Page 97 - My FlipBook

The
FIG. 47. In examining this figure the reader should have fixed in his mind the following : :
substance of the perfectly developed enamel of the tooth has not been successfully stained . being a
solid, it will absorb nothing into itself, therefore any staimn substance of the namel
ult of imperfect development which creates openings which will receive a stain.
The photomicrograph is of a portion of the crown of an incisor tooth from which all tr
of color had beer dissolved out. making the tooth very white. The piece was placea alcohol
for several days and then transferred to a solution of shellac which had been tinted with gen an
violet After remaining in that for two weeks it was mounted upon a cover-glass and dried
fOT fSying^hVttV'oe Teen that the labial surface of the tooth - the Portion most
injured by failure of the cementing substance between the enamel rods - has come out black.
Here the injury has been much
On the lingual surface a very different phenomenon occur
milder than on the labial surface, and it will be s. that areas of white run through the dark
This shows
areas, and that the brownin shows in long lines stead of making a full brown.
that only a portion of the cementing substance be een the enamel rods has failed.