Morphology of permanent dentition

Morphology of permanent dentition

DR.Sibtain LiaQat

General information• Humans have two generations of teeth :

deciduous and permanent • By the age of 3 years all deciduous teeth have

erupted .• By 6 years, the first permanent teeth appear and

hence the deciduous teeth are exfoliated one by one replaced by their permanent successors.

• A complete permanent dentition is present at around 18 years .

• 20 teeth – 10 in each jaw. (primary dentition )• 32 teeth – 16 in each jaw.

Numbering systems

Differences between deciduous teeth and permanent :1.The deciduous teeth are smaller, although the

mesiodistal dimension of the permanent premolars are generally less than those for deciduous molar .

2. Deciduous teeth have a greater constancy of shape .3. The crown of deciduous teeth appear bulbous , often

having pronounced labial or buccal cingula .4. the cervical margins of deciduous teeth are more

sharply demarcated and pronounced , enamel bulging rather than gently tapering .

5. the cusps of newly erupted deciduous teeth are more pointed .

6. the crowns of deciduous teeth have thinner enamel ( 0.5-1.0 mm ) than the crowns of permanent teeth (2.5 mm )

7. the enamel of deciduous teeth are more opaque , gives the crown a whiter appearance

8. the enamel is softer and more easily worn in deciduous teeth .

9. enamel is more permeable in dec. teeth .10. the aprismatic layer of surface enamel is

wider in dec. teeth .

11. the enamel and dentine of ALL dec . teeth exhibit neonatal lines .

12. the roots of dec. teeth are shorter and less robust than those of permanent teeth .

13. the roots of dec. incisors and canines are longer in proportion to the crown than those of permanent ones.

14. the roots of the dec. molars are widely divergent extending beyond the dimensions of the crown.

15. the pulp chambers of dec. are proportionally larger in relation to the crown than those of permanent teeth. the pulp horns in dec. are more prominent.

16. the root canals of dec. are extremely fine .17 . the dental arch for dec. dentition are smaller .

Proximal Contact Areas• All teeth contact adjacent teeth at a proximal contact area except:

– distal of the last tooth In the arch– diastemas– pathology (caries)– faulty restorations

Importance:– Ensures food will not be packed between

teeth causing inflammation to the supporting tissues thereby causing gingivitis & periodontitis

– It helps stabilize the dental arches by the combined anchorage of all the teeth in either arch in positive contact with each other (exception - third molars.)

– Each tooth is individually supported by these contact areas.

CONTACTS are OBSERVED from 2 views-• Labial /buccal aspect- demonstrates the cervicoincisal/cervico-occlusal position

• Incisal /occlusal aspect- demonstrates the facio-lingual position

• Anterior teeth have contacts that are generally centered faciolingually when view from the incisal

• Posterior teeth have contacts that are generally located buccal to the center of teeth when viewed from the occlusal

Proximal ContactsMaxillary Mesial DistalCentral incisor Incisal 1/3 Junc of

incisal/middle 1/3Lateral incisor Junc of

incisal/middle 1/3Middle 1/3

Canine Junc of incisal/middle 1/3

Middle 1/3

1st pre Middle 1/3 Middle 1/32nd pre Middle 1/3 Middle 1/31st molar Middle 1/3 Middle 1/32nd molar Middle 1/3 Middle 1/33rd molar Middle 1/3 n/a

Proximal Contacts

Mandibular Mesial DistalCentral incisor Incisal 1/3 Incisal 1/3

Lateral incisor Incisal 1/3 Incisal 1/3

Canine Incisal 1/3 Middle 1/3

1st pre Middle 1/3 Middle 1/3

2nd pre Middle 1/3 Middle 1/3

1st molar Middle 1/3 Middle 1/3

2nd molar Middle 1/3 Middle 1/3

3rd molar Middle 1/3 n/a

1. Contact area move cervically from anterior to posterior in each quadrant

2. On individual teeth the distal contact is more cervically located then the mesial contact

3. Contacts increase in size from anterior to posterior

2

**Note: Contacts on incisors in incisal1/3,Where as contacts on molars in middle /3

LMAXILLARY CENTRAL INCISORabial• It is the widest tooth in the maxillary arch.• The mesial margin is straight and meets the incisal

edge at right angle. The distal margin is shorter and more rounded.

• The distoincisal angle is more rounded than the mesioincisal angle.

Mesial margin straight

& meets at 90 degree

Distal margin shorter & rounded

Distoincisal angle more rounded, making an obtuse angle

Mesioincisal angle rounded, making somewht 90 degrees

The labial surface is marked by two developmental groove and has convexity in cervical third.

Mesiodistally the crown is narrowest cervically, & becomes broadest in the incisal 3rd.

Convexity in cervical third

a b

Lingual aspect• The crown profile is same as that of labial surface except

that there is a broad depression in the central portion called the lingual fossa and a well developed cingulum.

Maxillary incisor with a deep & large lingual fossa & prominent mesial & distal marginal ridges are called as SHOVEL SHAPED INCISOR

Due to the distal displacement of the cingulum, the mesial marginal ridge is slightly LONGER than the distal marginal ridge

Lingual fossa

Cingulum

Marginal ridges

Lingual ridge

The lingual fossa is bordered by mesial and distal marginal ridges on the sides and the cingulum cervically.

The cervical line on labial and lingual surface is convex apically.

Cervical line convex

Lingual aspectLabial aspect

Mesial aspect• From this aspect the crown appears WEDGE SHAPED, with

base of traingle at cervix & apex towards the incisal edge.• From the mesial aspect the labial margin is convex• The lingual margin is ‘S’ shaped, being convex near

cingulum and concave in the middle

Labial margin convex

Convex near cingulum

Concave in the middle

Mesial curvature of cervical line (3.5mm) is the most pronounced compared to any other tooth.

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

Cervical line

Distal aspect

Distal aspect Distal surface is very similar to the mesial

surface. when central incisor viewed from distal aspect,

the crown gives the impression of somewhat thicker towards the incisal 3rd, this is because the distoincisal angle is slightly lingually positioned than mesioincisal angle.

Incisal aspect• The crown and incisal margin are centered over root

• Crown profile is almost bilaterally symmetrical

• The incisal margin of newly erupted teeth show three elevations called mamelons. The middle One is smallest.They correspond to the developmental lobes.

