 Hello everyone, welcome back to another session in dentistry and more Today we have mantibular first molar from dental anatomy Maxillary teeth are out maxillary third molar, which is not very important Maxillary central lateral canine Maxillary first and second premolar Maxillary first and second molar Mantibular teeth also we finish till canine premolars and molars are left So I'll be doing Mantibular first molar then second molar then I'll be going to mantibular premolars So mantibular first molar, which is a very big tooth and the largest tooth in the mantibular arch So I'll coming to the tooth numbering system. We have universal system Zygmody Palmer system and FDA system universal system is just the numbering It starts from 1 here and 32 here. So since it's a mantibular premolar We have 17 here. So this is third molar, second molar and 19 will be the first lower molar on the third quadrant Whereas the fourth quadrant, this will be 30 because 32 is the last tooth So this will be the third molar, 31 will be the second molar and 30 is the Lower first molar on the right side. Okay So this should be the patient phase Zygmody Palmer system is like this third and fourth quadrant and FDA system we have 4 6 and 3 6 So that was about The tooth numbering system now, let's see what are the Chronology called details chronology We have first evidence of calcification at birth Then the crown completed by two to half two and a half to three years and Eruption by Six to seven years then the root completion By nine to ten years. So you can see that always there is a gap between The crown completion Eruption and root Completion so after eruption still root grows and it is finished by nine to ten years After crown completion it takes another three years to eruption So that was about the chronology or as a dimension we have The length is around 15.8 millimeter This is length Then the length of crown is around six mm. This is Overall, this is crown length then the length of root is around 9.8 mm and Mesiodisthel dimension of crown is around 7.7 and It is that cervix will be lesser So that is around 6.5 mm then the labia lingual diameter is seven and 5.3 at the cervix So this was about the dimensions and this is chronology now we'll start our each surfaces So Manipula first molar as you see the picture here does what five cuts but that is two buckle two lingual and one Distal, okay, so the buckle surface is more bulky And it is more towards Linkoly inclined with two developmental groups the crown is wider mesiodistheli than buckling glee and Occlusional outline is rectangular in shape and there is two well-developed roots one mesial and one distal compared to the Maxillary molars, which is wider buckling glee than mesiodistheli, but this is opposite It is wider mesiodistheli than buckling glee in maxillary molars. We have Palatal root and buckle root. This is opposite one mesial and one distal So the buckle aspect The mesial contact area is at the junction of the occlusional and middle thirds and the distal contact area is a little lower than the mesial contact area And the cervical line is regular Which curves apically and there are two developmental groups between the cusp Acting as lines of division between the buckle cusp can see the mesio buckle Developmental groove is shorter than the distal buckle developmental groove So you can see two groups which divides the buckle side into three cusp That is the mesio buckle cusp distro buckle cusp and the distal cusp and this mesio buckle groove is shorter Than the distro buckle groove. That is a developmental groove And the mesio buckle distro buckle and distal cusp are very visible and the mesiolingual and distalingual cusp tips are seen Okay, so the cusp tips of the lingual side. That is the mesiolingual and distalingual cusp Are seen from the buckle aspect From the buckle aspect we have three cusp Among the mesio buckle cusp is slightly wider than the distro buckle cusp So this mesio buckle and distro buckle cusp making 80 percentage of the total width The remaining 20 percentage will be the distal cusp And this buckle cusp are flat occlusively, but the distal cusp is more rounded Okay, so the buckle cusp that is the mesio buckle and distal cusps are flat occlusively Whereas the distal cusp is more like rounded And the point of bifurcation of the two roots About 3 mm below the cervical line as you see the picture here the bifurcation point is Around 3 mm below the cervical line Whereas the lingual aspect Three cusp can be seen that is a mesiolingual distalingual and the lingual portion of the distal cusp And the mesiolingual cusp is the widest Mesiodistally and has the highest cusp tip and the Distal cusp is the lowest one. Okay, the highest cusp tip is of mesiolingual cusp The two lingual cusps are pointed and form obtuse angle at their Cusp tip you can see the obtuse angle. So this is obtuse angle you can see here And the lingual developmental groove extends downward for about one-third of the crown length and acts as a line of division between two lingual cusps You can see the me lingual Developmental groove which extends