per arch) that divide the mouth into four equal parts. Quadrant means one fourth, and each quadrant is one fourth of the entire mouth. Teeth are described as being located in one of the four quadrants: right maxillary quadrant, left maxillary quadrant, right mandibular quadrant, or the left mandibular quadrant.

LOCATION OF THE TEETH

Normally, a human receives two sets of teeth during a lifetime. The first (deciduous or primary) set consists of 20 teeth ("baby" teeth). The second (permanent) set usually consists of 32 teeth. In each quadrant, there are eight permanent teeth: two incisors, one cuspid, two bicuspids, and three molars (fig. 4-14). The tooth positioned immediately to the side of the midline is the central incisor, so called because it occupies a central location in the arch. To the side of the central incisor is the lateral incisor. Next is the cuspid, then the two bicuspids (the first bicuspid, followed by the second bicuspid). The last teeth are three molars. After the second bicuspid comes the first molar, followed by the second molar, followed by the

Figure 4-14. - Names of the teeth in the right maxillary and mandibular quadrants; anterior and posterior teeth.