 Hello everyone, welcome back to another session in Tentistry and more. Today we have a topic from Dental Anatomy that is the details of Maxillary 2nd molar. So recently I was doing the part 2 subjects but I was getting repeated request from one of my student to do videos on Maxillary and Mantibular 2nd and 3rd molars because their exams are approaching. So I thought to finish the dental anatomy of Maxillary and Mantibular 2nd and 3rd molars. So we will start with our numbering system. So the universal numbering system is as we all know it will be 2 and 15 because it starts with 1 and so we have 1 here, we have 8 then 9, 16. So it is very easy to understand because each quadrant will be having eight teeth. So since it is second molar it will be next to the first and next to the last. So in universal system the numbers are 2 and 15. Then the Parma notation that is the Zygmunti Parma system I mentioned it here 7 and 7. This is the second molar on upper right and upper left. In the FDA system that is the two digit system we have 1, 7 and 2, 7. This indicates the quadrant, this indicates the tooth number. So after that we have chronology. In chronology the common sets of criteria that is the first evidence of calcification by 2.5 years then enamel will be completed by 7 to 8 years but erection is around 12 to 13 years. This is erection, erepting into the oral cavity but this is enamel completion. There is a difference between enamel completion and erection. So this is first evidence of calcification. So all the minerals are getting deposited into our heart tissues that is by 2.5 years. This is enamel completed by 7 to 8 years and erection by 12 to 13 years and root completion by 14 to 16 years. So you can make out there is continuous root completion even after the erection. Though it erefs around 12 to 13 years, the root completion is not complete. Its apex won't be properly closed but around 14 to 16 years the growth of maxillary second molar will be complete that is the growth of roots, the apex closure. Now we have the dimension that is the cervical occlusion length is 7 millimetre then the length of root that is buccal and lingual always the palatal we should call it as palatal. Palatal root is always length here that is around 12 millimetre and 11 millimetre then the mesiodistral diameter of crown is 9 and the mesiodistral diameter of crown at cervix is 7 because there will be a constriction at the cervix and buccopalatal diameter of crown is 11 that is buccopalatal diameter of crown is 11 the same at cervix is 10 and curvature line of mesial is 1 and distal is 0 because always mesial will be more curved in most of the teeth. So this is the dimensions. So dimensions of our maxillary second molar. So some peculiar factors about maxillary second molar that is this tooth supplements the maxillary first molar in function because it is almost same in dimension. So it supplements major mastication that is major chewing happens in the molar area. So it supplements maxillary first molar and it has the same form with little bit of variation from maxillary first molar the size is little less but most of the features are same. So it supplements in function because each set of teeth has different functions the incisors has a different function canines has different function. So the molars are mostly having our chewing the major chewing is happening in the molar area. So this second molar supplements axillary first molar in function and regarding the proximal contact area proximal contact area are both in the same level at the middle third okay at the middle third both are at same level most of the cases it will be somewhat cervical in one side but this is at same level at middle third on both side and there is no cusp of caribilly here okay the cusp of caribilly is absent in maxillary second molar which is present only in maxillary first molar this is absent okay. Now let's start with each surface the first one is buckle aspect so the crown is little shorter cervical crucially as you see the image here around by 0.5 millimeter and arrow mesiodistally by around 1 millimeter but of the same measurement bucko paratilly okay and the buckle groove is located further distally okay you can see it is it is located towards the distal side which is resulting in a larger mesio buckle cusp if it is placed towards the mesial side the distal buckle cusp will be larger but in this case it is placed more distally so the mesio buckle cusp is larger and longer and a shorter and sharper distal buckle cusp. So the occlusion outline on the buckle surface is tilted so vaguely from mesial to distal so you can see a small tilt in the picture so this makes the buckle surface of the crown appears to be shorter on the distal side than the mesial side because it is a tilting towards the distal side. So the three roots of the maxillary second molars are smaller less divergent and more parallel in comparison with first molar first molar roots are more divergent it is more like diverging from one point but in second molar cases they are comparatively smaller also and less divergent and more like parallel not much diverging from one point this is more like parallel and the palatal root is still the longest one and the largest one but is more straighter and less curved buckly okay less curved buckly because there is a buckle curvature of the palatal root with regard to the maxillary for smaller but in this case the palatal root is still the largest and longest but the curvature towards the buckle side is less prominent