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Maxillary 2nd permanent molar

The Buccal aspect;

From the buccal aspect this tooth is smaller. That means that the crown

in the maxillary 1st molar is wider. This tooth has less prominent

distobuccal cusp and its narrower mesiodistally. You can see that the

roots are closer to each other, and they are distally inclined, however in

the maxillary 1st molar the roots are straight not inclined.

The lingual aspect;

The distolingual cusp is smaller in width and height than the Maxillary

1st permanent molar. The lingual root is narrower and slightly distally

Inclined, however the lingual root in the maxillary 1st molar is upright.

We don’t have a cusp of Carabelli, but in some cases we might find but

Rarely. The cusp of cerebella van help identify the tooth because its

Present in all maxillary 1st molars but it is not 100% accurate because

Sometimes we can find this cusp of cerebelli in the maxillary 2nd molar.

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The mesial aspect;

We have less prominent marginal ridge and less numerous marginal

ridge tubercles. Mesiobuccal and lingual roots are less divergent, that

means that they are closer to each other.

The distal aspect;

We have smaller distal cusps. A greater portion of the occlusal aspect

is visible. The visible portion of the occlusal aspect in the distal aspect

in maxillary 2nd molar is greater than in the maxillary 1st molar.

The occlusal aspect;

The angles are more bordered and more acute than the maxillary

1st molar. The mesiobuccal and distobuccal are more acute &

mesiolingual and distobuccal angles are more obtuse. The talon is

more reduced in size.

We have more pit and groove pattern, however it is less variable

In maxillary 1st molar. There are more numerous supplementary

grooves. The crown is more constricted mesiodistally so the tooth

is narrower mesiodistally.

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The talon: is the portion that pulls the distolingual cusp.

The Pulp ;

The pulp is similar to that in the maxillary 1st molar, we have three roots. But the only difference in the pulp is system. In the maxillary 1st molar we have a 60 % possibility of having two canals in the mesiobuccal root, however here in the maxillary 2nd molar the possibility is less ya3ni its not common to find a forth canal in this tooth, so we have three roots each one with a canal. In rare occasions we can find a second root canal in the mesiobuccal root.

Maxillary 3rd molar

Buccal aspect;

In the buccal aspect the crown is smallest in all dimensions. The roots

are pretty much short and commonly fused and distally inclined. So

usually when you find a tooth with fused roots and distally inclined it

is most probably a 3rd molar. It shows a pronounced distal inclination.

Lingual aspect ;

The distolingual cusp is usually missing, we have only three cusps in

this tooth. The lingual roots are commonly fused with the buccal roots.

Now how can we differentiate between mandibular 2nd premolar

and maxillary 3rd molar? They both have 3 cusps but in the premolar

buccaly we have only one cusp however in the 3rd molar we have two

buccal cusps.

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Mesial aspect;

The crown profile is irregular, as well we can see fused, the

Mesiobuccal root is fused to the palatal or lingual root.

distal aspect;

The distolingual cusp is absent. More of the occlusal surface is

Visible

the occlusal aspect;

We can see two buccal cusps and one lingually. The tooth is

triangular or heart shaped. The distobuccal cusp is minimal in

size- the biggest cusp is the lingual.

Lingual cusp > masiobuccal cusp > distobuccal cusp

The oblique ridge is barely visible, as sometimes it cannot be seen.

There are many supplementary grooves.

we cannot do root canal treatment for the maxillary third molar..

as it’s very difficult, because this tooth is distally & buccally inclined.

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It’s important to remember that the maxillary 3rd molar is variable, as it’s the most variable tooth among all maxillary molars. (ya3ni it has a lot of different patterns);

1) the most common pattern is 3 cusps.2) sometimes we may have 4 cusps with a distolingual cusp that will make the

tooth look like a maxillary 2nd molar. 3) In rare occasions we will have only two cusps one buccal & one lingual.

Mandibular permanent molars

Upper & lower molars show progressive reduction in posteriorly and it’s a human trait. Now when you go posteriorly from the first molar- wither its mandibular or maxillary molar- teeth become smaller in size.

{So 1st molar > 2nd molar > 3rd molar} this is only in humans!

This tooth is the first to appear in the mouth, the mandibular 1st molar usually appears before the maxillary 1st molar.

Arch traits;

We have two roots in mandibular molars but three roots in the maxillary molars. In the mandibular we have two roots one buccal & one lingual, it has 4 cusps almost equal in size and sometimes we can see a 5th one especially in the mandibular 1st molar and it’s a small cusp located in the distobuccal corner of the tooth.

The crown is boarder mesiodistally than buccolingually and this is very important. So when you find a tooth with a crown wider MD than BL this is a mandibular molar and the opposite is true in the maxillary molar. The 2 L cusps are of equal size and MB & DB cusps are also of equal size.

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Check the pictures for the 3 patterns in the slides

mandibular 1st permanent molar;

The buccal aspect:

it is the widest tooth mesiodistally. The widest tooth buccolingually is the maxillary 1st molar. From this aspect we have 3 cusps, one mesiobuccal & one distobuccal & a distal one. The MB cusp is the widest and the DB but the amount of difference between them is very small. So we say that these two cusps are almost equal in size.

Mesiobuccal & distobuccal cusps are equal in size, distal cusp is conical and located in the distobuccal corner. We see groves between the cusps, the first groove is called the mesiobuccal groove that separates between the MB & DB cusps and we have the distobuccal groove separating between the DB cusp & the distal cusp. Theses grooves are important in the molar relationship.

We have in the mesial profile the cervical 1/3 is straight or concave & the occlusal 2/3s are convex. The distal profile is entirely convex. The Mesial & distal profiles are convergent cervically.

