Tooth Anatomy

point part or peak

Molars and Pre-molars: occlusal surface

Canines: incisal edge

Linear prominence

Each cusp tip has four
-mesial cusp ridge, distal cusp ridge, facial (buccal or labial) cusp ridge, and triangular cusp ridge

Cusp slopes or cusp arms

Slopes that converge as the cusp tip to form an angle when viewed from facial aspect

Incisor and Canine Teeth:
-mesial and distal border of the lingual surface
-converge toward cingulum
-cingulum is bump on lingual surface of all anterior teeth on the cervical third

Posterior Teeth:
-mesial and distal borders of occlusal surface

On each major cusp of posterior teeth

From cusp tip to depression (sulcus) on occlusal surface faciolingually

**mesiolingual cusp on maxillary molars has two all other teeth have one

Triangular ridge from facial cusp tip joins triangular cusp ridge from lingual cusp tip

Crosses occlusal surface of tooth in a buccolingual direction

Triangular ridges of buccal cusp tip joins triangular ridge of lingual cusp tip

Triangular ridge of mesiolingual cusp joins triangular ridge of distobuccal cusp

**Only on maxillary molar

**Crosses occlusal surface diagonally

Subtle ridge running cervico-occlusally
on posterior teeth

*Called labial ridge on canines
(most prominent on maxillary canines)

Facial surface of permanent molars and all primary teeth

Runs mesiodistally in cervical one-third of buccal surface crown

Minute horizontal ridges on enamel of newly erupted permanent teeth

Form from overlapping layer of enamel laid down during tooth formation

Lines are closer on cervical third of crown

Small scallops on incisal edge of newly erupted tooth

Formed from one of the three facial developmental lobes

Usually not on adult dentition b/c ware off after tooth comes in functional contact with opposing tooth

Broad depression on occlusal surface of posterior teeth

Inclines of sulcus are formed by triangular ridges that can converge at the bottom of the sulcus in developmental groove

Sharp, narrow linear depression formed during tooth development

Usually separate lobes or major portions of the tooth

In the buccolingual center of sulcus

Runs mesiodistally

May have fossa developmental grooves (triangulare fossa grooves) can be at both mesial and distal ends

Additional grooves that aren't developmental

Small, irregular, and don't occur at junction of lobes or major portions of tooth

Crevice at bottom of any groove

Caused by incomplete fussion of enamel during tooth development

Decay often begins at deepest part of fissure

Small depression

Anterior Teeth: between mesial and distal marginal ridges on lingual surface

Posterior Teeth: between mesial and distal marginal ridges on occlusal surface

Depth of fossa where two or more grooves join

Enamel defects where decay may begin

1. Apex of root
-tip at end
2. Apical foramina
-visible openings where nerves and blood vessels enter tooth pule
3. Cervix
-neck (root and crown unite)

1. Root Trunk
-next to cementoenamel junction and has not yet split
2. Furcation
-where root trunk divides
-bifurcation or trifurcation
3. Furcal Region
-space between two or more roots

Between buccal and lingual cusps

Curve of Spee

Cusp tips of posterior teeth follow curve anteroposteriorly

Maxillary arch is convex and mandibular arch is concave

Curve of Wilson

Side to side curve

Maxillary arch is convex where mandibular is concave

Crest of Curvature

Greatest convexity or bulge

Facial and lingual heights of contour in cervical third

Cingulum on lingual surface

Reason to have is to divert food away from gingiva

Facial surface: cervical third of crown

Lingual surface: middle third of crown

Small spot on mesial and distal surface of tooth which touches adjacent tooth

Greatest heights of contour on proximal surface

Cervical Embrasure

Interdental papilla occupies much of interdental area
(free gingival tissue)

If contact area is too long, gum would be sore b/c pushing onto gum

If contact is not tight enough food gets caught

Open spaces that sweep away from contact area

Allow chewed foods to escape from occlusal surface

Also expose tooth surfaces to oral fluids (i.e. saliva)

By height of contour

Contact location is determined by referring to thirds

1. More anterior the tooth, the more incisial/occlusal are the locations of the proximal contacts

2. On any tooth the mesial contact is more incisial/occlusial than the distal contact
***EXCEPT lower first premolar

IJ JM JM

Central Incisor: incisal third and junction of incisal and middle third

Lateral Incisor: junction of incisial and middle third and middle third

Canine: same as lateral incisor

All have contact areas in incisal third

EXCEPT....

Distal contact of canine at junction of incisal and middle third

Middle third

Distal contact is more cervical than mesial contact

First Premolar
-mesially at the junction of the occlusal and middle third
-distally in the occlusal third

Second Premolar
-mesially occlusal/middle thrid
-distally middle third

Mesially at occlusal/middle third junction

Distally at middle third

IJ, JM, JM, MM, MM, JM, JM, JM

All junctions are either at incisial and middle third or occlusal and middle third

II, II, IJ, JO, JM, JM, JM, JM

All junctions are either incisial and middle third or occlusal and middle third

Determined by location of contact faciolingually

Anterior Region: both embrasures have approximate equal depth
-proximal contacts bwt anterior teeth are centered

Posterior Region: lingual embrasures are deeper
-contacts toward facial surface

Best fitting together of teeth

Maxillary incisial edges overlap mandibular teeth

Maxillary incisial edges extend below incisial edges of mandibular teeth

Buccal cusps and surface of max are buccal to mandibular

Lingual cusps of max rest in occlusal fossae of mandibular

Buccal cusps of mandibular rest in occlusal fossae of max

Lingual cusps and surfaces of mandibular are lingual to max

Mesiobuccal cups of maxillary first molar is aligned directly over mesiobuccal groove on mandibular first molar

Maxillary canine fits into facial embrasure between the mandibular canine and first premolar

Mandibular central incisors

Maxillary last molar

Four lobes

Three facial lobes (three incisally located mamelons)

One lingual (cingulum area)

Four lobes

Three facial

One lingual (cingulum on canine and one lingual cusp on premolar)

Five lobes

Three facial

Two lingual (two lingual cusps)

Generally, each molar cusp forms from one lobe