Supplementary resource for tooth morphology. UNIT 1, www.oralhistology-viva.blogspot.in, by Rooban Thavarajah. Definition, Tooth nomenclature

1. Dr. Rooban Thavarajah

2. Dr. Rooban Thavarajah
Landmarks
• Cusp is an elevation on the crown portion
making up a occlusal part
• Tubercle: Small elevation of enamel
• Cingulum: Lingual lobe of anterior teeth
• Ridges: Elevated portion of tooth in a line
named for their location
– Marginal / Triangular / Transverse/ Oblique

3. Dr. Rooban Thavarajah
Cusps
Marginal ridge
Triangular ridge
Transverse ridge
Oblique ridge

4. Dr. Rooban Thavarajah
• Marginal Ridge: Ridge or elevation of
enamel forming the margin of the surface
of a tooth; specifically, mesial &distal of
occlusal surfaces posterior teeth &
mesial /distal margins of lingual surfaces
anterior teeth

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• Triangular Ridges: Main ridges on each
cusp that run from the tip of the cusp to
the central part of the occlusal surface
• Transverse Ridge: Union of 2 triangular
ridges that cross the posterior surface of a
tooth
• Oblique Ridge: ML –DB cusp max molars

6. Dr. Rooban Thavarajah
• Developmental grooves: Shallow grooves
that separate cusps or primary parts of
teeth
• Fossa: Depression or concavity
– Lingual / central / triangular
• Pit: small pinpoint depression found in
fossa
• Sulcus: Long depression

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8. Dr. Rooban Thavarajah
Contact areas, embrasures

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Proximal Contacts
Mesial or Distal
– Where one tooth touches another
– Prevents food from packing between them
– Prevents buildup of excessive bacteria, food
or debris
– Affords protection to the gum tissue
– Offer support and anchorage to one another

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Inter proximal Spaces
Triangular-shaped spaces between teeth,
formed by the bone on one side and the
proximal surfaces and their contact area
on the other side.
– Normally filled with gingival tissue
• Papillary gingiva
• Inter dental papilla

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Embrasures
• Open space
• Spillways
• Named for their location
– Names:
• Facial (buccal or labial)
• Lingual
• Incisal or occlusal
• Gingival/Cervical (if inter proximal space not
occupied by tissue or bone)

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Embrasures
Function
– Allow food to be forced away from contact
areas
– Reduce the forces of occlusal forces
– Self-cleansing
– Permit a slight amount of stimulation to the
gingiva

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Facial view Contact areas
• Anterior teeth
– Contact areas: close incisal third
– Except Distal of Canine -middle
third
• Occlusal / Incisal view Contact
areas
– Anterior teeth
• Contact areas in the center from a
facial to lingual direction

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Posterior teeth
• Contacts: more facially
• Middle to Cervical third
• Slightly buccal to the
center
• Lingual embrasure usually
larger

15. Dr. Rooban Thavarajah
Height of contour
• Imaginary curved line encircling a tooth at its
greatest bulge
• Afford correct amount of frictional massage to
gingiva
• Cleansing mechanism
• General rule:
– Contour will vary from tooth to tooth
– Height of contour for both anterior and posterior
teeth is in the cervical third
– Except lingual crest of curvature of posterior teeth
which is near the middle third

16. END OF UNIT
Dr. Rooban Thavarajah