 Hello everyone welcome back to another session in dentistry and more So we are continuing our dental anatomizations. So we're finished till maxillary second premolar Now we have maxillary first molar a tooth which has got many features on each with universal system then the Zygmonte Parma system and the FTA system, okay FTI is 1 6 and 2 6 Zygmonte is 6 and 6, okay Now we have the universal system 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 and 16 So central lateral canine first premolar second premolar and first molar Central natural canine first premolar second premolar and first molar so 3 and 14 other universal numbering systems Outward the chronology The first evidence of calcification is at birth and the enamel completion around three to four years Eruption by six to seven years and root completion by nine to ten years So it has got five surfaces and three roots the only tooth Which has got three roots commonly, but sometimes even premolar first premolar may have three roots But this is a tooth with three roots So we'll start with the buckle aspect So as you see the picture The geometric outline is trapezoidal with small uneven side present so acoly So I can see the mesial surface and distal surface The mesial outline is nearly Straight till the contact area at the junction of occlusion and middle one-third Whereas a distal outline which is convex till the contact area at the middle of middle one-third Whereas a occlusion outline that is a mesio buckle cusp is broader shorter and less sharp than the distal buckle cusp so distal buckle cusp is narrower longer and Sharper so you can see the distal buckle and mesio buckle cusp The cervical outline is irregular and slightly convex towards the root and The convex buckle surface which has got buckle groove Which may terminate at middle third by a fault buckle pit or by two shallow grooves and Also, there is a presence of cervical ridge on the buckle aspect or buckle side The roots from the buckle side that is the root trunk is almost like four millimeters and Three roots are seen from the buckle aspect The axis of the roots are inclined distally you can see a distal inclination for all the roots and There is deep developmental groove extent on the root trunk and The inclination that is a mesio buckle root, which is inclined distally distal buckle root which inclines Measily whereas the palatal root which incline buckly Okay, the mesio buckle root which is inclined towards the distal side Disturb buckle root incline towards the mesial side Whereas a palatal root which inclines towards the buckle side The longest root is the palatal root and the shortest root is disto buckle root Okay, so the palatal is the longest then the mesio buckle root then comes the Disto buckle root. So this is the longest palatal and Shortest is the disto buckle root. These are the three roots of maxillary for smaller Now the lingual aspect There is no lingual convergence the mesial outline It is nearly straight and form a perpendicular Angle with the mesial slope of the mesiolingual cusp. So you can see the mesiolingual and distalingual cusp So the mesial outline forms a perpendicular angle Whereas the distalingual cusp or the distal outline is just convex and form a semi circle With the distal slope of distalingual cusp. So you need to Correlate with the picture This is the mesiolingual cusp and this is the distalingual cusp This forms a perpendicular angle and this is a semi circle and Occlusion outlined that is the mesiolingual cusp is the largest and longest cusp. It's mesio Distal width about three-fifth of the mesio distal crown diameter. Okay and the distalingual cusp is feroidal and The cervical outline is irregular and slightly convex towards the root and The surface that is a convex lingual surface and the cusp of cariboulli is seen. Okay, it is a very important short knot cusp of cariboulli Which is seen on 60 percentage of lingual surface of mesiolingual cusp. Okay The cusp of cariboulli is seen where it is on the lingual surface of mesiolingual cusp. So it's a Cusp bridges is two millimeter serve equal to mesiolingual cusp That is cusp of cariboulli and there is presence of lingual developmental groove and Palatal root is conical End with a blend apex which is in line with the lingual groove So you can draw a straight line through the palatal root mid and the lingual groove and parts of buckle roots are seen from this aspect on both sides of the palatal root Now we have the mesiol aspect So in mesiol aspect the outline is trapezoidal with small uneven side on the occlusion side and The buckle outline so you can see the buckle outline here Which is convex at cervical one-third which is denoting the cervical ridge and concave at the middle one-third denoting the termination of buckle developmental groove and Slightly convex at the occlusion one-third which representing the mesiol buckle cusp So it can be divided into three the convex at cervical one-third denotes the cervical ridge then the buckle developmental groove and then the mesiol buckle cusp so The lingual outline it is convex with crest of curvature at the middle one-third and The lingual outline which dips inward to illustrate the tubercle Whereas occlusion outline which is represented by mesiolingual mesiobuckle cusps and there is irregular mesiomargin ridge which curves servically and Servical outline, which is irregular and convex occlusally and The mesial contact area at the junction of middle and occlusion one-third Which is buckle to the center and There is shallow concavity usually present cervical to the mesial contact area and which extend to the root and The roots are mesiobuckle root palatal root only be seen these two roots are seen That is mesiobuckle and palatal So mesiobuckle from this aspect is broad and flat So two roots are seen from this aspect that is a palatal root and mesiobuckle root So the mesiobuckle root is broad and flat ham. It's with that bifurcation area is nearly equal to the third third of the crown measurement that is a buckle lingual two-third of the total buckle lingual measurement and The buckle outline extend upward and lingual outline is almost straight line The palatal root is longer narrower than the mesiobuckle root and it's like a banana shaped Whereas a distro buckle root is hidden from this aspect so you can see the mesiobuckle root and palatal root the root trunk and the mesiobuckle Cusp, mesiolingual cusp, mesiocontact area Servical ridge So on the distal aspect and mesial aspect the distal convergence Whereas we can see the distal convergence here, but So you can see a comparison here from the distal aspect with respect to the mesiol on the distal aspect there is distal convergence, but here the wider mesial surface Here we can see the convex distal surface except small concavity at area of servical one-third Here the flat mesial surface and Here we can see the distal marginal ridge Which is curved servically here the mesial marginal ridge is less curved and The straight cervical line on distal side Servical line It is convex occlusively. Root trunk is 5 millimeter here. It is 3 millimeter and From distal aspect three roots are seen, but from the mesial aspect Just two roots are seen To the occlusional aspect the geometrical outline is rhomboidal Okay, so there is a distal buckle convergence and mesiolingual and Bucco distal angles are obtuse The mesiobuckle and distalingual angles are acute okay the mesiolingual and Bucco distal angle are obtuse whereas the mesiobuckle and Distalingual angle are acute and The crown is wider Linguely and measly So it has got four cusps with four triangular ridges and tubercle the oblique ridge between mesiolingual and disto buckle cusp So the oblique ridge Which is a very common short knot which is present between the distal cusp ridge of mesiolingual cusp that is a distal cusp ridge of mesiolingual cusp and triangular Ridge of the distal buckle cusp triangular ridge of distal buckle cusp So oblique ridge is present between distal and there is a major forza that is a central and distal minor forza mesiol and distal and there is triangular forza and The developmental grooves There is buckle developmental groove central developmental groove transfers groove of oblique ridge there is distal oblique groove lingual groove and fifth cusp groove so Maxillary first molar is the only molar that is wider lingually than Buckley and The pit is central pit. So these are Various features of occlusion aspect So that was all about maxillary first molar. It is a very commonly asked question and Many short notes will be asked The occlusion anatomy the buckle side Palatal side all will be asked as a separate short knot And the fours are's Ridges and the grooves so short knots The grooves of maxillary first molar or the ridges and the fours us So you need to draw a picture and label it properly. So I'll come up with maxillary second molar in my next session. Thank you