3. 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

4. General Description of Incisors Identify the incisors based on Class traitsArch traitsType traits * Incisors* Maxillary* Central Inc * Canines* Mandibular* Lateral Inc * Premolars * Molars

5. Traits = Characteristic Features Flat crown Class TraitMamelons Marginal ridges M D on lingual surface

6. Functions Cutting foodCutting food Enabling articulate speech (Phonetic) Enabling articulate speech (Phonetic) Helping to support the lip Helping to support the lip Maintain a good appearance (Esthetic) Maintain a good appearance (Esthetic)

7. Location Central incisors are located on either side of their respective arches (max. or mand.) with their mesial surfaces next to one another at the midline.Central incisors are located on either side of their respective arches (max. or mand.) with their mesial surfaces next to one another at the midline. Lateral incisors are just distal to the C.I. And their mesial surfaces in contact with the distal surfaces of the adjacent C.I.Lateral incisors are just distal to the C.I. And their mesial surfaces in contact with the distal surfaces of the adjacent C.I.

9. Labial Aspect A. Crown Shape and Size * The crown is the longest (Incisogingivally 11.2 mm) of all human tooth crown (class trait) and also the widest (8.6 mm) of all incisors (type trait)

10. A. Crown Shape and Size (cont’n.) *The crown is narrowest in the cervical third + broader toward the incisal third. * Distal outline of the crown is more convex than the mesial outline. Labial Aspect

11. B. Incisal Proximal Angles *Mesioincisal angle - slightly rounded, forms a right angle. *Distoincisal angle - more rounded angle, forms obtuse angle. Labial Aspect

12. C. Contact Area * Mesial - incisal third * Distal - near the junction of incisal and middle third. Labial Aspect

13. D. Root Shape : * It is thick in the cervical third mesiodistally (only max. tooth ) * It is thick in the cervical third mesiodistally (only max. tooth ) Arch traits * Narrows through the middle to a blunt apex. * 13 mm long. Labial Aspect

14. Lingual Aspect: A. Crown “scoop-like” inform *It is marked by a broad depression in its central portion lingual fossa * It is bordered by three elevations: M+D marginal ridges and the cingulum

15. Lingual Aspect * Cingulum well developed located off-center toward the distal All are an [Arch trait]

16. Lingual Aspect Lingual Aspect B. Root * It is narrower  b/cconverge lingually. lingually. * M + D can be seen [Arch Trait] * Mesial side has longitudinal depression depression * Distal side is convex

17. Proximal Aspects (Mesial & Distal) A. Crown A. Crown * Labial outline is convex in the cervical third and nearly flat in the middle and incisal third. * Labial outline is convex in the cervical third and nearly flat in the middle and incisal third. Cervical line Cervical line * It is convex * It is convex * Mesially the curvature is * Mesially the curvature is greater than distally [type trait]. greater than distally [type trait].

18. Proximal Aspects A. Crown (cont’n) Crest of Curvature * Labial surface - in the cervical third just incisal to the cervical line * Lingual surface - in the cervical third on the cingulum

19. Proximal Aspects Proximal Aspects B. Root * It is thick or wide at the cervix and tapers to a rounded apex. *Lingual outline - straight in the cervical third then curve labially in the middle and apical third. *Labial outline - slightly convex

20. Proximal Aspects Proximal Aspects Root (cont’n) Root (cont’n) Mesial Surface - longitudinal depression in the middle third.Mesial Surface - longitudinal depression in the middle third. Distal Surface - convex and no depressionDistal Surface - convex and no depression

21. Incisal Aspect * Crown width - wide mesiodistally [class trait] * Crown outline - triangular [type trait] * Labial profile - convex from the mesial to distal mesial to distal

22. * Cingulum - off-center to the distal, Mesial marginal ridge is longer than D.M.R. * Labial developmental depressions, labial grooves labial grooves

24. Labial Aspect *Crown shape – oblong-cervico incisally * Crown size – narrower mesiodistally (6.6 mm) (6.6 mm) shorter incisocervically (9.8 mm) shorter incisocervically (9.8 mm) * Crown outline - less symmetrical * Mesioincisal angle - round

25. * Distoincisal angle - more rounded * Distoincisal angle - more rounded * Mesial contact area - in the incisal third or near the junction of incisal and middle third. * Mesial contact area - in the incisal third or near the junction of incisal and middle third. * Distal contact area - at the junction of incisal and middle third or at the middle third. * Distal contact area - at the junction of incisal and middle third or at the middle third. * Root - longer (13.4 mm), narrower * Root - longer (13.4 mm), narrower mesio-distally and bent distally. mesio-distally and bent distally.

26. Lingual Aspect A. Crown * Lingual fossa - smaller and deep * Cingulum - narrower and centrally located. centrally located. * Mesial marginal ridge outline - nearly straight nearly straight

27. Lingual Aspect * Distal marginal ridge outline - curved cervico incisally and curved cervico incisally and shorter than M.M.R. shorter than M.M.R. All more prominent than cent. inc. B. Root  * narrower lingually than labially * Mesial depression * Mesial depression

28. Proximal Aspects (Mesial & Distal) * Incisal ridge - - thick faciolingually - thick faciolingually - sloped cervically toward the - sloped cervically toward the lingual lingual * Cingulum - more convex than C.I.

29. Proximal Aspects * Cervical line - less curved than central - mesial surface more curve than distally than distally * Root - tapered toward the apex - appears blunt - longitudinal depression on the mesial surface. the mesial surface.

30. Incisal Aspect * Crown outline - Round or ovoid in form. * Incisal ridge - Straight M.D. than on the central incisal. * Cingulum - Centered M.D. * Labial outline - More convex than central.

31. Pulp * The structure of the pulp cavity mirrors the external configuration of the crown and roots in labio-lingual and MD sections *The widest diameter of the cavity labio- lingually at the level of the cervix. *In the horizontal cross section pulp cavity is rounded. *No diagnostic differences between the pulp cavities of the central and lateral maxillary incisors.