 Hello everyone welcome back to another session in dentistry and more so there we have mantibular first premolar We have only two teeth left in dental anatomy. That is mantibular first and second premolar rest all teeth were done You can check the playlist of dental anatomy from maxillary central incisor to maxillary second molar and from mantibular central incisor till mantibular second molar Mantibular first premolar and second premolar will be done today and tomorrow So that's how we finish our dental anatomization. So each tooth can be a long assay and The features of each tooth can be a short assay or short note so All are very important You just cannot skip any tooth only the third molar maxillary and mantibular third molar is not very important Because features are very very less in those two teeth So we'll start with the mantibular first premolar So like the previous sessions will start with the tooth numbering system the universal system It will be 28 and 21 21 is left sorry left first premolar and 28 is a right first Premolar both are the lower one This is 17 is a third molar Lower left third molar 32 is a Lower right third molar. Okay, so you need to connect it with your third molar and Find the number for particular tooth because 32 31 30 29 and 28 here 17 18 19 20 and 21 the 5th tooth from the end Zygmunti pomegran fd system is very easy only thing is 4 and 4 this is 3 4 and 4 4 3 and 4 are the quadrants now, let's see the Dimensions and chronology of mantibular first premolar In chronology first we have the evidence of calcification. It is by 134 to 2 years then we have the enamel completion around 5 to 6 years after that Eruption by 10 to 11 years then root completion by 12 to 13 years in dimensions We have crown length 8.5 mm root length. It is 14 mm then mezier distal With is 7 mm and it is 5 mm at cervix the labelling goal is 7.5 mm and At cervix it is 6.5 mm and mezier curvature is 1 mm and distal is 0 now we'll start with our each surfaces first one is a Buckle aspect So in buckle aspect you can see the picture it is a trapezoid shape and the The sides are shorter at cervical region Because a trapezoid, you know how it is it is tapering towards the cervix and The longer side is on occlusion side the shorter side on cervical The outline that is a mesial outline. It's slightly concave Till the mesial contact area whereas the distal outline is slightly concave till the distal contact area and The mesial slope is shorter than the distal slope the buckle cusp is The buckle cusp tip is Mezier to the midline regarding the surface anatomy There is a cervical ridge and there is a buckle ridge and two developmental grooves which is mesial and distal to this buckle ridge Whereas a root is corn shaped with distal inclination at the apical third you can see a distal inclination at The apical third and the root is shorter than that of the canine. Canine has a longer root now coming to our lingual aspect Which is almost same as a buckle aspect, but in a reverse manner and with more lingual convergence The lingual cusp is two-third of the buckle cusp and this short lingual cusp can be called as a well developed Singulum, okay Well developed Singulum and the mesial and distal triangular forza can be seen and the lingual surface is spheroid and Cervical line is slightly convex or even straight and there is a characteristic feature of the lingual surface is a mesial lingual Developmental group you can see this red line mesial lingual developmental group now while moving to the mesial aspect means the last bit the outline is more of a rhomboidal shape due to the lingual inclination of the crown Okay, and the outline the buckle outline is convex from the cervical line to the cusp tip Where the maximum convexity at the cervical third or the cervical ridge? Whereas the lingual outline is convex the maximum convexity at the middle third Okay, the buckle outline the maximum convexity at the cervical third whereas the lingual outline the maximum convexity at the middle third and Can see a mesial lingual developmental group and the lingual cusp is two-third of the buckle cusp I already mentioned and the buckle cusp tip is in line with the rota pecs Where the lingual cusp tip is in line with the lingual border of the root? Okay, and this mesial margin which is sloping lingually the contact area is in line with the buckle cusp tip Whereas the root it tapers to pointed apex and has a deep developmental group so this deep developmental group is a very prominent feature of First smaller which is present on the mesial side whereas the distal aspect Distal aspect it is almost same as mesial acid, but it differs in few things that is a distal marginal ridge is straight and It is perpendicular to the long axis of the tooth and there is no developmental group and the contact area is broader and more Servically placed and the distal cervical line is less curved compared to the mesial outline now we'll come to our last aspect that is the occlusal aspect It is almost like a diamond or a round shape. Okay diamond or round shape and This occlusal surface tapers lingually and the buckle cusp has large triangular ridge and There is small lingual cusp which has small triangular ridge This buckle and lingual triangular edges are connected by a Transverse ridge, okay So this is the transverse ridge which connects a buckle and lingual Triangular just there is mesial and distal triangular forza. You can see in pink color and central developmental group Microsa transverse ridge So that is all about manipular first premolar Similarly like all other teeth you have to mention about the chronology dimensions tooth numbering system And all the five aspect. So I'll come up with mantabula second premolar in my next session. Thank you