(Oral Ana) Mandibular Second Molar

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Mandibular Second

Molar


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Mandibular SecondMolar

is the tooth located distally(away from the midline of the

face) from both the mandibularfirst molars of the mouth butmesial (toward the midline of theface) from both mandibular third

molars. This is true only inpermanent teeth.

In deciduous (baby) teeth, themandibular second molar is the

last tooth in the mouth and doesnot have a third molar behind it.


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there are usually four cusps on mandibularsecond molars: two on the buccal (side nearest

the cheek) and two palatal (side nearest thepalate).

There are great differences between thedeciduous (baby) mandibular molars and those of

the permanent mandibular molars, even thoughtheir function are similar. The permanentmandibular molars are not considered to haveany teeth that precede it.

Despite being named molars, the deciduousmolars are followed by permanent premolars.


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TOOTH NOTATIONo

Permanent Secondmolar Notation

o UNIVERSAL:

RIGHT: 31

LEFT :18

o INTERNATIONAL(FDI)

RIGHT: 47

LEFT: 37

Deciduous Second molarNotation

o

UNIVERSAL:RIGHT: T

LEFT : K

o INTERNATIONAL(FDI)

RIGHT:

85 LEFT: 75


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Age of eruption:

First evidence of calcification= 2 - 3 yr

Enamel completed= 7-8 yr

Eruption= 11-13 yr

Root completed= 14-15 yr


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Tooth Surfaces:


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Buccal aspect:

The crown is somewhat shorter cerveco-occlusally and narrower mesiodistally than isthe first molar.

The crown and root show a tendency towardgreater overall length but are not alwayslonger.

Only one development groove lies buccally-

the buccal developmental groove.

The groove acts as a line of demarcationbetween the mesiobuccal and thedistobuccal cusps, which are about equal intheir mesiodistal measurement.


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The cervical line buccally in many instancespoints sharply toward the root bifurcation.

The roots may be shorter than those of thefirst molar, but they vary considerably in thisand in their development generally.

The roots are usually closer together, andtheir axes are nearly parallel.

They may spread as much as those of thefirst molar, or they may be fused for all or

part of their length.


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Lingual aspect:

Differences in detail between the mandibularsecond molar and the mandibular first molar, to benoted from the lingual aspect.

1. the crown and root of the mandibular second

molar converge lingually but to a slight degree;little of the mesial or distal surfaces maytherefore be seen from this aspect.

2. the mesiodistal calibration at the cervixlingually is always greater accordingly than thatof the first molar.

3. The curvatures mesially and distally on the crown

that discribe the contact areas are morenoticeble from the lin ual as ect. The rove to


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Mesial aspect:

The cervical ridge bucally on the crown portionis in most instances less pronounced, and theocclusal maybe more constrectedbuccolingually.

The cervical line shows less curvature, beingstraight and regular in outline buccolingually.

The mesial root is somewhat pointed apically. Ifpart of the distal root is in sight, it is seen

buccally. In the first molar, when the distal rootis in sight from the mesial aspect, it is in viewlingually.


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Distal aspect:

From the distal aspect, the second molar issimilar in form to the first molar except forthe absent of a distal cusp and distal buccalgroove.

The contact area is centered on the distalbuccolingually and is placed equidistant fromcervical line and marginal ridge.


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Occlusal aspect:

The occlusal aspect of the mandibular secondmolar differs considerably from that of thefirst molar.

This variation serve as marks of identity.The small distal cusp of the first molar is not

present in the distobuccal lobe developmentis just as pronounce in sometimes more so

than that of the mesiobuccal lobe. In general the cusp slopes on the occlusal

surface are not as smooth as those found onthe first molars because they are roughened

by many supplemental grooves radiating from


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Characteristics of mandibularsecond molar from the occlusal

aspect:1. Many of them are rectangular from the occlusal

aspect.

2. Many show considerable prominence cervicallyon the mesiobuccal lobe.

3. Most 2nd molar exhibit more curvature of theoutline of the crown distally than mesially,

showing a simecircular outline to the disto-occlusal surface in comparison with the squareoutline mesialy.

4. The cusp ridge of the distobuccal cusp liesbuccal to the cusp ridge of the mesiobuccal.


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Types traits that distinguishmandibular 1st from mandibular

2nd molar:Mandibular 2nd molars

which have 4 cusp, (MB=1,DB=2, ML=3, DL=4) with a

cross pattern of occlusalgrooves versus mandibular1st molar which have 5cusps, the same cusps as

the 2nd molar which have4 cusps plus a smallerdistal cusps (D=5) with azigzag occlusal pattern.

Mandibular 2nd molar

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(Oral Ana) Mandibular Second Molar