Root canal anatomy Flashcards
Radiographic Hints of “Abnormal”
Things not normal size
Things not centered
Things that abruptly change
Things that look “off ”
Weine Classification
I - 1 canal
II - 2 canals that become one at apex
III 2 canals that remain separate
IV - 1 canal that splits in the apical third
Maxillary Anterior general anatomy considerations
Central incisor … broad M - D pulp horns
Lateral incisor … apical D curvature
Canine … canal broader in B - L dimension … apical F, B curvature
Lingual shelf
Max 1st premolar canal stats
1 canal ………………………………..9%
2 canals (2/3 stay separate)…85%
3 canals ………………………………6%
Max 2nd Premolar canal Stats
1 canal……………………………….48%
2 canals (1/2 stay separate)….51%
3 canals……………………………….1%
Max 1st Molar MF root stats
1 Canal ...20%
2 Canals....77%
Weine type II =>40%
Weine type III => 60%
3 Canals....3%Max 2nd Molar MF root stats
1 Canal….63%
2 Canals …..37%
Avg distance between MB1 and MB2 orifices
1.8mm
Maxillary Molar DB canal generalities
Straightest canal
most conical
Max Molar P canal generalities
Wider in M-D dimension
Often curves to B in apical third
Obturation may appear short
prone to perforation/ledging from large instruments
Man Ant incisor canal stats
1 Canal ….57%
2 Canals ….43%
1 Foramen …99%
Man Canine Canal Stats
2 Canals …22%
Man Ant generalities
Broader B - L than M - D
Lingual shelf
Canine may have 2 roots
Incisors … ideal access through incisal edge
Man 1st Premolar Canal Stats
1 Canal ….75%
2 Canals….24%
3 Canals…1%
Man 2nd Premolar Canal Stats
1 Canal 97%
2 Canals 3%
Man 1st Molar Canal Stats
2 Canals…7%
3 Canals….64%
4 Canals…29%
Man 2nd Molar Canal Stats
2 canals…4%
3 Canals 81%
4 Canals 11%
C shaped 3%
Man 1st Molar M root
93% have 2 canals
60% stay separate
40% join
Man 1st Molar D root
29% have 2 Canals
40% stay separate
60% Join
Middle Mesial in Man 1st Molar
2-13% but may be closer to 50%
usually join MF or ML (90%)
C shaped canal
–Difficult to debride –Difficult to obturate –Radiographic hints: - Conical roots - Indistinct features
Furcation, Lateral, & Accessory Canals
Breaks in root sheath
Can occur anywhere
Usually in apical third
Contact with pulp and PDL
Accessory Canals
Incidence: 10 - 47 %
Debridement
Obturation
Surgical removal
Furcation Canals
Incidence: 8 - 76 % Patency Isolated Furcal Defects Necrotic Pulp Medicaments Ca(OH)2
Anatomic Laws
Centricity Concentricity CEJ Symmetry Color Change Orifice Location
Law of Centricity
Pulp chamber in center of tooth at level of CEJ
Law of Concentricity
Chamber walls are concentric to external surface
Law of CEJ
landmark for pulp chamber location (97% of time)
Law of symmetry
Orifices are equidistant and perpendicular from MD line
Law of Color Change
Pulpal floor is darker than walls
Law of Orifice Location
at junction of floor and walls
Lateral Canals
Incidence: 10 - 76 % Suspect with lateral lesion More in posterior teeth Seldom a factor for success Debridement and obturation Ultrasonics Calcium hydroxide Softened gutta-percha Sealer
Root Concavities
DANGER ZONE Mesial root Man 1st molar Max premolars, especially on the mesial Max 1st molars, MB root Instrumentation moves canal towards the danger zone Watch for 2 PDL’s
% of canals with curvature
97%
Secondary canal curvature incidence
30%
Concresence
union of two or more teeth via fusion of the cementum; most commonly see in max permanent molars
Fusion
Union of 2 tooth germs during development
Dens invaginatus
4 types
.25-10% incidence
most common in max laterals
Dens Evaginatus
2.2% prevalence
84% of times occurs in Man premolars
Asian Female
Taurodontism
Increased pulp chamber size w/ or w/o pulp stones
shortened roots often with curvatures