Incisal ridge

Bilaterally symmetrical

RootThe root is straight and tapers from the cervical line to the apex giving it a conical shape

The root ends in a blunt apex.Root : crown ratio is 1.3:1.05

Straight conical blunt root

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Curvature of Cervical Line M D

LabiolingualDiameter atCervical Line

LabiolingualDiameter atCrest of Curvature

MesiodistalDiameter atCervical Line

MesiodistalDiameter of crown

RootLength

Crown Length

Average Dimensions in millimeters

Maxillary Lateral Incisor The general shape is similar to maxillary central

incisors except that they are shorter and narrower.

Next to third molars maxillary lateral incisors are the teeth that show most variation in crown size, shape and form

Maxillary central incisor bigger and lateral incisor smaller

The mesioincisal and distoincisal angles are more rounded than the corresponding angles of the maxillary central incisor

Distoincisal angle more rounded

Mesioincisal angle more rounded

Maxillary Lateral IncisorMaxillary Central Incisor

Mesioincisal angleDistoincisal angle

On the lingual aspect the marginal ridges and cingulum are more prominent

Prominent cingulum

Prominent marginal ridges

MAXILLARY CENTRAL INCISOR MAXILLARY LATERAL INCISOR

LABIALVIEW1. CROWN IS LARGER CROWN IS SMALLER2. MESIOINCISAL ANGLE AT 90 DEGREE &

DISTOINCIAL ANGLE SLIGHTLY ROUNDED

MESIOINCISAL ANGLE IS ACUTE & DISTOINCISAL ANGLE ROUNDED

3. MESIAL CONTACT AREA AT INCISAL 3rd DISTAL CONTACT AREA AT JUNC OF INCISAL & MIDDLE 3rd.

LINGUALVIEW

1. LINGUAL FOSSA LARGER & SHALLOWER LINGUAL FOSSA SMALLER & MORE CONCAVE.

2. LINGUAL PITS ARE LESS FREQUENT LINGUAL PITS ARE COMMON

3. CINGULUM IS POSTIONED SLIGHTLY DISTALLY

CINGULUM IS CENTERED

PROXIMALVIEW

1. CERVICAL LINE CURVATURES ARE MORE CURVATURE IS LESS

2. ROOT IS EVENLY TAPERED ROOT IS MORE CONVEX

INCISAL

1. CROWN WIDER MESIODISTALLY THAN FACIOLINGUALLY

CROWN SAME BOTH MESIODISTALLY & FACIOLINGUALLY

2. CROWN OUTLINE IS TRIANGLULAR CROWN OUTLINE IS ROUNDED OR OVAL

3. CINGULUM SLIGHTLY DISTAL CINGULUM CENTERED

4. INCISAL RIDGE SLIGHTLY CURVED MESIODISTALLY

INCISAL RIDGE RELATIVELY STRAIGHTER MESIODISTALLY

MANDIBULAR INCISORMandibular central incisor and lateral are similar in anatomy and complement each other in function.

Labial aspectLabial surface of mandibular central incisor is very small. It is the narrowest tooth mesiodistally of all the permanent teeth

Narrowest tooth in the dentition

It is bilaterally symmetrical,that it is difficult to tell the sides. The only differnce is the greater mesial than distal curvature.

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

Both mesioincisal and distoincisal angles are sharp

Lingual aspect The lingual aspect is concave from the incisal edge to

the cervical line Cingulum is smooth, barely visible & no development

lines mark the cingulum. Marginal ridges almost absent The surface is smooth and devoid of any grooves. No

other tooth in the mouth, except the mandibular lateral incisor, shows so few developmental lines and grooves.

No lingual pit is present. Root is slightly narrower on the lingual side than on the

labial side.

Mesial aspect Crown is wedge shaped, with the labial outline is

almost straight, except near cervical third where it is convex.

The labial surface is inclined lingually Root has longitudinal shallow depressions on the

middle 3rd of mesial root surfaces.

Labial surface inclined lingually

The lingual margin is ‘S’ shaped

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

‘S’ shaped lingual surface

Cervical line convex incisally

Distalaspect•Distal surface is very similar to the mesial surface.•The cervical line is less curved.

Distal aspect

Incisal aspect•This aspect illustrates the bilateral symmetry of this tooth.•The incisal edge or ridge is at right angles to the labiolingual root axis plane.

•The labiolingual diameter is greater than mesiodistal diameter.• Newly erupted teeth show mamelons which wear off upon mastication

Bilaterally symmetrical

Labiolingually bigger than mesiodistally

Mamelons

RootThe root is single and straight.

The deflection of the root if present is on the labial or distal side.Root : crown ratio is more in all mandibular teeth

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MesiodistalDiameter atContact Area

RootLength

Crown Length


Mandibular Lateral Incisor Mandibular lateral incisor is slightly wider mesiodistally The distal side of the crown from the labial aspect is

slightly bulging in comparison to mesial flatter surface. The crown is slightly tilted distally on the root, & due to

this tilt the distal outline of the crown is shorter in length than the mesial outline.

Bilateral symmetry not seen, Cingulum slightly towards the distal.

The cervical portion of the lingual aspect is narrower while the incisal portion is wider. This gives the crown a more or less a fan shaped appearance

Cervical portion narrower

Fan shaped appearance

The concavity in the lingual aspect is slightly more when compared to mandibular central incisor

The incisal edge follows the mandibular arch, giving the crown a slightly twisted appearance on its root

Lingual fossa more concave

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RootLength

Crown Length


MANDIBULAR CENTRAL INCISOR MANDIBULAR LATERAL INCISOR

1. CROWN MORE SYMMETRICAL LESS SYMMETRICAL

2. CROWN & ROOT ARE SHORTER CROWN & ROOT ARE LONGER

3 NO DISTAL SIDE BULGE ON CROWN DISTAL SIDE BULGE ON CROWN

4. CINGULUM CENTERED CINGULUM DISTAL TO CENTRE

5. NO DISTOLINGUAL TWIST OF INCISAL EDGE

DISTOLINGUAL TWIST OF INCISAL EDGE

6. MARGINAL RIDGES NOT PROMINENT LONGER MESIAL MARGINAL RIDGE

MAXILLARY INCISORS MANDIBULAR INCISORS

LABIAL

1. CROWN MESIODISTALLY WIDER & LESS SYMMETRICAL

CROWN 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

LINGUAL

1. LARGER CINGULUM SMALLER CINGULUM

2. DEEPER LINGUAL FOSSA SHALLOW FOSSA

3. SOMETIMES LINGUAL PITS PRESENT LINGUAL PITS ABSENT

4. PROMINENT MARGINAL RIDGES LINGUAL SURFACE SMOOTH, WITHOUT MARGINAL RIDGES

5 CINGULUM SLIGHTLY DISTAL CENTRAL ALMOST SYMMETRICAL

PROXIMAL

1. CINGULUM IS PROMINENT VERY SMALL CINGULUM

2. 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.

