Morphology Flashcards
Multiple canals in mandibular premolars is most prevalent in what population?
African American
In Mandibular incisors, which canal is more curved?
Lingual
What is the law of centrality?
Who came up with it?
Floor of pulp chamber is located at the level of the CEJ
Krasner and Rankow
What is the law of concentricity?
Who came up with it?
The walls of the pulp chamber are concentric to the external surface at the level of the CEJ
Krasner and Rankow
What is the law of color change?
Who came up with it?
the color of the pulp chamber is always darker than the surrounding walls
Krasner and Rankow
What is the first law of symmetry?
Who came up with it?
Except for the maxillary molars, the orifices of the canals are equidistant from a line drawn in a mesial-distal direction through the center of the pulp chamber floor
Krasner and Rankow
What is the second law of symmetry?
Who came up with it?
Except for the maxillary molars, the orifices of the canals lie on a line perpendicular to a line drawn in a mesial-distal direction through the center of the pulp chamber floor
Krasner and Rankow
What is the first law of orifice location?
Who came up with it?
The orifices of the root canals are always located at the junction of the walls and the floor
Krasner and Rankow
What is the second law of orifice location?
Who came up with it?
The orifices of the root canals are located at the vertices of the floor-wall junction
Krasner and Rankow
What is the most common pert for mandibular molars?
Out the lingual at the level of the bone.
Who found: no foramina located exactly at the apex, and the average distance of the foramen from the apex ranged from 0.2 mm to 3.8 mm.
Gutierrez and Aguayo 1995
Gutierrez and Aguayo 1995
found no foramina located exactly at the apex, and the average distance of the foramen from the apex
ranged from 0.2 mm to 3.8 mm.
What are the major constriction and minor constriction?
Major constriction=radiographic apex
Minor constriction=”apical stop”-doesn’t always exist.
These were concepts created before electronic apex locators
Who said the percentage of maxillary molars with MB2’s is:73.2% first molars,50.7% second molars, and 20.0% third molars. It occurred as a separate canal in 54.9% of first molars, 45.6% of second molars, and joined in all third molars
Stropko 1999
Who said as the operator became more experienced, scheduled sufficient clinical time, routinely employed the dental operating microscope, and used specific instruments adapted for microendodontics, MB2 canals were located in 93.0% of first molars and 60.4% in second molars.
Stropko 1999
What did Stropko say helped to find MB2’s?
What did it raise the percentage to?
More experienced operator, sufficient time, microscope, and specific instruments.
first molars: from 73 to 93 percent
second molars: from 50 to 60 percent
According to Stropko, percentage of maxillary molars with MB2s (initially)
first molars: 73.2%
second molars: 50.7%
third molars: 20%
According to Stropko, percentage of maxillary molars with MB2’s that do not join?
first molars: 55%
second molars: 46%
third molars: 100%
Who did a chart review of 1262 mandibular molars?
Hartwell and Bellizzi 1982
What did Hartwell and Bellizzi find about mandibular molars?
First mand molars canals: 1: 0, 2: 0.1%, 3: 65%, 4: 35%
Second mand molars: 1: 1%, 2: 4%, 3: 89%, 4: 6%
How did Hartwell and Bellizzi 82 study mandibular molar canal morphology?
chart review of 1262 mandibular molars
Who did a retrospective radiographic in vivo study of 514 maxillary first premolars and 630 maxillary second premolars?
Bellizzi and Hartwell 1985
What did Bellizzi and Hartwell 1985 find about maxillary premolars?
Maxillary first premolars: 1 canal: 6.2%, 2 canals: 90.5%, 3 canals: 3.3%. Maxillary second premolars: 1 canal: 40%, 2 canals 59%, 3 canals: 1%
How did Green 1956 study maxillary anteriors?
External exam of 150 maxillary anterior teeth with a stereomicroscope.
What did Green 56 find out about maxillary anterior teeth?
1 canal 100% of the time.
Who found 1 canal 100% of the time in maxillary anterior teeth (3)?
Green 1956, Pineda and Kuttler 1972, Vertucci
How did Pineda and Kuttler 1972 study maxillary anterior teeth?
Radiographs from MD and BL directions of extracted teeth.
How did Vertucci study maxillary premolars?
400 maxillary first and ? maxillary second premolars were decalcified, injected with dye, cleared and studied.
Results of Vertucci maxillary premolar studies (1974, 1979)?
First maxillary premolar at the apex:26% had one canal, 69% had two canals, 5% had three canals at the apex
Second maxillary premolar at the apex: 75% had one canal, 24% had two canals, 1% had three canals at the apex.
How did Kulild and Peters (1990) study maxillary molars?
The MB/MB2 of 51 1st and 32 2nd max. molars was studied. Accessed conventionally, then with a bur, then sectioned and examined under microscope.
Who found that the average distance between MB1 and MB2 is 1.82 mm?
