Page 12 - My FlipBook

8 THE TECHNICAL PROCEDURES IN FILLING TEETH.

portion of the enamel of this surface to the gingival of the pit,
or in the gingival third. All buccal cavities in the bicuspids are
smooth-surface cavities. All labial cavities in the incisors and
cuspids are smooth-surface cavities. All lingual cavities in the
upper incisors are pit or fissure cavities, and a few fissure cavities
occur in the occlusal half of the lingual surfaces of the molars.
All proximate, or mesial and distal cavities, whether in the
molars, bicuspids or incisors, are smooth-surface cavities. Lin-
gual cavities in the gingival half of the molars are also smooth-
surface cavities.
Pit and fissure cavities occur in surfaces of the teeth that are
habitually clean, except as the imperfections of the enamel — pits
and fissures—afford places for the lodgment and fermentation of
d6bris, which causes the beginning of decay. Therefore, in
their preparation for filling they require no extension for preven-
tion of recurrence of decay, further than a sufficient opening of
the cavity to completely uncover the^ carious area and to find
margins sufficiently level and smooth to allow of a good finish
of the margins of the filling. Smooth-surface cavities occur
in positions in which the surface of the enamel is habitually
unclean, and usually begin in the central portion of the unclean
area. The injury to the enamel surface tends to spread super-
ficially from the central area of first beginning toward the
margins of the unclean area. Therefore, such cavities require
such extension in their preparation for filling as will include the
habitually unclean area within their outline in order to prevent
the recurrence of caries.
Classification of Cavities.
In a classification of cavities it is the intention to group
together in classes cavities of decay that require a similar line
of treatment in order that these may be more closely asso-
ciated.
Class I.— Cavities beginning in structural defects in the
teeth, as pits and fissures.
Class 2.— Cavities in the gingival third — not pit cavities —
of the labial, buccal or lingual surfaces of the teeth.
Class 3.— Cavities in the proximate surfaces of the incisors
and cuspids which do not involve the removal and restoration of
the mesial or distal angle.