MAXILLARY CANINESCanines are very long and stable teeth

There are four canines placed at the corner of the mouth and hence called the ‘corner stones’ of the

dentition

They have a single pointed cusp (also called cuspids)

Labial aspect The crown of maxillary canine is narrower

mesiodistally than that of maxillary central incisor.

• The incisal aspect has a large cusp with a pointed cusp tip

• It has two slopes (cusp ridges), the mesial slope being shorter than the distal slope

• The labial surface is smooth and bulky in the middle because of the labial ridge, which runs cervicoincisally. All areas lies mesial to this ridge shows more convexity, while distal shows less convexity.

Labial aspect

Labial ridge

Cusp tip

Distal cusp ridge

Mesial Cusp Ridge

Lingual aspect

• The crown and root are narrower lingually

• The cingulum is well developed, large and sometimes pointed like a cusp & in center.

• Occasionally a well developed lingual ridge is seen that divides the lingual fossa into mesial and distal lingual fossae

• Heavy marginal ridges are associated with well formed cingulum and fossae

Lingual aspect

Cingulum

Distal marginal ridge

Distal lingual fossa

Lingual ridge

Mesial marginal ridge

Mesial lingual fossa

Mesial aspect• Crown outline is wedge shaped• From the mesial aspect canine looks similar but

bulkier than maxillary central incisor• Maxillary canine is the widest anterior tooth

labiolingually• The cervical line curvature is towards the cusp

(incisally)• The contact area is near the junction of the incisal

and middle third• From this aspect the entire labial otline is convex

from the cervical line to the cusp tip, & the lingual outline is convex at cingulum, thereafter it straightens out at the middle 3rd & again slight convex in the incisal 3rd.

Mesial aspect

Distal aspect• Distal surface is very similar to the mesial surface• The cervical line exhibits less curvature• The contact area is near the middle third,

Distal aspect

Incisal aspect• The labiolingual dimension is greater than the

mesiodistal dimension• The cusp tip is labial to the centre of the crown

labiolingually and mesial to the centre mesiodistally• Mesiodistally, the mesial half of the crown is narrower,

than the distal half.• The labial ridge and the cingulum are very noticeable

from this aspect.• The mesial half of labial outline is more convex, than

the distal half

Root – only oneThe root is the longest and strongest of all the teeth in the dentition

The mesial and distal surfaces of the root have developmental depressions.

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RootLength

Crown Length


Mandibular CanineLabial aspect Mandibular canines are similar to maxillary canines

except that they are slightly narrower mesiodistally

Mesial outline of the crown is almost straight and inline with the mesial outline of the root. The crown is more towards the distal to the root axis than mesial to it. Because of this crown appears to be distally tilted when the roots are held vertical position.

Cusp tip forms a more obtuse line (120 degree) Labial ridge is very rudimentary, & not as marked as

maxillary canine. The mesial cusp ridge is smaller than the distal cusp

ridge

Lingual aspect The lingual surface of the crown is smooth and flat simulating the

surface of mandibular lateral incisor

Cingulum is less prominent and marginal ridges are less distinct

Mesial and Distal aspects These aspects are very similar and the cervical line curves more

on the mesial aspect

The contact area on mesial aspect is in the incisal third and a little higher on the distal third

Incisal ridge is slightly lingual to the root axis. The distoincisal angle is slightly more lingual in position than the

cusp tip to give turn to the arch.

Incisal aspect Like maxillary canine the labiolingual dimension is more than the

mesiodistal dimension The cusp tip appears inclined in a lingual direction The root is shorter by 1 or 2 mm The developmental depression is more pronounced on the lower

canine

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RootLength

Crown Length


MAXILLARY CANINE MANDIBULAR CANINE

LABIAL

1. APICAL ROOT TIP IS DISTALLY BENT CROWN IS SLIGHTLY TIPPED DISTALLY ON ROOT

2.

3.4. 5.

MESIAL SIDE OF THE CROWN IS LESS CONVEX, WHILE DISTAL IS MORE CONVEXMORE ACUTE CUSP TIP i.e 105 DEGREELABIAL RIDGE IS MORE PRONOUNCEDBLUNT ROOT TIP

MESIAL SIDE OF CROWN IS ALMOST IN STRAIGHT LINE WITH THE MESIAL SIDE OF THE ROOT.120DEGREELABIAL RIDGE IS LESS PRONOUNCEDPOINTED ROOT TIP

120 degree

105 degree

LINGUAL

1. CINGULUM IN CENTRE SLIGHTLY DISTAL TO THE CENTRE

2. STRONG LINGUAL RIDGE & POOR DISTAL MARGINAL RIDGES.

DISTAL MARGINAL RIDGE IS MORE PROMINENT & SMOOTH SURFACE

PROXIMAL

1. ROOT DEPRESSION IS MORE DISTINCT ON THE DISTAL SIDE THAN ON THE MESIAL SIDE

DISTAL ROOT DEPRESSION IS LESS

2. CUSP TIP LABIAL TO ROOT AXIS CUSP TIP LINGUAL TO ROOT AXIS

INCISAL

1.

2.

CROWN IS ASYMMETRICAL, WITH MORE BUCCOLINGUAL BULK IN MESIAL HALF, DISTAL HALF IS THINNER.LESS DISTLINGUAL CROWN TWIST

DISTAL HALF IS SLIGHTLY THICKER.

MORE DISTOLINGUAL CROWN TWIST.

3. ATTRITION OF CUSP TAKES PLACE LINGUALLY

ATTRITION OF CUSP TAKES PLACE LABIALLY

4. INCISAL OUTLINE IS ASYMMETRICAL INCISAL OUTLINE IS SYMMETRICAL

5. CUSP TIP- LABIAL TO CENTER LINGUAL TO CENTER

6. MORE BULKY CUSP TIP DUE TO HEAVY LINGUAL RIDGE

CUSP TIP & LINGUAL RIDGE IS LESS BULKY

MAXILLARY PREMOLARS

Premolars are so named because they are placed between the anterior teeth and the molars

Maxillary premolars have two cusps and sometimes one or two roots

They develop from four lobes, like anterior teeth.

