ENDO Posttreatment Evaluation

Question 1

___ is a major cause of endodontic failure

Answer 1

• coronal leakage
• more endodontically treated teeth are lost because of restorative factors than because of failure of the root canal treatment itself

Question 2

describe coronal leakage as a major cause of endodontic failure

Answer 2

• after RCT, the internal chambers of the tooth may become reinfected if coronal leakage occurs
• saliva contamination with bacteria and endotoxins can cause endodontic failure, a risk that increases with the duration of saliva exposure

Question 3

do temporary restorations provide protection against occlusal forces?

Answer 3

• not complete protection

- when an immediate restoration is impossible, a bonded temporary restoration at the canal orifice can be used

Question 4

why is it best to place permanent restorations as soon as possible after obturation?

Answer 4

to seal the internal aspect of the tooth from contamination

Question 5

what is the course of action when the root canal space has been grossly recontaminated?

Answer 5

retreatment

Question 6

T or F:

endodontically treated teeth become brittle

Answer 6

• false

- the moisture content of endodontically treated teeth is not reduced even after 10 years, so they do NOT become brittle

Question 7

after endodontic treatment, why do teeth become weakened?

Answer 7

• loss of tooth structure

- loss of marginal ridges is a major contributor to reduced cuspal strength

Question 8

what leads to a higher occurrence of fractures in endodontically treated teeth compared with vital teeth?

Answer 8

the loss of structural integrity with access preparation (rather than changes in dentin)

Question 9

the most important part of the restored tooth is the ___

Answer 9

• tooth itself

- no combination of restorative materials can substitute for tooth structure

Question 10

when a crown is needed, the axial walls of the crown engage the axial walls of the prepared tooth, forming the ___

Answer 10

• ferrule
• the ferrule is a band that encircles the external dimension of the residual tooth, similar to the metal bands around a barrel
• it is formed by the walls and margins of the crown

Question 11

a longer ferrule increases ___

Answer 11

resistance to fracture

Question 12

fracture resistance (to cervical tensile strength) increases significantly with increasing amount of ___

Answer 12

sound tooth structure

Question 13

a ___ ferrule increases fracture resistance and resists lateral forces from posts and leverage from the crown in function

Answer 13

longer

Question 14

crown preparations with ___mm coronal extension of dentin above the margin have double the fracture resistance compared with when the core terminates immediately above the margin

Answer 14

• 1mm
• the ferrule must encircle a vertical wall of sound tooth structure above the margin and must not terminate on restorative core material

Question 15

insufficient remaining tooth structure to construct a ferrule should be evaluated for ___ or ___

Answer 15

crown lengthening surgery or orthodontic extrusion to gain access to additional root surface

Question 16

what is the primary purpose of a post?

Answer 16

to retain a core in a tooth with extensive loss of coronal structure

Question 17

the need for a post is dictated by ___

Answer 17

the amount of remaining coronal tooth structure

Question 18

T or F:

posts reinforce the tooth

Answer 18

• false
• posts actually further weaken the tooth by additional removal of dentin and by creating stress that predisposes to root fracture

Question 19

when placing a post in an endodontically treated tooth, at least ___mm of remaining gutta percha is recommended

Answer 19

5-7mm

Question 20

what are 11 causes of endodontic failures?

Answer 20

1. inadequate seal of the root canal system
2. poor access cavity
3. inadequate debridement
4. missed canals
5. vertical fractures
6. procedure errors (perforation, ledging, loss of length)
7. leaking temporary or permanent restoration
8. periodontal involvement
9. resorption
10. compromised host factors (systemic conditions)
11. misdiagnosis

Question 21

in terms of long-term success and avoidance of endodontic failures, is coronal seal or apical seal more important?

Answer 21

coronal seal

Question 22

historically, which endodontic step has been considered the most critical step and the cause of most treatment failures?

Answer 22

• obturation
• however, the two events are associated by not by cause and effect because poorly obturated canals are usually poorly debrided as well

Question 23

what 4 main factors influence success rate of endodontics?

Answer 23

1. apical pathosis
2. bacterial status of the canal
3. quality of endodontic work
4. quality of coronal seal

Question 24

how does apical pathosis affect endodontic success rate?

Answer 24

the presence of an apical lesion before treatment reduces the success rate of endodontic treatment by 10-20%

Question 25

how does the bacterial status of the canal affect endodontic success rate?

Answer 25

the presence of bacteria in the canal before obturation results in a poorer prognosis

Question 26

what are the 7 principles of successful endodontics?

Answer 26

1. microbial disinfection
2. debridement - key to success
3. obturation
4. diagnosis
5. treatment plan
6. knowledge of anatomy and morphology
7. restoration
   * factors 1-3 represent the traditional endodontic triad*