Kulild and Peters 1990
What did Kulild and Peters 1990 find was the average distance between MB1 and MB2?
1.82 mm
According to Kulild and Peters, what percentage of maxillary molars have MB2s, and how did they discover that?
An MB2 was located in the coronal half of 95.2% of roots: 54.2% with hand instruments, 31.3% with bur, and 9.6% with microscope.
According to Kulild and Peters, what Weine classification do MB/MB2 fall under?
Canal systems were type 1: 5%, type 2: 49%, type 3: 46 %.
Two studies on mandibular anteriors and how they were done.
Henry & Rankine-Wilson 1965: Radiographic analysis and vertical sectioning
Benjamin & Dowsen: Probed with #15 file, MD and FL radiographs
Results of Henry & Rankine-Wilson 1965
Mandibular anteriors: 1 canal: 60% 2 canals that join: 35% 2 separate canals: 5%
Results of Benjamin & Dowson
Mandibular anteriors: 1 canal 59%, 2 canals 61%
Who used surgical telescopes, headlamps and a modified access to search clinically for MB2’s?
Fogel, Peikoff & Christie 1994
Results of Fogel, Peikoff & Christie (firsts?)
Maxillary first molars: 71% two MB canals (32% of the time they are separate, 39% of the time they join). 29% 1 MB canal
Who studied maxillary second molars with a retrospective chart review of 520 maxillary second molars?
Peikoff, Christie and Fogel 1996
Results of Peikoff, Christie, and Fogel (seconds)?
Maxillary second molars have 3 roots and 3 canals 57%, 3 roots and 4 canals (2 MB) 23%, three roots but MB and DB canals join 9%, B and P canal and roots: 7%, 4 roots and 4 canals (2 palatal): 1%
Who said mandibular canines have two canals 20% of the time, but two separate apical foramina only 6%
Vertucci 1994
How did Vertucci do his study of mandibular canines?
Decalcified, injected dye, cleared
Results of Vertucci’s mandibular canine study?
mandibular canines have two canals 20% of the time, but two separate apical foramina only 6%
Who did a lit review of mandibular first and second premolars?
Cleghorn 2007
Results of Cleghorn’s 2007 lit review
Mandibular first molars: 1 canal-76%, 2 canals 24%, 1 foramen 79%
Mandibular second molar: 1 canal-91%, 2 canals 9%, 1 foramen 92%
How did Cleghorn study mandibular first and second premolars?
Lit review
Who did a mandibular premolar study looking at races?
Trope 1986
Results of Trope’s mand first premolar study?
1 canal: 76%, 2 canals: 24%. B: 67.2 and 33 W: 86 and 14
Results of Trope’s mand second premolar study?
1 canal 95%, 2 canals 5%. Black: 92% and 8%. White: 97% and 3%
How did Trope do his 1986 mandibular premolar study?
Radiographs of 400 black and 400 white patients in vivo
How did Skidmore and Bjorndal study mandibular first molars?
Resin casts of internal anatomy
Who studied resin casts of internal anatomy for mandibular molars? Which mandibular molars?
Skidmore and Bjorndal 1971. First molars.
Results of Skidmore and Bjorndal’s first mandibular molar study?
Mandibular first molars: 2 canals: 7%, 3 canals 63%, 4 canals 28%.
What did Skidmore and Bjorndal find about how how often mesial and distal canals join in first mand. molars?
For mesial canals 40/60 Weine type II/III. For distal canals 60/40 Weine type I/II.
Who studied mandibular second molars with files in place in extracted teeth from MD and BL direction?
Weine 1988
What did Weine find out about mandibular second molars?
Mandibular second molars: 1 canal: 1%, 2 canals: 7%, 3 canals: 81%, 4 canals: 11%
Two studies to quote for mand second molars?
Weine and Hartwell& Bellizzi
Two studies to quote for mand first molars?
Hartwell & Bellizzi and Skidmore & Bjorndal
Two studies to quote for mand premolars?
Trope and Cleghorn
Study to quote for incidence of C-shaped canals in mand second molars?
What is it?
8% Cooke and Cox 1979
Study to quote for incidence of middle medials in mand first molars?
What is it?
1-15% Baugh 2004 (case report and lit review)
Morphology of the maxillary lateral incisor: percentage of dens in dente according to Hovland
.04 to 10%
Who said that 52% of maxillary lateral incisors had a DB dilaceration?
Chohayeb 1983
Chohayeb 1983
52% of maxillary lateral incisors have a DB dilaceration.
Who said furcation canals occur 28% of the time in molars, but only extend to the PDL 10%?
Gutmann 1978
Who said lateral, secondary and accessory canals occur in 27% of all teeth, most often in the apical area?
DeDeus 1975
Who studied the radix entomolaris? (higher in mongolian-feature populations)
Calberson 2004
Weine type II? type IV?
Type II: Two canals converge into one apically
Type IV: One canal splits into two apically