Buccal aspect• The crown is roughly TRAPEZOIDAL• This tooth has two cusps, buccal and lingual cusps. The buccal cusp is long with a pointed tip resembling the cusp of a canine TIP of buccal cusp lies DISTAL to the line bisecting the buccal surface of crown. The mesial slope of the buccal cusp is longer than the distal slope, which is the opposite of canine

The buccal surface is convex, showing a strong buccal ridge

The crown exhibits little cervical line curvature Mesial & distal side of the buccal ridge from the occlusal tothe middle 3rd, shows development depressions k/a mesiobuccal &

distobuccal development depressions.

Lingual aspect crown tapers towards the lingual aspect Mesial outline of the crown is convex. Distal outline is straight. The lingual cusp is shorter than the buccal cusp

The lingual cusp is smooth from the cervical portion to the area near the cusp tip

The cusp tip is pointed with mesial and distal slopes meeting at an angle of about 90 degrees

90 degree

Sometimes lingual ridge is present, formed by termination of crest of lingual portion at a point. Small portion of the buccal cusp can be seen from this aspect• Lingual root is slightly shorter than the buccal root.• Apex of lingual root- more blunt buccal root- pointed.

Mesial aspect From this aspect crown appears roughlyTRAPEZOIDAL, with longest uneven arm Towards the cervical 3rd, while shortest Arm at occlusal 3rd. From this aspect both the buccal and lingual cusps are visible Tips of cusp are within the confines of root trunk of the same side A well developed mesial marginal ridge and a mesial marginal developmental groove is present Buccal outline- curves outwards from the cervical line

till the crest of curvature, & from crest of curvature it shows less convexity.

Lingual outline from cervical 3rd to the lingual cusp tip forms a smooth curve.

There is a depression at just cervical to the mesial contact area k/a MESIAL DEVELOPMENTAL DEPRESSION.. This feature differentiates it from right & left & also from second premolar

ROOT- •The outline of the crown bucally is straight, with a tendency towards the lingual inclination • Lingual outline also straight.

• Bifurcation is present at half of total length of root.

Distal aspect

There is no developmental depression or groove on this aspect, instead it is convex at almost all pointsThe curvature of the cervical line is less on this aspectThe contact area is near the junction of occlusal and middle third.Bifurcation of root is more towards the apical 3rd.

Occlusal aspect The occlusal aspect is roughly hexagonal(6 sided i.e

MB, M,ML,DB,D,DL) in shape. With mesial side shorter than the distal side. Buccal sides are nearly equal. Mesiolingual side is shorter than distolingual side.

The buccolingual dimension of the crown is much greater than the mesiodistal dimension

The occlusal surface is circumscribed by the cusp ridges and marginal ridges

Following structures can be seen- • The distance from the buccal crest to the distal crest is

shorter than the distance from the buccal crest to mesial crest.

• The distance from the mesial crest to the lingual crest is much shorter than the distance from the distal crest to the lingual crest.• Buccal portion of the crown is more wider than the lingual portion.• Central developmental groove- Runs mesiodistally with pits at both ends. The length of central groove is more than one third of the mesiodistal width of occlusal surface.

• Mesial marginal developmental Groove- it crosses the mesial marginal ridge. This groove connects the central groove in the mesial triangular fossa.• Distal marginal groove may be found, but less frequent than mesial marginal groove• Mesial and distal developmental pit - are closer to each other than in 2nd premolar.• Mesial and distal triangular fossa• Buccal and lingual triangular ridge, buccal ridge more prominent arising from the central

groove & converging with the tip of the buccal cusp.• Lingual cusp is more pointed, than buccal cusp.

Root Most Maxillary first premolars have 2 roots, but one and three roots can also be seen. Two roots; buccal and lingual

The buccal portion of the root resembles canine The root when viewed from the proximal side shows a big trunk and bifurcation area from where the buccal and lingual root separate

A developmental depression is seen on the mesial aspect of the trunk.

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RootLength

Crown Length


Maxillary 2nd PremolarBuccal aspect The maxillary second premolar resembles the maxillary

first premolar in form and function The buccal cusp is not as long as that of maxillary 1st premolar It is less pointed. The mesial slope of the buccal cusp ridge is shorter than the distal cusp ridge, as in maxillary canine. Crown & root are thicker at the cervical portion.

Lingual aspect The lingual cusp is more or less the same size as the buccal cusp Root is single, & tapered towards apex & towards the lingual side.

Mesial and Distal aspects There is greater distance between the cusps which widens the occlusal surface buccolingually. No developmental depression is present nor any developmental groove crossing the marginal ridge on the mesial aspect On the distal aspect there is a developmental depression which is deeper than the depression on the mesial surface of maxillary 1st premolar

Occlusal aspect The occlusal aspect is more rounded/ oval The central developmental groove is shorter, & mesial marginal groove is absent. Triangular fossae are smaller & farther from marginal ridges. Mesiodistal diameter is more on the buccal side than the lingual side. There are multiple supplementary grooves radiating from the central groove

