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MAXILLARY PERMANENT LATERAL INCISORS

MAXILLARY PERMENENT LATERAL INCISOR

PRESENTING BY AISWARYA DILEEP 1st BDS NO :7

INTRODUCTION

There are four lateral incisors in both arches The Maxillary lateral incisor is a tooth that is located mesially from both side of maxillary central incisors .  Distally from both side of  maxillary canines. It supplements central incisors in function they are similar anatomically . Functions are shearing or cutting food ,helps in speech and support for lips.  

TOOTH NUMBERING SYSTEMSUNIVERSAL SYSTEM - 7,10

ZSIGMONDY / PALMER - 2 2

FDI SYSTEM - 12,22

CHRONOLOGY •First evidence of calcification : 10-12 months•Enamel completed : 4-5 years•Eruption : 8-9 years•Root completed : 11 years

DIMENSIONS

Cervico incisal Length of crown : 9.0 mmLength of the root : 13.0 mm Mesiodistal diameter of crown : 6.5 mmMesiodistal diameter of crown at cervix : 5.0mmLabio or Buccolingual diameter of crown : 6.0 mmLabio or Buccolingual diameter of crown at cervix : 5.0 mmCurvature of cervical line -Mesial : 3.0 mmCurvature of cervical line –Distal : 2.0 mm

ASPECTS

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LINGUAL ASPECT (PALATAL)Marginal ridges and Cingulum are more prominentFossa will be rounded at the mesiomarginal ridge which is straight and longer whereas distal marginal ridge will be slightly curved and small.Root is narrower

MESIAL ASPECTThe crown is shorter and root is relatively long.The curvature of the cervical line is marked in the direction of the incisal ridgeLabial outline of the root from this aspect is straightCingulum often appears more convex in outlineRoot appears as a tapered cone with bluntly rounded apical endLine drawn through centre of the root tends to bisect the incisal ridge of the crown

DISTAL ASPECT

Width of the crown distally appears thicker than it does on the mesial aspect from marginal ridge to labial faceCurvature of the cervical line is usually a millimeter or so less in depth than on the mesial sideA developmental groove present distally on this crown extending on the root The distal contact area is located farther from the incisal margin as compared to the mesial contact area

INCISAL ASPECT

oIt sometimes resembles central incisor or canineoIt is more or less ovoid in formoCingulum may be large ,as is the incisal ridgeoLabiolingual dimensioon may be greater than usual in comparison with mesiodistal dimensionoExhibit more convexity labially and lingually from incisal aspect than maxillary central incisoroThe mesiolabial and distolabial line angles are much more rounded and the lobes of labial surface are less clearly demarcated in the lateral incisors is,because of the high degree of convexity of the labial surface

TRAITS

ARCH TRAITS MAXILLARY LATERAL INCISOR

1. Rectangular , broader crown2. Mesial and distal out line is

convex3. Mesioincisal and distoincisal

angle is rounded 4. Prominent marginal ridge5. Fossa will be deep and ‘V’

shaped

6. More prominent cingulum

MANDIBULAR LATERAL INCISOR

1. Long and narrower mesiodistally

2. Long Mesial and distal out line is straight

3. Mesioincisal and distoincisal angle is straight and sharp

4. Less prominent marginal ridge

5. No fossa 6. Less prominent cingulum

TYPE TRAITS CROWN

1. LABIAL ASPECT

MesiodistallyMesioincisal angle Distoincisal angleMesial profileDistal profile Mesial contact

Distal contact

Labial surface

2. LINGUAL ASPECT

Marginal ridges and cingulum

Lingual fossa

CENTRAL INCISOR

WideSharp (90 degrees)Slightly roundedStraightRoundIncisal third

Junction of incisal and middle thirdsRelatively flat

Moderately pronounced

Moderately deep

LATERAL INCISOR

NarrowSlightly roundedDistinctly roundedSlightly roundedHighly roundedJunction of incisal and middle thirdMiddle third

Rounded

More prominent

Deep

CROWN

3. MESIAL ASPECT

CEJContact area

Cingulum

4. INCISAL ASPECT

OutlineLabial surfaceLobesMesio and Distolabial angles

CENTRAL INCISOR

Moderately curvedIncisal third

Moderately convex

TriangularSlightly convexVisible labiallyProminent

LATERAL INCISOR

Less curvedJunction of incisal and middle thirdConvex

OvoidHighly convexSlightly visible to absentRounded

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