morphology of primary maxillary teeth

MORPHOLOGY OF PRIMARY MORPHOLOGY OF PRIMARY MAXILLARY TEETHMAXILLARY TEETH

PRESENTED BY: RAHEL CHARIKARPRESENTED BY: RAHEL CHARIKAR

MAXILLARY CENTRAL INCISORMAXILLARY CENTRAL INCISOR

Labial Aspect:Labial Aspect:• Crown: mesio-distal Crown: mesio-distal

diameter is more than diameter is more than cervico-incisal lengthcervico-incisal length

• Developmental lines Developmental lines not seennot seen

• Root-cone shaped with Root-cone shaped with even tapered sideseven tapered sides

• Root length is greater in Root length is greater in comparison with crown comparison with crown length (in relation to length (in relation to permanent)permanent)


Lingual Aspect:Lingual Aspect:• Well developed marginal Well developed marginal

ridges and a highly ridges and a highly developed cingulumdeveloped cingulum

• Root narrows lingually Root narrows lingually and is flatter labiallyand is flatter labially

• Cingulum extends Cingulum extends towards the incisal ridge towards the incisal ridge and makes a partial and makes a partial division of the concavity division of the concavity on lingual surface , on lingual surface , dividing it into mesial dividing it into mesial and distal fossa.and distal fossa.

MAXILLARY CENTRAL INCISORMAXILLARY CENTRAL INCISOR Mesial and distal aspect:Mesial and distal aspect:• Crown appears thick at

the middle third.• The curvature of the

cervical line, which represents the CEJ is distinct , curving toward the incisal ridge.

• Root- blunt at the apex• Mesial surface of the root-

developmental groove or concavity, whereas distally the surface is generally convex.


Incisal Aspect: Incisal Aspect: • Incisal edge is centered

over the main bulk of the crown and is relatively straight

• Mesial and distal surfaces at the incisal third are generous enough to make good contact areas with the adjoining teeth

MAXILLARY LATERAL INCISORMAXILLARY LATERAL INCISOR

Maxillary lateral is Maxillary lateral is similar to central similar to central incisor from all incisor from all aspect, but its aspect, but its dimensions differ .dimensions differ .

The cervico-incisal The cervico-incisal length is greater than length is greater than its mesio-distal width its mesio-distal width

Disto-incisal angles Disto-incisal angles are more rounded are more rounded

MAXILLARY CENTRAL AND MAXILLARY CENTRAL AND LATERAL INCISORLATERAL INCISOR

Application: root canal are almost round Application: root canal are almost round but somewhat compressedbut somewhat compressed

Have 1 canal without bifurcationHave 1 canal without bifurcation Apical ramifications or accessory canals Apical ramifications or accessory canals

and lateral canals are rare but do occur.and lateral canals are rare but do occur.

MAXILLARY CANINE MAXILLARY CANINE Labial Aspect:Labial Aspect:• Crown is more constricted at

the cervix in relation to its mesio-distal width, and the mesial and distal surfaces are more convex.

• It has a long, well developed, sharp cusp.

• A line drawn through contact area of the deciduous canine would bisect a line drawn from cervix to the tip of cusp.

• The root of the primary canine is long , slender, and tapering and is more than twice the crown length.

MAXILLARY CANINEMAXILLARY CANINE Lingual Aspect:Lingual Aspect:• Pronounced cingulum, mesial

and distal marginal ridges, and incisal cusp ridges that merge with each other .

• Tubercle at the cusp tip, which is continuation of the lingual ridge connecting cingulum and cusp tip.

• lingual ridge divides the lingual surface into shallow mesio-lingual and disto-lingual fossae.

• Root-tapers lingually, inclined distally.

MAXILLARY CANINEMAXILLARY CANINE

Mesial Aspect:Mesial Aspect:• Measurement labio-

lingually at the cervical third is much greater.

• Increase in crown dimension, in conjunction with the root width and length, permits resistance against forces the tooth must withstand during function.


Distal Aspect :Distal Aspect :• Distal outline of this tooth is reverse of the

mesial aspect.• Curvature of the cervical line toward the

cusp ridge is less than on the mesial surface.

MAXILLARY CANINEMAXILLARY CANINE Incisal Aspect:Incisal Aspect:• Crown is essentially

diamond shaped..• Angles that are found at

the contact areas mesially and distally; the cingulum on the lingual surface are more pronounced and less rounded.

• Tip of the cusp is distal to the center of the crown, and the mesial cusp slope is longer than distal cusp slope.


Application: root canals correspond to the Application: root canals correspond to the exterior root shape, a rounded triangular exterior root shape, a rounded triangular shape with base toward facial surfaceshape with base toward facial surface

Lumen of root canal is compressed in Lumen of root canal is compressed in mesial-distal directionmesial-distal direction

Bifurcation does not normally occurBifurcation does not normally occur Lateral and accessory canals are rareLateral and accessory canals are rare

MAXILLARY FIRST MOLARMAXILLARY FIRST MOLAR

Buccal Aspect:Buccal Aspect:• Widest measurements of the

crown is at the contact areas mesially and distally.

• Crown converges toward the cervix, measurement at the cervix being fully 2mm less than the measurement at the contact areas.

• The occlusal line is slightly scalloped.

• In function it acts as a compromise between the size and shape of the anterior primary teeth and the molar area.

• The roots are slender and long, and they spread widely.

• The distal root is considerably shorter than the mesial one.

• The bifurcation of the roots begins almost immediately at the site of the cervical line.

