Policies, Access & Working Length Flashcards
What is the procedure for the outline part of access?
- Create outline form just through enamel with number 2 round or 330 bur
*bur is somewhat perpendicular to lingual surface of tooth - Stay shallow at this point. Just through enamel < 1mm.
What is the procedure for the penetration part of access?
- Penetrate pulp chamber roof with bur angled approaching parallel to long axis of root in center of outline form.
- You should reach the pulp in most cases by 7 mm.
- Confirm Pulp canal entry with endodontic explorer
What is the procedure for the un-roofing part of access?
- Un-roof Pulp Chamber with brushing out-strokes. Take care not to gouge axial walls.
- Remove obstructions & smooth the walls
- Irrigate well (NaOCl)
– Vision
– Remove Debris
– Begin Disinfection
What is the procedure for the refining part of access?
- Refine access prep with Safe ended diamond bur or Endo–Z bur to help provide straight-line access to mid-root.
- The non-cutting tip is simply a pilot.
What is the next step after accessing a tooth?
determine the working length
The correct WL is: ___mm. SHORT of the CANAL EXIT
1.0
How do you find the canal exit in your hand?
Look at it
– Observe the canal exit
– Measure before you MOUNT tooth
How do you find the canal exit in the mouth?
Start w/ Average Length
– Chart
– Apex Locator (only in clinic setting)
– Radiograph (with #15 file in canal)
Where do you use an apex locator?
use on a patient in the clinic
- cannot use in lab
How do you use an apex locator?
- Place a #15 hand file in the access and extend it in the canal to the estimated canal length
- Take a radiograph and adjust until you determine the correct Working Length
Everything you do following an inaccurate working length is……..
WRONG!
The GOAL for the working length is 1mm.short of the…
canal exit
1.0mm short of canal exit places the working length in close proximity to the natural…
Apical Constriction
What happens if the working length is too short?
The canal is NOT well CLEANED
What happens if the working length is too long?
Even ¼ of a mm. long of the constriction – we have created a “BLOW-OUT” which guarantees incomplete compaction at the apex and an explosion of sealer in the PA tissues.
How do you measure the working length?
Select a solid, reproducible location on the tooth
* Tip of incisal edge (anteriors)
* Tip of cusp for which the canal is named (molars)
What is the first step after DX?
Access (Cleaning and Shaping)
Access to the Pulp Chamber FACILITATES:
– Locating the Canals
– Negotiating the Canals
– Gaining Patency
– Establishing Working Length
– Maintaining Apical Constriction
– A GOOD OUTCOME
Proper ______ is arguably the single most important requisite contributing to routine endodontic success
Access
Poor ACCESS yields PROBLEMS such as…
- You will NOT have a predictable result
- You will routinely miss canals
- You will NOT be able to clean properly
- You will NOT be able to shape completely
- You will NOT be able to fill adequately
What should the shape be of an access?
– SMOOTH
– CONSTANTLY TAPERING
– RESPECTING THE SHAPE OF THE NATURAL CANAL
– CONSTRICTING NEAR THE TERMINUS OF THE ROOT
What is the “coke bottle” affect?
canal is bigger than the cervical access at some more apical point in the canal
What are the requirements of access?
- Visibility of pulp chamber and all canal orifices from a single vantage point
- Straight-line access to mid-root for instrument placement
- Complete removal of pulpal roof & pulp horns
- Avoidance of unnecessary weakening of tooth
What should you be able to see with access?
Visibility of pulp chamber and all canal orifices from a single vantage point
Straight-line access to __________ is required for instruments & obturating materials
mid-root
Cross-hatched area of secondary dentin should be _________ to create better access to mesial root (this is also called a dentin triangle).
removed
What are the three steps of access?
- Outline Form (2 dimensional surface shape)
- Coronal Access (Extending into pulp)
- Radicular Access (Adjustments to allow easy straight-line entry to mid-root of each canal)
What is the outline form for access?
The 2 dimensional plan for the initial opening
What is the function of coronal access?
To allow unobstructed visualization of the pulpal floor and ALL canal orifices from a single vantage point
During coronal access you should reach the pulp at ___mm
7 mm or less
Pulpal FLOOR should NOT be
touched by the…
access bur
Walls of the coronal access should
DIVERGE to the occlusal because…
- better light
- better visualization
- Your temporary restoration which is placed between visits will not be easily dislodged to Leak & Contaminate
What is the function of radicular access?
To allow straight-line access to midroot for all shaping instruments and obturation materials (observe canal path not long axis of tooth)
What are the types of common canal configurations?
– Type I: one canal from pulp chamber to apex
– Type II: 2 canals from pulp chamber, join prior to apex
– Type III: 2 canals from pulp chamber to apex
– Type IV: one canal from pulp chamber divides prior to apex (most difficult to treat)
What is a type I canal?
one canal from pulp chamber to apex
What is a type II canal?
2 canals from pulp chamber, join prior to apex
What is a type III canal?
2 canals from pulp chamber to apex
What is a type IV canal?
one canal from pulp chamber divides prior to apex (most difficult to treat)
What shape is the access on maxillary central incisors?
Triangular
What shape is the access on maxillary lateral incisors?
triangular/oval
What shape is the access on maxillary canine?
triangular/oval
What shape is the access on mandibular incisors?
oval
What shape is the access on mandibular canine?
oval
What shape is the access on maxillary 1st premolars?
thin oval access
What shape is the access on maxillary 2nd premolar?
thin oval
What shape is the access on mandibular 1st premolar?
thin oval
What shape is the access on mandibular 2nd premolar?
thin oval
What shape is the access on maxillary 1st molar?
triangle (apex to palatal)
What shape is the access on maxillary 2nd molar?
triangle (apex to palatal)
What shape is the access on mandibular 1st molar?
trapezoid
What shape is the access on manidbular 2nd molar?
trapezoid/triangle
What are some common errors during access?
- access too large
- access skewed to mesial or distal
- pulp horns not cleaned
- straight-line access to mid-root is inhibited
How many canals in maxillary 1st premolar?
- Two canals most prevalent
– 85% two canals
– 9% one canal
– 6% three canals
How many roots in maxillary 2nd premolar?
- 2 roots (15 -25%)
- 3 roots very rarely
How many roots and canals does the mandibular 1st premolar have?
- Usually one root, 1 canal (type I), 73.5 %
- Type IV, 24 %
- Three canals less than 1%
How many roots and canals does the mandibular 2nd premolar have?
- Usually one root, 1 canal (type I), 85.5 %
- Type III, 11.5 %
- Three canals less than 1%
How many canals in maxillary 1st molar?
4 canals most of the time
5 canals 2.4%
How many canals in mandibular 1st molar?
4 or 3 canals
- 64% 3 canals
- 29% 4 canals
How many canals in mandibular 2nd molar?
3 canals 81%
4 canals 11%
