Operative dentistry aje qualtrough, jd satterthwaite la morrow, pa brunton

Softened gutta-percha methods
Several methods have been described to plasticise gutta-percha.
These may be divided into:
• Heat applied inside the canal
—
warm vertical condensation
—
warm lateral condensation
—
thermomechanical compaction
• Heat applied outside the canal
—
injection technique
• Carrier-based methods
—
heat applied outside the canal
—
mechanical sources of heat
• Solvent methods
Warm lateral condensation involves the use of a heated spreader
applied to a master gutta-percha cone inside the canal. Heat may be
derived either from an external source (such as a warm Bunsen) 
or from a thermostatically heated spreader. Pressure is applied and
the heated mass is adapted to the canal walls. The warm spreader is
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Principles of endodontics


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removed and a cold spreader creates space for further cones to be
added. This process is repeated.
Warm vertical condensation involves a process similar to the above,
except vertically directed forces are applied. The disadvantage is that
there is a danger of overextension of filling material and sealant if
there is not good resistance to apical extrusion.
Gutta-percha may be warmed in a thermostatically heated delivery
gun and applied/injected into the canal via a needle
14
. A cold vertical
condenser is used to compact the material. This method is particularly
useful to fill root canal systems of non-conventional morphology 
(e.g. internal resorption). Again, there is a danger of overextension 
of material in the absence of a positive apical stop. Prior placement of
a master cone precludes this potential problem.
Use of a mechanically operated thermomechanical compacter 
softens a gutta-percha cone which is adapted to the canal walls.
Placement of a gutta-percha cone is essential to preclude overexten-
sion of material. Disadvantages include the risk of instrument separa-
tion, results may be inconsistent and even if a master cone is placed,
apical extrusion of material may result.