MAXILLARY FIRST MOLAR Lingual Aspect:Lingual Aspect:• The mesiolingual cusp is the most

prominent cusp on this tooth.• Longest and sharpest cusp.• Distolingual cusp is poorly

defined; small and rounded when it exists at all.

• From the lingual aspect the distobuccal cusp may be seen, since it is longer and better developed than the distolingual cusp.

• All three roots also may be seen from this aspect.

• The lingual root is larger than the others.

MAXILLARY FIRST MOLAR

Mesial Aspect:Mesial Aspect:• The mesiolingual cusp is longer and

sharper than the mesiobuccal cusp.• A pronounced convexity is evident

on the buccal outline of the cervical third.

• This convexity is an outstanding characteristic of this tooth.

• The cervical line mesially shows some curvature in the direction of the occlusal surface.

• The mesiobuccal and lingual roots are visible.

• The distobuccal root is hidden behind the mesiobuccal root .The lingual root from this aspect looks long and slender.


Distal Aspect:Distal Aspect:• Distobuccal cusp is long and sharp, and the

distolingual cusp is poorly developed.• The cervical line may curve occlusally, or it may

extend straight across from the buccal surface to lingual surface.

• All three roots may be seen from this angle but distobuccal root is superimposed on the mesiobuccal root

• The point of bifurcation of the distobuccal root and the lingual root is near the CEJ.

MAXILLARY FIRST MOLAR Occlusal Aspect:Occlusal Aspect:• The occlusal surface has a central

fossa.• A mesial triangular fossa is just

inside the mesial marginal ridge, with a mesial pit in this fossa and a sulcus with its central groove connecting the two fossae.

• Buccal developmental groove divides the mesiobuccal cusp and distobuccal cusp occlusally.

• Supplemental grooves radiate from the pit in the mesial triangular fossa as follows: one buccally, one lingually and one toward the marginal ridge, with the last sometimes extending over the marginal ridge mesially.

• Well defined triangular ridge connecting the mesiolingual cusp with the distobuccal cusp.

• When well developed, it is called oblique ridge.

• The ridge is indefinite and the central developmental groove extends from the mesial pit to the distal developmental groove.

• Distal marginal ridge is thin and poorly developed in comparison with the mesial marginal ridge.


Application: 2-4 canals Application: 2-4 canals Palatal root is round and longer than the Palatal root is round and longer than the

two facial rootstwo facial roots 75% cases- bifurcation of mesial-facial 75% cases- bifurcation of mesial-facial

root into two canalsroot into two canals

MAXILLARY SECOND MOLARMAXILLARY SECOND MOLAR

Buccal Aspect:Buccal Aspect:• Two well defined buccal cusps with

a buccal developmental groove between them.

• Crown is narrow at the cervix• Crown much larger than that of first

molar• Point of bifurcation between the

buccal roots is close to the cervical line of the crown

• Two buccal cusps- equal in size and development

MAXILLARY SECOND MOLARMAXILLARY SECOND MOLAR Lingual Aspect:Lingual Aspect:• Crown shows the following cusps:

Mesiolingual cusp, Distolingual cusp, Tubercle of Carabelli- fifth cusp

• Tubercle of Carabelli- apical to mesiolingual cusp, supplemental cusp, acts as a buttress to the bulk of mesiolingual cusp.

• Well defined developmental groove separates the mesiolingual cusp from the distolingual cusp and connects with the developmental groove, which outlines the fifth cusp.

• Three roots are visible- lingual root is large and thick

MAXILLARY SECOND MOLARMAXILLARY SECOND MOLAR Mesial Aspect:Mesial Aspect:• Crown appears short• Crown 0.5 mm longer than crown of first

deciduous molar• Buccolingual measurement 1.5 mm to 2

mm greater• Roots-1.5 to 2 mm longer• Mesiolingual cusp+fifth cusp- appears

larger• Mesiobuccal cusp- short and sharp• Cervical line-straight across from buccal

surface to lingual surface• Mesiobuccal root-broad and flat• Point of bifurcation between mesiobuccal

root and lingual root is 2 to 3 mm apical to the cervical line of the crown


Distal Aspect:Distal Aspect:• Outline of crown-lingually: smooth rounded line,

bucally:almost straight• Distobuccal and distolingual cusp- same in length• Cervical line- approx. straight• All three roots seen- distobuccal root superimposes

over mesiobuccal• Distobuccal-shorter and narrower• Point of bifurcation between the distobuccal root and

lingual root is more apical in location

MAXILLARY SECOND MOLARMAXILLARY SECOND MOLAR Occlusal Aspect:Occlusal Aspect:• Rhomboidal in shape• Four well developed cusps:

mesiobuccal, distobuccal, mesiolingual and distolingual

• One supplemental cusp• Buccal surface –flat and

developmental groove between cusps are less marked

• Occlusal surface- central fossa with central pit, mesial triangular fossa –distal to mesial marginal ridge with mesial pit at its center.

• Well defined developmental groove called central groove- connects mesial triangular fossa with the central fossa

• Buccal developmental groove- extends buccally from central pit and separates the triangular ridges

• Oblique ridge- prominent- connects the mesiolingual cusp with distobuccal cusp

• Distal to oblique ridge- distal fossa found- harbors distal developmental groove

• Distal groove continues on to the lingual surface as lingual developmental groove


Application: 2-5 canalsApplication: 2-5 canals 85-95% cases - Mesial-facial root usually 85-95% cases - Mesial-facial root usually

bifurcates or contains two distinct canalsbifurcates or contains two distinct canals

morphology of primary maxillary teeth

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