3-DIMENSIONAL DIRECTION AND INTERRELATIONSHIP OF PRISMS IN CUSPAL ANDCERVICAL ENAMEL OF DOG TOOTH

The three-dimensional architecture of enamel prisms was examined in cu spal enamel and compared with that in cervical enamel by light and ele ctron microscopy as well as computer-assisted reconstruction using the developing enamel of several dog teeth. Dog tooth enamel consists of two groups of alternately arranged enamel prisms oriented in opposite sideward directions basically forming thick horizontal rings, partly b ranching off from the stem. Along a 8-10 enamel prism-wide group, the enamel prisms emerge in parallel tilting uniformly to the same sidewar d direction. In cervices, groups of enamel prisms are arranged nearly in parallel displaying a regular arrangement of prisms. Approaching th e cusp of tooth, the groups of enamel prisms fuse to a concentric cusp -centered arrangement and the prisms exhibit no periodic arrangement a s shown in the cervical enamel. It is suggested that the three-dimensi onal structure of enamel becomes complicated close to the cusp, contri buting to the chewing stress of tooth. Anat. Rec. 252:355-368, 1998. ( C) 1998 Wiley-Liss, Inc.