Maxillary first molar is the 6th tooth from the midline. Its tooth number in FDI system is 1 6 and 2 6, in Universal System 3 and 14 and in Zsygmondy Palmar System the tooth number is 6 with appropriate quadrant brackets. It is the 1st permanent tooth to erupt in the arch. It erupts posterior to the 2nd deciduous molar, not removing any of the primary teeth. Thus, like all permanent molars, it is not a succedenous tooth as it has no predecessor. It is positioned approximately at the middle of a fully grown jaw antero-posteriorly. Due to the significance of its location it is also called the 'Cornerstone'. Maxillary 1st molar is the strongest tooth in the arch. It has 4 well-formed cusps and a 5th supplemental cusp called the 'fifth cusp' or 'Cusp of Carabelli'. The 5th cusp is unique to maxillary first molar and not seen in any other tooth. As with all maxillary molars it has a strong anchorage with 3 roots, lingual, mesiobuccal and distobuccal. Maxillary first molar develops from 5 developmental lobes. One lobe for each cusp. The function of molars is grinding. Maxillary first molar erupts at the age of 6 years. Coming to measurements. The cervico-occlusal length of the crown is 7.5 mm. The length of both the buccal roots is 12 mm and lingual root is 13 mm. Mesio-distal diameter of the crown is 10 mm and at cervix is 8 mm. The bucco-lingual diameter of the crown is 11 mm and at cervix is 10 millimeters. The cervical line has a curvature of 1 mm on mesial side and on distal side it is flat. The morphology of teeth is studied under 5 aspects, let us start with the 1st aspect, buccal aspect. The outline form of the crown is trapezoidal with the shorter side towards the cervix and longer side towards the cusps. Both buccal cusps, mesio-buccal cusp and disto-buccal cusp are seen. Where the mesio-buccal cusp is larger. Though, the disto-buccal cusp is sharper as its cuspal slopes meet at a right angle. Whereas cuspal slopes of the mesio-buccal cusp meet at an obtuse angle. Parts of lingual cusp, mesio-lingual cusp and disto-lingual cusp are also seen. The mesial contact area, by which the tooth contacts the 2nd premolar is approximately at the junction of occlusal third and middle third. Whereas, the distal contact area, by which the tooth contacts the second molar is at the middle of middle third. The distal outline of the crown is more convex than the mesial outline. From the buccal aspect, more of distal surface is visible than the mesial surface. This is because, the crown from the occlusal aspect is rhomboidal in shape, in which the disto-buccal line angle is obtuse. This makes the distal surface visible from the buccal aspect. The cervical line is irregular or slightly convex towards the root. A buccal developmental groove is seen in the middle of the buccal surface between the two cusps, which runs cervically and terminates half way from the cervical line. Faint concavities are seen lateral to the terminus of the groove running in proximal directions. All three roots are visible from this aspect. The root trunk bifurcates at about 4 mm from the cervical line into mesio-buccal root and disto-buccal root. The lingual root is partially seen and is slightly longer. A developmental groove is seen running on the root starting at the bifurcation and ending at the cervical line. Next, the lingual aspect. The outline features of the crown from the buccal aspect are same in the lingual aspect as well. From the lingual aspect both the lingual cusps mesio-lingual cusp and disto-lingual cusp are seen and also the 5th cusp. No part of the buccal cusp are visible, as they are completely hidden by the lingual cusps. The mesio-lingual cusp is larger than the disto-lingual cusp, forming almost 3/5th of the diameter of the crown mesio-distally. Its cuspal slopes meet at an obtuse angle whereas the disto-lingual cusp is more spherical. The Cusp of Carabelli is seen attached to the lingual surface of the mesio-lingual cusp. It is generally 2 mm cervical to the mesio-lingual cusp tip. Like the buccal developmental groove, a lingual developmental groove is present between the two lingual cusps running cervically. All 3 roots are visible with the larger lingual root in front and parts of the mesio-buccal and disto-buccal roots on the sides. Next, the mesial aspect. The outline form is trapezoidal with the shorter side towards the cusps and the longer side towards the cervix. Only 3 cusps are seen, mesio-lingual cusp, mesio-buccal cusp and 5th cusp. The buccal outline is generally convex with its height of contour in the cervical third. A shallow concavity is seen just occlusal to the height of contour, which was also seen from the buccal aspect. The lingual outline is smoothly convex with its height of contour in the middle third. The cervical line is convex and the convexity is towards the crown. The mesial marginal ridge is seen in the occlusal third confluent with the mesio-buccal and mesio-lingual cuspal ridges. Only 2 roots, lingual root and mesio-buccal root are visible from this aspect. The bifurcation of the trunk is more cervical in comparison to the bifurcation from the buccal aspect. The mesio-buccal root is almost 2/3rd the width of the root trunk at the bifurcation. The lingual root has a 'banana-like' shape due to a *buccal curvature. Coming to the next, distal aspect. The gross outline of the mesial aspect is similar to the distal aspect as well. Some differences are, only the distal cusps, disto-buccal cusp and disto-lingual cusp are seen from this aspect. The distal marginal ridge is slightly more cervical than the mesial margin ridge, because of which the triangular ridges on the occlusal surface are visible. All 3 roots are visible from this aspect. The disto-buccal root is narrowest at its base among all the 3 roots. The bifurcation is more apical on the distal side about 5 mm from the cervical line.