dental anatomy of mandibular incisors permanent teeth

Download Dental Anatomy of Mandibular Incisors permanent teeth

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Permanent Mandibular IncisorsDr.Najdalizade

MANDIBULAR INCISOR

Mandibular central incisor and lateral are similar in anatomy and complement each other in function.The most simple teeth in shapeSmallest teeth permanentCentral a little smaller than the Latral, Unlike the Maxillary IncisorCrowm is a little larger than Maxillary Incisor in incisocervical and Narrow in mesiodistal

MANDIBULAR CENTRAL INCISORMandibular central incisors are two in number

First tooth from the midline in each lower quadrant

bite and cutting

Mesial conatact with each other and distal contact with latral incisor

They are smaller than the maxillary central incisors

erupts at the 7

Narrowest tooth mesiodistally of all permanent teeth

TOOTH NUMBERING SYSTEMSUniversal system24-25

Palmer

1 1

FDI3 1 4 1

3141

3.0 2.0

5.3

6.0

3.5 5.0

12.5

9.0Curvature of Cervical Line M DLabiolingualDiameter atCervical LineLabiolingualDiameter atCrest of CurvatureMesiodistalDiameter atCervical LineMesiodistalDiameter atContact AreaRootLengthCrown Length

Average Dimensions in millimeters

Labial Aspect

The Labial surface is Convex in both Mesiodistal and Incisocervical

The H.OFC and max Convex of This surface is in cervical third

Reverse trapezoid Like rectangular

CEJ

Labial Aspect

Mamelons are usually present on newly emerged teeth

3 Mamelons (like Maxilary incisor)

Labial Aspect

The mesial and distal outlines is straight in the incisal third

The crown tapers to the cervical third

Contacts are well within the incisal one third

Labial Aspect

Mesio and distoincisal angle is nearly 90 degrees

Mesioincisal Sharp than other incisor angle

It is the only incisor where both mesioincisal and distoincisal angles are sharp and at right angles

Labial Aspect

Distoincisal angle may be more rounded than the mesioincisal angle

Labial Aspect

The tooth is so symmetrical it is difficult to tell left from right

Only difference is the mesial cervical line curve more incisally than the distal

Labial Aspect

H.OFC is in the incisal third and its in contact area

Mesial and distal contact areas are within the incisal third at roughly the same height and its near to incisal edge

Labial Aspect

Can have two shallow depressions in the incisal third (similar to maxillary, but far less pronounced)

Its from incisal edge to cervical third

No Imbrication Line

Lingual Aspect

Mesial contour is like labial surface but som time its concave in gingival semi

Distal contour is like labial surface

The Crown incisocervical length is more than labial surface And CEJ is Closer to Apex

No grooves, pits or accessory ridges are present

Marginal ridge

Mesilingual and distolingual Primery Depression seen sometimesin insical part

CEJ

Lingual Aspect

The lingual crown surface is smooth and shallow witha slight concavity in the middle and incisal thirds

The cingulum is convex, small and centered

H.OFC is cingulum

Proximal Aspect

triangle

The labial contour is so slightly curved than cervical third

The lingual contour is convex on the cingulum(1/3), concave in the fossa(2/3)

The lingual margin is S shaped

The cervical line on the mesial and distal surface is convex incisally

CEJ in distal Surface have lower arch

S shaped lingual surfaceCervical line convex incisally

Proximal Aspect

The facial height of contour is located in the cervical third

The lingual height of contour is located on the cingulum, within the cervical third

Contact area is in center and in incisial third and its oval

17

Proximal Aspect

The incisal edge is on or lingual to the long axis of the root

The slope of the incisal edge is to Lingual(occlusion)

Incisal Aspect

The labiolingual measurement of the crown is greater than the mesiodistal measurement

rhombic(Unlike maxilary)

bilateral symmetry (Unlike maxilary)

The incisal edge or ridge is at right angles to the labiolingual root axis plane(Unlike maxilary)

Cingulum have veryfaint tendency to distal

RootThe root is single and straight

From labial or lingual view, root is generally symmetricalt,Root and tapers gradually to a relatively sharp apex

tip may curve to the distal

wide faciolingually

Root is narrow mesiodistally, tapering gradually fromthe cervical line to the apex

