 Hello everyone, welcome back to another session in dentistry and more so we are continuing our dental anatomy sessions so far We finished maxillary central incisor maxillary lateral incisor Maxillary canine then we gem to mandibular canine now. We are back to maxillary that is the first primolar So we finished anterior session. I mean anterior teeth now. We are into the posterior teeth okay, so posterior teeth are two primolas and three molars So primolas are so named because they are placed between the anterior teeth and the molars, so it is pre to Molars it is before molars that is why this name pre molars So primolar Assist canine and molars in tearing and chewing food So we know the function of teeth that is incising then tearing and Grinding okay, so this primolar it helps tearing that is function of canines and grinding that is a function of molars It has got two cusp. That is why it is also known as by Cuspids so cuspid be learnt that is canine. This is by cuspid because it has got two cusp And it has got two roots Okay, it has got two roots and two cusp And the tooth number so we have three systems So which are the systems? The systems are universal Zygmonte Palmer system and FTI system So in universal it will be 1 2 3 4 5 6 7 8 9 10 11 then comes 12. This is universal system and Zygmonte Palmer system is 4 and FTI system is 1 4 and 2 4 now the chronology Chronology the first evidence of calcification by 1.5 to 1.75 years enamel completion This is years Canines were in months central incisor and lateral incisor were in months That is the first evidence of calcification then we have enamel completion by five to six years eruption is very late 10 to 11 years I mean compared to enamel completion and Finally root completion by 12 to 13 years and the dimension The length of crown is 8.5 and the root is 14 Musial distal diameter of crown is 7 and 5 at contact and service area and Bacolingal is 9 and 8 at contact and cervix area the curvature of Lion and mesial and distal is 1 and 0 okay distal side it is 0 So we have a crucial surface in Place of incisal surface on posterior teeth So we'll start with the buckle side not label side. So this is buckle side So crown is pentagonal shape you can see here crown is pentagonal shaped and Crown closely resembles to maxillary canine and second premolar The mesial margin joins the meso occlusal slope to create an obtuse meso occlusal angle and The contour of the mesial outline is concave from the contact area to the cervical line Okay, so that is a peculiar feature of maxillary first premolar. There is a concavity and The mesial slope of the buckle cusp is longer than the distal slope, which is the opposite of canine, okay? Usually the mesial slope is Shorter than the distal slope Okay Here the mesial slope of buckle cusp is longer than the distal slope and Distal occlusal angle is a little less prominent and the cervical concavity is not as deep and The occlusal margin of the tooth is similar to the incisal margin of the maxillary canine and there is presence of buckle ridge And meso buckle and distal buckle developmental depressions on each side of buckle ridge Now we have the lingual aspect the crown tapers towards the lingual aspect. Okay, you can see the Outline of the buckle cusp from the lingual side and the lingual cusp is shorter than the buckle cusp and It is smooth from the cervical portion to the area near to cusp tip and the cusp tip is pointed with Mesial and distal slope meeting at an angle about 90 degree Small portion of the buckle cusp can be seen from the aspect. I mentioned it already And it is convex in all direction. There is no clearly defined lingual ridge Mesial and distal outlines are normally somewhat Convex and shorter than the same outlines on the buckle surface Cusp tip is not as sharply pointed as a buckle one. Okay, and mesio occlusal slope is shorter than the distal occlusal slope Now we have the mesial aspect From the mesial and distal aspect both buckle and lingual cusps are visible and There is a well developed mesial marginal ridge and a mesial marginal developmental groove is present In the middle of mesial surface is a mesial developmental depression Which is continuous beyond the cervical line, which is very peculiar for Accelerated first primolar on the mesial side. There is a developmental depression So this is a mesial concavity So shape of the mesial surface is tropizoid and buckle outline is generally convex with the height of contour on the cervical third and Linguely the outline takes the form of even a arc with the height of contour on the middle third Occlusal margin is irregularly concave and the majority of it is made up of medial marginal ridge and A prominent mesial marginal groove is usually present Intending the occlusal margin almost Two-third of the way from the buckle to the lingual outline Now we have the distal aspect So there is no developmental depression or groove on this aspect Instead it is convex at almost all points And the curvature of the cervical line is less on this aspect compared to mesial just like any other tooth The contact area is near the junction of occlusal and middle third and Distal side is Remarkably similar to the mesial surface although it is slightly shorter occlusal gencivally and lingual margin is almost symmetrical and Is quiet convex especially in the middle third where the height of contour is located and Occlusally the distal is similar to mesial aspect except that marginal is just located at a more cervical line There is normally no marginal groove and finally we have the occlusal aspect so within Cusp Ridge and The marginal edges the following are present that is the tip of buckle and lingual cusps and the buckle and lingual triangular ridge and distal buckle developmental groove and Distal and mesial triangle of Fossa and the central groove all you can see here It is a central forza triangular forza and the distal buckle developmental groove and Buckle and lingual triangular ridge and the buckle and lingual cusp The outline of the crown can be described as a hexagonal or six sided and it is wider bucklingly than meso distally. Prominent buckle ridge is primary, contributed to generally convex buckle outline and lingual margin is evenly convex or most in a semi-circle. Proximal margins are relatively straight and they converge towards the lingual. Finally the root, so most maxillary first primolar have two roots but one and three roots can also be seen so you need to be very cautious while doing an extraction of first primolar. Two roots that is buckle and lingual roots, buckle portion of the root resemble canine and the root when viewed from proximal side shows a big trunk and bifurcation area from where the buckle and lingual root separates and there is a developmental depression is seen on the mesil aspect of the trunk. So that is all about maxillary first primolar. The special feature of this tooth is that concavity which is present on the mesial side and the lots of features are on occlusional side such as central groove, triangular fossa and those developmental grooves. So this is also commonly asked as a question maxillary first primolar. So I will come up with maxillary second primolar in my next session, thank you.