It is related to Anterior group Quadrant – 4 quadrants UR, UL, LL, LR – Two incisors in each quadrant Two types central incisors lateral incisors FDI.

• It is related to Anterior group

• Quadrant– 4 quadrants UR, UL, LL, LR

– Two incisors in each quadrant

• Two types central incisors

lateral incisors

• FDI system 12 11 21 22

42 41 31 32

General Description of IncisorsGeneral Description of Incisors

Identify the incisors based on

Class traits Arch traits Type traits

* Incisors * Maxillary * Central Inc

* Canines * Mandibular * Lateral Inc

* Premolars

* Molars

TraitsTraits == Characteristic Features Characteristic Features

Flat crown

Class Trait Mamelons

Marginal ridges

M D

on lingual surface

FunctionsFunctions

• Cutting foodCutting food

• Enabling articulate speech Enabling articulate speech (Phonetic)(Phonetic)

• Helping to support the lip Helping to support the lip

• Maintain a good appearance Maintain a good appearance (Esthetic)(Esthetic)

LocationLocation

• Central incisorsCentral incisors are located on are located on either side of their respective arches either side of their respective arches (max. or mand.)(max. or mand.) with their mesial with their mesial surfaces next to one another at the surfaces next to one another at the midline.midline.

• Lateral incisorsLateral incisors are just distal to the are just distal to the C.I. And their mesial surfaces in C.I. And their mesial surfaces in contact with the distal surfaces of contact with the distal surfaces of the adjacent C.I.the adjacent C.I.

Labial AspectLabial Aspect

A. Crown Shape and SizeA. Crown Shape and Size

* * The crown is the longest The crown is the longest (Incisogingivally 11.2 mm)(Incisogingivally 11.2 mm) of all of all human tooth crown human tooth crown (class trait)(class trait) and also the and also the widestwidest (8.6 mm)(8.6 mm) of all of all incisors incisors (type trait)(type trait)

A. Crown Shape and Size (cont’n.)A. Crown Shape and Size (cont’n.)

** The crown is The crown is narrowestnarrowest in the in the cervical third cervical third ++ broaderbroader toward toward the incisal third.the incisal third.

* * Distal outline of the crown is Distal outline of the crown is more more convexconvex than the mesial than the mesial outline. outline.

Labial AspectLabial Aspect

B. Incisal Proximal AnglesB. Incisal Proximal Angles

** Mesioincisal angle - slightly Mesioincisal angle - slightly rounded, forms a rounded, forms a right angleright angle..

** Distoincisal angle - more Distoincisal angle - more rounded angle, forms rounded angle, forms

obtuse obtuse angle.angle.

Labial AspectLabial Aspect

C. Contact AreaC. Contact Area

** MesialMesial - incisal third - incisal third

** DistalDistal - near the junction of - near the junction of incisal and middle incisal and middle

third.third.

Labial AspectLabial Aspect

D. Root ShapeD. Root Shape::

** It is thick in the cervical third It is thick in the cervical third mesiodistally mesiodistally (only max. (only max.

toothtooth) ) Arch traits

** Narrows through the Narrows through the middle to a blunt apex.middle to a blunt apex.

* * 13 mm long13 mm long..

Labial AspectLabial Aspect

Lingual Aspect:Lingual Aspect:

A. CrownA. Crown

““scoop-like”scoop-like” inform inform

** It is marked by a broad It is marked by a broad depression in its central portion depression in its central portion

lingual fossalingual fossa

** It is bordered by three elevations: It is bordered by three elevations: M+D marginal ridgesM+D marginal ridges and the and the cingulumcingulum

Lingual AspectLingual Aspect

* * CingulumCingulum well developedwell developed

located off-center located off-center toward the distaltoward the distal

All are an All are an [Arch trait][Arch trait]

Lingual AspectLingual Aspect

B. RootB. Root** It is narrower It is narrower b/c b/c convergeconverge lingually.lingually.

* * M M ++ D can be seen D can be seen [Arch Trait][Arch Trait]

* * Mesial side has longitudinal Mesial side has longitudinal

depressiondepression

* * Distal side is convex Distal side is convex

ProximalProximal Aspects (Mesial & Distal)Aspects (Mesial & Distal)

A. CrownA. Crown * * Labial outline is convex in the Labial outline is convex in the

cervical third and nearly flat in cervical third and nearly flat in the middle and incisal third.the middle and incisal third.

Cervical lineCervical line

** It is convex It is convex ** Mesially the curvature is Mesially the curvature is

greater than distally greater than distally [type trait].[type trait].