The cervical line is similar to that in the upper 1st molar.

The buccal surface;

The buccal cervical ridge is prominent in the cervical third; the

mesiobuccal groove that ends half way. The distobuccal groove

extends more than the mesiobuccal groove, as it extends most of

the buccal surface length.

We see two roots from the from the buccal aspect which are the mesial and buccal roots. These roots are widely separated and as you go posteriorly these become closer to each other and they are commonly fused in the mandibular 3rd molar, these shares a common trunk that has a shallow vertical depression, the apical half the mesial root is distally inclined and this is very important feature in

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dentistry especially in root canal treatment. We have a portion called danger zone it is located when the mesial root is inclined distally. The distal root goes distally without any curvature.

The lingual aspect;

From this aspect we only see two cusps; the mesiolingual & disto lingual cusps. They are usually higher and more conical than the buccal cups& almost equal in size.

We have the lingual groove located between the two cusps, and of course its narrower mesiodistally than the buccal profile. The tooth from the

buccal aspect is wider.

The mesial and distal profiles are generally convex, but in the cervical

third they tend to be straight or concave and convergent cervically.

The lingual surface;

in the lingual aspect the occlusal two thirds are convex in both vertical

& horizontal planes. As its entirely convex and that’s a common feature

in posterior teeth. The cervical third is flat or concave.

The roots we see a vertical depression as the depression seen in the buccal aspect. This depression is located in the midline of the root trunk. The proximal surfaces of the root are visible.

the mesial aspect;

We see the mesiolingual & mesiobuccal cusps. The ML cusp is slightly higher than the MB cusp. Notice the height of contour it is located in the mid portion of the crown lingually, but buccally it is located at the buccal cervical ridge. Mesially the marginal ridge is higher and you can find a mesial marginal groove.

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Now from the buccal cervical ridge the outlines curve sharply

lingually and this is an arch trait. In the maxillary molars we

don’t have this sharp lingual inclination. The lingual profile is

entirely convex.

As for the root, we only see one root which is the mesial root;

it’s very broad buccolingually, it has a blunt apex “it is not pointed” as well as a proximal root concavity.

The distal aspect ;

In this aspect there are 3 cusps the distolingual, distobuccal & distal cusps. From the distal part we can see part of the occlusal surface because the mesial marginal ridge is higher than the distal marginal ridge.

As a rule; in all posterior teeth the mesial marginal ridge is

higher than the distal marginal ridge except the mandibular

1st premolar. The distal cusp is lingual to the distobuccal cusp,

notice that the distal cusp is not located at the same level of

the buccal cusps as it goes slightly lingually. We can see the

distobuccal groove. The distal marginal ridge is shorter than

the mesial one has the distal marginal groove and half of the buccal surface is visible; we see part of the buccal surface because this angle between the buccal surface and the distal surface is obtuse.

The cervical line is nearly straight and narrower buccolingually than on the mesial surface.

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The distal root is buccolingually wide but smaller than the mesial root. That’s why we can see the profile of the mesial aspect. It may have a shallow depression but not like the mesial side.

The occlusal surface;

The tooth from the occlusal aspect, the crown is pentagonal. This is a type trait. It goes into a mandibular second molar the crown is square. The buccal profile is longer than lingual profile, making the mesial and distal profile’s converging lingually. In the buccal profile we see three regions, the mesiobuccal, distobuccal and distal cusp region. The distobuccal region is the most prominent. The maximum buccolingual diameter is just distal to

mesiobuccal groove. This is a type trait, because in

the mandibular second molar it’s not the same.

The mesiobuccal angle is sharp and the distobuccal

angle is rounded. The lingual profile have two regions

. Two thirds of the buccal surface are visible, and this

is an arch trait. The lingual profile, only the occlusal 1/3 is visible. There is of course 5 cusps, and this is a type trait, no 5 cusps in the mandibular second molar. The biggest cusps are the 2 lingual mesiobuccal mesiodistal distal (which is the smallest)

The difference however between these cusps is very small, not like the difference between the maxillary molars.

The mesial and distal marginal ridges converge lingually. The mesial marginal ridge is higher than the distal marginal ridge. Notice because of the presence of the distal cusp, the distal marginal ridge is not located at the same level of the mesial. The mesial marginal ridge is located at the mid portion of the crown

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buccolingually. But the distal marginal ridge is more toward the lingual than the buccal.

We have a central fossa and two triangular fossa’s. the central groove which extends from the mesial pit to the distal pit. We have a mesiobuccal groove and a distobuccal groove and a lingual groove. A central pit between the mesiobuccal, distobuccal and lingual grooves. It’s the maximum depth. Carving this tooth is easier, the only problem with carving this tooth is the distal cusp.

In a mesiodistal section we see two pulp horns. The mesiobuccal is higher than the distobuccal. In the buccolingual section, the mesiobuccal is higher also the mesiolingual. It is important to remember that we have a possibility 40% 1 canal in the distal root. In the mesial root there is 2 roots usually. The possibility of having 4 canals 60%. And the possibility of having 3 canals is 40%.

In the transverse section it is rectangular.

End of the lecture

All regards to my beloved sisters; Sarah Kazkaz (love you), Bayan el share3 ( the one

of a kind) , Remaz ( my sweet neighbor), Tuqa waqfi( allah ye7fazik) , Enas Allouh ( bent

bladii), Deena Abawi (Didii) , Maryam Faisal & Asil Al A3raj ( entu el 2alib) ♥

Special thanks to my dear neighbor & friend ♥ NADINE AL HOMOUD ♥ for helping me, shukran sister!

❀ Bil tawfee2 lal jamee3 inshallah ❀

Done by: Areej Nabil A.J ✿

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