Oral Ana Lec #5

- Landmarks of the Tooth

Facial Surface

Facial Surface

• May be labial or buccal surface

• Towards the lips and cheeks

Morsal surface

surfaces in contact when the mouth is in occlusion (closed)

A. Incisal ridge - anterior

B. Occlusal surface - posterior

Cups, ridges, mamelons, tubercles

Elevation on tooth surface

Cusp

• A pointed or round elevation or mound on the crown of a tooth

• Makes up a divisional part of the occlusal surface

• Representative of lobes

Lobe

• is one of the primary sections of formation in development of crown of a tooth.

Mamelons

are three rounded protuberances found on incisal ridges of newly erupted incisor teeth.

Ridge

A linear elevation on the surface of a tooth a and is named according to its location and or form

A. Marginal ridges:

B. Triangular ridge

C. Transverse ridge

D. Oblique Ridge

E. Labial Ridge

F. Buccal Ridge

G. Lingual ridge

H. Cervical ridge

I. I. Cusp Ridge

Marginal ridges

linear elevations of enamel running buccolingually at the crown of a posterior tooth occlusally. Forms the mesial and distal borders of the crown occlusally.

• Mesial

• Distal

Triangular ridge

• Linear elevation of enamel that descend from the tip of the cusps of molars and premolars going towards the central part of the occlusal surfaces.

• Slopes of each side of the ridge are inclined to resemble two sides of a triangle.

• Named after the cusps to which they belong

Oblique ridges

• Union of two triangular ridges that crosses the occlusal surface of maxillary molars obliquely or diagonally

• Present in second molars but smaller

Labial ridge

linear elevations of enamel running cervico- incisally at the crown of an anterior teeth labially

Buccal ridge

linear elevations of enamel running cervico- occlusally at the crown of a posterior teeth buccally.

Lingual Ridge

linear elevations of enamel running cervico- incisally at the crown of a tooth lingually.

Cervical Ridge

Linear elevation of enamel running mesiodistally on the cervical third of the buccal surface of the crown, found on all deciduous teeth but only on permanent

Cusp Ridge

• Linear elevations of enamel that forms the cusp/s of the teeth.

• There are 2 cusp ridges for each cusp

• MCR & DCR

Pit, Fossa, Sulcus, Groove, and Fissures

Depressions on tooth surface

Pit

A sharp pinpoint depression on the surface of enamel located at the junction or at terminal ends of grooves.

1. Central pit

2. Mesial developmental pit

3. Distal developmental pit

4. Buccal pit

5. Lingual pit

Fossa

An irregular depression or concavity on surface of tooth.

• Central fossa

• Mesial triangular fossa

• Distal triangular fossa

• Distal fossa

• Lingual fossa

Sulcus

A long/broad depression or valley on the occlusal surfaces of posterior teeth, the inclines of which are formed by the triangular ridges.

Groove

Is a shallow linear depression on the surface of a tooth.

Supplementary groove

• A _ less distinct and does not mark the junction of primary parts.

• Small, less distinct, irregularly placed, do not occur at the junction of lobes, radiates out of a major groove

Developmental groove

• A short, shallow groove or line between the primary parts of the crown or root.

• It usually separate lobes or major part of the tooth.

Fissures

A very narrow cleft or crevice at the depth of any groove cause by incomplete fusion of enamel during development where dental caries / decay often begins.

1. U

2. V

3. I

4. IK

5. Inverted Y

Tubercle

• Small bulges on the crown portion

• Extra-formation of enamel

Canine Eminence

Developmental depression

root surface showed longitudinal developmental depression which is deeper distally than mesially

Contact point/area

That part of the proximal surface of tooth which touches the adjacent tooth mesially or distally.

Synonyms: contact point, point of proximal contact.

Crest of curvature

Height of curvature; widest area ng crown from facial/lingual or proximal (mesial/distal)

Diastema

Interproximal space

Usually filled with gingival tissue, this helps prevent food collecting

Embrasure or spillways

• It is an open space between the proximal surfaces of adjacent teeth in the same dental arch. They diverge from the contact area…

  • Occlusally

  • Incisally

  • Buccally

  • Labially

  • Lingually

  • Cervically

Line angle

When two surfaces of a tooth meet, a ____ is formed and

point angle

when three surfaces meet a ____ is formed

Origin of cusp

Mature form of lobe

Sites of cusp

1. Occlusal surface of posterior teeth

2. Incisal third of canine

Shape of cusp

• Pyramidal structure

• 4 surfaces

• 4 ridges

Structure of cusp

• Enamel, dentin, pulp horn

Cone shape

The root is ___ with distal inclination of the apical 3rd

Tubercle

• Marginal ridges of posterior teeth

Tubercle

• Tip of the cingulum of anterior teeth

Cusp Ridge

• Cusp arms

• Mesial/Distal slope

2 parts of cusp

1. Cusp tip

2. Cusp slope

Largest lobe

Mesial

Smallest lobe

Middle

• Deciduous max. 2nd molars

• Permanent max. molars

Which teeth has the oblique ridges?

Facial Surface
Lingual Surface
Proximal Surface
Incisal or Occlusal Surface

Crowns of all teeth have 5 surfaces, namely...