Proximal AspectsProximal Aspects

A. Crown (cont’n)A. Crown (cont’n)

Crest of CurvatureCrest of Curvature

** Labial surfaceLabial surface - in the cervical - in the cervical third just incisal to the cervical third just incisal to the cervical line line

* * Lingual surfaceLingual surface - in the cervical - in the cervical third on the third on the cingulumcingulum

Proximal AspectsProximal Aspects

B. RootB. Root

* * It is thick or wide at the cervix It is thick or wide at the cervix and tapers to a rounded apex.and tapers to a rounded apex.

** Lingual outlineLingual outline - straight in the - straight in the cervical third then curve labially cervical third then curve labially in the middle and apical third.in the middle and apical third.

** Labial outlineLabial outline - slightly convex - slightly convex

Proximal Proximal AspectsAspects

Root (cont’n)Root (cont’n)

• Mesial SurfaceMesial Surface - longitudinal - longitudinal depression in the middle third.depression in the middle third.

• Distal SurfaceDistal Surface - convex and no - convex and no depressiondepression

Incisal AspectIncisal Aspect

** Crown widthCrown width - wide mesiodistally - wide mesiodistally [class trait][class trait]

** Crown outlineCrown outline - triangular - triangular [type trait][type trait]

* * Labial profileLabial profile - convex from the - convex from the mesial to distalmesial to distal

** CingulumCingulum - off-center to the distal, - off-center to the distal,

Mesial marginal ridge is longer than Mesial marginal ridge is longer than

D.M.R.D.M.R.

** Labial developmental depressions, Labial developmental depressions,

labial grooveslabial grooves

Labial AspectLabial Aspect** Crown shapeCrown shape – oblong-cervico – oblong-cervico incisally incisally

* * Crown sizeCrown size – narrower mesiodistally – narrower mesiodistally

(6.6 mm) (6.6 mm) shorteshorter incisocervically r incisocervically

(9.8 mm)(9.8 mm)

* * Crown outlineCrown outline - less symmetrical - less symmetrical

* * Mesioincisal Mesioincisal angle - roundangle - round

* * Distoincisal angleDistoincisal angle - more rounded - more rounded

* * Mesial contact areaMesial contact area - in the incisal - in the incisal

third or near the junction of incisal third or near the junction of incisal and middle third.and middle third.

* * Distal contact areaDistal contact area - at the - at the

junction of incisal and middle junction of incisal and middle third or at the third or at the middle third.middle third.

** RootRoot - longer - longer (13.4 mm),(13.4 mm), narrower narrower mesio-distally and bent distally.mesio-distally and bent distally.

Lingual AspectLingual Aspect

A. CrownA. Crown

** Lingual fossa - smaller and deep Lingual fossa - smaller and deep

* * Cingulum - narrower and Cingulum - narrower and

centrally locatedcentrally located..

* * Mesial marginal ridge outline - Mesial marginal ridge outline - nearly straightnearly straight

Lingual AspectLingual Aspect

* * Distal marginal ridgeDistal marginal ridge outline - outline - curved cervico incisally andcurved cervico incisally and shorter than M.M.R.shorter than M.M.R.

All more prominent than cent. All more prominent than cent. inc.inc.

B. RootB. Root ** narrower lingually narrower lingually than labially than labially

* * Mesial depression Mesial depression

Proximal Aspects (Mesial & Distal)Proximal Aspects (Mesial & Distal)

** Incisal ridge -Incisal ridge - - thick faciolingually- thick faciolingually - sloped cervically toward the- sloped cervically toward the

linguallingual

** CingulumCingulum - more convex than - more convex than C.I.C.I.

Proximal AspectsProximal Aspects

* * Cervical lineCervical line

- less curved than central- less curved than central- mesial surface more curve- mesial surface more curve than distallythan distally

* * RootRoot- tapered toward the apex- tapered toward the apex

- appears blunt- appears blunt- longitudinal depression on- longitudinal depression on

the mesial surface.the mesial surface.

Incisal AspectIncisal Aspect

* * Crown outline Crown outline - - Round or ovoid Round or ovoid in form. in form.

** Incisal ridgeIncisal ridge - - Straight M.D. Straight M.D. than on the central incisal than on the central incisal..

** Cingulum Cingulum - - Centered M.DCentered M.D..

** Labial outlineLabial outline - - More convex than central. More convex than central.

PulpPulp* The structure of the pulp cavity * The structure of the pulp cavity mirrors mirrors the the

external configuration of the crown and external configuration of the crown and roots in labio-lingual and MD sectionsroots in labio-lingual and MD sections

** The widest diameter of the cavity labio- The widest diameter of the cavity labio- lingually lingually at the level of the cervix .at the level of the cervix .

** In the horizontal cross section pulp cavity In the horizontal cross section pulp cavity is rounded .is rounded .

** No diagnostic differences between the pulp No diagnostic differences between the pulp cavities of the central and lateral maxillary cavities of the central and lateral maxillary incisors . incisors .