Morphology Flashcards
What is morphology?
The study of the shape, size, and distinguishing features of teeth that highlight unique biological relationships between human
What’s Cingulum?
Rounded raised area of enamel found on cervical 1/3rd of L of anterior teeth (around the gum line)
What’s diastema?
Unusually large open space between 2 teeth
What’s cusp of carabelli?
5th cusp located on ML cusp of max. 1st molar
May not always be present or if it is, may not be well developed
What’s ridges?
Linear elevation of tooth structure
Named according to its location or form
What’s marginal ridge?
Elevated crests or rounded folds of enamel
Form M & D margins of O surfaces of posterior teeth
Form M & D margins of L surfaces of anterior teeth
What’s oblique ridge?
(At a slant/diagonal line)
Elevated prominences on O surfaces of max. Molars
Runs diagonally from ML cusp to DB cusp
What’s triangular ridge?
(Premolars and molars only)
Prominent, triangular cross section elevations
Extend from tip of a cusp toward central portion of O surface
What’s transverse ridge?
Made up of 2 or more triangular ridges of a B & L cusp
Join to form a continuous elevation across the O surface of a posterior tooth
What’s fossa?
Wide, shallow depression
Lingual fossa
Wide, shallow depression
Found on L surface of an anterior tooth
Central fossa
Depression found in center of posterior teeth
Not on pre molars
Triangular fossa
Triangular shaped depression found near the marginal ridges
Pit
Sharp, pinpoint depression where 2 developmental grooves meet or cross each other
Forms a deep area that’s too small for bristles of toothbrush to clean
Enamel is thin; prone to decay
Occlusal developmental pit (not in pp)
Located in the deepest portion of the fossa; each pit is a sharp pinpoint depression where two or more grooves meet
Incisal edge/ridge
Ridge on perm. Incisors
Starts off at ridge then becomes incisal edge
Appears flattened on La, L, or I view after tooth eruption
Angle formed by the merging of 2 flat surfaces
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Ridge: newly erupted incisor and the portion is rounded
Mamelon
Rounded extension of enamel on incisal edge of newly erupted incisors
Usually 3
Disappears as a result of wear
Grooves
Depression in form of a line
Formed during development
Developmental groove
Sharp, deep, v shaped linear depression
Found on O surface
Any linear depression
B to L
Central groove
Most prominent groove
Travels MD and divides O surface in half
Supplemental groove
Branches off developmental groove
Gives O surface of tooth a wrinkled appearance
Triangular groove
Separate a marginal ridge from the triangular ridge of a cusp
Marginal groove (not in pp)
Fissured area on the L surface of anterior teeth and O surface of posterior
Fissure
Fault along a developmental groove on the O surface
Caused by imperfect joining of lobes during tooth formation
Decay often starts in fissure
What perm. incisors erupts first?
Central incisors erupt a year or so before the lateral incisors
Max. Central incisors
Thin, sharp edge used to cut
MI angle is at 90 degree; DI angle is more rounded
L surface slightly concave w/ prominent cingulum
1 root shorter than roots of other perm. Max. Teeth
Man. Central incisors
Smallest teeth in either arch
M & D incisal angles are sharp
L surface is concave
1 root
Imbrication lines
Developmental horizontal lines in anterior teeth; slightly ridges that runs MD in the cervical third of the teeth
Max. Lateral incisors
Shorter, more narrow and thinner than max. Central incisor
1 root
Frequently congenitally missing (at birth you didn’t get the part to develop a tooth)
Pegged laterals (not in pp)
Incisors pointed or tapered shape
Man. Lateral incisor
Slightly wider from M to D than man. Central incisor
Incisal edge slope down toward distal
M side if crown is longer than D
1 root
Canine eminence
External vertical bony ridge on La surface of canines
Cusp
Major elevation on the masticatory surfaces of canine and posterior teeth
Cuspid max
Erupts after man. Canines, Max incisors, max premolars
Longest & strongest tooth
1 root which curves toward the D
Lingual ridge separates L surface resulting in 2 smaller lingual fossa’s
Cuspid man.
