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.