(oral ana) man 3rd molars

8/4/2019 (Oral Ana) Man 3rd Molars

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Mandibular

Permanent molars

Reporters:Ciarra Jansen Rodrigez

Janine Villas

Virginia

Kyra Jean Blacano


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Arch traits

2 roots; M & D

4 major cusps & 1 lesser-sized5th cusp

(in 1st

molars) Crowns broader MD than BL

The 2 L cusps are of equal size

MB & DB cusps are of equal size


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Mandibular

3rd molar


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Mandibular 3rd molar


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Dental Notation

Right Left

Palmers

Universal 32 17

Two digit 48 38

8 8


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Chronology

Permanent Mandibular 3rd Molar

Calcification 8 - 10 yrs

Crown complete 12- 16 yrsEmergence 17 21 yrs

Root complete 18 25 yrs


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Buccal aspect

Highly variable

Roots are short, fused & D inclined

Lingual aspect

Short crown of highly bulbous

outline Rounded cusps


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Mesial B & L profiles are highly convex

Distance between apices of M cusps is

shorter Distal

Almost entire B surface is visible

D root is the narrowest BL & shortestof all mandibular molars


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Pulp

similar to mandibular 2nd molar

BL section Usually 2 canals in M root

Sometimes 1 canal in M

root

T-section

M dimension > D



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Occlusal aspect

Ovoid in outline

M half is wider BL than D half

B & L Profiles converge D Highly restricted occlusal table in

MD & BL dimensions (type trait)

4 narrow conical cusps

Highly convex MRs

Irregular pit/groove pattern

Shorter grooves


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Type traits


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Buccal aspect

Mandibular 2nd Molar

-From this aspect the

crown is shorter cervico-

occlusally

- Two buccal cusps are seen:

mesiobuccal cusp anddistobuccal cusp

- Both the cusps are equal in

size

- Buccal developmental

groove separates the two

buccal cusps

Mandibular 3rd Molar

- From this aspect the toothvaries considerably.

- The four cusp type has two

buccal cusps

- The buccal cusps are

shorter and rounded

- Both the cusps are equal in

size


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Buccal aspect

Mandibular 2nd Molar Mandibular 3rd Molar


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Lingual aspect


- Two lingual cusps areseen: mesiolingual cusp and

distolingual cusp

- lingual developmental

groove separates the twolingual cusps

- Crown and root converge

lingually but to a lesser

degree


- A well developed 3rd molarclosely resembles a 2nd

molar except for the size

and root development


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Lingual aspect

Mandibular 2nd Molar Mandibular 3rd Molar


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Mesial aspect


- The mesiodistalmeasurement is a fraction

less than 1stmolar

- The cervical ridge on the

buccal surface is lesspronounce

- The cervical line is less

curved, being straight


- From this aspect 3rd molarresembles 2nd molar except

for its dimensions


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Mesial aspect

Mandibular 3rd MolarMandibular 2nd Molar


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Distal aspect


- When compared with 1st

molar this aspect doesnt

have distal cusp and

distobuccal groove


- From this aspect too thistooth resembles 2nd molar

except for its dimensions


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Distal aspect

Mandibular 3rd MolarMandibular 2nd Molar


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Occlusal aspect of Mandibular 3rd molar

When fully developed the occlusal aspect of 3rd molar is

quite similar to the 2

nd

molar

Occlusal aspect


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Roots


- The tooth has two welldeveloped roots; one mesial

and one distal

- They are broad

mesiodistally but not asbroad as 1stmolar

- They are inclined distally


-- Roots are short andpoorly formed

-- An average tooth shows

two roots; one mesial and

one distal

-- They may be separated or

fused


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Anomalies of



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Anomalies of Mandibular 3rd molar

IMPACTED 3RD MOLAR


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Deciduous Mandibular

1st and 2nd Molar


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Deciduous mandibular 1st molar

Deciduous mandibular 1st molar


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Dental Notation of Deciduous Tooth

1st Molar 2nd Molar

R L R L

Palmers

Universal S L T K

Two Digit 84 74 85 75

D D E E


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Chronology

Deciduous Mandibular 1st Molar

Calcification (weeks in utero) 15

Crown complete 5 months

Eruption 16 months

Root complete 2 yrs


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Chronology

Deciduous Mandibular 2nd Molar

Calcification (weeks in utero) 18

Crown complete 10 months

Eruption 27 months

Root complete 3 yrs


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Set traits More bulging B & L cervical ridges

Constricted cervix

Buccal cervical ridges on deciduous

molars

Occlusal aspect: constricted occlusal table


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Deciduous dentition

Set traits

Smaller in size

Smaller crown height/toothlength ratio

Greater crown width/heightratio


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Deciduous dentition

Set traits

Molar roots

More slender & relatively longer

More bowed & flared outward

Shorter root trunk

Milk-white in color

Enamel is thinner & pulp chamber islarge

Some class, arch & type traits in permanentdentition are applied to deciduous dentition

Only new traits will be discussed


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Mandibular 1st molar

Molariform unlike max. 1st

4-cusped tooth

Buccal aspect 2 cusp: MB & DB

M half > D half M half projects more occlusally &

occupies 2/3s of crown area

M profile is straight

D profile is curved and overhanging

CL inclines downward from D to M

Roots

2 divergent roots; M & D

M is longer


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Lingual aspect 2 cusps: ML & DL

ML cusp is conical & larger

than DL Outlines of B cusps are visible

CL is more straight &

horizontal than that of the B

aspect


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Mesial aspect

Buccal cervical ridge (BCR)

From MB cusp tip a straight incline toBCR

Transverse ridge connecting MB & ML

M MR is high & prominent

Mesial marginal groove separates M MRfrom ML cusp ridge

CL is convex occlusally & lower on the Bend

Root

Extremely broad BL (sometimes asbroad as the crown)

Frequently bifid apex


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Distal aspect All 4 cusps & M root profiles

are visible

B profile is less bulging than

from mesial aspect

D MR is lower and less

prominent than M MR

CL is more straight &horizontal than that of M

aspect


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Occlusal aspect

Without the BCR, it is rectangular

BL width is grater from M than D

MB cusp is the largest, followed by ML,DB & DL

M Transverse groove, interrupted by Central groove; extends from M pit to

central pit

M pit

2 supplemental grooves; of which MLcrosses M MR

Central pit

B& L grooves

Often a D pit


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Mandibular 2nd molar

Morphologically considereda model for the permanent1st mandibular molar

Allows prediction of what

the 1st

mandibular molarwill look like

This concordance is calledisomorphy

Set traits Cervical constriction

Cervical 1/3 bulging

Little root trunk

Roots thinner & divergent


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Thats All !!!

(oral ana) man 3rd molars

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