Y3 L2 Anatomy and access for anterior teeth

Question 1

What should you consider before preparing your access cavity?

Answer 1

• Position of tooth in arch i.e. 2nd/3rd molars have poor access
• Angulation of tooth (rotated/tilted)
• Relative crown root angle radiographically

Question 2

Why is straight line access necessary?

Answer 2

• File should be almost parallel to long axis of the tooth
• Gives better control over the head of the file, you can clean and shape the canal better, minimises iatrogenic damage (e.g. ledge and perforations)

Question 3

What do the red and yellow areas each signify?

Answer 3

Red: orifice to apical foramen, this is the area prepared during shaping and cleaning
Yellow: reaches orifice level, this is the area prepared in the cavity access stage

Question 4

What is Vertucci’s classification?

Answer 4

A classification system for canal configurations.
Type begins with odd or even i.e. type 1 beigns with 1, type 4 begins with 2

NB: not exhaustive, teeth with multiple roots can also have different Vertucci’s types for each canal

Question 5

What Vertucci’s classification is this?

Answer 5

Type VI
- 2:1:2

Question 6

How does the cross section of canals vary?

Answer 6

Different shapes: round, oval, hourglass, irregular.
Some will also have extensions (see image).

Question 7

What anatomical tooth features may complicate RCT?

Answer 7

• Accessory canals/lateral canals
• Apical delta: a network of communication/complex branching at the apex

Question 8

Can you instrument accessory canals?

Answer 8

No, but if you do a good enough job of chaping and cleaning, the pulpal tissue in these accessory canals will dissolve and can be filled with GP.

Question 9

What is the average length of the maxillary anterior teeth?

Answer 9

• Central incisors: 23mm
• Lateral incisors: 22mm
• Canines: 26-27mm

Question 10

What is unique about endodontic treatment of canines?

Answer 10

• Very long, need to use longer files
• Roots often curve buccally
• Patients can feel pain associated with apical periodontitis over the root due to buccal root curvature and bone fenestration- will report pain when location of roots on face is pressed

Question 11

How many canals do the maxillary anterior teeth typically have?

Answer 11

Centrals, laterals and canines almost always have 1 canal. Very rare to have 2.

Question 12

What is the average length of the mandibular anterior teeth?

Answer 12

• Incisors: 21mm
• Canines: 26mm

Question 13

How many canals do mandibular incisors typically have?

Answer 13

1

Question 14

How many canals do mandibular canines typically have?

Answer 14

• Most common is 1
• 30-40% have 2 canals
• 2 canals with 1 foramen > 2 canals with 2 foramina
• Canals are usually situated buccally and lingually
• The lingual canal is often missed in RCT (hidden by shelf of dentine)

Question 15

What forms of magnification are used in endo?

Answer 15

• Loupes: 2.5-8x magnification
• Operating microscope: up to 20x magnificaiton

Question 16

Why is a rubber dam always needed in endo?

Answer 16

• Aseptic field
• Protects the airways
• Reduces risk of re-infection
• Protects the soft tissues
• Reduces aerosols
• Improved patient and operator comfort

Question 17

Describe the technical aspects of access cavity preparation.

Answer 17

• Guiding principle: shape, size and position of access cavity should reflect the shape, size and position of the pulp chamber
• Entire pulp chamber roof must be removed
• Outline of access dictated by number and position of orifices
• Visualise orifices at floor of pulp chamber

Question 18

What are the 3 objectives of access preparation?

Answer 18

• Removal of pulp chamber roof (and coronal pulp tissue) and identification of the orifices for subsequent preparation and filling of the root canal system
• Attainment of straight-line access
• Conservation of tooth structure

Question 19

What does an optimal access preparation allow?

Answer 19

• Thorough debridement of necrotic and infected pulp tissues
• Straight line access to maintain instrument control and reduce risk of procedural errors
• Facilitates obturation
• Avoids unnecessary tooth tissue removal

Question 20

What are the criteria for a successful access?

Answer 20

• Caries free
• Defective restorations removed and replaced with stable restorations
• No overhanging enamel or dentine
• Pulp chamber floor must be clearly visible
• Canal orifices should be undamaged and identifiable
• Dentine overhanging orifices removed

Question 20

What are the potential access cavity faults?

Answer 20

• Incorrect position
• Inadequate size
• Inadequate flare
• Too shallow/incomplete removal of roof
• Damage to floor and/or walls
• Perforation of root or furcation