The facial and lingual sides of theroot are nearly straight from the cervical line to the middle third

Longitudinal grove and

cross section in CEJ and Mid

Root

In cross section at neck, outline is roughly a rectanglewith rounded corners, but it is slightly wider at labial than at lingual

When there are root concavities present, they are reflectedas concavities in the mesial and distal outlines

The mid root cross section is similar to the cervical section,only more ovoidRoot section

Variations and Anomalies:

Anomalies are rare, but occasionally a bifurcated root is found

MANDIBULAR latral INCISORMandibular latral incisors are two in number

Second tooth from the midline in each lower quadrant

bite and cutting and complements the central in function

Mesial conatact with Central Incisor and distal contact with Canine

slightly wider mesiodistally

Bilateral symmetry not seen

erupts at the 8

slightly larger in all respects than the mandibular central incisor

TOOTH NUMBERING SYSTEMSUniversal system23-26

Palmer

2 2

FDI3 2 4 2

3.0 2.0

5.8

6.5

4.0 5.5

14.0

9.5Curvature of Cervical Line M DLabiolingualDiameter atCervical LineLabiolingualDiameter atCrest of CurvatureMesiodistalDiameter atCervical LineMesiodistalDiameter atContact AreaRootLengthCrown Length

Average Dimensions in millimeters

Labial aspect

Lingual aspect

Mesial aspect

Distal aspect

Incisal aspect

Labial Aspect

The Labial surface is Convex in both Mesiodistal and Incisocervical

The H.OFC and max Convex of This surface is in cervical third

Reverse trapezoid Like rectangular

CEJ

minimal depressions

Labial Aspect

Mamelons are usually present on newly emerged teeth

3 Mamelons (like Maxilary incisor)

Labial AspectThe cervical portion of the lingual aspect is narrower while theincisal portion is wider. This gives the crown a more or less a fanshaped appearance

The crown tapers to the cervical third

Contacts are well within the incisal one third

Mesial and distal contact areas are within the incisal third but not at roughly the same height and The distal contactcervical to the level of the mesial contact

H.OFC is in the incisal third and its in contact area

Contact area on distal is more cervically located than onThe mesial, thus creating a more cervically located height ofcontour on distal outline

Incisal margin may slope slightly gingivally toward distal,which results in a distoincisal angle that is more rounded than same angle of central incisor

This feature creates a slightly shorter distal margin, when compared to mesial outline

Labial Aspect

Labial Aspect

Can have two shallow depressions in the incisal third (similar to maxillary, but far less pronounced)

Its from incisal edge to cervical third

minimal depressions(central)

No Imbrication Line

Lingual Aspectnot bilaterally symmetrical

Crown is tilted distally

Mesial contour is like labial surface

Distal contour is like labial surface

The Crown incisocervical length is more than labial surface And CEJ is Closer to Apex

No grooves, pits or accessory ridges are present

Marginal ridge

Mesilingual and distolingual Primery Depression seen sometimesin insical part

CEJ

Lingual Aspect

The lingual crown surface is smooth and shallow witha slight concavity in the middle and incisal thirds

The cingulum is slightly distal to the long axis of the root,similar to the maxillary central

This makes the mesial marginal ridge longer than the distal

The cingulum is convex, small and centered

H.OFC is cingulum

Marginal ridges and lingual fossa are not conspicuous and generally smooth

Mand. Lat. InciosorMand. Central IncisorMDDM

Proximal Aspect

triangle

The labial outline in the incisal third is slightly convex andin the middle and incisal thirds is nearly flat

The lingual contour is convex on the cingulum(1/3), concave in the fossa(2/3)

The lingual margin is S shaped

The cervical line on the mesial and distal surface is convex incisally

Both cervical line curvatures are slightly less than theircounterparts in the central.

CEJ in distal Surface have lower arch

S shaped lingual surfaceCervical line convex incisally

Central Lateral

Proximal Aspect

The facial height of contour is located in the cervical third

The lingual height of contour is located on the cingulum, within the cervical third

mesial Contact area (H.ofc) is in center(lab

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