• Root Maxillary 2nd premolar has one root, which is

usually as long or a millimeter longer than the root of maxillary 1st premolar

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RootLength

Crown Length


MAXILLARY 1ST PREMOLAR MAXILLARY 2ND PREMOLAR

BUCCAL

1. BUCCAL RIDGE IS PROMINENT NOT PROMINENT

2. MESIAL CUSP SLOPE IS LONGEST MESIAL CUSP SLOPE SHORTEST

3. CERVIX NARROW & TAPERS MORE CERVIX BROAD & TAPERS LESS

LINGUAL

1. LINGUAL CUSP SHORTER THAN BUCCAL CUSP

LINGUAL CUSP ALMOST EQUAL TO BUCCAL CUSP

2. CROWN NARROWER & MORE TAPERS TOWARDS LINGUAL

LESS TAPER TOWARDS LINGUAL

PROXIMAL

1. TWO ROOTS ONE ROOT

2. BUCCAL CUSP IS LONGER THAN LINGUAL

BUCCAL & LINGUAL OF SAME LENGTH

3. CUSP TIP ARE CLOSE TOGETHER CUSP TIPS ARE SPREAD APART

4 MESIAL MARGINAL RIDGE GROOVE IS PRESENT

MESIAL MARGINAL RIDGE GROOVE IS ABSENT

OCCLUSAL

1. LONGER CENTRAL GROOVE SHORTER CENTRAL GROOVE

2. MORE CONVERGENCE OF PROXIMALS TOWARDS LINGUAL

SLIGHT CONVERGENCE TOWARDS LINGUAL

3. PROMINENT BUCCAL RIDGE LESS PROMINENT RIDGE

4. BUCCAL CUSP INCLINES ARE LONGER THAN LINGUAL

LINGUAL CUSP INCLINES ALMOST EQUAL TO BUCCAL

6. VERY FEW SUPPLEMENTARY GROOVES MORE SUPPLEMENTARY GROOVES

7. MESIAL SIDE SHORT & SLIGHTLY CONCAVE OR FLATDISTAL SIDE CURVED OR CONVEX OR LONGER

BOTH MESIAL & DISTAL OUTLINES OF CROWN ARE MORE SYMMETRICAL

8. CROWN OUTLINE HEXAGONAL CROWN OUTLINE IS OVAL

9. MESIAL MARGINAL RIDGE GROOVE IS PRESENT IN 97% OF CASES

LESS COMMON, PRESENT IN ONLY 37% OF CASES

10.

MESIOBUCCAL CUSP RIDGE & MARGINAL RIDGE MEETS AT RIGHT ANGLE

MESIOBUCCAL CUSP RIDGE & MARGINAL RIDGE MEETS AT OBTUSE

Mandibular First Premolar

Buccal aspect A large well formed, pointed buccal cusp is seen.. The mesiobuccal cusp ridge is shorter than the distobuccal cusp ridge (similar to canines) Tip of buccal cusp is locateda liitle MESIAL to the centre of the crown buccally. The mesial and distal slope of the buccal cusp sometimes show concavity. Mesial & distal outline of the crown is Slightly concave above the cervical line.

Lingual aspect The crown tapers and inclines lingually, Making it narrower mesiodistally The lingual cusp is small, pointed and nonfunctional and in some specimens it is no longer than the cingulum of maxillary canine. Between the mesiobuccal and lingual lobe is the mesiolingual developmental groove, & extends into the mesial fossa ofOcclusal surface.• This grooves separates the mesial marginal ridge from mesial slope of lingual cusp.• Occlusal surface slopes greatly towards the lingual in a cervical direction down to the short lingual cusp.

• Root tapers more on the lingual side.• A smooth convex narrow linear ridge runs along the full length of the

root, because of this ridge & lingual taper most of the proximal surface is visible from this aspect.

Mesial aspect The lingual inclination of the crown can be seen from this aspect,because of which the tip of buccal cusp is nearly centered over the root axis• Buccal outline is prominently curved.• Crest of curvature on buccal side- just occlusalTo the cervical line, lingual side- near the tip of the lingual cusp. The lingual cusp is approximately two thirds the size of the buccal cusp The mesial marginal ridge has extreme lingual slope, it is located cervically as comparedto distal marginal ridge. The mesial marginal ridge is almost parallel to the triangular ridge of the buccal cusp, & slopes cervicallyFrom bucccal towards the centre of occlusal surface at 45Degree angle.

2/3rd

Mesiolingual developmental groove is present between the mesial marginal ridge and the mesiolingual cusp ridge The distal contact areas are in the middle third,.

• Root- buccal & lingual outline almost runs parallel in cervical & middle 3rd, then tapers apically to end in a pointed apex, situated in line with buccal cusp tip.

Distal aspectConvexity on the distal surface is less as compared to mesial surface. Distal marginal ridge is higher ( occlusal) and does not have the extreme lingual slopeThe cervical line curvature is less curved.Root surface is more convex as compared to mesial surface.A shallow linear developmental depression On distal root surface.

Occlusal aspect The crown converges sharply to the centre of the

lingual surface Crown appears asymmetrical, being somewhat

DIAMOND SHAPE. distal outline is more convex, there appears to be

more bulk in the distal half of occlusal aspect. Most common form of mandibular 1st premolar shows

a mesiolingual depression and mesiolingual developmental groove.

• The occlusal surface has two depressions; mesial and distal fossae, both of them are circular in shape, hence not termed as triangular fossae

• Mesial fossa is more linear, & contains mesial developmental groove, extending buccolingually.

• Distal fossa is more circular in shape & harbours a cresent shaped distal developmental grove.

• Mesial marginal ridge is at an acute angle with the mesiobuccal cusp ridge

• Distal marginal ridge is at right angle to the distobuccal cusp ridge.• Distal ridge more bulky than mesial marginal ridge.

Root The mandibular 1st premolar has one root

The root is approximately (3-4mm)shorter than the root of mandibular canine but the outline bears a close resemblance to the canine

A deep developmental groove is seen on the mesial aspect on the root

On the distal aspect there is a shallow depression devoid of any developmental groove.

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Mandibular Second Premolar Mandibular 2nd premolar resembles the mandibular 1st

premolar from the buccal aspect only

The crown assumes two common types. more common 3-cusp type- more angular 2-cusp type- more rounded

The two differ mainly in the occlusal designBuccal aspect The buccal cusp is shorter with the cusp slopes

presenting less degree of angulations

Lingual aspect There may be one or two lingual cusps – mesiolingual and distolingual cusps The cusp are more developed than the lingual cusp of lower first premolar • groove separates the two lingual cusps. 2 cusp type- no groove but a distolingual developmental depression appears where the lingual cusp ridge joins the distal marginal ridge 3 cusp type- there is a longer mesiolingual & a comparatively smaller distolingual cusp. A groove is present between the two cusps

Mesial and Distal aspects The crown and root are wider buccolingually Buccal cusp is shorter. Mesiolingual developmental groove absent More of occlusal surface is visible form the distal aspect because the distal marginal ridge is at lower level than the mesial marginal ridge

Occlusal aspect From the occlusal aspect the 3-cusp type appears

square and the 2-cusp type appears rounded.3-cusp type: each cusp is separated by deep developmental

grooves forming a “Y” shape in the centre - BUCCAL cusp largest, then ML & DL shortest. - the occlusal surface also includes

a. central pitb. mesial developmental groove travels in a mesiobuccal direction & ends in mesial triangular fossac. mesial triangular fossad. distal developmental groove travels

in a distobuccal direction & end in distal triangular fossa.

e. distal triangular fossaf. lingual developmental grooveg. supplemental grooves

2-cusp type: - one buccal cusp and one well developed lingual cusp

is present - crown outline is less oval on the lingual side. - a central groove travels in a mesiodistal direction and end in mesial and distal fossa (forming ‘H’

shape) - buccolingual bulk is more in the mesial half than the

distal halfRoot-Mandibular 2nd premolar has a single root which is larger and longer than the root of mandibular 1st premolar