and there is a great chance for the fusion of the two buckle roots or even the fusion of the three roots okay so the high chances of fusion mostly it will be between mesio buckle and distal buckle sometimes all the three roots palatal roots so extraction of the maxillary second molar is more easier than the maxillary for smaller because most of the times the roots are either it is parallel or sometimes used so extraction is easier compared to maxillary for smaller because the maxillary for smaller roots are more divergent longer larger roots and it's not parallel the palatal root has got a buckle curvature and the buckle roots are about the same length so you can see the media buckle and distal buckle roots are of same length they are more nearly parallel and are inclined distally more than those of maxillary for smaller so that the end of the distal buckle root is slightly distal to the distal extremity of the crown you can see the distal extremity the crown is like this but the root is slightly distal okay if you draw a line this tip of the root is slightly distal not within the outline of crown it is slightly distal to the distal extremity of the crown so the apex of the mesio buckle root is on in line with the buckle groove of the crown instead of the tip of the mesio buckle as found on the maxillary for smaller so you can see the mesio buckle root in case of maxillary for smaller it is in line with the mesio buckle cuts but in this case it is in line with the buckle groove of the crown okay okay. Buckle grown of the crown. In fact, maxillary for smaller it is more towards the meso buckle cusp. Now we have the next, suppose that is a palatal aspect. In palatal aspect the meso palatal cusp which is smaller and not well developed as in maxillary for smaller and there is no fifth cusp that is cusp of caribilly is absent here. Then the apex of the palatal root is in line with the distro palatal cusp instead of the palatal groove which was found in the maxillary for smaller. So in maxillary for smaller maxillary for smaller this apex of the palatal root is in line with palatal groove okay. Whereas in maxillary second molar the palatal root is in line with the distro palatal cusp that is a second molar. So that is the difference. So I repeat in first molar that is a maxillary for smaller our palatal root is in line with the palatal groove. Whereas in second molar the palatal root is in line with distro palatal cusp. Now we have the next aspect that is mesial aspect when you are studying molars always study first molar, second molar, third molar in the same day or in same time because it is very easy when you combine study all the molars because most of the features are same only little bit of difference here and there. So if you are studying first molar today then you are studying canine and after two days you are studying maxillary second molar it is very difficult. So if you are studying first and second molar on the same time or same day it will be very easy to understand because always compare and study. Okay moving on we have a mesial aspect so the bucko palatal dimension is about the same as that of maxillary for smaller. The roots do not spread as for bucko palatilly and it is being within the confines of bucko palatal crown outline. So you can see the bucko palatal crown outline. So this roots is not getting spread bucko palatal it is within the outline of crown. Whereas distal aspect because of this distro buckal cusp is smaller than the one which is present in the maxillary for smaller more of the mesio buckal cusp may be seen from this angle because the distro buckal cusp is smaller. So you can see the mesio buckal cusp from this side and the apex of the palatal root is in line with the distro palatal cusp. And now we have the last one that is a occlusal aspect. So occlusal aspect the crown is more constricted in mesio distal dimension. There are two major types of crown form one is rhomboidal one is rhomboidal type and second one is heart shaped okay heart shape. So there are two forms of outline occlusal aspect one is rhomboidal shape second one is a heart shape. So rhomboidal type resembling the maxillary for smaller it is the most frequent and is similar to the first smaller except that the rhomboid form is more accentuated okay. Whereas heart shape form which resembles the maxillary third molar because the distro palatal cusp being poor developed. So that is why this will become a heart shape because of distro palatal cusp is poorly developed. So again see the pictures you can clearly make out two forms and it is common to find supplemental grooves on the occlusal surface of maxillary second molar which makes the surface more wrinkled okay. So that was all about maxillary second molar. So next video I will do on maxillary third molar so it will be a smaller video because most of the features will be same and less prominent in maxillary third molars. So whenever you write any question in dental anatomy the picture carries the half of the mark if it is a question for 10 marks the picture has 5 marks. If you write all content without any picture you won't get more than 5 marks because picture is a must without picture it's very difficult to understand because who is reading your paper the first thing what she notices is your picture. So pictures is a must in dental anatomy any question some questions might not need a picture but most of the time you need to have a picture with your answers. So okay I will come up with maxillary third molar in next session thank you.