tubules

133
Q

most common cells in necrotic pulp

A

PMN

134
Q

Root canal failed on upper canine b/c

A

lack of seal

135
Q

RCT done 1.5 yrs ago, now radiolucency and fistula -

A

incomplete RCT

136
Q

Pt comes in for a RCT on a non-vital tooth with 1 mm apical lucency. 5 mo later, comes back with 5 mm lucency, why?- Improperly
done endo, another canal present, osteosarcoma, carcinoma.

A

improperly done endo, retreat

137
Q 
Incomplete removal of bacteria, pulp debris, and dentinal shavings is commonly caused by failure to irrigate thoroughly. Another
reason is failure to:
A. use broaches.
B. use a chelating agent.
C. obtain a straight line access.
D. use Gates-Glidden burs.
A

C. obtain a straight line access.

138
Q

Least likely cause for failed RCT

a. GP beyond apex
b. clean & shaping no good
c. obturation no good

A

a. GP beyond apex

139
Q

Reason for failed endo?
Seal 2mm away from apex
Bacterial infection
RCT sealer beyond apex

A

Bacterial infection

140
Q

Endo file breaks when you are at 15 file, what do you do?

A

Retrieve or Refer to endodontist.

141
Q

You separate an endo file 3mm from the apex and obturate above it… which case will show the best prognosis?

a. vital pulp w/ no periapical lesion
b. vital pulp wI periapical lesion
c. necrotic pulp wI no periapical lesion
d. necrotic pulp wI periapical lesion

A

a. vital pulp w/ no periapical lesion

142
Q

You being the best doctor in the world, you broke a 5mm dental instrument in a canal during RCT procedure, what’s the best thing
to do? Tell the patient what happened, and refer her to an endodontist, take a picture and only tell patient if you see
the instrument in there, re-schedule patient to continue with RCT, Put a watch on it

A

Tell the patient what happened, and refer her to an endodontist,

143
Q

Which has worst prognosis? File fracture, transportation, perforation through furcation

A

perforation through furcation

144
Q

During root canal you notice you left debris in the canal most likely due to lack of use of which? Gates burs, broaches, chelating
agents, irrigant, etc

A

chelating

agents

145
Q

J radiolucency

A

vertical fracture

146
Q

Most common causes of vertical root frx:

A

In endo tx’d teeth: excessive lateral condensation of GP

• In vital teeth: physical trauma

147
Q

Hz root fracture more common in

A

anteriors

148
Q

Patient comes back few months after RCT & crown with pain upon biting, what happened? cracked tooth, hypersensitivity

A

cracked tooth,

149
Q

Pt has pain 1 month after cementing a crown on a tooth with RCT + post. Pain has been present for several days esp during biting
and cold:

A

vertical root fracture

150
Q

Pt has crown cemented 2 weeks ago & is sensitive to pressure and cold, why?

A

Occlusal trauma

151
Q

RCT in vertical root fracture?

A

no

- vertical root fracture = non-restorable tooth

152
Q

Vertical Root Fracture is most likely found?

A

Mand posteriors

153
Q

Most common tooth associated w/ cracked tooth syndrome:

A

Mandibular 2nd molars

- followed by mandibular 1st molars and maxillary PM are the most commonly affected teeth.

154
Q

What teeth most likely to have crown/root fracture … max anteriors, mand anterior, max posteriors, mand posteriors

A

mand posteriors

155
Q

Which tooth is least likely to fracture: mx premolar, mx molar, md premolar, md molar?

A

mx molar

156
Q

Cracked tooth with no pulpal involvement, what is the treatment? Endo, extracoronal restoration, occlusion reduction, amalgam
with adhesive

A

extracoronal restoration,

157
Q

What causes most vertical root fractures during RCT?

A

Condensation of gutta percha

158
Q

Best indicator of vertical root fracture -

A

isolated deep pocket depth

159
Q

Which allows the enitre tooth tooth to light up under transillumination? Craze lines, cracked tooth, crown & root fracture,
separated tooth, etc)

A
  • TRANSILLUMINATION: shows cracks. Whole tooth = craze line
160
Q

When does transillumiator show evenly through tooth: craze line, crack, fracture from crown to root:

A

Craze line

161
Q 
Which will show up on transillumination best?
Cracked tooth
Fractured cusp
Vertical root fracture
Craze line
A

Cracked tooth

162
Q

Vertical root fractures are also called cracked teeth. The prognosis of cracked teeth varies with extent and depth of crack.

a. Both statements are true
b. Both statements are false.
c. First statement is true, second is false.
d. First statement is false, second is true.

A

a. Both statements are true

163
Q

If 2 cavities were thought to be two separate fillings but upon exam it was a crack through the isthmus. What do we tx this
symptomless crack with?

