Dentition and terminology
Biol. 425
Orientation terms:
labial (=buccal): side of a tooth closest to the lip
lingual: side of a tooth closest to the tongue
anterior: towards the front
posterior: towards the back
occlusal: refers to the surfaces of contact (occlusion) between upper and lower teeth
quadrant: one side of the upper or lower dental arcade (4 quadrants total: upper left, upper right, lower left, and
lower right)
Kinds of teeth (all lower teeth rooted in the dentary!):
incisors: anteriormost teeth, rooted entirely within the premaxilla (in upper teeth)
canine: single tooth behind the incisors; the first tooth (when present!) rooted partially or entirely in the maxilla
(in upper teeth)
premolar: teeth posterior to the canine (when present) and anterior to the molars, rooted entirely in the maxilla
(in upper teeth)
molar: posteriormost teeth in the dental arcade of adult mammals; rooted entirely in the maxilla (in upper
teeth), without deciduous precursors (=homophyodont)
carnassial (=sectorial): refers to the secodont 4th upper premolar and 1st lower molar in Carnivora
Tooth anatomy:
alveolus (pl. alveoli): socket in the jaw which accommodates the root of a tooth
cementum: bony material that usually surrounds the root of a tooth
dentine: Tooth tissue underlying (and softer than) enamel
enamel: hard substance covering part of a tooth's crown
pulp cavity: inner-most layer of a tooth, filled with nerves and blood vessels to maintain the dentine.
root: portion of a tooth below the gumline
General dental morphology terms:
bicuspid: a tooth having two major cusps
unicuspid: a tooth having one major cusp
incisiform: incisor-like in general morphology
caniniform : canine-like in general morphology
molariform: molar-like in general morphology
heterodont: dentition in which teeth are clearly differentiated (e.g., incisors, canines, premolars, molars)
homodont: dentition in which all teeth are generally similar in form and function
Crown patterns
brachydont (also "brachyodont"): teeth having relatively low-crowned teeth, usually found in omnivores
bunodont: low-crowned teeth with rounded cusps, generally roughly quadrate in shape. Typically indicative of
broad diet with many kinds of food of varying consistency.
dilambdodont: cheektooth characterized by a W-shaped ectoloph
euthemorphic: modified tribosphenic tooth, frequently square in outline
hypsodont: teeth having relatively high-crowned teeth, usually found in herbivores
lophodont: a tooth consisting of a series of lophs
quadrate (also "quadritubercular"): upper tooth with four major cusps (paracone, metacone, protocone, and
quadritubercular: upper cheektooth (molar or premolar) characterized by the four major cusps (paracone,
metacone, protocone, and hypocone)
secodont: refers to teeth that are blade-like (e.g., carnassials)
selenodont: cheekteeth characterized by primary cusps elongated in an anterior-posterior direction to form
crescent-shaped ridges
tribosphenic (also "tritubercular"): upper cheekteeth characterized by three main cusps arranged in a triangular
pattern (constituting the trigon) or lower cheekteeth with a triangular arrangement of the trigonid and the
adjacent talonid. Believed to be ancestral condition for marsupial and placental mammals
hypocone) that is generally square in outline
zalambdodont: cheektooth characterized by a V-shaped ectoloph
General features of a tooth:
cingulum: shelf-like ridge on the outside of an upper molar or premolar (cingulid on lower teeth)
crista ( or cristid, for lower teeth; pl. cristae): a crest or ridge on a tooth, usually used to shear food.
crown: portion of a tooth above the gumline
cusp: point, projection, or bump on a tooth crown that usually serves to puncture food.
diastema (pl. diastemata): a pronounced gap between teeth, resulting from the loss of intervening teeth and/or
the elongation of the upper or lower jaw.
ectoloph: a ridge on the labial side of a cheektooth connecting the smaller cusps of the stylar shelf (e.g.,
parastyle, mesostyle, and, when present, metastyle) to the paracone and (when present) metacone.
loph (lophid for lower teeth): a ridge formed by the elongation (and sometimes fusion) of cusps on a tooth
stylar shelf: an expanded cingulum, usually bearing stylar cusps
-cone: major cusp on an upper tooth
-conule: minor cusp on an upper tooth
-conid: major cusp on a lower tooth
-conulid: minor cusp on a lower tooth
General dental development terms:
deciduous: refers to the milk or juvenile dentition; later replaced by permanent or adult dentition.
permanent: refers to teeth that are not deciduous
diphyodont: having two (and only two) sets of teeth in a lifetime
monophyodont: having only one set of teeth in a lifetime
rooted (also "closed-root"): root canal is closed and the pulp cavity is sealed off.
rootless (also "open-root"): root canal remains open and the tooth continues to grow indefinitely
supernumerary: refers to extra teeth in a position
edentulate: lacking teeth
Cusp(id)s features to be able to identify:
UPPER TEETH:
protocone
paracone
metacone
hypocone
paraconule
metaconule
metastyle
mesostyle
parastyle
trigon
LOWER TEETH:
protoconid
paraconid
metaconid
entoconid
hypoconid
hypoconulid
trigonid
talonid