MANDIBULAR INCISORMandibular 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 INCISOR Mandibular 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 SYSTEMS Universal system24-25
Palmer
1 1
FDI3 1 – 4 1
3141
3.0 2.0 5.3 6.0 3.5 5.0 12.5 9.0
Curvature of Cervical Line M D
LabiolingualDiameter atCervical Line
LabiolingualDiameter atCrest of Curvature
MesiodistalDiameter atCervical Line
MesiodistalDiameter atContact Area
RootLength
Crown 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
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 it’s in contact area
Mesial and distal contact areas are within the incisal third at roughly the same height and it’s near to incisal edge
LABIAL ASPECT
Can have two shallow depressions in the incisal third (similar to maxillary, but far less pronounced)
It’s from incisal edge to cervical third
No Imbrication Line
LINGUAL ASPECT
Mesial contour is like labial surface but som time it’s 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 surface
Cervical 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 it’s oval
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
ROOT The 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 ovoid
ROOT SECTION
MANDIBULAR LATRAL INCISOR Mandibular 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 SYSTEMS Universal system23-26
Palmer
2 2
FDI3 2 – 4 2
3.0 2.0 5.8 6.5 4.0 5.5 14.0 9.5
Curvature of Cervical Line M D
LabiolingualDiameter atCervical Line
LabiolingualDiameter atCrest of Curvature
MesiodistalDiameter atCervical Line
MesiodistalDiameter atContact Area
RootLength
Crown 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
minimal depressions
LABIAL ASPECT
Mamelons are usually present on newly emerged teeth
3 Mamelons (like Maxilary incisor)
LABIAL ASPECT The 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 it’s 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)
It’s from incisal edge to cervical third
minimal depressions(central)
No Imbrication Line
LINGUAL ASPECT not 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
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 surface
Cervical 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(labioligual) and inIncisial third and it’s oval
Distal Contact area (H.ofc) is in central but in incisial andmedial third(only)
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)
From the mesial a distolingual twist of the incisal edge places the distal portion more lingual
Central Lateral
INCISAL ASPECT
The labiolingual measurement of the crown is greater than the mesiodistal measurement
Not bilaterally symmetrical, distal is twisted (Unlike central)
The cingulum is off center to the distal
ROOT The root is single and straight
Root length is normally a little greater than in central incisor
Root is also slightly thicker and wider
Not 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.It may have a distal curvature
The facial and lingual sides of theroot are nearly straight from the cervical line to the middle third
Longitudinal(distal>mesial) grove and …
Root concavities may be found on the mesial anddistal root surfaces, and if present, concavity in distal is usually more pronounced
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 ovoid
ROOT SECTION
MANDIBULAR CENTRAL INCISOR MANDIBULAR LATERAL INCISOR
1. CROWN MORE SYMMETRICAL LESS SYMMETRICAL
2. CROWN & ROOT ARE SHORTER CROWN & ROOT ARE LONGER
3. CINGULUM CENTERED CINGULUM DISTAL TO CENTRE
4. NO DISTOLINGUAL TWIST OF INCISAL EDGE
DISTOLINGUAL TWIST OF INCISAL EDGE
5. MARGINAL RIDGES NOT PROMINENT LONGER MESIAL MARGINAL RIDGE
MAXILLARY INCISORS MANDIBULAR INCISORSLABIAL1. CROWN MESIODISTALLY WIDER & LESS
SYMMETRICALCROWN IS LONG, NARROW & MORE SYMMETRICAL
2. DISTOINCISAL ANGLES MORE ROUNDED MESIOINCISAL SHARP, & DISTOINCISAL ANGLES ARE SLIGHTLY ROUNDED
3. SHALLOW LABIAL DEPRESSIONS ARE COMMONLY PRESENT
NOT PRESENT
LINGUAL1. LARGER CINGULUM SMALLER CINGULUM2. DEEPER LINGUAL FOSSA SHALLOW FOSSA3. SOMETIMES LINGUAL PITS PRESENT LINGUAL PITS ABSENT
4. PROMINENT MARGINAL RIDGES LINGUAL SURFACE SMOOTH, less MARGINAL RIDGES
5 CINGULUM SLIGHTLY DISTAL CENTRAL ALMOST SYMMETRICALPROXIMAL1. CINGULUM IS PROMINENT VERY SMALL CINGULUM2. INCISAL EDGE LABIAL TO ROOT AXIS INCISAL EDGE LINGUAL TO ROOT AXIS
INCISAL
1. CROWNS ARE WIDER MESIODISTALLY THAN FACILINGUALLY
CROWNS WIDER FACIOLINGUALLY THAN MESIODISTALLY
2. INCISAL EDGE LABIAL TO ROOT AXIS INCISAL EDGE LINGUAL TO ROOT AXIS
3. CINGULUM OF CI IS SLIGHTLY DISTALCINGULUM OF LI IS IN CENTRE
CINGULUM OF CI IS CENTEREDCINGULUM OF LI IS SLIGHTLY DISTAL
4. LABIAL SURFACE OF LI IS SLIGHTLY CONVEX CENTRAL & LATERALS HAVE ALMOST FLAT LABIAL SURFACES AT INCISAL & MIDDLE 3rd.