Descriptive anatomy of the human teeth / by G.V. Black.

  • Greene Vardiman Black
Date:
[1897]
Catalogue details

Licence: Public Domain Mark

Credit: Descriptive anatomy of the human teeth / by G.V. Black. Source: Wellcome Collection.

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    one of three directions: Inciso, or occluso-gingivally into incisal, or occlusal third, middle third, and gingival third; mesio-distally into the mesial third, middle third, and distal third; bucco-lingually into the buccal third, middle third, and lingual third. Each of the five surfaces may be divided into thirds in either one of two directions. The labial, or buccal, and the lingual surfaces are divided inciso- or occluso-gingivally, into the incisal, or occlusal third, middle third, and gingival third; mesio-distally into the mesial third, middle third, and distal third. Mesial and distal surfaces are divided inciso- or oc- cluso-gingivally into the incisal, or occlusal third, middle third, and gingival third; bucco-lingually, into the buccal third, mid- dle third, and lingual third. The occlusal surfaces are divided mesio-distally into the mesial third, middle third, and distal third; bucco-lingually, into the buccal third, middle third, and lingual third. The cutting edges, or incisal surfaces of the in- cisors and cuspids, are divided mesio-distally only. These di- visions are the mesial third, middle third, and distal third. 6. The incisors present a cutting edge by the junction of the labial and lingual surfaces along a line. In the cuspids, thisjoining of the surfaces to form an edge is raised to a point near the center of its length, forming a cusp, hence the term cuspid, a tooth with one point. The cutting edges of the in- cisors, and the occlusal surfaces of the bicuspids and molars, come in contact with the similar surfaces of the teeth of the opposing jaw when the mouth is closed, as in the act of biting. The incisors and cuspids of the upper jaw do not occlude ex- actly on the cutting edges or cusps, but generally just back of them; though for convenience, the term occlusal may be ap- plied to them as if they did, though they will generally be called cutting edges, and the adjective form incisal will be used in all compound words. The occlusal surfaces of the bicuspids have two cusps, hence the term bicuspid, a tooth with two points; and the occlusal surfaces of the molars have four cusps and sometimes more.