A

Observe

164
Q

Tooth w/ horizontal root fracture

A

Reduce & immobilize

165
Q 
How do you first tx a horizontal root fracture?
Immobilize the segments
Rct
Splint
CaOH
A

Splint

166
Q

Apical horiziontal root fracture & no pain, what do you do? Rct, scaling, RCT if tested nonvital, monitor 1 year

A

RCT if tested nonvital,

167
Q

Horizontal rooth fracture:

A

take multiple vertical angulated xrays

168
Q

Boy has horizontal root fracture in apical 3rd, no symptoms, no pain or mobility, what tx? Monitor, RCT, extract, pulpotomy, splint

A

Monitor

169
Q

A maxillary central incisor of an adult patient is traumatized in an accident. The tooth is slightly tender to percussion, is in good
alignment, and responds normally to pulp vitality tests. Radiographic examination shows a horizontal fracture of the apical third of the root.
The best treatment is which of the following?
A. Root canal treatment
B. Splint and re-evaluate the tooth for pulpal vitality at a later time
C. Apexification
D. Apicoectomy to remove the fractured apical section of the root followed by root canal treatment

A

B. Splint and re-evaluate the tooth for pulpal vitality at a later time

170
Q

Worst prognosis for RCT – ledge formation, vertical fracture during obturation, instrument gets stuck in apical 1/3

A

vertical fracture during obturation

171
Q

Fracture at apical 1/3, how long do you splint – 7-10 days, 2-3 weeks, 4-6 weeks

A

4-6 weeks

172
Q

Nonvital after a fracture?

A

Reevaluate at a later time

173
Q

Tooth #30 has huge MOD amalgam that is deep. It hurts pt when he eats french bread. What is the cause?

A

Root fracture

174
Q

Patient has a line of separation coronoapical, the tooth is asymptomatic and it only hurts when patient eats French bread. What
should you do?

A

Ext only if moveable pieces. If asymptomatic & not moveable –> fair prognosis –> RCT
- separation of coronoapical means vertical fracture (they won’t say vertical fracture on the test)

175
Q

Days after placed an MOD amalgam, pt present pain in biting and cold:

A

check occlusion.

176
Q

How many canals do you expect in primary M2?

A

4

177
Q

What is the shape of the access of mandibular 1st molar?
A. Square
B. Trapezoid

A

Trapezoid

178
Q

Maxillary 1st molar access opening -

A

triangular

179
Q

Premolar most likely to have 3 canals?

A

Max 1st

180
Q

Mx central incisor access

A

trinagular

181
Q

Why do you do triangular access on incisors (ex. max central incisor?)

a. to help with straight line access
b. help expose pulp horn
c. to follow the shape of the crown

A

b. help expose pulp horn

182
Q

Most critical for pulpal protection is?

A

Remaining dentin thickness (2mm)

183
Q

What will not regenerate after RCT: dentin formation, cementum, PDL, alveolar bone

A

dentin formation

184
Q

Each of the following can occur as a result of successful RCT tx except what?

A

formation of reparative dentin

185
Q

Pt with an RCT in a molar tooth, after one year a cyst form, the tooth was extracted, after another year the cyst was bigger what
happened?

A

Bad endo, the dentist did not curettage well when the extraction was done

186
Q

Taurodontism has enlarged pulp chamber in which direction? apical, occlusal or apical AND occlusal

A

apical
body of the tooth and pulp chamber is enlarged
vertically at the expense of the roots

187
Q 
Which of the following tests is the least useful in
endodontic diagnosis of children?
A. Percussion
B. Palpation
C. Electric pulp test
D. Cold test
A

C. Electric pulp test
Electric pulp test. Until apical closure occurs,
teeth do not respond normally to electric pulp
testing. In addition, a traumatic injury may
temporarily alter the conduction capability of
nerve endings and/or sensory receptors in the
pulp. A patient with a vital pulp may not
experience any sensation right after trauma.

188
Q

Irreversible pulpitis pain in which of the
following sites is most likely to radiate to the
ear?
A. Maxillary premolar
B. Maxillary molar
C. Mandibular premolar
D. Mandibular molar

A

D. Mandibular molar
Mandibular molar. The perception of pain in
one part of the body that is distant from the actual
source of the pain is known as referred pain.
Teeth may refer pain to other areas of the head
and neck. Referred pain is usually provoked by
stimulation of pulpal C-fibers, the slowconducting
nerves that, when stimulated, cause
an intense, dull, slow pain. It always radiates to
the ipsilateral side. Posterior teeth may refer pain
to the opposite arch or periauricular area.
Mandibular posterior teeth tend to transmit
referred pain to the periauricular area more often
than do the maxillary posterior teeth.

189
Q
  1. Which of the following diagnostic criteria is least
    reliable in the assessment of the pulpal status of
    the primary dentition?
    A. Swelling
    B. Electric pulp test
    C. Spontaneous pain
    D. Internal resorption
A

B. Electric pulp test
Electric pulp test. The relatively late appearance
of A fibers in the pulp may help to explain why
the electric pulp test tends to be unreliable in
young teeth, since A fibers are more easily
electrically stimulated than C fibers. Accuracy of
pulp testing also depends on the patient’s ability
to describe how the tooth reacts to stimuli.
Clinicians must rely on experience, radiographs,
clinical signs or symptoms, and their knowledge
of the healing process to assess pulp vitality of
young patients.

190
Q 
Which of the following can be viewed on a
conventional radiograph?
A. Buccal curvature of roots
B. Gingival fibers
C. Calcification of canals
D. Periodontal ligament
A

C. Calcification of canals. Buccal curvature cannot
be seen from the conventional radiographs.
Gingival fibers and the periodontal ligament,
being connective tissues, are radiolucent
radiographically.

191
Q

Which of the following most likely applies to a
cracked tooth?
A. The direction of the crack usually extends
mesiodistally.
B. The direction of the crack usually extends
faciolingually.
C. Radiographic exam is the best way to detect it.
D. A and C only.
E. B and C only.

A

A. The direction of the crack usually extends
mesiodistally. Cracks extend deep into the
dentin and are usually propagated mesiallydistally.
in posterior teeth, often in the region of
the marginal ridge. Dyes and transillumination
are very helpful in the visualization of cracks.
Unfortunately, it is often impossible to determine
how extensive a crack is until the tooth is
extracted.

