Page 145 - My FlipBook

occlusal (referring to chart) ; later the gum line will be more
to the gingival (indicating)—the position of the free margin
of the gum on the tooth is changing—and as the patient
grows older it goes farther and farther toward the gingival
line. Now, as it passes on down toward the gingival line and
passes the prominence of the rounding of the surface, there
comes to be a position on the buccal surface, where, with
this rounding of the tooth and the fullness of the gum, there
is a point near the gum line at which the tooth is not kept
well cleaned, and that becomes an area of liability to decay,
usually occurring at from i8 to 25 years of age, generally
—
not earlier. Then zve have these three areas of liability pits,
fissures and grooves in occlusal surfaces of molars and bicuspids,
and in the lingual surfaces of incisors; the proximate surfaces
of all of the teeth; and the buccal and labial surfaces
of all of the teeth, coming one after the other.
Now, if you will recur in your minds to the little patients
who have come to you in the infirmary, the children, you will
remember that the first cavities which you meet are in the
pits or fissures in the molars, usually, occasionally in the lin-
gual surfaces of the upper lateral incisors. These are the
cavities that are the first to occur in the little fellows.
Those that are a little older begin to have cavities in the
proximate surfaces, and those that are still older begin to
have these buccal and labial cavities, gingival third cavities.
Now, gentlemen, when a child of fourteen or fifteen comes
to you, having at the same time all of these classes of cavities,
you have a case that is exceedingly difficult to manage, a case
of unusual intensity of decay, one that will put you to your
wits' ends in your after practice to manage successfully, and
yet it can be done. We will have more to say of that later.
(During the following remarks Prof. Black referred con-
tinually to charts and drawings of teeth illustrating the be-
ginnings and progress of caries.)
Now, to repeat in some degree by the aid of these illus-
trations. The beginning in the molars and bicuspids and in
the lateral incisors, in pits and fissures something such as I
have shown here (indicating), caries breaks through the
enamel and forms a cavity like this (indicating). These you
will see continually ; they are open to the vision and they are
much more easily and readily understood. The area of lia-
bility is confined to the pit. This portion of the tooth around

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