Access Morphology

							Access Morphology

Maxillary central incisor: straight
Tic-tac toe, start in the center equidistant all the way around, then all the way down to
cingulum, base of triangle towards incisal edge tip at cingulum.

Maxillary lateral incisor: Pulp horns, reason why its triangular at the CEJ, type of access
opening, know the shape at the CEJ. Triangular at the CEJ, so access opening is the same
two major pulp horns.
Historically has failed the most, reason is the distal curve (53%).
Key is straight line access to the middle third. !) by accessing 2) by shaping
No ledges (especially lingual).

Maxillary Canine: root configuration is ovoid, so access opening will also be ovoid.
Most will be straight.

Maxillary First Premolar: Root configuration. Buccal and palatal, ovoid to round. Two
roots. Outline has to be ovoid, should be short of cusp tip to get straight line access to
coronal third to middle third. Go halfway up the cusp tip. Key is to extend far enough to
get straight line access.

Maxillary second premolar. Buccal pulp horn, go half way up the cusp tip.
2mm into dentin.
Long axis of the tooth, make sure you are on it when you access.

Maxillary First Molar: Palatal root curves to the buccal 55% of the time.
Four pulp horns, mesial buccal, lingual ,distal palatal distal buccal. This is the second
tooth that fails the most. Different configuration for each root. This one looks more like
a parallelogram. Missed canal is why it fails in the mesiobuccal root. Also buccal
curvature of palatal root.
Most configurations are round at the apex.
Start in central pit, then unroof the area.
Do not cross the oblique ridge when going distally. Base of triangle towards buccal,
apex at palate.
When you are at gray, you are at the pulpal floor, do not go deeper.
When you take an x-ray and it doesn’t look like its centered, space on one side of
root or another, then another canal. Needs to be centered on root.
Identification of fourth canal in maxillary molars
Follow Developmental groove
Ultrasonic
Main canal
Shape fourth canal

MB2 should be parallel to mesial marginal ridge. Will be more mesially and more
palatally than MB1. Line from MB1 to palate, MB2 will be more mesial to that.
Clean main canal, pulp tissue remaining may be another canal.
Mandibular centrals and laterals
Ribbon shaped, two canals 41.4% of the time reason why they fail, missed canal.
Usually lingual canal is missed
Gain access to where pulp chamber is, then put file in there, put the file in and get one
canal.
Watch out for lingual ledge, get rid of that so you can get straight line access to lingual
canal.

Mandibular canine
Cervical is ovoid, ovoid access opening, apex is round.
Also has two canals.

Mandibular First premolar: most of the time has one canal, usually access is oval.
Tooth is tilted, make sure you memorize where the access line is.
Second Premolar: pretty much the same
On xray, see pulp chamber goes all the way down to the end, one canal. If it goes down
and disappears, has to be another root system. Also another root system if its off center.

Mandibular first molar: Four pulp horns again. Most people perforate through lingual if
they go straight down, tooth is rotated, tilted.
Just past center, not going into distal, must be broadened, morel like rectangle., stay away
from mesial marginal ridge (3-4mm). Mesial, parallel to mesial marginal ridge.

Mandibular second molar: C shaped canals, lingual is separate, mesiobuccal joints to the
distal, looks like a C.

Common errors: not opening enough, not unroofing, not extending far enough distally or
lingually. If access is too small, scrape along side of margin, get gold dust in canal.


Don’t remember numbers, straight line access, how to find fourth canals.