Morphology of Incisors

How many lobes do the maxillary and mandibular incisors have

4 lobes (3 facial lobes and 1 cingulum)

Mamelons

three rounded elevations on the incisal edge of the incisors (visible on the lingual side)

Class traits of incisors from the facial view

1. Straight or slightly curved incisal edge

2. crowns are rectangular (longer incisogingivally than they are wide mediodistally)

3. widest at incisal edge and taper towards the cervical line

4. distal outlines are more convex than mesial outlines (EXCEPT mandibular central incisors - symmetrical)

5. mesioincisal angles are sharper than distoincisal angles (EXPECT mandibular central incisors - symmetrical)

6. incisal edge slopes cervically (like this “/”)

7. incisal roots taper from cervical line to the apex

8. roots are wider faciolingually than mesiodistally

9. roots often bend at the apex (EXCEPT maxillary central incisor roots)

Class traits of incisors from the lingual view

1. incisor crowns have less bulk in the lingual half (due to convergence of mesial and distal surfaces)

2. mesial and distal margins converge lingually

3. lingual fossa located incisal to the cingulum

Class traits of incisors from the proximal (mesial/distal) view

1. wedge-shaped/triangular

2. facial surface is more convex cervically compared to the incisal surface

3. facial crest present in the cervical third

4. a convex lingual crest on the cingulum

5. lingual outline is S shaped

6. incisor roots are widest in the cervical third and gradually tapers towards the apex

Class traits of incisors from the incisal view

1. concave lingual fossa

2. incisal ridge at the widest portion of the crown

3. marginal ridges converge from the mesial and distal incisal angles toward the cingulum

4. narrower lingual than labial surface

Differences between mandibular and maxillary teeth

• mandibular crowns are wider faciolingually compared to maxillary which are wider mesiodistally

• mandibular teeth have larger root-to-crown ratio compared to maxillary teeth

• mandibular incisors tip lingually, maxillary incisors tip labially

Traits of the maxillary central incisors from the labial view

• larger crown, wider cervically

• mesial-incisal angle forms near right angle

• less likely to bend at root tip

• incisal edge closer to horizontal

• distal contact at junction of incisal/middle third

Traits of the maxillary lateral incisors from the labial view

• smaller crown, narrowly cervical

• mesial incisor angle is rounder

• distal contact is near middle third

• root tip bends distally

• incisal edge slopes cervically to distally

Traits of the maxillary central incisors from the lingual view

• larger, shallow lingual fossa

• cingulum positioned distally

• less frequent lingual pit

Traits of the maxillary lateral incisors from the lingual view

• deep but small fossa

• cingulum centered on tooth

• more common lingual pit

Traits of the maxillary central incisors from the proximal view

• more concave lingual crown outline

• root outline more convex on lingual surface than the facial surface

Traits of the maxillary lateral incisors from the proximal view

• less concave lingual crown outline

• more even root taper facially compared to lingually

Traits of the maxillary central incisors from the incisal view

• crown wider mesiodistally than faciolingually

• crown outline triangular

• cingulum centre-to-distal

• incisal edge curves mesiodistally

Traits of the maxillary lateral incisors from the incisal view

• crown minimally wider mesiodistally than faciolingually

• crown outline more round than oval

• centered cingulum

• incisal edge straighter mesiodistally

Traits of the mandibular central incisors from the labial view

• more symmetrical crown

• minimal distal and medial bulge of the crown

• proximal contacts on the same level mesial and distal

• smaller than later incisors

Traits of the mandibular lateral incisors from the labial view

• less symmetrical crown

• distally bulge causing crowns to appear to tilt distally

• mesial contact more incisal

• larger than central incisors

Traits of the mandibular central incisors from the lingual view

• centered cingulum

• same length of mesial and distal ridges

Traits of the mandibular lateral incisors from the lingual view

• cingulum distal to the centre

• longer mesial margin line

Traits of the mandibular central incisors from the proximal view

• no distolingual twist

Traits of the mandibular lateral incisors from the proximal view

• distal incisal ridge is more lingual

Traits of the mandibular central incisors from the incisal view

• no distolingual twist on the incisal edge

• cingulum is centred

Traits of the mandibular lateral incisors from the incisal view

• distolingual twist on incisal edge

• cingulum is off centre to distal