Page 17 - skinner

*3 tible of decay ; but, on the contrary, they are more liable to it than bones of any other defcription. The enamel of the teeth is nearly allied to inanimate mat ter : The texture is extremely clofe, and there is con- fequently a greater comprefiion of the veffels. Ob structions therefore, are more easily occafioned. If the juices of the teeth are vitiated, they muft be liable to contamination, proportionably to the impreffions they receive. Caries may arife, as before obferved, from either internal or external caufes ; they may be divided into foftanddry: The former is rapidly deftruftive, and affects the root, and oftentimes the bulb, or internal part of the body. A caries of this defcription is more difficult to be afcertained and cured, than when it pro ceeds from external caufes ; for when it attacks the neck or root of the tooth it cannot be eafily difcovered, for the former is ufually covered with the gum, and the latter lies buried in the focket ; to obtain perma nent cafe in this cafe, it is abfolutrly neceffary to extract the tooth. Dry caries generally proceed from perceptible external caufes, and are to the eye or touch of inftruments; and by early and judicious treatment, be may effectually removed, the painful operation of extracting obviated, and the tooth preferved (often times) during life. But on the contrary, if no effort is made to put a flop to the decay, it foon penetrates to the nerve and blood veffels, and creates excrutiating pain : Extraction of the tooth mud then follow, or the actual or the former is potential cautery's applied ; preferable, as the latter can feldom be applied without injuring the adjoining teeth. In all cafes where a de cay is perceptible, the rotten part fhould be thoroughly and judicioufly removed, and the cavity perfectly and folidly filled with gold, filver or lead foil, prepared for that purpofe. If the decay has penetrated to the nerve of the tooth, and pain enfucs, it mud never- thelefs be thoroughly removed, and the nerve effeclu-