192
Q 
Which is the most likely to cause pulp necrosis?
A. Subluxation
B. Extrusion
C. Avulsion
D. Concussion
A

C. Avulsion. To have pulp space infection, the
pulp must first become necrotic. This will occur
in a fairly serious injury in which displacement of
the tooth results in severing of the apical blood
vessels.

193
Q
  1. Which of the following statement(s) is(are) true
    regarding treatment of a tooth presenting with a
    sinus tract?
    A. Treat with conventional root canal therapy.
    B. Antibiotics are not needed.
    C. The sinus tract should heal in 2 to 4 weeks after
    conventional root canal therapy.
    D. If the tract persists post-root canal therapy, do
    root-end surgery with root-end filling.
    E. All of the above choices are true.
A

E. All of the choices are true. Suppurative apical
periodontitis: continuously or intermittently
draining sinus tract, usually drains into the oral
mucosa. The exudate can also drain through
the gingival sulcus of the involved tooth,
mimicking a periodontal lesion with a “pocket.”
However, this is not a true periodontal pocket
because there is not a complete detachment
of connective tissue from the root surface. It
should be treated with conventional root canal
therapy. Antibiotics are not needed, since the
infection is localized and draining. If the tract
does not heal within a few weeks, root-end
surgery may be required. If left untreated,
however, it may become covered with an
epithelial lining and become a true periodontal
pocket.

194
Q
  1. Features of focal sclerosing osteomyelitis often
    include:
    A. A nonvital pulp test.
    B. A history of recent restoration of the tooth in
    question.
    C. A radiolucent lesion which, in time, becomes
    radiopaque.
    D. None of the choices is true.
A

B. A history of recent restoration of the tooth in
question. Focal sclerosing osteomyelitis (FSO)
consists of a localized, usually uniform zone of
increased radiopacity adjacent to the apex of a
tooth that exhibits a thickened periodontal
ligament space or an apical inflammatory lesion.
The size of the lesions usually measure less than
1 cm in diameter. There is no radiolucent halo
surrounding this type of lesion. The osteitis
microscopically appears as a mass of dense
sclerotic bone.
FSO is most often found in patients younger
than 20 years of age, around the apices of
mandibular teeth (most commonly molars) with
large carious lesions and chronically inflamed
pulps or with recent restorations. Most sources
agree that the associated tooth may or may not
be vital.
Gender is not a predisposing factor. FSO can
be asymptomatic or the patient can experience
mild pain, depending on the cause. FSO is
usually discovered upon radiographic analysis. It
represents a chronic, low-grade inflammation.

195
Q

Once the root canal is obturated, what usually
happens to the organism that had previously
entered periradicular tissues from the canal?
A. They persist and stimulate formulation of a
granuloma.
B. They are eliminated by the natural defenses of the
body.
C. They reenter and reinfect the sterile canal unless
root-end surgery is performed.
D. They will have been eliminated by various
medicaments that were used in the root canal.

A

B. They are eliminated by the natural defenses of the
body. Obturation prevents coronal leakage and
bacterial contamination and seals the remaining
irritants in the canal. After root canal obturation,
the remaining bacteria should have lost their
source of nutrition, becoming susceptible to the
body’s immune system.

196
Q
  1. The major objectives of access preparation
    include all of the following except which one?
    A. The attainment of direct, straight-line access to
    canal orifices.
    B. The confirmation of clinical diagnosis.
    C. The conservation of tooth structure.
    D. The attainment of direct, straight-line access to
    the apical portion of the root.
A

B. The confirmation of clinical diagnosis.
Confirmation of clinical diagnosis should be made
before treatment is rendered. Access is the first
and arguably the most important phase of
nonsurgical root canal therapy. The objectives are:
(1) to achieve straight-line access to the apical
foramen or curvature of the canal, (2) to locate all
root canal orifices, and (3) to conserve sound tooth
structure.

197
Q

Which of the following best describes the
anesthetic effects of a posterior superior
alveolar nerve block?
A. Pulpal anesthesia of the maxillary second and
third molars.
B. Pulpal anesthesia of the maxillary first molar.
C. Pulpal anesthesia of the maxillary first and second
premolars.
D. Pulpal anesthesia of the second premolar.

A

A. Pulpal anesthesia of the maxillary second and
third molars. Posterior superior alveolar nerve
block anesthetizes the entire second and third
maxillary molars; the first maxillary molar fully
anesthetized in about 70% of patients and
partially anesthetized (except for mesiobuccal
root) in about 30%. This block is highly effective
but carries significant risk of hematoma, so
frequent aspiration during injection is crucial

198
Q

Which one of the following cannot be observed
on a conventional radiograph?
A. Canal calcification of tooth #15.
B. Buccal curvature of the mesial root of tooth #30.
C. Type of canals of tooth #21.
D. Open apex of tooth #8.

A

B. Buccal curvature of the mesial root of tooth #30.
Radiographs provide a two-dimensional, mesialdistal
view of a tooth. The buccal-lingual aspect
of a tooth cannot be fully appreciated. Curvatures
buccal or lingual are often not appreciated. Canal
calcifications can be seen as relatively
radiopaque obliterations of the pulp chamber
and canal space. Tooth #21 is a mandibular
premolar. The radiograph can give telling clues
as to the anatomy, be it one or two canals. A
canal that suddenly disappears midroot or
appears off-center is often indicative of two
canals. Open apices are often clearly visualized
with radiographs.