Erupts before the max canines and after most incisors have erupted
Smaller and more slender than max cuspid
Narrower LaL and MD
Less prominent cingulum; smooth L surface
Inclined cuspal planes
Sloping areas between cusp ridges
Perm. Premolars
Succedaneous replaced primary 1st and 2nd molars
B premolars rounded, prominent vertical B ridge is noted in center of the crown
2 B depressions are present on each side of B ridge
Anterior to molars
Max. 1st premolar
2 roots: B & L
2 cusps: B & L
Both max premolars erupt earlier than man. Premolars
Bifurcated
2 roots
Furcation
2 or more roots
Max 2nd premolar
Smaller than 1st premolar
1 root
2 cusps: B & L
Isn’t sharp as max 1st premolar
Man 1st premolar
Smallest of all 4 premolars
Doesn’t resemble max premolar
Erupts later than max premolars
2 cusp: B & L cusp
1 root
Man 2nd premolar
Erupts distally to the man 1st premolar; replaces primary man. 2nd molar
3 cusps: 2 small L cusps; 1 large B cusp
1 root
Tricanineate
3 cusp type
Tricanineate premolars groove pattern is y-shaped
Bicanineate
2 cusp type
2 cusp type groove pattern is U-shaped (also called C-shaped) or H-grooved
Molars
Grinding teeth
1st and 2nd molars erupt around 6-12 years old
Consist of 4 or 5 short, blunt cusps and 2 or 3 more molars
Max molars
Includes 4 majors cusps w/ 2 cusps on B portion of O table and 2 in L
Trifurcated
3 roots tooth
Trifurcation
The area at which 3 roots divide
Location: M, D, B surfaces
Max 1st molar
First perm teeth to erupt into maxillary arch; erupts distal to the primary max 2nd molars
Largest crown in dentition
4 developed cusps: ML (longest), MB, DL, DB; 5th cusp on the ML cusp called cusp of carabelli
3 roots: MB, DB, L (largest & longer)
Max. 2nd molar
Smaller to 1st molar
4 cusps: MB, DB, ML, DL
3 roots: MB, DB, L
Non-succedaneous
Do not replace the primary teeth
Man molar
Erupts 6 months - 1 year before permanent max molars erupt
Crown includes 4-5 major cusps
Wider MD than BL
2 roots: M & D
Bifurcation
2 roots divides
Man 1st molar
Erupts around 6-7 years old; first perm teeth in oral cavity
5 cusps: ML, MB, DL, DB, D
2 B grooves separating the B cusps: B, DB
2 roots: M, D
L surface is smaller than B
Man 2nd molar
Erupts between age 11-12
Smaller than 1st perm molars; Nonsuccedaneous
4 cusps: MB, ML, DB, DL
2 roots: M, D
Man 3rd molar
Smaller w/ more grooves on O, resembling a wrinkled look
4 cusps: MB, ML, DB, DL
2 roots
Primary dentition: characteristics
Smaller in size
Whiter, thinner enamel
Thicker dentin layer
Large pulp chambers
Crown is shorter in relation to total length of tooth
Roots are longer and more narrow than crowns
Primary max. Central incisors (not in pp)
Wider MD than IC
No mamelons
Cingulum and marginal ridges are more prominent than perm successors and L fossa is deeper
Primary max lateral incisors (not in pp)
Smaller and similar to central incisors
Incisal angles on lateral are more rounded
Primary man central incisor (not in pp)
Extremely symmetrical
Not constricted at the CEJ like prim max incisor
L surface is smooth and tapers toward the Cingulum
Marginal ridges less pronounced
Primary man lateral incisors (not in pp)
Wider and longer yet similar in form to central incisors
Incisal edge slopes D and DI angle is more rounded
Root maybe D curvature and usually has D longitudinal groove
Primary max canine (not in pp)
Longer and sharper cusp than perm canines
M and D outlines are rounder
Cingulum is well developed so the lingual ridge and marginal ridges
ML & DL fossae are shallow
Primary man canine (Not in pp)
Small LaL
D cusp slope longer than M cusp slope
L surface is marked by a shallow L fossa
I edge is straight and centered over the crown LaL
Root is long and narrow and twice the length of the crown
Primary max 1st molar
Occlusal table had prominent transverse ridge
H-shaped groove pattern and 3 fossae: central, M triangular, and D triangular
4 cusps: MB, DB, ML, DL
3 roots: B, DB, L
Primary max 2nd molar
Larger than primary max 1st molar
4 cusps with 1 supplemental cusp: MB, DB, ML, DL
3 roots: MB, DB, L
Usually has a cusp of carabelli, minor 5th cusp
Primary man 1st molar
4 cusps: MB, DB, ML, DL
ML cusp is long, pointed, and angled into O table
2 roots: M, D
Primary man 2nd molar
Larger than 1st primary man molar
5 cusps: MB, DB, D, ML, DL
2 roots: M, D
Perm max. 3rd molar
Much smaller in size than 2 previous molars
Roots are often fused together and curve distally
