Access for Anterior and Single Roots Flashcards
Working Length
From incisal edge to minor apical diameter (apical constriction)
Working length is 0.5mm LESS than the radiographic length
WL + 1mm establishes patency
Objectives of Access Preparations
- Straight line access to canal orifice or first point of curvature
- Conservation of tooth structure
- Complete unroofing of the pulp chamber
Straight Line Access
Coronal access achieves straight line to the canal orifices at the level of the CEJ
Radicular access takes your coronal access beyond the level of the CEJ to the apical 1/3 or the first point of curvature of the canal
T/F: Old restorations should be removed for access preparation even if decay is not suspected
TRUE
This will let you examine the tooth for cracks or fractures that may not otherwise be evident
Determine if the tooth is restorable before doing RCT
Yes, if you do the root canal therapy and then figure out that the tooth is not restorable, the patient is going to lose their confidence in your ability.
Coronal Endodontic Access
Progressive development of a class I cavity prep on the occlusal or lingual surface penetrating into and eventually unroofing the pulp chamber
Shapes are tooth specific and shaped to match the external shape of the tooth at the CEJ level
Series of 2mm depth cuts that funnel inward
Outline Forms for anterior and single rooted posterior teeth
TRIANGULAR:
- maxillary central and lateral
OVAL:
- maxillary canine, mandibular premolars
LONG OVAL with near inclusion of incisal edge:
- mandibular canine, mandibular centrals and laterals
Level of ______ should never be exceeded during coronal access preparations
CEJ
DO NOT cross the level of the CEJ on coronal access preps
Coronal Access Burs
1157 or # 2 friction grip
- used for all initial outline forms, chamber penetration
2, # 4 round latch
- used to remove chamber roof once chamber is penetrated
Friction grip course flame diamond
- final chamber refinement and smoothing of walls
5 Explorer
used to check if roof of pulp chamber still remains
DG-16 Explorer
Used to search for canal orifice
Maxillary Central and Lateral Access
TRIANGLE outline
Triangle base is towards incisal edge. Base may approach within 3-4mm of incisal edge
Width of base determined by distance between mesial and distal pulp horns
Entire orifice should be seen through the access opening
Teeth may have a lingual shoulder that must be removed in order to mechanically instrument the lingual surface of the canal
Maxillary Canine Access
OVAL or slot-shaped
Incisal extent can approach within 2-3mm of incisal edge
Mesial and distal extension determined by medial and distal pulp chamber walls
This tooth can also have a lingual shoulder
Pulp chamber is very narrow M-D and wider Faciolingually
Mandibular Canine Access
OVAL or slot-shaped
incisal extent can approach cusp tip, especially if the cusp tip is worn down
Lingual extent can approach the cingulum in order to look for a second canal
Mandibular canine can have more than one root or canal
MD extent corresponds to the MD walls of the pulp chamber
Mandibular Incisor Access
OVAL
Buccal extent within 2-3mm of incisal edge in intact teeth
Teeth are narrow in MD direction so access is difficult– make sure to stay in long axis
Lingual shoulder may hide lingual canal– access should extend to the lingual and remove the shoulder to search for the lingual canal.
LINGUAL CANAL IS MOST COMMONLY MISSED CANAL ON MANDIBULAR INCISORS
Mandibular 1st Premolar Access
1st premolars:
- one root 95%
- one canal 75%
Access will put you very close to buccal cusp tip due to lingual inclination of crown
Narrow MD direction target
1st 2mm bur penetration is PARALLEL to buccal surface
- reorient bur into long axis for 2nd 2mm depth cut
Mandibular 2nd Premolar Access
OVAL
crown has less lingual inclination so less extension to buccal cusp is required (compared to mand 1st premolar)
Lingual cusp more pronounces so lingual extension is further up the inclination of the lingual cusp
Mand 2nd premolar can have TWO LINGUAL CUSPS
- access is centered on a line connecting the buccal cups and the lingual groove between the 2 lingual cusps
MD extent determined by mesial and distal extent of the pulp chamber
1st 2mm depth cup parallel to facial surface
2nd 2mm depth cut in long axis
