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Fifi. 25a.

Kifi. 2.-)4.
Fui. 250.

KiG. 257.

KlCiS. 2Jl-2">7. A scries illiistiiUini^ Uw iiijiiitiinni and inaxiiimni Cii i'x{t'ii>ion
proximal cavities.
F[<;. 2jl. The distal surface of a central incisor with a decay in which the enamel rods have
just l)cgun to fall away. There is practically no burrowing of decay in the dentin, though some
softening has occurred. No matter what the extension demanded to prevent recurrence of decay, no
part of this cavity needs to be cut deeper than may be required for safe anchorage.
KiG. 252. The cavity preparation, exhibiting a miniinnm extension, and the ouUine form that
should generally be used.
Fuj. 25.S. The finished filling.
Fig. 2.t4. The finished filling as seen from the labial.
Fig. 2ri.'i. Mesio-distal section of the tooth and the filling, showing the depth I'f cutting and the
incisal anchorage.
Fig. 25(1. A cross section of the touth :iihI llic tilling close in the gingival wall, showing the
retention in the gingival portion.
Fig. 257. A cavity preparation showing extreme extension. Practically the extension for
prevention in incisor cavities should always be kept between this and that shown in Figure 252. Its
amount should depend upon the conditions demanding extension in each particular case. A filling
made after the cavity preiuiration in Figure 257 wuuld be seen from the labial verv little more than
that in Figure 254.