more about access and WL Flashcards
how is RCT a service to pt?
- To relieve acute pain
- To retain otherwise lost natural tooth
Excellent Practice Builder:- creates grateful disciples
may send you many patients
- creates grateful disciples
most common failure in endo?
access
Access Procedure- making the outline
- Create outline form just
through enamel with number
2 round or 330 bur HS - At this point bur is
somewhat perpendicular to
lingual/occlusal surface of tooth - Stay shallow at this point.
Just through enamel < 1mm.
Access Procedure - Penetration
- 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. – if not,
call for instructor help. - Confirm Pulp canal entry with
endodontic explorer DG16:
PUSH
Access Procedure – Un-roofing
what is used during this? why?
- 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
Access Procedure - Refining
- Refine access prep with Safe
ended diamond bur or Endo–Z
bur to help provide straight-line
access to mid-root. ( Mostly in
molar access). - The non-cutting tip is simply a
pilot.
- After ACCESS, your
next big task is:
WL
poor WL results in
poor outcome
proper WL
1mm short canal exit
How do you FIND the Canal exit?
in hand and mouth
- In your HAND; Look at it
– Observe the canal exit
– Measure before you MOUNT tooth - In the MOUTH; Start w/ Average Length
– Chart
– Apex Locator (if possible)
– Radiograph (with #15 file in canal)
is apex locator used in lab
not really
radiograph for WL procedure
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
why 1mm short of canal exit?
this places the WL in close proximity to the natural Apical Constriction
too short of WL canal will be:
the canal is NOT well CLEANED
WL 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.
must have what for WL
Reliable Reference Point
– Select a solid, reproducible location on the tooth
* Tip of incisal edge (anteriors)
* Tip of cusp for which the canal is named (molars)
– Don’t reduce it after WL is determined
– No need to reconfirm unless something has changed.
Write it down when determined
– Access to the Pulp Chamber FACILITATES:
– Locating the Canals
– Negotiating the Canals
– Gaining Patency
– Establishing Working Length
– Maintaining Apical Constriction
– A GOOD OUTCOME
1st step after dx?
access
Proper _______ is arguably the single most
important requisite contributing to routine
endodontic success.
Proper Access is arguably the single most
important requisite contributing to routine
endodontic success.
what can occur with poor access
results? canals? clean? shape? fill?
- You will NOT have 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
- *** You will easily create problems and make your RCT far more difficult, dangerous and time-consuming than it needs to be.
OBJECTIVE of ACCESS
Create effective SHAPE:
– SMOOTH
– CONSTANTLY TAPERING
– RESPECTING THE SHAPE OF THE NATURAL CANAL
– CONSTRICTING NEAR THE TERMINUS OF THE ROOT
avoid what with access
- “Coke Bottle” effect (canal is bigger than the cervical access at some more apical point in the canal)
Requirements from 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
“DRAW” of access
Visibility of pulp chamber and all canal orifices from a single
vantage point
Straight-line Access to Mid-root
3 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) *
outline form of access
The 2 dimensional plan for the initial opening (Could be traced onto crown)
While canal anatomy & tooth damage somewhat determine shape, size and location of initial entry into tooth – there is an “Ideal” to be mastered ***
First Shape the Outline Form in a shallow (1/2 to 1mm) fashion ( #4 round for molars, #2 for PM and Anteriors)
coronal access
To allow unobstructed visualization of the pulpal floor and ALL canal orifices from a single vantage point . . .
You should reach the pulp at 7mm or less. Mark your bur at 7mm
Extend your bur within the Outline Form to remove Pulpal Roof.
Pulpal FLOOR should NOT be touched by access bur
walls of coronal access angulation
why?
Walls of the coronal access should DIVERGE to the occlusal (B)
1. better light
2. better visualization
3. Your temporary restoration which is placed between visits
will not be easily dislodged to Leak & Contaminate***
Radicular Access:
To allow straight-line access to midroot for all shaping instruments and obturation materials ( observe canal path- not long axis of tooth)
Flare into canals to remove obstructions and make instrument placement simple and foolproof without looking.
Facilitates “Crown-Down” procedure.
Hand files generally require _____ strokes/file
before going to next larger size file *
Hand files generally require 100 strokes/file
before going to next larger size file *
common canal configurations
difficulties of max LI
- Thinner root than central
(narrower access M-D
narrower pulp horns) - Root often curves to distal
- Apex tips to palatal (most
difficult of max. ant. teeth)
max C apex tips towards?
palate
preventing perforation
Line up penetration in 2 planes: M-D & F-L
Visualize cervical cross section
Perforations often spell the demise of the tooth = iatrogenic error
if access is too small/cervical in the anterior what can happen
can miss the pulp horns
inadequate access and shaping
Inadequate access compromises shaping:
*induces unnecessary bending of file
*creates apical transportation of canal
max m1 access shape
Triangle –
apex to palatal: should
not cross oblique ridge
perforations are what sort of error
mental,Get your perception RIGHT :
Line it up in 2 planes (Know
where the root angles)
STAY FOCUSED***
worst error to make in access
perforation
