牙体牙髓学：根管治疗.ppt

Steps of lateral compaction technique
Selection of the master cone
The primary point should be selected to match
the size of the last instrument used at the apex
It should not be able to be forced bevond
the working distance
The cone should bind in the apical
portion of the canal
Four methods used to determine
the proper fit of the primary point
Visual test
Tactile test
Patient response
· Radiographic test
Visual test
Measured and grasped with cotton pliers at a position
within 1mm short of the prepared length of the canal
Carried into the canal until the cotton pliers touch
the external reference point of the tooth
Tried in a wet cana
If the working length of the tooth is correct and the
point goes completely to position
the visual test has been passed
If the point can be pushed to the root end
it might well be pushed beyond into the tissue
Either the foramen was originally large or it has
been perforated
If the point can be extended beyond the apex
the next larger size point should be tried
If this larger point does not go into place, the
original point may be used by cutting pieces off
the tip Each time the tip is cut back 1 mm, the diameter
becomes larger by approximately mm
By trial and error the point is retried in the cana
until it goes to the correct position
3~4mm
试尖时牙胶尖超出根尖孔
trial and error试尖
Tactile test
he cone should bind in the apical
portion of the canal
the apical 3 to 4 mm of the canal
It should exhibit tugback"or
resistance to withdrawa
It should not be able to be forced beyond the
working distane
If the point is loose in the canal, the next
larger size point should be tried or the
method of cutting segments from the tip of
the initial point
Patient response
Patients may feel the gutta- percha penetrate
the foramen not anesthetized during the
treatment or nonvital pulp
Adjustments can be made until it is completely
comfortable
This is a good test when t