from the crown around one-third of the length and it divides the two lingual cusps That is the mesiolingual distalingual cusp Now we have the mesial aspect on mesial aspect the shape is almost rhomboidal Okay, the shape is rhomboidal With a lingual tilt of the buckle outline. So you can see a slight lingual tilt of the buckle outline So this is a buckle outline you can see a slight tilt So this buckle outline of the crown is convex at the junction of the cervical and middle third That is a buckle cervical ridge Then the outline straightens to form the buckle cusp tip. Okay, so you can see here The buckle outline of the crown is convex at the junction of the cervical and middle third the cervical and middle third It is convex then the outline straightens to the buckle cusp tip Like whereas lingual outline is less convex compared to the it's not much convex It's less convex with the crest of curvature at the center of the middle third So you can see the The cervical line is more of irregular and higher lingually than buckling Okay, whereas the buckle cusp is flat and the lingual cusp is sharp Okay, so the buckle this cusp is flat and the lingual cusp is sharp with greater cusp height And the mesial margin will be located one mm below the level of cusp tip Still aspect because the crown is shorter distally Than misery most of the buckle lingual and occlusal surfaces can be seen from the distal aspect So you see from the picture here you can see the mesial side the occlusal side because the distal side of the crown is shorter So most of the teeth, uh, this will be the same where the distal crown is shorter And the distal cusp, uh, which is located buckle to the, uh Long axis of the tooth so you can see the distal cusp which is present, uh buckle to the long axis of the tooth And the distal margin ridges shorter and curves Servically to form an obtuse angle So you can see here it curves and forms an obtuse angle And the cervical line is more of irregular and the distal root is narrower than the mesial root Uh, well coming to the occlusal surface the crown is more of a rectangular in shape It is a larger in mesial distal around one mm Compared to the buckle lingual whereas the buckle lingual measurement of the crown is greater on the mesial side than the distal side And the mesial distal Measurement is greater on the buckle than lingual. So I repeat Buckle lingual measurement Okay, it's greater on the mesial side. Okay The mesio distal measurement is greater on buckle side than the lingual. Okay And the raffae cusp, uh, that is a mesio buckle, which is the largest Mesio buckle is the largest Uh, then the mesio lingual Uh, then comes the distal lingual Then comes the distal buckle and finally the distal. Okay, so this Order is very important mesio buckle mesiolingual distalingual distal buckle and distal The distal contact area is on the distal cusp. Okay, I can see the distal contact area is on the distal cusp And there are four developmental groups Uh, there is one central developmental group which runs The central part then the mesio buckle developmental group divides the mesio buckle and distal buckle cusp Then the distal buckle developmental group which divides the distal buckle and distal cusp Then the lingual developmental group divides the mesiolingual and distalingual cusp And there are three forzas Central forza, which is uh more like a circle Which is bounded by distal slope of mesio buckle cusp And both mesiol and distal slopes of disto buckle cusp Mesial slope of distal cusp and the distal slope of mesiolingual cusp And lastly the mesial slope of disto lingual cusp. It forms the Central forza. Okay Then the mesial triangular forza. It is distal to the mesial marginal ridge distal triangular forza It is mesial to the distal marginal ridge and there are three pits Uh the dots you can see There is a central pit in the center of the central forza Mesial pit it is in the mesial triangular forza and the distal pit It is in the distal triangular forza So that was all about uh mantibular force molar uh the basic uh difference between the maxillary molar and mantibular molar The mesio distal dimension is larger in mantibular teeth compared to the maxillary teeth and the roots Mesial and distal Whereas maxillary it is more like buckle and lingual and it is Having well developed five cusps in the mantibular for smaller Largest is a mesio buckle and the smallest is a distal and occlusion anatomy It has got central forza and the boundaries are a little confusing But if you know the occlusion anatomy well all the cusp it's very easy Central forza and the mesial and distal triangular forza then pits are there Central pit distal pit and mesial pit So you need to draw a picture for every uh dental anatomy tooth morphology question And write about each aspect in the beginning you need to write about the chronology and dimension And the tooth numbering system then you can start the surface one by one buckle, lingual, mesial, distal and occlusion with proper diagram So i'll be coming with the maxillaries, sorry the mantibular second molar in my next video. Thank you