Page 285 - My FlipBook

I)y this plan of study it is found that the areas of Ha-
bihty of proximate surfaces broaden out to tlie buccal, or
labial, and to the lingual along the line of the free margin
of the gum or near it. Therefore, by extending the cavity
so as to include these points within its marginal lines, squar-
ing out the bucco-gingival (or labio-gingival angle) and the
linguo-gingival angle, making the buccal (or labial) and
the lingual margins straight until the gum margin is reached,
and the gingival margin straight from labial (or buccal) to
lingual, these areas of liability to the recurrence of decay
will be included in the cavity. At the same time the form
of the cavity will be greatly improved in the physical sense
so that the filling is more quickly and easily made, facili-
tating accuracy in the operative procedure.
Studies of this nature will, after some time, enable the
operator to form a better estimate of the necessity for ex-
tension in particular cases. As the general rule it will be
found that as persons grow older and the intensity of sus-
ceptibility has diminished, and especially in those in whom

the tendency to caries has never been great, the areas of
liability are comparatively smaller. In these the extension
required will be correspondingly less.
These processes are carried out for their curative and
prophylactic value. Much simpler fillings, in the technical
sense, may be made, and have been made, in these cavities
in the past, but have been found lacking in prophylactic value.
Decay is continually recurring about the margins of. the fill-
ings, whenever these are involved in habitual uncleanliness,
and they are soon undermined and destroyed. Extension for
prevention intelligently adapted to the conditions and skill-
fully carried out has been found an effective remedy.

Prophylactic Value of Form of Proximate Fillings.

The form given to proximate surface fiUiiigs is of the ut-
most importance in the prevention of recurrence of decay,
and in the prevention of the occurrence of disease of the
gums and peridental membranes. The points to^be attained
are : The preservation of the full mesio-distal breadth of
the tooth crown ; a correct form of proximate surface ; a
\correct form of interproximate contact, and the health of the

273