The root is usually wide with a blunt apex

MANDIBULAR 1ST PREMOLAR MANDIBULAR 2ND PREMOLAR

BUCCAL

1. PRESENCE OF LONGER BUCCAL CUSP CROWN IS SHORTER BUT WIDER.

2. MORE POINTED CUSP(110 DEGREE) ROUNDED CUSP (130 DEGREE)

3. NOTCH PRESENT ON MESIAL CUSP SLOPE NOTCH ON DISTAL CUSP SLOPE

4. LINGUAL SURFACE MORE TAPER FROM CONTACTS TO CERVIX

LINGUAL SURFACE RELATIVELY WIDER AT CERVIX

5. ROOT IS SHORTER WITH POINTED APEX ROOT IS LONGER WITH BLUNT APEX

6. BUCCAL RIDGE MORE PROMINENT LESS PROMINENT

110 DEGREE 130 DEGREE

LINGUAL

1. CROWN IS NARROWER THAN SECOND PREMOLAR

CROWN IS WIDER

2. LINGUAL CUSP IS SHORT & NARROW & NONFUNCTIIONAL

LINGUAL CUSP LARGER & FUNCTIONAL

3. FROM THIS ASPECT MORE OF OCCLUSAL SURFACE IS VISIBLE

VERY LESS OCCLUSAL SURFACE IS VISIBLE

4 MESIAL MARGINAL RIDGE IS DIVIDED BY MESIOLINGUAL GROOVE

MESIAL MARGINAL GROOVE IS ABSENT

PROXIMAL1. LINGUAL CUSP MUCH SHORTER THAN

BUCCAL CUSP & NON FUNCTIONALLINGUAL CUSP ONLY SLIGHTLY SHORTER THAN BUCCAL CUSP & IS FUNCTIONAL

2. CROWN IS MORE TILTED TO LINGUAL SIDE CROWN IS LESS TILTED TO LINGUAL SIDE3 MESIAL MARGINAL RIDGE IS LOWER &

PARALLEL TO TRIANGULAR RIDGE OF BUCCAL CUSP, HENCE MUCH OF OCCLUSAL SURFACE IS VISIBLE

MESIAL MARGINAL RIDGE IS HIGH & IS IN HORIZONTAL PLANE, HENCE ONLY LITTLE OCCLUSAL SURFACE IS VISIBLE

4. ROOTS HAVE DEEP LONGITUDINAL DEPRESSIONS

NO DEPRESSIONS PRESENT.

OCCLUSAL

1. CROWN OUTLINE IS ASYMMETRICAL OUTLINE IS SQUARE

2. SMALL OCCLUSAL & LESS GRINDING SURFACE LARGE OCCLUSAL & MORE GRINDING SURFACE.

3. CONVERGENCE OF MESIAL SIDE TOWARDS LINGUAL IS MORE

VERY SLIGHT CONVERGENCE. 3 CUSP - CROWN WIDER LINGUALLY.

4. PRESENCE OF TWO CIRCULAR FOOSAE, TWO GROOVES( MESIAL & DISTAL)

2 CUSP- 2 CIRCULAR FOSSAE3 CUSP-3 FOOSAE, & 3 GROOVES ( MESIAL, DISTAL & LINGUAL)

SOME TERMINLOGIES-• RIDGE- is any linear elevation on the surface of a

tooth & is named according to its location i.e buccal,incisal or marginal ridge

• FOSSA- it is an irregular depression or concavity. Eg central fossa are on the occlusal surface of molars, formed by the convergence of ridges terminating at a central point in the bottom of the depression where a junction of grooves occurs.

• SULCUS- it is a long depression or valley in the surface of a tooth between ridge or cusp

• GROOVE- it is a shallow linear depression on the surface of the tooth

• DEVELOPMENTAL GROOVE- it is a shallow groove or line between the primary part of the crown or root.

• SUPPLEMENTAL GROOVES- it is less distinct & does not mark the junction of primary parts

• PITS- a small pinpoint depression located at the junction of developmental grooves or at terminals of those grooves

Maxillary First Molar

It has a large crown with four well developed cusps and occasionally a small fifth cusp. In addition to the cusps it has three well formed roots; two buccal and one lingual.

Buccal aspect The crown is roughly trapezoidal• two buccal cusp. Mesiobuccal & distobuccal cusp • MB cusp is broader, as its mesial slope Meets its distal slope at an obtuse angle.• DB cusp- its mesial slope meets the distalSlope at approx rite angles. Therefore the DB cusp is sharper. MB surface of crown is longer & wider than DB surface.• Part of mesiopalatal and distopalatal cusps are seen from this aspect as the distopalatal line angle is obtuse• The buccal developmental groove divides the two buccal cusps.this grooves mostly ends in a buccal pit.

• Mesial outline of crown is straight, while distal outline is convex from this aspect.

• All 3 roots are visible from the buccal aspect.• MB root curves distally, starting at the middle 3rd.

distal root is straighter.• Point of bifurcation of the 2 buccal roots is approx at 4mm from the cervical line.• Point of bifurcation of the palatal root is approx 3mm • The common root base is k/a root trunk.

4mm

Lingual aspect• General outline of lingual aspect is reverse of buccal aspect

• The mesiopalatal, distopalatal and fifth cusp are the only cusps seen from this aspect

• Mesiopalatal cusp is largest of all the cusps. Its MD width is about 3/5th of the MD crown diameter. Its mesial & distal slopes meet at 90degree or so. • Distopalatal cusp is small and spheroidal & smooth.

The lingual developmental groove separates the lingual cusps

3/5th

• Sometimes a fifth cusp called the cusp of carebelli may be present.When present it attached to the mesiopalatal surface of the mesiopalatal cusp. This morphological trait can take the form of a well developed fifth cusp, or it can grade down to a series of grooves, depressions, or pits on the mesial portion of the lingual surface.

• All 3 roots are visible,palatal root is the largest, with bluntly rounded apex.

Mesial aspect• Mesiobuccal, mesiopalatal and fifth cusps are visible from this aspect also

• Mesial marginal ridge is placedHigher & is confluent with the mesiobuccal and mesiopalatal cusp ridges and is curved cervically

• The cervical line is irregular, curving occlusally

Mesial aspect

Distal aspect Distobuccal and distopalatal cusps are seen

The marginal ridge dips sharply cervically, exposing triangular ridges on the distal portion.

