After removing the disc of bone isolated by the trephine,
control all hemorrhage and then enlarge the opening and
remove the bony tissues till the tooth fang is bared its entire
width. Insert a scalpel or bone chisel betwen the external
face of the bone and the soft tissues at the oral margin of
the trephine opening, and having one hand in the oral cavity
with the fingers resting upon the alveolar border on the
lateral side of the tooth to serve as a guide, push the scalpel
or chisel along. between the bone and soft tissues until it
emerges from the gums alongside the affected tooth.
Extend. this separation backward and forwards until the
soft tissues are completely detached from the alveolar wall
over the entire area of the diseased member.
When operating upon the superior molars, the fangs of
which are covered by the zygomatic ridge, the chisel or
scapel cannot be pushed directly from the trephine opening
into the mouth between the soft tissues and the bone because
the line is concave instead of direct. In these cases it is
best to detach the soft parts from the zygoma only, at first
and then remove the plate of the ridge with the bone for-
ceps or chisel, after which the line into the mouth is direct
and the instrument can be readily pnshed between the soft


REPULSION OF TEETH 9


and osseous tissues for the remainder of the distance and
the separation completed.
