 Hello everyone, welcome back to another session in dentistry and more. So we are continuing our dental anatomy sessions. So today's session is about mantibular central incisor. Mantibular central incisor as you all know they are two in number right and left and the central incisor and lateral incisor are similar in anatomy and complement each other in function. They are smaller than the maxillary central incisors and mantibular central incisor erupts between the age of 7 to 8 years. Now we'll see our system that is universal, Zygmunti system that is Zygmunti Parma system and FTA system. Universal it will be 24 and 25 because this starts from here 1, 8, 9, 16, 17, 20, 24, 25, 32. In Zygmunti system it is 1 and 1 and FTA system it is 3, 1 and 4, 1, 3 and 4 are the quadrant the left lower and the left right quadrant and 1 is the central incisor. And the chronology first evidence of calcification by 3 to 4 months, crown completion by 4 to 5 years, eruption by 7 to 8 years and root completion by 10 years. And the dimension the crown length is 9, root length is 12.5, mesiodistal diameter at contact area is 5 and 3.5 at cervix, the labilingule is 6 and 5.3 and the curvature on the mesial is 3 and distal is 2 millimeter. So we'll start with the labile aspect. So can see the picture. The labile surface of mandibular incisor is very small, narrowest tooth mesiodistally of all permanent teeth and it is bilaterally symmetrical. Both mesioincisal and distal incisal ankles are very sharp and it is the only incisor where both mesioincisal and distal incisal ankles are sharp and at right ankles. Now the lingual aspect. The lingual aspect is concave from incisal edge to the cervical line, singulum is smooth and barely visible and the shallow lingual fossa and the smooth singulum can see here. The surface is smooth without any grooves and no other tooth in the mouth except the mandibular lateral incisor shows so few developmental lines and grooves. So we don't have many features in mandibular central incisor but as a mesial aspect the labile outline is almost straight except near the cervical third where it is convex. So the lingual margin is like S shape. The cervical line on the mesial and distal surface is convex and sizely you can see the S shape lingual surface and the contact area and the labile surface is inclined lingually whereas the distal aspect the distal surface is very similar to the mesial surface but the cervical line is less curved and contact area is almost at the incisal third just like the mesial side. Now the incisal aspect. This aspect illustrates the bilateral symmetry of the tooth. The labilingual diameter is greater than the mesio distal and the newly erupted teeth choose mammolones which wear off upon the mastication. Mammolones are like three small lobe like structures which is seen on the newly erupted teeth. Now the root sinkle and straight from labile or lingual view the root is generally symmetrical and tapers gradually to relatively a sharp apex. From mesial or distal view the root is much wider and it is slightly convex cervical apically on both labile and lingual merchants and the central portion of mesial and distal surface is usually flattened or concave but the cross section at nick outline is roughly a rectangle with rounded corners but it's slightly wider at labile than the lingual when there are root concave it is present they are reflected as concave it is in the mesial and distal outlines. The main root cross section is similar to the cervical section but only more avoidant shape. So basically the question will come the difference between maxillary central and mandibular central incisor. In maxillary central incisor the crown is wider mesiu distally than labiolinguli but here it is crown wider labiolinguli than mesiu distally. In maxilla the lingulfosso is pronounced often with lingual pit here it is shallow without groove so pit and in maxilla there is more prominent singulum and marginal ridges they are not prominent in mandibular. Now the comparison between mandibular central and lateral incisor so that is also again a common question on labial aspect the symmetry it is bilateral on central but lateral it is asymmetrical. The mesio incisor and distal incisor ankle are sharp in central but rounding in mesial and more rounded in distal incisor angle. But the contact area is all at incisal, mesial or distal irrespective of the teeth and incisal aspect the incisal ridge from right ankle with labiolinguli bisecting line but incisal ridges twisted on crown with respect to the lateral incisor. So that is all about mandibular central incisor so form of difference between maxillary central and mandibular central or mandibular central and mandibular lateral just like the maxillary central incisor. So that is all about mandibular central incisor it is a very small tooth similarly very small features very few features there is no much features on the labial lingual or mesial and incisal side because it is the smallest tooth in the oral cavity but question might come with regard to the comparison with lateral or maxillary central incisor. So I'll come up with mandibular lateral incisor my next session thank you.