P1-ENDO-CHAPTER 7

fast break/Fast break guidelines

a sudden disappearance or narrowing of a canal as a sign of canal division

sequential application of 17% EDTA then 95% ethanol

what is recommended for effective cleaning and drying of the pulp chamber floor for inspecting the canal system

root canal system

The entire space in the dentin where the pulp is housed

pulp chamber

pulp canal

what are the 2 portions of the root canal system

pulp chamber

portion of RCS in the anatomic crown

pulp canal

portion of RCS in the anatomic root

root canal orifice

it is the opening of the root canal and extends apically from the cervical line all the way to the apical foramen

faciolingually

what direction are root canals usually curved?

it may have more than one canal

what can be expected of the root canals if the root is oval-shaped?

accessory canals

are minute canals that extend in a hori zontal, vertical, or lateral direction from the pulp to the peri odontium

apical third (74% of cases)

where are accessory canals most commonly found?

middle third (11% of cases)

where are accessory canals least commonly found?

Accessory canals

They are formed by the entrapment of periodontal vessels in Hertwig's epithelial root sheath during calcification.

apical deltas

multiple accessory canals that branch near the root apex

Furcation canals

accessory canals located at furcation areas

chamber canals

what are furcation canals also called as?

furcation canals

form as a result of the entrapment of periodontal vessels during the fusion of the epithelial diaphragm, which becomes the pulp chamber floor

mandibular molars

in which teeth will furcation canals have 3 distinct patterns?

1.) a single furcation canal from the pulp chamber to the intraradicular area

2.) a lateral canal extends from the coronal third of a major root canal to the furcation region

3.) both lateral and furcation canals

what are the 3 distinct patterns of furcation canals? (figure 7-6)

distal root canal

which root canal will most commonly have a lateral furcation canal in lower molars?

Type I

what type of root canal system:

A single canal extends from the pulp chamber to the apex

(1)

configuration of type 1 root canal system

type II

what type of root canal system:

Two separate canals leave the pulp chamber and join short of the apex to form one canal

(2-1)

configuration of type II root canal system

type III

what type of root canal system:

One canal leaves the pulp chamber and divides into two in the root; the two then merge to exit as one canal

(1-2-1)

configuration of type III root canal system

type IV

what type of root canal system:

Two separate, distinct canals extend from the pulp chamber to the apex

(2)

configuration of type IV root canal system

type V

what type of root canal system:

One canal leaves the pulp chamber and divides short of the apex into two separate, distinct canals with separate apical foramina

- the furcation is near the apex

(1-2)

configuration of type V root canal system

type VI

what type of root canal system:

Two separate canals leave the pulp chamber, merge in the body of the root, and redivide short of the apex to exit as two distinct canals

(2-1-2)

configuration of type VI root canal system

type VII

what type of root canal system:

One canal leaves the pulp chamber, divides and then rejoins in the body of the root, and finally redivides into two distinct canals short of the apex

(1-2-1-2)

configuration of type VII root canal system

type VIII

what type of root canal system:

Three separate, distinct canals extend from the pulp chamber to the apex

(3)

configuration of type VIII root canal system

maxillary 2nd premolar

which tooth can show all 8 variations of the root canal system

true

true/false

gender plays a role in determining canal morphology

gender and ethnic origin

what are the 2 patient factors to be considered in the pretreatment evaluation for RCT

only one canal is present

on examination, the root canal orifice is in the center

extra canals in the maxillary first premolar and mandibular second premolar

what are the variations in the root canal morphology of patients with African descent?

higher incidence of single rooted and C-shaped canals in mandibular 2nd molars

what are the variations in the root canal morphology of patients with Asian descent?

there is another root canal somewhere

on examination, there is only one orifice but it is not centered

the two canals join somewhere in the root

on examination, there are 2 orifices that are close to each other. what does it imply?

greater chance the canals are separated and are less curved

on examination, there are 2 orifices that are far from each other. what does it imply?

there is a second canal

on examination: when a file is inserted into a canal, it points buccal/lingually. what does it imply?

true

true/false

two canals are smaller than a single canal

palatal/lingual canal

how to treat:

- obturate the lingual canal to the apex

- obturate the buccal canal to the point of juncture only

IF NOT, then an hourglass appearance will occur if both canals are prepared to the apex in this kind of anatomy

when two canals join to form one canal, which canal will have general access to the apex?

how is this anatomic configuration treated?

buccal and lingual/palatal

when a single canal separates into two, what is the division of the roots?

lingual canal

when a single canal separates into two, which canal is the one that splits off from the main canal at a sharp angle? (h-configuration)

apical constriction (AKA minor apical diameter, minor foramen)

apical foramen (AKA major apical diameter, major foramen)

cementodentinal junction

what are the 3 anatomic and histologic landmarks of the apical root

apical constriction (AC)

smallest diameter of canal as it exits tooth

cementodentinal junction

inner surface of cementum where cementum joins dentin

because pulp blood vessels are narrow at the AC

why is post-treatment discomfort greater at the apical constriction?