199
Q

The indications for periradicular surgery
include all of the following except which one?
A. Procedural accidents during previous nonsurgical
endodontic treatment.
B. Irretrievable separated files in the canals.
C. Failed nonsurgical endodontic treatment and
persisting radiolucency.
D. Treatment for a nonrestorable tooth.

A

D. Treatment for a nonrestorable tooth. Perpetuation
of apical inflammation or infection after
nonsurgical root canal therapy is often due to
poorly obturated canals, tissues left in the canal,
broken instruments, procedural accidents during
treatment, or remnants of necrotic tissue in
accessory canals. The removal of the apical
segment of the tooth via root-end surgery usually removes the nidus of infection. Nonrestorable
teeth should be extracted.

200
Q 
14. Which of the following teeth has the most
consistent number of canal(s)?
A. Mandibular incisor
B. Mandibular canine
C. Maxillary canine
D. Mandibular premolar
A

C. Maxillary canine. The percentage of one canal in
maxillary canines has been found in some
studies to be between 97% and 100%, making it
one of the most consistent anatomical teeth in
the mouth.

201
Q

Which is not a property of sodium hypochlorite
(NaOCl)?
A. Chelation
B. Tissue dissolution at higher concentrations
C. Microbicidal activity
D. Flotation of debris and lubrication

A

A. Chelation. Sodium hypochlorite is the most
widely used irrigant and has effectively aided
canal preparation for years. NaOCl is a good
tissue solvent as well as having antimicrobial
effect. It acts as a lubricant for root canal
instrumentation. It is toxic to vital tissue, so always
use a rubber dam. Hypochlorite’s antibacterial
action is based upon its effects on the bacterial
cell wall. Once the cell wall is disrupted, the vital
contents of the bacteria are released. The
bacterial membrane and intracellular associated
functions cease. Sodium hypochlorite is an
effective necrotic tissue solvent. NaOCl remains
the irrigating solution of choice because it fulfills
all the above requirements.

202
Q 
Initial instrumentation in endodontic treatment
is done to the level of the \_\_\_\_\_.
A. Radiographic apex
B. Dentinoenamel junction
C. Cementodentinal junction
D. Cementopulpal junction
A

C. Cementodentinal junction. At the apex, or
bottom of the tooth, the canal narrows. This
narrowing is the cementodentinal junction (CDJ)
or the apical constriction. This narrow spot
provides a natural stop for debris, irrigation and
filling materials from being forced into the
periapical tissue. Most dentists will work to clean
the canal down to this point in their root canal
procedures.

203
Q
  1. While performing nonsurgical endodontic
    therapy you detect a ledge. What should you do?
    A. Use a smaller instrument and get by the ledge.
    B. Fill as far as you have reamed.
    C. Use a small, round bur and remove the ledge.
    D. Continue working gently with larger files to
    remove the ledge.
A

A. Use a smaller instrument and get by the ledge.
Ledges can sometimes be bypassed; the canal
coronal to the ledge must be sufficiently
straightened to allow a file to operate effectively.
This may be achieved by anticurvature filing (file
away from the curve). Precurve the file severely
at the tip and use it to probe gently past the
ledge. Otherwise, clean to the ledge and fill it,
but you must warn the patient of a poorer
prognosis.

204
Q 
18. Which perforation location has the best
prognosis?
A. Coronal third of root
B. Apical third of root
C. Chamber floor
D. Middle third of root
A

B. Apical third of root. Apical perforations occur
through the apical foramen or the body of the
root (a perforated new canal). In general, the
more subcrestally located the lesion, the better
the prognosis. However, all perforations have an
inherently worsened prognosis.

205
Q
  1. Which of the following statements best describes
    treatment options for a separated instrument at
    the initial stage of cleaning and shaping?
    A. Immediate attempt to remove the instrument.
    B. Stop canal instrumentation, do not attempt
    removal, and obturate.
    C. Attempt to bypass the obstructed instrument.
    D. Both A and C are options.
A

D. Both A and C are options. There are basically
three approaches for the treatment of separated
instruments: (1) attempt to remove the
instrument, (2) attempt to bypass it, and (3) prepare
and obturate to the segment. Using a small
file and using the guidelines for negotiating a
ledge, attempt to bypass the separated instrument.
If this is successful, broaches or Hedstrom
files are used to try to grasp and remove the
segment. Then the canal is cleaned, shaped, and
obturated to its new working length. If the
instrument cannot be bypassed, preparation and obturation should be performed to the coronal
level of the fragment.

206
Q 
Which of the following is the most significant
cause of ledge formation?
A. Infection
B. Remaining debris within the canal
C. No straight-line access
A

C. No straight-line access. After the orifice has been
found, the clinician must decide if straight-line
access has been achieved. Unnecessary deflection
of the file can result in numerous consequences
related to loss of instrument control. Attempts to
clean and shape without straight-line access often
lead to procedural errors such as ledging,
transportation, and zipping.

207
Q

A classic teardrop-shaped periradicular lesion
on a radiograph can be indicative of a vertical
root fracture. The prognosis of a vertical root
fracture is hopeless, and the tooth should be
extracted.
A. First statement is true, second is false.
B. First statement is false, second is true.
C. Both statements are true.
D. Both statements are false.

A

C. Both statements are true. Often the radiographic
interpretation of a vertical root fracture is the
pattern of bone loss occurring in a teardropshaped,
J-shaped, or halolike radiolucency, with
the bone loss originating apically and progressing
coronally up one side of the root. Because
vertical root fractures are susceptible to
microleakage and because of their compromised
internal structure, they have a poor
prognosis and should be extracted.

