General Traits of Incisors, Study notes of Dentistry

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GENERAL

TRAITS OF

INCISORS

Jhommel P. Torreliza, DMD

Jhommell P. Torreliza. DMD F A C I A L V I E W

a. Crown shapes are rectangular; longer

inciso-gingivally than mesiodistally.

b.Crowns taper from the contact areas to

cervical lines.

c.Crown outlines on the distal are more

convex than on the mesial EXCEPT on

mandibular central incisors, which are known

for their symmetry

Jhommell P. Torreliza. DMD a. Roots taper from the cervical line toward the apex (facial and proximal views) and from the facial toward the lingual (best seen on an actual tooth or model). b. Roots are wider faciolingually than mesiodistally(comparing proximal to facial view) EXCEPT maxillary central incisors where dimensions are about equal.

Jhommell P. Torreliza. DMD a. When bent, roots often bend to the distal in the apical third (facial views). b.Roots are slightly-to-considerably longer than crowns (facial and proximal views).

Jhommell P. Torreliza. DMD Cervical lines on the facial (and lingual) surfaces are convex (curve) toward the apex (facial and lingual views). Proximal outlines are wedge shaped (proximal views).

a.Incisal edges terminate mesially and distally at the widest portion of the tooth crown (incisal views). b.Facial outlines are more broadly rounded than lingual outlines due to lingual convergence (incisal views). Jhommell P. Torreliza. DMD

Jhommell P. Torreliza. DMD M a x i l l a r y C e n t r a l I n c i s o r

• (^) Widest among all anterior teeth
• (^) Crown is longest of all maxillary teeth

Jhommell P. Torreliza. DMD M a x i l l a r y C e n t r a l I n c i s o r

• (^) Centered in the maxilla, one on either side of median line, with mesial surface of each in contact with mesial surface of other
• (^) Two in number
• (^) Larger than the lateral incisor
• (^) These teeth supplement each other in function, and they are similar anatomically
• (^) Shearing or cutting teeth
• (^) Major function is to punch and cut food material during the process of mastication
• (^) These teeth have incisal ridges or edges rather than cusps such as are found on canines & posterior teeth

 Crown is 10-11 mm long.  Mesiodistal measurement is 8- mm wide at the contact areas.  Mesiodistal measurement, where the root joins the crown is 1.5 to 2 mm less.  Cervical outline of the crown follows a semicircular direction  Root is cone-shaped, has relatively blunt apex, and the outline mesially and distally is regular.  Root is usually 2-3 mm longer than crown  The mesial outline of the crown is only slightly convex  Distal outline of the crown is more convex than the mesial outline  In the labial aspect, the distoincisal angle is not as sharp as the mesioincisal angle The incisal outline is usually regular and straight incisal outline tends to curve downward toward the center of the crown outline 03 Jhommell P. Torreliza. DMD F a c i a l V i e w

 Faces the tongue  More irregular in form. It has convexities and concavities  The crown has a developed cingulum (also known as linguocervical ridge) and marginal ridges* (a projecting structure)  Mesially and distally confluent with the cingulum are the marginal ridges* (mesial and distal marginal ridge)  Has lingual fossa that is positioned between the marginal ridges 03 Jhommell P. Torreliza. DMD L i n g u a l V i e w

Jhommell P. Torreliza. DMD A V E R A G E D I M E N S I O N S ( i n m m )

03 Jhommell P. Torreliza. DMD M a x i l l a r y L a t e r a l I n c i s o r

• (^) Smaller than the central incisor in all dimensions except root length
• (^) Vary in form more than any other tooth except the 3rd molar
• (^) May be entirely missing in some individuals (anodontia)

Jhommell P. Torreliza. DMD A V E R A G E D I M E N S I O N S ( i n m m )

Jhommell P. Torreliza. DMD T O O T H N U M B E R I N G

• (^) UNIVERSAL SYSTEM - 7, 8
• (^) PALMER NOTATION - 2 2
• (^) FDI SYSTEM - 12, 21