(oral ana) max 1st and 2nd molars

8/4/2019 (Oral Ana) Max 1st and 2nd Molars

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Permanent Maxillary 1stand 2nd Molar


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PermanentMolars


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Molars comes from the Latin word for grinding.

3 types of molars: the 1st molar, 2nd molar, and 3rd molar.

The 1st and 2nd molars are also calledthe 6-year and 12-year

molars because of the approximate eruption ages.


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There are 12 molars, three in each quadrant, in the permanent

dentition.

The molar crowns have four or five short, blunt cusps, and each

molar has two or three roots that help to support the larger crown.


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Maxillary Molars

usually the first permanent teeth to erupt into the maxillary arch.

usually has four major cusps, with two cusps on the buccal portion of

the occlusal table and two on the lingual.

has three well-separated

and well-developed roots. A tooth with 3 roots is said to be

trifurcated, which means divided into thirds.


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Permanent

maxillary

1st molars


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Location

laterally (away from the midline ofthe face) from both the maxillary second

premolars of the mouth

mesial (toward the midline of the face)

from both maxillary second molars


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Chronology

Calcification At birth

Crown completed 3 years

Eruption 6 years

Root completed 9 years


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Notation

Right Left

Palmers6

6

Universal 3 14

Two Digit 16 26


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function The function of this molar is similar to

that of all molars in regard to grinding

being the principal action

during mastication, commonly known as

chewing.


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Surfaces


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Buccal aspect


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features

Outline: Trapezoidal

Four Cusps:

Mesiobuccal

Distobuccal

Mesiolingual

Distolingual


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LR, Lingual Root;

MBR, Mesiobuccal Root;

BDG, Buccal Developmental groove;

MBC, Mesiobuccal Cusp;

MLC, Mesiolingual Cusp;

DBC, Distobuccal Cusp;

CL, Cervical Line;

DBR, Distobuccal Root.

Maxillary 1st molar, buccal aspect


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Lingual


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Features of 1st Molar

Two cusps of unequal size dominate the occlusal profile. The largermesiolingual cusp often displays the Carabelli trait. It is a variable

feature. It appears most often as a cusp of variable size, but is

occasionally expressed merely as a pit.


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DBR, Distobuccal Root;

LR, Lingual Root;

CL, Cervical Line;

LDG, Lingual Developmental Groove;

DLC, Distolingual Cusp; MLC,

Mesiolingual Cusp;

FC, Fifth Cusp;

MBR, Mesiobuccal Root..

Maxillary 1st Molar, lingual aspect


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Mesial


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Features has an unusually large

cusp of Carabelli

lingual height of contour

is on occlusal 3rd.

wide mesiobuccal roothides the narrower

distobuccal root. mesiolingual cusp, mesial marginal ridge,

and mesiobuccal cusp comprise the

occlusal outline.


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Tubercle of carabelli

The fifth smaller cusp on

the palatal side. This

extra cusp is usually

found on the first molar,

and becomes

progressively less likely in

the second, third

molars.


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LR, Lingual Root;FC, Fifth Cusp;

MLC, Mesiolingual Cusp;

MMR, Mesial Marginal Ridge;

MBC, Mesiobuccal Ridge;

MCA, Mesial Contact Area;

CR, Cervical Ridge;

MBR, Mesiobuccal Root.

Maxillary 1st Molar, mesial aspect.


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Distal


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Outline : trapezoidal

The two distal cusps are clearly seen;

the distal marginal ridge is somewhat shorter

than the mesial one.

A small concavity on the distal surface that

continues onto the distobuccal root.

Features


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Maxillary 1st Molar, distal aspect

DBR, Distobuccal Root;

MBR, Mesiobuccal Root;

BDG, Buccal Development Groove;

DBC, Distobuccal Cusp;

DMR, Distal Marginal Ridge;DLC, Distolingual Cusp;

DCA, Distal Contact Area;

CL, Cervical Line;

LR, Lingual Root.


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Occlusal


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features

Outline : rhomboidal

Cusp order according to

size: (largest to smallest)

Mesiolingual

Mesiobuccal

Distobuccal

Distolingual

ll h l l l


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Maxillary right 1st molar, occlusal aspect.