208
Q

The 02 taper on hand K-files is _____.
A. 0.2-mm increase in diameter per 1-mm increase
in length
B. 0.02-mm increase in diameter per 1-mm increase
in length
C. 0.2-mm increase in diameter per 2-mm increase
in length
D. 0.02-mm increase in diameter per 2-mm increase
in length

A

B. 0.02-mm increase in diameter per 1-mm
increase in length. Taper is the amount the file
diameter increases each millimeter from the tip
toward the handle. For a 0.02 taper file with 16-
mm working surface, its diameter at the tip (D0)
plus 0.32 mm (i.e., for a No. 8 file, it’s 0.08 + 16 ×
0.02 = 0.40) should be equal to D16.

209
Q 
How should a vital second permanent molar
with a 2.0-mm exposure on a 12-year-old patient
be treated?
A. Apexification
B. Direct pulp capping
C. Indirect pulp capping
D. Extract
E. Apexogenesis
A

A. Apexification. Induces further root development
in a pulpless tooth; stimulates the formation of a
hard substance at the apex so as to allow
obturation of the root canal space. 2.0-mm pulp
exposure is too big to perform vital pulp therapy.
Pulpotomy should not be performed on permanent
teeth (unless apexogenesis) because it
causes calcification of the root canal system.

210
Q
  1. At what stage is endodontic treatment
    considered complete?
    A. When a temporary restoration is placed and the
    rubber dam removed.
    B. When canals are seared off and plugged.
    C. When the coronal restoration is completed.
    D. When the patient is asymptomatic.
A

C. When the coronal restoration is completed.
After root canal therapy, the canals inside the
roots have been cleaned and permanently
sealed. However, there is a temporary filling in
the outer surface of the tooth. The patient must
be told that they need a permanent filling or
crown for the tooth. This is very important for the
protection of the tooth against fracture or
reinfection of the root canal.

211
Q

A patient complains of recent severe pain to
percussion of a tooth. The most likely cause is
_____.
A. Acute periradicular periodontitis
B. Chronic periradicular periodontitis
C. Reversible pulpitis
D. Irreversible pulpitis

A

A. Acute apical (periradicular) periodontitis (AAP):
characterized by pain, commonly triggered by
chewing or percussion. AAP alone is not indicative
of irreversible pulpitis. It indicates that apical
tissues are irritated, which may be associated with
an otherwise vital pulp.

212
Q

Which of the following statements regarding
post preparation is incorrect?
A. The primary purpose of the post is to retain a
core in a tooth with extensive loss of coronal
structure.
B. The need for a post is dictated by the amount of
remaining coronal tooth structure.
C. Posts reinforce the tooth and help to prevent
vertical fractures.
D. At least 4 to 5 mm of remaining gutta-percha
after post space preparation is recommended.

A

C. The most important part of the restored tooth is
the tooth itself. No combination of restorative
materials can substitute for tooth structure.
Posts do not reinforce the tooth but, rather,
further weaken it by additional removal of
dentin and by creating stress that predisposes to
root fracture.

213
Q
  1. Prolonged, unstimulated night pain suggests
    which of the following conditions of the pulp?
    A. Pulpal necrosis
    B. Mild hyperemia
    C. Reversible pulpitis
    D. Periodontal abscess
A

A. Lingering spontaneous pain is evidence of C-fiber
stimulation. Even in degenerating pulps, C fibers
may respond to stimulation. The excitability of C
fibers is less affected by disruption of blood flow
as compared with A fibers. C fibers are often able
to function in hypoxic conditions (e.g., at the early
stage of pulpal necrosis).

214
Q
  1. A nasopalatine duct cyst is located between
    _____.
    A. Two maxillary central incisors
    B. Maxillary central and lateral incisors
    C. Maxillary lateral and canine
    D. Maxillary canine and first premolar
A

A. Nasopalatine duct cyst: a circular radiolucent area
seen as a marked swelling in the region of the
palatine papilla. It is situated mesial to the roots of
the central incisors, at the site of the incisive foramen.
The pulps of the anterior teeth test vital
(whereas a periapical cyst tests nonvital). This is
the most common type of maxillary developmental
cyst. They often remain limited in size and are
asymptomatic; they may become infected and
show a tendency to grow extensively.

215
Q

Severity of the course of a periradicular infec-
tion depends upon the _____.

A. Resistance of the host
B. Virulence of the organisms
C. Number of organisms present
D. Both A and B only
E. All of the choices are true
A

E. A patient’s immune response to a periradicular
infection varies according to the person. The size
and volume of the pulp, the number and quality of
the nerves, and the pulpal vascularity and cellularity
are all unique to the person. The different
virulence of organisms causing the infection may
cause differences in pain experienced, differences
in the amount of orthoclastic activity, etc. Sheer numbers of organisms can influence their
virulence.

216
Q

Informed consent requires that the patient be
advised of the following except for which one?
A. The benefits of endodontic treatment
B. The cost of endodontic treatment
C. The risks of endodontic treatment

A

B. Any notion of moral decision making assumes
that rational agents are involved in making
informed and voluntary decisions. In health care
decisions, our respect for the autonomy of the
patient would, in common parlance, mean that
the patient has the capacity to act intentionally,
with understanding, and without controlling
influences that would mitigate against a free and
voluntary act. It implies knowledge and understanding
of the risks and benefits to treatment. This
principle is the basis for the practice of “informed
consent” in the physician–patient transaction
regarding health care.