The cervical line is almost straight.

Concavity present on the distal Surface of the DB root,from the cervical line to the area of the root that is on a level with birfurcation separating the DB & lingual roots.

Occlusal aspect• The occlusal aspect is roughly rhomboidal in shape. Acute

angles- MB,DL obtuse angles-ML & DB.• Lingual side of crown is slightly wider than the buccal side,

& mesial side is wider than the distal side.• Maxillary first molar crown is wider mesially than distally

and wider lingually than buccally• The triangular arrangement of 3 imp molar cusp is called as

the MAXILLARY MOLAR PRIMARY CUSP TRIANGLE.• The elevations and depression on this surface are: 1. Cusps

• Mesiopalatal cusp is the largest followed by mesiobuccal, distopalatal, distobuccal, and the smallest being the fifth cusp.

2. Ridges Mesial marginal ridge and distal marginal ridge Oblique ridge( union of MP & DB cusp ridges)

3. Fossae Major fossae: central fossa (roughly triangular &

mesial to the oblique ridge) and distal fossa (roughly linear & distal to the oblique ridge)

Minor fossae: mesial triangular (immediately distal to the MMR) and distal triangular( immediately mesial to the DMR)

4 Grooves Central developmental groove Buccal developmental groove Lingual developmental groove

Fifth cusp groove5. Pit

Central developmental pit( from it the buccal development groove radiates bucally)

Transverse groove of the oblique ridge ( runs mesiodistally across the oblique ridge)

Supplemental grooves

RootMaxillary first molar has three roots; two buccal and one palatal

The palatal root is long and slender with bluntly round apex

Mesiobuccal root is broader and curves distally while the distobuccal root is narrower at the base and a lot straighter

Both the buccal roots are of equal size but smaller than the palatal root

The level of bifurcation area is more closer to the cervical area on the mesial side than on the distal side.

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Maxillary Second MolarThe crown is shorter cervico-occlusally(0.5mm) and about the same width buccolingually when compared with maxillary first molar.

The distobuccal cusp is not as well developed and the distolingual cusp is also small. The fifth cusp is absent

The roots are almost the same size as that of the first molar. Roots are more inclined distally

The apex of the lingual root is in line with the DL cusp tip instead of the lingual groove as was found on 1st molar- buccal aspect.

• Less prominent oblique ridge is present.• Occlusal parallelogram is more twisted & is

faciolinguallly more oblong, whereas the first molar is wider & squarish.

• Buccal groove is shorter & mostly without a buccal pit.

MAXILLARY 1ST MOLAR MAXILLARY 2ND MOLAR

1. CROWN IS LARGER CROWN IS SMALLER

2. OCCLUSAL OUTLINE IS ROUGHLY RHOMBOIDAL

OCCLUSAL OUTLINE- MORE OBLONG, BECAUSE OF THE REDUCED MESIODISTAL DIMENSIONS

3. CUSP OF CARABELLI IS PRESENT CUSP OF CARABELLI IS ABSENT

4. PROMINENT OBLIQUE RIDGE LESS PROMINENT OBLIQUE RIDGE

5. DISTOPALATAL CUSP IS LARGER THAN DISTOBUCCAL CUSP

BOTH DISTAL CUSPS ARE COMPARATIVELY SMALLER

6. OCCLUSAL TABLE IS WIDER & MORE SQUARISH

OCCLUSAL PARALLELOGRAM IS MORE TWISTED

7. BUCCAL GROOVE LONGER & ENDING IN A BUCCAL PIT

BUCCAL GROOVE SHORTER & WITHOUT A BUCCAL PIT.

8. LESS PROMINENT BUCCAL CERVICAL RIDGE

MORE PROMINENT BUCCAL CERVICAL RIDGE

Mandibular Molars Mandibular molars are the biggest teeth in

the mandibular arch.

They have two broad roots for superior anchorage.

The crown of lower molars are wider mesiodistally than buccolingually, the

opposite is true of upper molars.

Mandibular First Molar

It has five cusps ; two buccal, two lingual and one distal

It has two roots; one mesial and one distal

Buccal aspect The crown is roughly trapezoidal from this aspect• MB cusp is largest, widest & highest on buccal side• DB cusp is slightly smaller, shorter & may be Sharper than the MB cusp. • Distal cusp is present On the distobuccal angle of the crown.

• Two developmental grooves appear on this aspect; mesiobuccal (longer & deeper) and distobuccal developmental grooves.

• A cervical ridge is found near the cervical line. • Point of bifurcation 3mm from the cervical line.

• Mesial root- curved mesially from the cervical portion to the middle 3rd. & then curved distally upto the apex.

• Distal root- less curved, distally from cervical line till apex.

3mm

Lingual aspect• Three cusps may be seen; two lingual and the lingual portion of

the distal cusp• The mesiolingual and distolingual cusps are pointed and have cusp ridges that are high enough to hide the buccal cusps• The lingual developmental groove separates the lingual cusps• The cervical line lingually is irregular.• ML cusp is widest MD,with its cusp tip higher than the DL cusp.• Mesial outline- convex, from cervical to the marginal ridge.• Distal outline-straight from cervical line to a point immediately

below the distal contact area.• Roots appear 1mm longer lingually than bucally,coz the cusp

ridges & cervical lines are at higher level. & MD dimension of the root trunk is less, therefore this slenderness makes roots appear longer.

• Root bifurcation is 4mm below the cervical line.

4mm

Mesial aspect• Two cusps; mesiobuccal and distobuccal cusps, and

one root; mesial root, are visible from this aspect• Crown of mand. 1st molar are slightly lingually tilted.Because of this they fit beneath & lingual to the maxillaryBuccal cusps.• Crown outline is roughly rhomboidal.• The mesial aspect of the tooth is broader and the mesial cusps are higher hence the distal portion cannot be seen

• The mesial marginal ridge is confluent with the mesial ridges of the mesial cuspsIt is occlusally positioned hence triangular ridges notVisible.

• The contact are is in near the junction of middle and occlusal third.• Buccal outline CONVEX immediately above the cervical

line.• Lingual outline is STRAIGHT from cervical to the middle

3rd.• Cervical line slopes occlusally.

Distal aspect• The gross outline is similar to the mesial aspect• More of the tooth is seen from this aspect because the distal portion is smaller & distal sloping of occlusal surface. and the buccal and lingual surfaces converge distally• DMR is short & made up of DCR of the distal cusp & DLCR of the DL cusp.• Surface is CONVEX, & apical portion of the root appears

to be more rounded.• The cervical line is usually straight• Distal root is more narrower BL than the mesial root.

