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Permanent Mandibular Incisors.

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Presentation on theme: "Permanent Mandibular Incisors."— Presentation transcript:

1 Permanent Mandibular Incisors

2 Morphology of Mandibular Incisors

3 General of Mandibular Incisors: Description
They are generally the first permanent teeth appear in the oral cavity. C.I. Usually erupts during the seventh year of life and followed within 1 year by the lateral incisors. Mandibular incisors might be referred to as the “moving cutting blades” of the dentition, thereby providing the cutting function of masticatory apparatus.

4 Morphology of Central Incisors

5 Labial Aspect * The narrowest mesiodistally (5.3 mm) [type trait]
a. Crown shape and size (8.8 mm) * The narrowest mesiodistally (5.3 mm) [type trait] * Bilaterally symmetrical [type trait] * Shallow developmental depression. * Mamelon on newly emerged teeth.

6 b. Incisal Proximal Angles
Labial Aspect b. Incisal Proximal Angles * Mesioincisal Angles  sharp form 900 angles * Distoincisal angle  sharp

7 c. Contact Area * Mesial  in the incisal third Type trait
Labial Aspect c. Contact Area * Mesial  in the incisal third Type trait * Distal  in the incisal third

8 d. Root (12.5 mm) * Narrow M.D., wide F.L.
* Tapers uniformly from cervical line to the apex. * Apex curve slightly to the distal. Root to crown ratio is larger than maxillary central incisor. [Arch Trait]

9 Lingual Aspect * Crown outline is symmetrical
a. Lingual fossa - shallow depression. b. Cingulum - convex, small and centered. c. M & D marginal ridge - less prominent. [Arch Trait]. * Root  is narrower from the lingual than labial.  M & D longitudinal depression.

10 Proximal Aspects * Labial surface  incisal to the cervical line.
* Mesially - deep curvature * Distally - less curvature than M.  Crest of curvature * Labial surface  incisal to the cervical line. * Lingual surface  in the cervical third, on the cingulum.

11  Root  Broad and flat  Tapers in the apical third  Blunt apex
Proximal Aspects  Root  Broad and flat  Tapers in the apical third  Blunt apex  Shallow depression on M & D

12 Incisal Aspect * Crown proportions  wide labiolingually [Arch trait].
* Crown outline  triangular Cingulum  centered, narrow convex outline.

13 Morphology of Mandibular Lateral Incisors

14 Labial Aspect  Crown (9.4 mm.)  Asymmetric [Type trait]
 Wider than C.I. (5.7 mm) * Mesioincisal angle  slightly round * Distoincisal angle  more rounded.

15 third, near the incisal edge. * Distal contact area  in the incisal
* Mesial contact area  in the incisal third, near the incisal edge. * Distal contact area  in the incisal third but cervical to the mesial contact area.  Root (13.5 mm) * Narrow M.D. * Tapers from cervical line toward the apex. * Apex curve slightly to the distal

16 Lingual Aspect  Crown - not bilaterally symmetrical  Cingulum small
distally located  Mesial marginal ridge is longer than D.M.R.  Marginal ridges and lingual fossa are not conspicious.

17  Root   Narrower than labial
Lingual Aspect  Root   Narrower than labial  Longitudinal depressions on the proximal surfaces can be seen.

18 Proximal Aspects  Incisal edge - twisted disto - lingually
 Cervical line - less curved than C.I., M. more curved than D.  Crest of Curvature: * Labially - near the cervical in the cervical third. * Lingually - on the cingulum.

19 Proximal Aspects  Root * Its outline is straight from the cervical line to the middle third; then it tapers. * Longitudinal depression mesially and distally, but less distinct on the distal.

20 Incisal Aspect  Crown is broader labiolingually than MD.
 Crown outline is not bilaterally symmetrical.  Incisal ridge contour has a distolingual twist.  Cingulum is slightly off center to the distal.  Labial outline is slightly convex.

21 PULP The pulp cavity is flattened mesio-distally in confirmity with the root shape In the coronal portion similar to its maxillary counterpart The pulp cavity of mandibular lateral incisor is identical to central incisor

22 Comparison

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