217
Q

Which of the following statements best describes
pulpal A-delta fibers when compared to C fibers?
A. Larger unmyelinated nerve fibers with slower
conduction velocities
B. Larger myelinated nerve fibers with faster
conduction velocities
C. Smaller myelinated nerve fibers with slower
conduction velocities
D. Smaller unmyelinated nerve fibers with faster
conduction velocities

A

B. The pulp contains two types of sensory nerve
fibers: myelinated (A fibers) and unmyelinated
(C fibers). A fibers include A-beta and A-delta, of
which A-delta is the majority. A-delta fibers are
principally located in the region of the pulp–
dentin junction, have a sharp pain associated
with them, and respond to relatively low threshold
stimuli. C fibers are probably distributed
throughout the pulp, are associated with a throbbing
pain sensation, and respond to relatively
high threshold stimuli.

218
Q

When compared to the bisecting-angle tech-
nique, the advantages of the paralleling tech-
nique in endodontic radiology include all of the

following except_____.
A. A significant decrease in patient radiation
B. A more accurate image of the tooth’s
dimensions
C. That it is easier to reproduce radiographs at
similar angles to assess healing after treatment
D. The most accurate image of all the tooth’s
dimensions and its relationship to surrounding
anatomic structures

A

A. The paralleling, not right-angle, technique is best
for endodontics. The film is placed parallel to the
long axis of the tooth and the beam placed at a
right angle to the film. The technique allows for the
most accurate and reproducible representation of
tooth size.

219
Q
  1. The primary reason for designing a surgical
    flap with a wide flap base is _____.
    A. To avoid incising over a bony protuberance
    B. To obtain maximum access to the surgical site
    C. To maintain an adequate blood supply to the
    reflected tissue
    D. To aid in complete reflection
A

C. The principles of flap design include the
following: (1) flap design should ensure adequate
blood supply and the base of the flap
should be wider than the apex; (2) reflection of
the flap should adequately expose the operative
field; and (3) flap design should permit atraumatic
closure of the wound.

220
Q 
The apical portion of maxillary lateral incisor
usually curves to the \_\_\_\_\_.
A. Facial
B. Palatal
C. Mesial
D. Distal
A

D. Studies have shown that as many as 50% of the
roots of maxillary lateral teeth were distally dilacerated.
Oversight of the distal direction of root
dilaceration of upper lateral incisors can be a
contributing factor in the failure of endodontic
treatment of these teeth.

221
Q 
Aqueous EDTA is primarily used to \_\_\_\_\_.
A. Dissolve organic matter
B. Dissolve inorganic matter
C. Kill bacteria
D. Prevent sealer from extruding out of the canal space
A

B. EDTA is the chelating solution customarily used
in endodontic treatment. Chelators remove inorganic
components, leaving the organic tissue elements
intact.

222
Q

A noncarious tooth with deep periodontal
pockets that do not involve the apical third of
the root has developed an acute pulpitis. There
is no history of trauma other than a mild
prematurity in lateral excursion. What is the
most likely explanation for the pulpitis?
A. Normal mastication plus toothbrushing has
driven microorganisms deep into tissues with
subsequent pulp involvement at the apex.
B. During a general bacteremia, bacteria settled in
this aggravated pulp and produced an acute
pulpitis.
C. Repeated thermal shock from air and fluids
getting into the deep pockets caused the pulpitis.
D. An accessory pulp canal in the gingival or the
middle third of the root was in contact with the
pockets.

A

D. Periodontal disease can have an effect on the
pulp through dentinal tubules, lateral canals, or
both. Primary periodontal lesions with secondary
endodontic involvement differ from primary
endodontic-secondary periodontic lesions in their
temporal sequence. Primary periodontal problems
have a history of extensive periodontal disease.

223
Q

On a radiograph, the facial root of a maxillary
first premolar would appear distal to the
lingual root if the _____.
A. Vertical angle of the cone was increased
B. Vertical angle of the cone was decreased
C. X-ray head was angled from a distal position
relative to the premolar
D. X-ray head was angled from a mesial position
relative to the premolar

A

D. The buccal object rule [Clark’s rule or “SLOB”
rule (Same Lingual, Opposite Buccal)] is used to
identify the buccal or lingual location of objects
in relation to a reference object. If the image of
the object moves mesially when the x-ray tube is
moved mesially, the object is located on the
lingual. If the image of the object moves distally
when the x-ray tube moves mesially, the object is
located on the buccal (facial).

224
Q
  1. If a canal is ledged during instrumentation, the
    best way to handle the problem is to _____.
    A. Continue instrumenting at the ledge. Although it
    may take some time, you will eventually bore
    your way to patency in the periodontal ligament
    space.
    B. Immediately stop and fill to where the ledge
    begins.
    C. Bind your irrigating needle in the canal and use
    short bursts of irrigant to loosen any debris
    blocking the canal. This will reopen the natural
    canal.
    D. Prebend the tip of a small file, lubricate, and try
    to negotiate around the ledge.
    E. Place citric acid or EDTA in the canal to soften
    the dentin. A small Gates Glidden or other rotary
    can be used to bypass the ledge.
A

D. Ledges can sometimes be bypassed; the canal
coronal to the ledge must be sufficiently straightened
to allow a file to operate effectively. This
may be achieved by anticurvature filing (file away
from the curve). Precurve the file severely at the
tip and use it to probe gently past the ledge.
Otherwise, clean to the ledge and fill; warn the
patient of poorer prognosis.

