Page 155 - My FlipBook

decay was making rapid progress. It requires that the acid ;
be formed at the particular point, at the particular spot, and
that it be held in position against the tooth's surface by some-
thing that will prevent its ready dissipation in the saliva in
order that caries may occur. We copy this unwittingly now

and then when we cement bands upon teeth and hold them in
position for a number of months, or a year or so, and fail to
have the cement perfect in some position. Under the band
decay of the enamel occurs ; micro-organisms have grown
in the slight open space, and the band has acted to prevent
the dissipation of the acid formed, and it has acted upon the
tooth. We may in this way cause decay to occur in mouths
that are otherwise inmiune. I have done this myself, and
have had some ugly cavities occur on the labial across from
mesial to distal in cuspid teeth, once in an incisor, and several
times in buccal surfaces of bicuspids, simply because my band
went on either without the cement filling the space or the
cement was washed out later and micro-organisms grew in
this position and produced decay. These decays were pro-
duced in positions of surface ordinarily immune to decay.
And in two instances it has so happened that I have done
this in mouths in which there was absolutely no decay oc-
curring in any other position.
This much, then, to try to express' to you the necessity
that acids be formed at the immediate spot, and be held in
position in order that decay may start in the enamel. You
should know well the positions in which this occurs. There
are the three prominent positions—the pits, fissures and
grooves, wherever they occur, those that are deep enough to
afford lodgment for micro-organisms ; the proximate surfaces
and the buccal and labial surfaces ; also overlaps of fillings
under which micro-organisms may grow and be sheltered
imperfect contacts which admit food to push away the gum ^
tissue and serve to hold lodgments in which micro-organisms
may grow and be sheltered on proximate surfaces. The den-
tist unwittingly makes places for the beginning of decay over
and over again and loses his fillings in consequence of it.
One of our graduates of a few years' experience came to me
the other day and said: "I had an observation yesterday.
There were three patients, new to me, w^ho put themselves
under my care. In one of these I found fourteen proximate
fillings, said to have been in three years, and in every one

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