Chapter 7

What is the standard of care for isolation during endodontic treatment in Canada and the US?

Rubber dam

What does a rubber dam prevent during endodontic treatment?

Ingestion and aspiration

What type of field does a rubber dam create?

Aseptic field

What effect does a rubber dam have on RCT success?

Increases success

What does a rubber dam retract?

Lips, cheek, and tongue

What does rubber dam isolation provide for the clinician?

Unobstructed visibility

What does a rubber dam block to reduce cross-infection?

Aerosols, saliva, and blood

What is the legal standard regarding rubber dam use in Canada?

Presumed standard of care

What may failure to use a rubber dam imply in Canada?

Negligence

When should the rubber dam be placed if crown anatomy must first be visualized?

Before locating canals

What can be done before rubber dam placement when crown anatomy needs visualization?

Initial access

What is the primary purpose of endodontic access opening?

Straight-line access

Straight-line access should extend to what area?

Apical foramen

Straight-line access should avoid what canal feature?

First curvature

What should be completely removed from the pulp chamber during access?

Pulp chamber roof

What should be located during access preparation?

All canal orifices

What carious tissue should be removed during access?

All caries

What pulp tissue should be removed during access?

All pulp tissue

What type of tooth structure should be preserved during access?

Sound tooth structure

What should access preparation establish for the final restoration?

Restorative margins

What does straight-line access reduce?

File stress

What does reduced file stress decrease?

File fracture

What is outline form?

Ideal access shape and location based on pulp-chamber anatomy

What does outline form provide?

Straight-line access

What is convenience form?

Modified outline form

Why is convenience form modified?

To accommodate instrument orientation

What type of instruments may require convenience form modification?

NiTi rotary files

What else may require convenience form modification?

Unusual root anatomy

What happens if dentin is not removed from the mesial access wall?

Instrument bending

What can instrument bending during canal insertion cause?

Instrumental errors

What does removing additional dentin from the access opening provide?

Straight-line access

What access outline is recommended for a maxillary central incisor?

Rounded triangle

What access outline is recommended for a maxillary lateral incisor?

Rounded triangle or oval

What access outline is recommended for a maxillary canine?

Oval or slot

What access outline is recommended for maxillary premolars?

Oval or slot

What access outline is recommended for maxillary molars?

Triangle

Where is the triangular maxillary molar access located?

Mesial half

What is the base direction of a maxillary molar triangular access?

Facial

What is the apex direction of a maxillary molar triangular access?

Lingual

What anatomical structure should be preserved during maxillary molar access?

Transverse/oblique ridge

Where is the MB2 located relative to MB1?

Mesiolingual

How far is MB2 usually located from MB1?

1–3 mm

What are common pulp-chamber floor shapes?

Round, ovoid, ribbon/figure-8, and bowling-pin

What does pulp-chamber floor morphology guide?

Orifice search pattern

What classification describes root canal morphology?

Vertucci classification

What is Vertucci Type I configuration?

1–1

What is the canal pattern in Vertucci Type I?

One canal from chamber to apex

What is Vertucci Type II configuration?

2–1

What is the canal pattern in Vertucci Type II?

Two canals merge into one

Where do the two canals merge in Vertucci Type II?

Short of the apex

What is Vertucci Type III configuration?

1–2–1

What is the canal pattern in Vertucci Type III?

One canal divides and then merges

What is Vertucci Type IV configuration?

2–2

What is the canal pattern in Vertucci Type IV?

Two distinct canals

What is Vertucci Type V configuration?

1–2

What is the canal pattern in Vertucci Type V?

One canal divides into two at the apex

What is Vertucci Type VI configuration?

2–1–2

What is the canal pattern in Vertucci Type VI?

Two canals merge and divide again

What is Vertucci Type VII configuration?

1–2–1–2

What is the canal pattern in Vertucci Type VII?

One canal divides, merges, and divides again

What is Vertucci Type VIII configuration?

3–3

What is the canal pattern in Vertucci Type VIII?

Three distinct canals

In which tooth is C-shaped canal anatomy most commonly found?

Mandibular second molar

What is the main clinical difficulty with C-shaped canals?

Cleaning and obturation

What causes C-shaped canals developmentally?

Failure of HERS fusion

What is HERS?

Hertwig's epithelial root sheath

Where does HERS fail to fuse in C-shaped canals?

Buccal and lingual aspects

Which canals most commonly fuse in a mandibular second molar with a C-shaped canal?

Mesiobuccal and distal canals

Which canals can form a C-shaped canal in maxillary molars?

Mesiobuccal and palatal canals

What other canal combination can form a C-shaped canal in maxillary molars?

Distobuccal and palatal canals

How many roots does a maxillary central incisor usually have?

1

What percentage of maxillary central incisors have a single root?

99.9%

How many roots does a maxillary lateral incisor usually have?

1

How many roots does a maxillary canine usually have?

1

What percentage of maxillary canines have a single root?

99%

How many roots does a maxillary first premolar usually have?

2

What percentage of maxillary first premolars have 2 roots?

~55%

What percentage of maxillary first premolars have 1 root?

~43%

How many roots does a maxillary second premolar usually have?

1

What percentage of maxillary second premolars have 1 root?

86%

How many roots do maxillary first and second molars have?

3

What are the three roots of maxillary molars?

MB, DB, and palatal

How many roots does a mandibular incisor have?

1

How many roots does a mandibular canine have?

1

What percentage of mandibular canines have 1 root?

98.6%

How many roots does a mandibular first premolar have?

1

What percentage of mandibular first premolars have 1 root?

~97%

How many roots does a mandibular second premolar have?

1

What percentage of mandibular second premolars have 1 root?

~85%

How many roots does a mandibular first molar usually have?

2

What are the two roots of a mandibular first molar?

Mesial and distal

What percentage of mandibular first molars have 2 roots?

~86%

How many roots does a mandibular second molar usually have?

2

What percentage of mandibular second molars have 2 roots?

~79%

What percentage of mandibular second molars have 1 root?

~19%

How many canals does a maxillary central incisor have?

1

What percentage of maxillary central incisors have 1 canal?

100%

How many canals does a maxillary lateral incisor usually have?

1

What percentage of maxillary lateral incisors have 1 canal?

99.9%

How many canals does a maxillary canine have?

1