225
Q

Which of the following factors affects long-term
prognosis of teeth after perforation repair?
A. Size of the defect.
B. Location of the defect.
C. Time elapsed between the perforation and its
repair.
D. All of the choices are true.

A

D. Factors affecting the long-term prognosis of teeth
after perforation repair include the location of the
defect in relation to the crestal bone; the length
of the root trunk; the accessibility for repair; the
size of the defect; the presence or absence of a
periodontal communication to the defect; the
time lapse between perforation and repair; the
sealing ability of the restorative material; and
technical skill. Early recognition and repair
improve the prognosis. Smaller perforations
(< 1 mm) cause less destruction. Subcrestal
lesions, especially those closer to the apex, have
better prognosis.

226
Q

Which of the following statements best
describes treatment options for a separated
instrument (e.g., finger spreader) at the filling
stage of treatment?
A. Immediately attempt to remove the instrument.
B. Do not attempt removal and proceed to
obturate.
C. Attempt to bypass the obstructed instrument.
D. Both A and C are options.

A

B. If an instrument is broken at the filling stage, it is
not necessary to remove or bypass the instrument
because the canal has already been cleaned and
shaped. Prognosis depends largely on the extent of
undebrided material remaining within the canal.
Attempt to obturate as much of the canal as possible.

227
Q

Endodontically treated posterior teeth are more
susceptible to fracture than untreated posterior
teeth. The best explanation for this is _____.
A. Moisture loss
B. Loss of root vitality
C. Plastic deformation of dentin
D. Destruction of the coronal architecture

A

D. Teeth that have been endodontically treated have
lost much of their coronal dentin in the access
formation, irrespective of the pre-endodontic
caries state. This loss of dentin compromises the
internal architecture of the tooth. Less internal tooth structure, combined with the absorption of
external forces (usually occlusal) may exceed the
strength of dentin and result in fracture.
Endodontic treatment and loss of pulp vitality are
no longer thought to desiccate the tooth to the
point of increasing risk of fracture.

228
Q

There is a horizontal root fracture in the mid-
dle third of the root of tooth 10 in an 11-year-
old patient. The tooth is mobile and vital. How

should this be treated?
A. Extract.
B. Pulpectomy immediately and splint.
C. Splint and observe.
D. Do nothing and follow-up in 10 to 14 days.
A

C. When a root fractures horizontally, the coronal
segment is displaced to a varying degree, but
generally the apical segment is not displaced.
Because the apical pulpal circulation is not disrupted,
pulp necrosis in the apical segment
is extremely rare. Pulp necrosis in the coronal segment
results because of its displacement and
occurs in only about 25% of cases. Because 75%
do not lose vitality, emergency treatment involves
repositioning the segments in as close proximity
as possible and splinting the teeth for 2 to 4
weeks. After the splinting period is completed,
follow-up is as with all dental traumatic injuries,
at 3, 6, and 12 months and then yearly thereafter.

229
Q

Which of the following is the best radiographic
technique to identify a suspected horizontal root
fracture in a maxillary anterior central incisor?
A. Multiple Water’s projections
B. Multiple angulated periapical radiographs in
addition to a normal, parallel-angulated,
periapical radiograph
C. A panoramic radiograph
D. A reverse Towne’s projection

A

B. Radiographic examination for root fractures is
extremely important. Because a root fracture is
typically oblique (facial to palatal), one periapical
radiograph may easily miss its presence. It is
imperative to take at least three angled radiographs
(45, 90, 110 degrees) so that in at least
one angulation the radiographic beam will pass
directly through the fracture line and make it visible
on the radiograph.

230
Q

An 8-year-old boy received a traumatic injury to
a maxillary central incisor. One day later, the
tooth failed to respond to electric and thermal
vitality tests. This finding dictates _____.
A. Pulpectomy
B. Apexification
C. Calcium hydroxide pulpotomy
D. Delay for the purpose of re-evaluation

A

D. For decades, controversy has surrounded the
validity of thermal and electric tests on traumatized
teeth. Only generalized impressions may be
gained from these tests subsequent to a traumatic
injury. They are, in reality, sensitivity tests for nerve
function and do not indicate the presence
or absence of blood circulation within the pulp. It
is assumed that subsequent to traumatic injury,
the conduction capability of the nerve endings or
sensory receptors is sufficiently deranged to
inhibit the nerve impulse from an electric or thermal
stimulus. This makes the traumatized tooth
vulnerable to false negative readings from these
tests.
Teeth that give a positive response at the initial
examination cannot be assumed to be healthy or
that they will continue to give a positive response
over time. Teeth that yield a negative response or
no response cannot be assumed to have necrotic
pulps because they may give a positive response
at later follow-up visits. It has been demonstrated
that it may take as long as 9 months for normal
blood flow to return to the coronal pulp of a traumatized,
fully formed tooth. As circulation is
restored, responsiveness to pulp tests returns.

231
Q 
Twisting a triangular wire best describes the
manufacturing process of a \_\_\_\_\_.
A. Reamer
B. Barbed broach
C. Hedström file
D. K-Flex file
A

A. The K-file and K-reamer are the oldest instruments
for cutting and machining dentin. They
have been made from a steel wire that is ground
to a tapered square or triangular cross section
and then twisted to create either a file or a reamer. A file has more flutes per unit length than
does a reamer. The K-FlexTM file is a modification
of the shape of the K-file, with a noncutting tip
design.