Facial Surface

May be labial or buccal surface

Labial Surface

Surfaces of incisors and canines that are towards the lip

Buccal Surface

Surfaces of premolars and molars that are toward the face cheek

Lingual Surface (Palatal Surface)

Surfaces facing the tongue

Mesial Surface & Distal Surface

Two types of Proximal Surfaces

Mesial Surface

Surface towards the midline

Distal Surface

Surface away the midline

Incisal Edge
Occlusal Edge

Two types of Incisal or Occlusal Surface

Incisal Edge

The surface of incisors and canines that come in contact with those in the opposite jaws during the act of closure are called _____

Occlusal Surface

The surface of the premolars and molars that come in contact with those in opposite jaws during act of closure are called _____

Occlusal Table

Come in contact during mastication. Also known as Occlusal Surface.

Cusp

A pointed or rounded elevation or mound on the crown of a tooth.

Can be found on molars, premolars, cuspid, and bicuspid

Cusp

Peak

Present in occlusal

Chewing grinding

Mesial and Distal Cusp Slope

Inclined surfaces that from an angle at the tip of the two cusps

Mesial and Distal Cusp Slope

2 cusp slopes / cusp ridge slopes

Cingulum

Is the lingual lobe of an anterior tooth and makes up the bulk of the cervical third of the lingual surface.

Maxillary anterior & Permanent dentition

Cingulum is prominent to ______ teeth

Girdle or Belt

Other name of Cingulum in Latin

Lobe

Is one of the primary sections of formation in development of crown of a tooth

Cusps & Mamelons

Representative of lobes

Mamelons

Are three rounded protuberances found on incisal ridges of newly erupted incisor teeth

Mamelons

Small rounded protuberance/ projections

Prominent on edges of newly erupted permanent
incisors maxillary and mandibular

3 Facial / Labial
1 Palatal / Lingual

4 Lobes of anterior teeth

Mesial Lobe
Middle Lobe
Distal Lobe
Cingulum / Palatal Lobe

Name the 4 lobes of anterior teeth

Middle Lobe

Smallest lobe

Grooves

Separates the lobes in mamelons

In posterior teeth, the number of lobes is to the number of cusps

Ridge

A linear elevation on the surface of a tooth and is named according to its location and or form.

Marginal Ridge
Triangular Ridge
Transverse Ridge
Oblique Ridge
Labial Ridge
Buccal Ridge
Lingual Ridge
Cervical Ridge

Types of Ridges

Marginal Ridges

Linear round borders of the enamel that form the mesial and distal margins of the occlusal surfaces of the posterior teeth or the lingual surfaces of the anterior teeth.

Can only be seen on the margins of the teeth

Triangular Ridge

Descends/ inclines from the tip of the cusp towards the center or part of the occlusal surface.

Present only on premolars and molars.

Named according to the cusp and its location

Transverse Ridge

Formed by the union of the buccal and lingual triangular ridges that crosses the surface of the posterior teeth in transverse direction

90

Transverse Ridge: about __ degrees to both the buccal and lingual surfaces

Transverse Ridge

Present particularly on the occlusal surface of premolars and mandibular molars

Oblique Ridge

Is formed by the union of triangular ridges of the mesio-lingual and distal ridge of distobuccal cusp in oblique direction

Oblique Ridge

Present only on the occlusal surface of maxillary deciduous 2nd molar and all the permanent maxillary molars

Oblique Ridge

Is a ridge crossing obliquely the occlusal surfaces of maxillary molars and formed by the union of the triangular ridge of the distobuccal cusp and the distal cusp ridge of the mesio-lingual cusp.

Labial Ridge

On the labial surface of the tooth that runs cervico-incisally almost at the center of the labial s.

Labial Ridge

Prominent labial ridge running from cusp tip to the cervical area

Buccal Ridge

Runs cervico-occlusally approximately at the center of the buccal surface

Lingual Ridge

Found on center of lingual surface of tooth which extends from cingulum to the cusp tip in the permanent canine and posterior teeth

Cervical Ridge, Neck of the teeth

Runs mesio-distally at the cervical third of the labial surface of the crown that is present particularly on the deciduous teeth and only on the permanent molars also known as ____

Mesial Cusp Ridge
Distal Cusp Ridge
Triangular Ridge
Buccal Ridge

Cusp ridge is made up of?

4

Cusp Ridge: Each cusp has ____ cusp ridge extending in different directions from its tip

Inclined Planes

The sloping are found between two cups ridges.

Valley

Pit

A sharp pinpoint depression on the surface of enamel

Fossa

An irregular depression or concavity on surface of tooth

Small Defect

Pit is sometimes called a ____ _____ on the enamel crown of tooth.

Buccal Pit
Central Pit
Lingual Pit

Examples of Pit

Buccal Pit

Terminal part of buccal developmental groove

Central Pit

Center of occlusal fossa where development grooves join

Lingual Fossa

Found on lingual surface of incisors and cuspids

Major Fossa

Central Fossa is considered as?

Minor Fossa

Triangular Fossa is considered as?

Central Fossa

Depressions on center of occlusal surface of maxillary and mandibular molars