Access, Cleaning and Shaping, Obturation Flashcards
What is the first step in accessing any tooth?
identifying the shape and position of the CEJ
How can one determine the angulation of a tooth?
radiographs and clinical observation (CBCT can also help!)
How can the estimated depth of access (EDA) be calculated?
using the preoperative radiograph
What is the EDA?
measurement form the mid-lingual surface of anterior teeth and the occlusal surface of posterior teeth to the coronal portion of the pulp chamber
If the estimated depth of access is reached and the pulp has not been encountered, what should you do?
reevaluate depth and orientation
take parallel radiograph with rubber dam removed
how is the initial penetration point decided upon?
- radiographic examination
- periodontal probing
- mental picture of CEJ
why does all caries and defective restorations need to be removed before placement of files in canals? (4)
- assess restorability of tooth
- provide aseptic environment
- prevent reinfection
- prevent restorative materials from entering canal
the law of color change states that the color of the pulp chamber is always (darker / lighter) than the surrounding walls
darker
What instrument should be used to detect orifices?
endodontic probe
Why do you need to remove the lingual dentin triangle?
to obtain straight line access
When would you access a tooth without a rubber dam in place?
in difficult cases, to allow visualization of tooth shape, angle, and position in the arch
major objectives of access opening (4)
- unroof chamber
- locate all canals
- straight line access
- conservation of tooth structure
what bur should be used for accessing through PFM crowns?
diamond
How can one prevent metal shavings from entering and blocking the canal when accessing through PFM crown?
remove metal before chamber has been opened
mechanical objectives of cleaning and shaping
- developing a continuously tapered funnel
- maintaining original shape / curvature
- maintain apical foramen in original position
- keep apical opening small