232
Q

Direct pulp cap is recommended for teeth with
_____.
A. Carious exposures
B. Mechanical exposures
C. Calcification in the pulp chambers
D. Closed apices more than teeth with open apices

A

B. The indications for a direct pulp cap are (1)
asymptomatic tooth; (2) with little or no hemorrhaging;
(3) small (< 1 mm); and (4) well-isolated
traumatic pulp exposure. It acts to stimulates the
formation of a reparative dentin bridge over the
exposure site and to preserve the underlying pulpal
tissue. It is especially successful in immature teeth.
Failure of direct pulp cap is indicated by (1)
symptoms of pulpitis at any time; and (2) lack of
vital pulp response after several weeks. Failures
result in pulpal necrosis (continual pulpal insult),
calcification of the pulp, or (rarely) internal
resorption.
Direct pulp capping is primarily used on permanent
teeth. (Not used often in primary teeth
because the alkaline pH of calcium hydroxide.) It
can irritate the pulp either mildly or (often)
severely. With severe irritation, it increases the
risk of internal resorption. With primary teeth,
severe resorption is more common; in permanent
teeth, formation of reparative dentin occurs
more often.

233
Q

Which of the following is the treatment of
choice for a 7-year-old child with a nonvital
tooth 30 with buccal sinus tract?
A. Gutta-percha filling
B. Gutta-percha filling followed by root-end surgery
C. Extraction
D. Apexogenesis
E. Apexification

A

E. If an immature tooth is nonvital, the diseased tissue
must be removed via pulpectomy.
Apexification is the treatment of choice.

234
Q

Which of the following is the main side effect of
bleaching an endodontically treated tooth?
A. External cervical resorption
B. Demineralization of tooth structure
C. Gingival inflammation

A

A. Internal bleaching alone causes 3.9% of external
cervical root resorption (also referred to as
peripheral inflammatory root resorption); The
presence of a barrier (base material) between the
root filling material and the internal bleaching
material should be ~4 mm to prevent this
resorption.

235
Q 
What is the safest recommended intracoronal
bleaching chemical?
A. Hydrogen peroxide
B. Sodium perborate
C. Sodium hypochlorite
D. Carbamide peroxide
A

B. Sodium perborate is more easily controlled and
safer than concentrated hydrogen peroxide solutions.
Therefore, it should be the material of
choice for internal bleaching.

236
Q
  1. Pulp capping and pulpotomy can be more suc-
    cessful in newly erupted teeth than in adult

teeth because _____.
A. A greater number of odontoblasts are present
B. Of incomplete development of nerve endings
C. An open apex allows for greater circulation
D. The root is shorter

A

C. In newly erupted teeth, the apical root end has
not fully formed, allowing for greater blood supply
to the tooth. Subsequent pulpal regeneration leads
to greater long-term success.

237
Q

Zinc oxide eugenol is a good temporary restora-
tion because _____.

A. It is less irritating
B. It has increased strength over other restorations
C. It provides a good seal
D. It is inexpensive

A

C. It is the physical and chemical properties of zinc
oxide eugenol that are beneficial in preventing
pulpal injury and in reducing postoperative tooth
sensitivity. Importantly, it provides a good biological
seal; also, its antimicrobial properties enable it
to suppress bacterial growth, thus reducing formation
of toxic metabolites that might result in
pulpal inflammation.

238
Q

During a routine 6-month endodontic treatment
recall evaluation, you note a marked decrease
in the radiographic size of the periradicular
radiolucency. Which of the following is the
most appropriate treatment plan?
A. Extraction.
B. Nonsurgical endodontic retreatment.
C. Recall the patient in another 6 months.
D. Surgical endodontic retreatment.

A

C. When endodontic treatment is done properly,
healing of the periapical lesion usually occurs with
osseous regeneration, which is characterized by
gradual reduction and resolution of the
radiolucency on follow-up radiographs. The rate of
bone formation is slow, and complete resolution
may take longer than the standard 6-month followup,
especially with elderly patients. As long as the radiolucency appears to be resolving as opposed
to enlarging, an extended re-evaluation is in order.

239
Q 
What is the radiographic sign of successful
pulpotomy in a permanent tooth?
A. Open apex
B. That the apex has formed
C. Loss of periradicular lucency
D. No internal resorption
A

B. Pulpotomy is normally not recommended in permanent
teeth unless root development is incomplete.
If incomplete, the calcium hydroxide
pulpotomy is recommended. This is performed in
permanent teeth with immature root development
and with healthy pulp tissue. The success is
indicated when the root apex, if not completely
formed, completes its full development. This
procedure is only done on teeth free of symptoms.

240
Q

Which of the following statements is not true
regarding internal root resorption?
A. It happens rarely in permanent teeth.
B. It appears as an asymmetrical “moth-eaten”
lesion in radiographs.
C. Chronic pulpal inflammation is the primary
cause.
D. Prompt endodontic therapy will stop the
process.

A

B. Internal resorption is most commonly identified
during routine radiographic examination.
Histologically, it appears with chronic pulpitis,
including chronic inflammatory cells, multinucleated
giant cells adjacent to granulation tissue,
and necrotic pulp coronal to resorptive defect.
Only prompt endodontic therapy will stop the
process and prevent further tooth destruction.

241
Q

When would elective endo treatment be contraindicated?

A

Uncontrolled diabetes

242
Q

What disease will alter healing after root canal treatment? HIV or Diabetes

A

Diabetes

NBDE II (12 decks)

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