. The Dental cosmos. nges occurin the angle. Fig. 5 is an illustrationof a mandible of a typical Caucasianskull about twenty-five years of age. Themental process gives prominence to thechin and lower part of the face. Theteeth are set back, the third molar ex-tending beyond the ramus, the anglebeing 125°. The incisors are normal ininclination. Fig. 6 is taken from a man- WEINBERGER. NORMAL DENTAL ARCHES AND NORMAL OCCLUSION. 069 dible of a South African negro. Thebody of the mandible is fairly typical,except that the angle is nearer a rightangle, viz, 118°. The mental process isnot as prominen
. The Dental cosmos. nges occurin the angle. Fig. 5 is an illustrationof a mandible of a typical Caucasianskull about twenty-five years of age. Themental process gives prominence to thechin and lower part of the face. Theteeth are set back, the third molar ex-tending beyond the ramus, the anglebeing 125°. The incisors are normal ininclination. Fig. 6 is taken from a man- WEINBERGER. NORMAL DENTAL ARCHES AND NORMAL OCCLUSION. 069 dible of a South African negro. Thebody of the mandible is fairly typical,except that the angle is nearer a rightangle, viz, 118°. The mental process isnot as prominent as in Fig. 5, owingpartly to the carrying forward of theteeth and the alveolar process. Theprognathous features are caused by the teriorly about midway between the lowerborder of the jaw and the top of thealveolar process and between the rootsof the first and second premolars. InFig. 6 the mental foramen is underthe first molar instead of being on a linebetween the roots of the premolar asinstanced above. Fig. Skull in normal occlusion. (Turner.) position of the teeth and the alveolarprocess. The position of the molars isnoteworthy, there being room for anothermolar, behind the third. The mentalforamen will be found below the firstmolar, showing that in skulls like thoseof the Fan tribe, the teeth are carriedforward by the width of a molar. (SeeFig. 7.) In this skull the mental pro-cess lies almost directly below the teethand is in direct contrast with the twopreceding figures. The third molars arefound almost hidden behind the anteriorborder of the ramus, the angle beingalmost a right angle, viz, 103°. InFigs. 5 and 7 we find the mental foramento be rather a fixed point antero-pos- THE RELATION OF THE TWO JAWS. The lower jaw is developed slightlyin advance of the upper, as shown inFig. 8; for if a vertical line is drawnthrough the centers of the tooth germand the alveolar process of each jaw, itwill be found that the line of the upperjaw is on the inner side of those
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