Endodontic Access- Anterior and Molars Flashcards
what are the objectives of endo access
- to gain access to the pulpal space
- to maintain strength of the tooth
why would you want to gain access to the pulpal space
- visualization
- instrumentation
- obturation
how would you maintain strength of the tooth
- preserve incisal edge
- conserve marginal ridges
- maintain correct shape, size, and position
what is the outline form of maxillary central incisors
triangular with the base of the triangle toward the incisal edge
what is the outline form of the maxillary lateral incisors
follow the same form of maxillary central incisors but are narrower and less flared incisally
what is the outline form of maxillary canines
same general form of central incisors but are closer to an oval
what is the general outline form of maxillary anteriors
triangular to ovoid
what are penetration points
where you would generally expect to find the pulp
- usually in the center mass of the root form
describe the access in mandibular central and lateral incisors
- very narrow M-D
- 2 canals 40% of the time
- extends further incisally
describe the outline form of mandibular canines
oval and similar to maxillary canine access
why must you be aware that mandibular incisors are very narrow M-D
avoid ruining the tooth by tipping our access bur to the mesial or distal and drilling out the side of the tooth
what visual and spatial understanding should you have for the tooth/pulp you are attempting to access
- review dental anatomy and morphology
- general size and shape of the tooth and the pulp
- relationships of the pulpal space to the tooth structure
- how many canals and variations
- positioning of teeth in the mouth
dont ever look for the canals with:
the bur
dont expect to feel ______ into the pulp chamber
a drop
you will find the _____ of the pulp chamber first
roof
mark your access at _____
7 mm
if you dont know for certain where you are:
- stop and take a radiograph
- have someone else take a look
- dont become disoriented
how do you access the maxillary central incisor
- triangular access- base of triangle at incisal
- angles of triangles are slightly rounded
- M and D marginal ridges are not invaded or weakened
- base of triangle parallels with incisal edge
- pulp horns and chamber are free of tissue and caries
what is ideal access of maxillary central incisor
- does not require a crown and could be adequately restored with a composite restoration
- variations occur due to trauma, caries, existing restorations or just plain aberration that could create another situation
- few patients present with a perfect tooth and ask for RCT to be performed
what is the ideal access for maxillary lateral incisor
- use #2 round
- triangular/oval access
- thinner root than central ( narrower access M-D narrower pulp horns)
- incisal compromise on all anterior teeth
what is the ideal access for maxillary canine
- use #2 or #4 round bur
- oval access
- canal narrower M-D than F-L
- one root
- usually single canal - most maxillary anteriors
what is the ideal access for mandibular incisors
- oval access
- use #2 round bur
- root wider F-L than M-D
- very narrow M-D easy to perforate to side of root
- one canal 60%, two canals 40%
- when two canals- mostly type II
- cervical access will miss lingual canal
what is a type I canal configuration
one canal from pulp chamber to apex
what is a type II canal configuration
2 canals from pulp chamber, join prior to apex
what is a type III canal configuration
2 canals from pulp chamber to apex
what is a type IV canal configuration
one canal from pulp chamber divides prior to apex- most difficult to treat
what is the outline form of maxillary first premolars
- have a Buccal and Lingual canal in at least 85% of cases
- M-D width of the access is no wider than a #4 round bur
- opening usually extends from near the tip of the buccal cusp lingually as a narrow oval
what is the outline of maxillary second premolars
- contain a second canal in at least 35% of cases
- the access form is very similar to the first PM
- if there is a single canal, it is centrally located and wide from B to L
all premolars are very easy to perforate to the________
mesial or distal
what bur should you use with premolars
2
access on posterior teeth is always gained through:
the occlusal approach
describe the ideal access of the maxillary 1st premoalr
- thin oval access
- width of #4
- thin M-D root