Occlusal aspect• The occlusal aspect is roughly hexagonal in shape

• The crown is wider mesiodistally than buccolingually • The buccolingual measurement on the mesial portion

is bigger than on the distal portion• Two mesial cusp are larger than the two distal cusp.• From a development point- all mandibular molars

have 4 major cusps, while maxillary molars have 3 major cusps.

1

2

34

The elevations and depressions on this surface are: 1. Cusps

Mesiobuccal cusp is the largest followed by the two lingual cusps, then the distobuccal, and the smallest being the distal cusp.

2. Ridges-Mesial marginal ridge and distal marginal ridge. Two transverse ridges are present formed by the TRIANGULAR RIDGES OF MB & ML CUSPS, & DB & DL CUSPS.

3. Fossae Major fossae: central fossa( roughly circular, & placed

centrally between the buccal & lingual cusp ridges) Minor fossae: mesial triangular(distal to MMR) and distal

triangular fossae( mesial to DMR)

4. Grooves Central developmental groove Mesiobuccal developmental groove Distobuccal developmental groove Lingual developmental groove Supplemental grooves

5 Pit Central developmental pit

RootsMandibular first molar has two roots; mesial and distal roots

The apical third of the both the roots tend to curve distally

Both roots are wider buccally than they are lingually

Deep developmental depression is found on the root trunk

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MANDIBULAR SECOND MOLAR• Crown is wider mesiodistally than cervicoincisally or

buccolingually• 2 buccal cusps & 2 lingual cusps are present. MB cusp WIDER

than DB CUSP.• The tip of ML & DL cusp are visible from the buccal aspect.• Only one buccal groove, separating the MB & DB CUSPS.• Cervical line almost straight• Mesiolingual cusp is longest & wider than the distolingual cusp.• Both lingual cusps are pointed.• Mesiodistal width at the cervix is greater than that of 1st molar.• Crown & root both converges lingually.

Occlusal aspect of Mandibular 2nd molar

The occlusal aspect of 2nd molar differs considerably from the 1st molar

Shape is roughly rectangular.

The distal cusp and distobuccal groove are absent

The buccal and lingual grooves meet in the centre at right angles. The occlusal surface is roughened by numerous supplemental grooves

The elevations and depressions on this surface are: 1. Cusps

Mesiobuccal, distobuccal, mesiolingual and distolingual cusps2. Ridges

Mesial marginal ridge and distal marginal ridge3. Fossae

Major fossae: central fossa Minor fossae: mesial triangular and distal triangular fossae

4 Grooves Central developmental groove buccal developmental groove Lingual developmental groove Supplemental grooves

5 Pit Central developmental pit

Occlusal aspect of Mandibular Second Molar

MANDIBULAR 1ST MOLAR MANDIBULAR 2ND MOLAR

BUCCAL1. MORE CONVERGENCE OF CROWN LESS CERVICAL CONVERGENCE OF CROWN.2. TWO BUCCAL GROOVES ONLY ONE BUCCAL GROOVE3. CONTACT AREA NOT LOCATED CERVICALLY MORE CERVICALLY LOCATED CONTACT AREA4. LONGER ROOT TRUNK & CURVED ROOTS SHORTER ROOT TRUNKS & STRAIGHTER ROOTS5. ROOTS ARE NOT CLOSER TOGETHER ROOTS ARE CLOSER TOGETHER

OCCLUSAL1. CROWN OUTLINE ROUGHLY

PENTAGONMORE RECTANGULAR OUTLINE

2. CROSS SHAPED GROOVE PATTERN NOT OBSERVED

A CROSS SHAPED GROOVE PATTERN

3. CROWN TAPERS MORE FROM BUCCAL TO LINGUAL.

CROWN TAPER FROM BUCCAL TO LINGUAL IS LESS

4. CENTRAL GROOVE IS ZIG-ZAG CENTRAL GROOVE IS STRAIGHT5. LESS PROMINENT BUCCCAL CERVICAL

RIDGEA MORE PROMINENT BUCCAL CERVICAL RIDGE

MAXILLARY MOLARS MANDIBULAR MOLARS1. CUSPS MOSTLY FOUR, SOMETIMES THREE,

ROOTS THREE (MB,DB,& PALATAL)CUSPS MAINLY FOUR, SOMETIMES FIVE & TWO ROOTS ( MESIAL & DISTAL)

2. CROWN WIDER FACIOLINGUALLY THAN MESIODISTALLY

CROWN WIDER MESIODISTALLY THAN BUCCOLINGUALLY

3. LARGE & SMALL LINGUAL CUSP 2 NEARLY EQUAL SIZED LINGUAL CUSPS.4. 1ST MOLARS- WIDER ON LINGUAL THAN

BUCCAL1ST MOLARS- TAPER FROM BUCCAL TO LINGUAL

5. ONE BUCCAL GROOVE PRESENT TWO BUCCAL GROOVES ARE PRESENT ON 1ST MOLAR

6. OBLIQUE RIDGE IS PROMINENT NO OBLIQUE RIDGE, BUT HAS TWO TRANSVERSE RIDGES

7. FOUR FOSSA, INCLUDING LARGE DISTAL FOSSA

THREE FOSSA (LARGE CENTRAL FOSSAE)

8. OCCLUSAL SURFACE- PARALLELOGRAM IN FOUR CUSP- RECTANGULARIN 5 CUSP- PENTAGONAL

9. ROOT TRUNK SHORTER IN 1ST MOLAR ROOT TRUNK LONGER10. 3 ROOTS- MB, DB, PALATAL 2 ROOTS- MESIAL & DISTAL11. ON VIEWING FROM PROXIMAL SIDE-

CROWN ARE CENTERED ON ROOTSCROWN APPEARS TO BE SLIGHTLY LINGUALLY TILTED.

12. NEAR CERVIX CROWNS ARE NARROW CROWNS ARE NOT NARROW ON CERVIX.

REFERENCES-1. WOELFEL – Dental anatomy & its relevance to dentistry 5th edition2. WHEELERS- Dental anatomy, Physiology, & Occlusion 8th edition3.SATISH CHANDRA- Textbook of Dental & oral anatomy,

physiology & occlusion.

• THANK YOU.

Health & Medicine

Morphology of permanent dentition