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NBDE II > ENDO Procedural Complications > Flashcards

ENDO Procedural Complications Flashcards

1
Q

___ is an artificial irregularity created on the surface of the root canal wall that impedes the placement of instruments to the apex

A

ledge

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2
Q

what happens to working length when a ledge is formed?

A

it can no longer be ascertained

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3
Q

radiographically, what might indicated ledge formation?

A
  • instrument or obturation material is short of the apex

- instrument or obturation material no longer follows the true curvature of the root canal

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4
Q

what are 5 reasons ledges occur?

A
  1. lack of straight line access
  2. anatomy of the canal
  3. inadequate irrigation or lubrication
  4. excessive enlargement of curved canal with files
  5. obstruction or the packing of debris in the apical portion of the canal
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5
Q

lack of straight line access can be caused by improper access preparation and can compromise the negotiation of the ___ of a canal through improper ___

A

apical third, coronal flaring

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6
Q

what components of anatomy of the canal can cause ledge formation?

A
  • length (longer canals; want to recapitulate to confirm patency)
  • canal diameter (smaller diameter)
  • degree of curvature (greater degree of curvature; BL curvature is difficult to assess given buccal radiographic exposure)
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7
Q

describe how ledges can be avoided with irrigation and lubrication

A
  • NaOCl is a good irrigant for disinfection and removal of debris, but an additional lubricant is necessary
  • lubricants allow for ease of file insertion, decrease of stress on instruments, and ease of debris removal
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8
Q

___ is the process where files cut dentin toward the outside of the curvature at the apical portion of the root

A

transportation

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9
Q

describe how transportation causes ledging

A
  • the transported tip of the file may gouge into the dentin and create a ledge or perforation outside the original curvature of the canal
  • each successive file size should be used before a greater sized file is attempted (do not jump sizes)
  • flexible files reduce ledge formation
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10
Q

how is ledge formation corrected?

A
  • the canal first must be relocated and renegotiated
  • a precurved (1-2mm apically) small file is helpful to reestablish WL (use plenty of lubrication and use a picking motion)
  • if true canal is located, use a reaming motion and up-and-down movement to maintain the space and debride the canal
  • flaring the access may help improve access to the apical third of the canal
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11
Q

despite all effort, correction of a ledge is difficult because ___

A

instruments and obturating materials tend to be directed into the ledge

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12
Q

if unable to bypass a ledge, what should you do?

A

clean and shape at the “new” WL

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13
Q

successful treatment and prognosis after ledge creation depends on ___

A
  • the extend of debris remaining in the region past the ledge
  • short and clean apical ledges have better prognoses
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14
Q

during ledge formation, the amount of debris remaining in the region past the ledge depends on what?

A

when the ledge formation occurred int he cleaning and shaping process

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15
Q

what should you tell your patient if a ledge forms?

A

inform the pt of the prognosis, and instill the importance of recall and the signs that would indicate failure

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16
Q

what are 3 ways instruments separate?

A
  1. limited flexibility and strength of the instrument
  2. improper use (overuse, excessive force, wrong movement, etc)
  3. manufacturing defects of instruments causing breakage are rare
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17
Q

what are 5 ways to avoid separating instruments?

A
  1. recognize the stress limitations of the instruments being used
  2. continual lubrication of the instrument within the canal
  3. examine the instruments to be placed into the canal
  4. replace files often
  5. do not proceed to larger files until the smaller ones fit loosely within the canal
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18
Q

before separation, steel instruments often exhibit ___

A

fluting distortions, highlighting unwound or twisted regions of the file (signs of fatigue)

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19
Q

how do you check for fatigue of nickel-titanium files?

A

they do not show the same visual signs of fatigue that steel files do, and should therefore be discarded before visual signs occur

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20
Q

how do you treat a canal with a separated instrument?

A
  1. bypass the instrument (same principles as bypassing a ledge)
  2. remove the instrument (usually unsuccessful, and referral to endodontist is necessary)
  3. prepare and obturate the canal to the point of instrument separation (clean to “new” WL, which corresponds to the coronal most aspect of the separated instrument)
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21
Q

successful treatment and prognosis of a separated instrument depends on ___

A
  • extent of debris remaining in the region below the separated instrument
  • prognosis improves if instrument separation occurred during later stages of cleaning and shaping
  • prognosis is poor for teeth where smaller instruments have been separated
  • overall, if instrument separated is managed properly, the prognosis is favorable
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22
Q

what must you tell your patient if a file separates?

A

inform the pt and document history of the separated instrument

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23
Q

when instrument separation has occurred, if the pt has residual symptoms, what should you do?

A

the tooth is best treated surgically (root end resection)

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24
Q

___ is an iatrogenic communication of the tooth with the outside environment

A

perforation

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25
Q

what are the 4 kinds of perforations?

A
  1. coronal perforation
  2. furcal perforation
  3. strip perforation
  4. root perforation
26
Q

what is the cause of a coronal perforation?

A

failure to direct the bur towards the long axis of the tooth during access

27
Q

how can coronal perforation be avoided?