- two canals most prevalent: 85% two canals, 9% one canal, 6% three canals
- canal orifices lie under respective cusp tips
- finish with ENDO-Z bur
what is the most common error in access to maxillary 1st premolar
not totally unroofed
final width of ideal maxillary 1st premolar is no wider than:
width of round #4 bur
what is the ideal access of the maxillary second premolar
- access: thin oval - width of #4
- slightly less F-L extension than 1st
- most often type I root canal (75-85%); type II, III and IV less frequently
- 2 roots (15-25%_
- 3 roots very rarely
- if one canal found but not in center F-L, there are probably 2 canals
type IV are very hard to:
shape, clean and fill
describe the outline form of mandibular premolars
- very narrow M-D width and access extends from near the tip of the buccal cusp lingually
- 2 canals in mandibular PMs are rare and very difficult
- 2nd canals can occur in both mandibular canals
what do 2nd canals in mandibular premolars appear as
- look for 4 PDLs
- “fast break” or “fuzzy” canal somewhere in the mid root
what is the ideal access for the mandibular first premolar
- access: thin oval
- usually one root, 1 canal (type I), 73.5%
- type III, 19.5%
- three canals less than 1%
- vertucci study
what is the law of color change
the color of the pulp chamber is always darker than the surrounding walls
what is the law of centrality
pulp chamber in the center of the tooth
what is the law of concentricity
walls of the pulp chamber are always concentric to the external surface
what is the law of CEJ
CEJ is the most consistent landmark for locating the position of the pulp chamber
what is the worst error you can make at access
perforation
what is the outline form of mandibular molars
- trapezoidal form with rounded angles because of the probability of 2 distal canals (30%)
where is the wider base of the form for mandibular first molar and why
- to the mesial
- to preserve the mesial marginal ridge
- extends as far distally to provide clear access tot he distal canals or canal
a missed canal is a:
failed RCT
what shape access is for 3 canals
triangular
what shape access is for 4 canals
trapezoidal
how can you tell if there are 3 or 4 canals
when you enter the tooth
if there is a singular distal canal in mandibular molars it will be:
generally in the center of the form and may be wide B-L
what is the C shaped canal
- in mandibular molars
- tooth contains 3 or more canals associated by an irregular network of thread like canals and areas that are variable in size, shape and complexity
- extremely difficult to find and instrument
- mostly in 2nd molars
which is more difficult: 2nd or 1st mandibular molars
2nd
what percentage of mandibular molars are variably shaped canals and what are the variations
- 2-8%
- middle mesial canal
- C-shaped canal
what is the biggest challenge of maxillary molars
MB2 canal
what percentage of maxillary molars have 4 canals
95%
what does the endo Z bur do
used to define the walls as they meet the floor of the prep
variations are ____
not rare
MB2 may require as much time as _____
all 3 other canals in total
what are the common variations of maxillary incisors
multiple canals- rare
what are the common variations of mandibularincisor
- single root +1 canal = 60%
- single root + 2 canals = 40%
what are the common variations of maxillary canine
multiple canals- rare
what are the common variations of mandibular canine
- single canal = 78%
- 2 canals = 22%
what are the common variations for maxillary first premolar
- 2 canals = 85%
- single canal = 9%
- 3 canals = 6%
what are the common variations for maxillary second premolar
- single canal = 50%
- 2 canals = 50%
what are the common variations for mandibular first premolar
- single canal = 74%
- 2 canals = 25%
- 3 canals = 1%
what are the common variations for mandibular second premolar
- single canal = 98%
- 2 canls = 2%
what are the common variations of maxillary first molar
- 3 roots and 4 canals = 95%
- 3 roots and 3 canals = 5%
what are the common variations for maxillary second molars
- 3 roots 4 canals = 60%
- 3 roots and 3 canals - 40%
what are the common variations for mandibular first molars
- usualyl 2 roots
- mesial= 2 canals 98%, 1 canal = 2%
- distal = 1 canal 70%, 2 canals 30%
- rare = 3 roots and 4 canals
what are the common variations for mandibular second molars
- 2 roots and 3 canals = 81%
- 2 roots and 2 canals = 15%
- 1 root and 1 canal = 4%