1mm

what is the distance of the CDJ from the apical foramen

funnel-shaped, hyperbolic, or morning glory

what are the shapes that describe the space between the apical constriction (minor apical diameter) and the apical foramen (major apical diameter)?

0.5mm

what is the distance between the AC and AF in a young person

0.67mm

what is the distance between the AC and AF in an older person

apical foramen

circumference or rounded edge, like a funnel or crater, that differentiates the termination of the cemental canal from the exterior surface of the root.

due to cementum buildup

why is the distance between the AC and AF greater in older individuals?

false

the offset is 0.5-3mm

true/false

the apical foramen directly exits at the root apex

labiolingual diameter (50 um wider)

which diameter of the apical foramen is wider, labiolingual or mesiodistal?

Scanning Electron Microscopy (SEM)

This is use to determine:

1. Number and size of main apical formaina

2. Siz of accesoy foramina

maxillary premolars

which teeth have the most and largest accessory foramen and the most complicated morphologic make up, and is a possible reason why root canal therapy may fail in these teeth

210 um

What is the size of the mean foramen in maxillary premolars

392 um

What is the size of the mean foramen in distal roots of mandibular molars

variability and unpredictability

what are the hallmarks of the apical region

Premdominantly Circular

What is the apical canal shape in apaltal and MB-2 canals?

Mostly flat

What is the apical canal shape in MB-1 canal

mix of circular and flat shapes

What is the apical canal shape in distobuccal canal

1mm from the apex

what is the recommended termination point when no bone or root resorption has occured

1.5mm from the apex

what is the recommended termination point when only bone resorption has occured

2mm from the apex

what is the recommended termination point when both bone and root resorption have occurred.

at or within 3mm

what is recommended termination point from the radiographic apex

vital case - 2 to 3mm

necrotic case - within 2mm

retreatment case - 1 to 2mm

what is the recommended termination points in the ff cases from the radiographic apex?

a. vital case

b. necrotic case

c. retreatment case

1. anatomy of the root canal system

2. dimension of the canal walls

3. final size of enlarging instrument

what are the 3 factors that successful RCT will depend on

best prognosis: terminate at AC

worst prognosis: terminating beyond AC

2nd worst prognosis: terminating 2mm from AC

what are the termination points that provide (a) best prognosis, (b) worst prognosis, and (c) 2nd worst prognosis?

isthmus

is a narrow, ribbon-shaped communication between two root canals that contains pulp or pulpally derived tissue

type I isthmus

what type of isthmus?

- incomplete, faint communication between canals

type II isthmus

what type of isthmus?

- complete, definite connection between canals

type III isthmus

what type of isthmus?

- very short complete isthmus between canals

type IV isthmus

what type of isthmus?

- complete or incomplete isthmus between three or more canals

type V isthmus

what type of isthmus?

- no isthmus between canals

rounded triangle with base towards incisal edge

what is the external access outline for MX central incisors

triangle or oval (if pulpal horns are not present)

what is the external access outline for MX lateral incisors

palatoradicular groove and dens invaginatus

what are the common anomalies that often occur in MX lateral incisors?

type I: confined to the crown

type II: past the CEJ w/o periradicular involvement

type III: past the CEJ w/ periradicular involvement

what are the three types of dens invaginatus

surgical and orthograde root canal therapy

what is the treatment for dens invaginatus

permanent apical pressure sensitivity

fenestrations are common in maxillary canines, and what is a complication that occurs after RCT as a result of fenestration?

oval or slot-shaped

external access outline form of maxillary canines

palatal orifice

which orifice of maxillary 1st premolars are slightly larger and kidney shaped?

mesial

in maxillary premolars, which direction should the clinician be careful during preparation to avoid root perforation due to a concavity on this aspect of the root?

oval or slot-shaped, triangle if 3 canals are present

external access outline form of maxillary premolars

rhomboid

what is the shape of the maxillary first molar pulp chamber?

acute angle: mesiobuccal angle

obtuse angle: distobuccal angle

right angles: both palatal angles

in the maxillary first molar, which angles make up the (a) acute, (b) obtuse, and (c) right angles in the rhomboid shape of the pulp chamber?

mandibular incisors

what teeth are the 2nd most difficult to treat with RCT due to their complex root anatomy?

40%

what is the incidence of mandibular incisors having 2 canals?

18%

what is the incidence of mandibular canines having multiple canals?

type 4

what is the most common weine classification of mandibular first premolars?

type I

what is the most common weine classification of mandibular second premolars?