A
  • during access preparation, visualize the long axis of the tooth periodically (loupes or microscope aids, transillumination to visualize pulpal floor, radiographs)
  • in cases of rotated or tilted teeth, misoriented cast cores, or calcified chambers, follow the long axis of the roots carefully
28
Q

furcal perforations usually occur during ___ and should be repaired ___

A
  • the search for canal orifices

- immediately

29
Q

___ perforations involve the furcation side of the coronal root surface

A

strip

30
Q

strip perforations are a result of ___

A

excessive flaring with instruments

31
Q

apical root perforations can be a result of ___

A

canal transportation, resulting in a perforated new canal

32
Q

midroot perforations usually occur after ___

A

ledge formation, when a file is misdirected and creates an artificial canal

33
Q

what are some signs that a perforation has been created?

A
  • hemorrhage
  • sudden pain
  • radiographic evidence
  • apex locator readings (far short of initial file entry’s WL)
  • deviation of a file from its previous course
  • unusually severe postoperative pain
34
Q

describe hemorrhaging that occurs when a perforation has been created

A

perforation into the PDL or bone may cause immediate hemmorhage (bone, being relatively avascular, may cause little hemorrhage)

35
Q

describe the sudden pain that occurs when a perforation has been created

A
  • occurs usually during evaluation of the WL
  • usually the anesthetic used was adequate for access but not for WL determination
  • burning pain or bad taste when NaOCl is used
36
Q

what is the prognosis if the perforation is into the PDL?

A

questionable (be sure to inform pt)

37
Q

what affects the prognosis of a perforation?

A
  1. location
  2. size of defect
  3. timing of perforation
  4. timing of repair
  5. isolation
  6. accessibility of the repair
  7. sealing ability of the restorative material
  8. pt oral hygiene
  9. capabilities of dentist performing the repair
38
Q

what is the prognosis of a perforation if is it located at or above the alveolar bone?

A
  • favorable
  • can be easily repaired with restorative materials (similar to class V lesion)
  • may require flap surgery
39
Q

what is the prognosis of a perforation if it is located below the crestal bone or at the coronal third of the root?

A
  • poor
  • attachment often recedes, usually to the extent of the defect
  • permanent periodontal pocket forms
40
Q

how does the size of the perforation affect ease of repair?

A
  • smaller perforations (<1mm) are more amenable to repair

- cause less tissue destruction when smaller

41
Q

how does timing of the perforation affect prognosis?

A

perforations that occur later in treatment, after complete or partial debridement of the canal, have a better prognosis

42
Q

how does the timing of the repair of a perforation affect prognosis?

A
  • the sooner the perforation is repaired, the better the prognosis
  • minimizes the damage to the periodontal tissues by bacteria, files, and irrigants
  • immediate sealing of defect reduces periodontal breakdown
43
Q

how does isolation affect the prognosis of a perforation?

A

if the tooth was well isolated at the time of the repair, prognosis is more favorable

44
Q

how are coronal perforations treated?

A

refer to an endodontist to locate the canals

45
Q

how are furcal perforations treated?

A
  • usually accessible and able to be repaired nonsurgically

- usually good prognosis if repaired (sealed) immediately

46
Q

how are strip perforations treated?

A
  • rarely accessible

- usual sequelae are inflammation followed by periodontal pocket

47
Q

how are root perforations treated? what is the prognosis?

A
  • prognosis depends on the size and shape of the perforation
  • open apex is difficult to seal and allows for extrusion of sealing materials
  • surgical treatment may be necessary
48
Q

describe follow up of perforations

A
  • perforations should be monitored
  • assess symptoms
  • evaluate radiographs
  • periodontal probing to evaluate periodontal status
49
Q

what is the goal of perforation treatment?

A
  • to clean, shape, and obturate as much of the canal as is accessible
  • avoid using high concentrations of NaOCl because it may inflame the periodontal tissues
50
Q

describe the surgical repair of a perforation

A
  • try to position the apical portion of the defect above the crestal bone
  • orthodontic extrusion
  • flap surgery and crown lengthening is used when the esthetic result is not compromised or if adjacent teeth require perio therapy
  • hemisection
  • root amputation
  • intentional reimplantation is indicated when the defect is inaccessible or when multiple problems exist
51
Q

what is the prognosis of a perforation treated surgically?

A
  • guarded because of increased technical difficulty of procedures
  • remaining roots are often prone to caries, periodontal disease, and vertical root fracture
52
Q

what material is used in nonsurgical internal repair of perforations and why?

A
  • repaired with MTA

- very biocompatible and promotes the deposition of cementumlike material

53
Q

what is the prognosis of a vertical root fracture?

A

poor

54
Q

___ root fracture occur along the long axis of the tooth

A

vertical

55
Q

what are vertical root fractures often associated with?

A
  • severe periodontal pocket in an otherwise periodontially sound dentition
  • sinus tract
  • lateral radiolucency extending to the apical portion of the root fracture
56
Q

how can a vertical root fracture be identified?

A

only with visualization

57
Q

what is often necessary to confirm the presence of a vertical root fracture?

A

visualization is the only way to identify a vertical root fracture, so surgery is often necessary to confirm the fracture

58
Q

what are some ways vertical root fractures occur?

A
  • after cementation of a post

- can be a result of excessive condensation forces during obturation of an underprepared or overprepared canal

59
Q

how can vertical root fractures be avoided?

A
  • appropriate canal preparation

- balanced pressure of condensation forces during obturation

60
Q

how are vertical root fractures treated?

A
  • removal of the involved root in multirooted teeth or extraction
  • extraction if single-rooted

NBDE II (35 decks)

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