MBCR, Mesiobuccal Cusp Ridge; CF,

Central Fossa; MTF, Mesial triangular

Fossa; MMR, Mesial Marginal Ridge;

MLCR, Mesiolingual Cusp Ridge; OR,

Oblique Ridge; DLCR, Distolingual Cusp

Ridge; DF, Distal Fossa; DTF, Distal

Triangular Fossa; DMR, Distal Marginal

Ridge; DBCR, Distobuccal Cusp Ridge.


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BG, Buccal Groove;

BGCF, Buccal Groove of Central Fossa;

CGCF, Central Groove of Central Fossa;

FCG, Fifth Cusp Groove;

LG, Lingual groove;

DOG, Distal Oblique Groove;

TGOR, Transverse Groove of Oblique

Ridge;

CP, Central Pit.

Maxillary right first molar, occlusalaspect, developmental grooves.


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Permanent

maxillary2nd molars


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Location distally (away from the midline

of the face) from both

the maxillary first molars of the

mouth

mesial (toward the midline of

the face) from both maxillary

third molars


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Chronology

Calcification at birth

Crown completed 3 years

Eruption 7 years

Root completed 14 years

N t ti


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Notation

Right Left

Palmers 7 7

Universal 2 15

Two Digit 17 27


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Function

The function ofthis molar is similarto that of all molars inregard to grindingbeing the principalactionduring mastication,

commonly known aschewing.


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Surfaces


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Buccal


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Features Buccal aspect

- the crown is a little shorter cervico-oclusally and narrower mesiodistally.

distobuccal cusp is smaller and allows part of the distal marginal ridge and part

of the distolingual cusp.

The buccal roots are about the same length.


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Lingual


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features

1. Distolingual Cusp of the crown is smaller.

2. Distobuccal Cusp may be seen through the sulcus between the

mesiolingual and distolingual cusp.

3. No fifth cusp is evident.

4. The apex of the lingual root


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Mesial


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features

The buccolingual dimension of the second molar is about the

same as that of the first molar, but the crown length is less. The

roots do not spread as far buccolingually but are within the

confines of the buccolingual crown outline.


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Distal

features


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Distobuccal cusp is smaller in maxillary 2nd molar.

Mesiobuccal cusp may be seen from this angle.

The mesiolingual cusp cannot be seen.

The apex of the lingual root is in line with the distolingual

cusp.

features


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Occlusal


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Features

Outline : rhomboidal

and heart-shaped

Cusp size order:

(largest to smallest)

Mesiolingual

Mesiobuccal

Distobuccal

Distolingual


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First Molarvs

second Molar


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Similarities

same number of roots

same number of facial cusps

same number of facial grooves

Diff (b l i )


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Differences (buccal view)

1st Molar 2nd Molar

Roots more spread out, shorter trunk Roots less spread out, longer trunk

Buccal cusps almost same size Mesiobuccal cusp larger than Distobuccal

Roots with less distal bend Roots with more distal bend

Buccal groove longer, possible pit Buccal groove shorter, no pit


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Differences (lingual view)

1st Molar 2nd Molar

Buccal roots spread out behind lingual root Buccal roots less spread out

Lingual cusps nearly the same length Distolingual cusp much shorter


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Differences (proximal view)

1st Molar 2nd Molar

More mesial marginal ridge (86%) Few mesial marginal ridge (38%)

Parallelogram shape less twisted Parallelogram shape more twisted

Some root flare beyond crown Less root flare

Cusp of Carabelli on Mesiolingual Cusp No Cusp of Carabelli

Differences ( occlusal view)


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e e ces ( occ usa e )

1st Molar 2nd Molar

Distolingual Cusp slightly smaller the Mesiolingual Cusp Distolingual Cusp much smaller the Mesiolingual Cusp or absent

Crowns often wider on lingual half Crowns narrower on lingual half

Crown outline nearly square Crown outline more twisted

Crown larger (in same mouth) Crown smaller(in same mouth)

More prominent oblique ridge Smaller prominent oblique ridge

Fewer supplemental grooves More supplemental grooves

Less prominent Mesiobuccal Cervical Ridge More prominent Mesiobuccal Cervical Ridge


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Lingual

Cusp of Carabelli present on mesiolingual

(ML) [46%]

ML cusp is larger than distolingual (DL)


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Maxillary 1st molar pulp

(oral ana) max 1st and 2nd molars

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