Dental cosmos . f this tooth is shorter, thicker, and at the cutting-edge broader than that of the first bicuspid. It is provided with three cusps, of nearly equallength, the buccal being slight-ly the longest. Both the an-terior and posterior approximalfaces are rounded, and the en-amel surface extends furtheston the buccal aspect. Thegreatest breadth is through thebases of the cusps, whence thetooth narrows rapidly towardthe neck, with comparativelylittle loss of thickness, whichat this latter point is nearlydouble the width. As in thecorresponding tooth of the up-per jaw, the root, which is
Dental cosmos . f this tooth is shorter, thicker, and at the cutting-edge broader than that of the first bicuspid. It is provided with three cusps, of nearly equallength, the buccal being slight-ly the longest. Both the an-terior and posterior approximalfaces are rounded, and the en-amel surface extends furtheston the buccal aspect. Thegreatest breadth is through thebases of the cusps, whence thetooth narrows rapidly towardthe neck, with comparativelylittle loss of thickness, whichat this latter point is nearlydouble the width. As in thecorresponding tooth of the up-per jaw, the root, which isrelatively short, is nearly cen-tral with the crown, showingalmost no deflection from eitherview, and retains its size and shape nearly to the apex, roundingoff abruptly. The inferior second bicuspid is so placed in the jaw that the con-vexity of the lingual face overhangs the neck. The buccal cusp isthus inclined inwardly. The shorter anterior buccal cusp wallgives it a pitch toward the median line of the Plate M.—Inferior First Molar. In this tooth we reach the true grinders of the lower jaw, asevidenced by the broad, multicuspid crown, the largest of the entireseries. Unlike the anterior teeth and the superior molars, thebreadth of the crown exceeds its thickness. The greatest width isfound across the base of the posterior buccal cusp, whence itdecreases gradually to the gum line. All four faces are slightlyconvex, the buccal and approximal most so. The highest line ofenamel surface is along the buccal face. The excess of breadth overthickness is carried throughout the length of the crown to the TYPICAL TOOTH-FORMS. 607 Plate M cervix, as seen in the sectional views, which show clearly themassive character of the nearly square crown. There are five cuspson the grinding-face, three buc-cal and two lingual. A shortdistance within the gum linethe root is divided from thebuccal to the lingual face in-to two somewhat irregularly-shaped flattened branches, ofnearly equal
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Keywords: ., bookauthor, bookcentury1800, bookdecade1880, booksubjectdentistry
