Gutta-percha obturation technology is used more and more popularly in root canal filling due to simple operation, rapid filling and compactness. In the process of clinical application, attention should be paid to the following aspects:

1. The diameter of the main gutta-percha apex should match that of the main apical file for root canal preparation. If the main gutta-percha tip is too slim, it will bend when it is pressurized to the root apex, resulting in inadequacy of the root apex filling. Conversely, the gutta percha tip cannot reach the working position of root canal apex if it is too thick.

2. The taper of the main gutta-percha tip should match that of the apex during root canal preparation. If the taper is too big, the gutta-percha tip will be resisted and cannot fit with the wall well in the middle and upper apex of the root canal. If the taper is too small, it only matches the apical foramen at 1mm of the apex , and there will be a relatively bigger gap between the dentin wall and the apex at 3-5mm section.

3. Choose the right working tip with heater to avoid thermal damage. The size and diameter of the working tip should match that of section at 4-5mm from apex in the root canal. When the working tip with heater is extruded toward the root apex, it should not contact the wall of root canal avoiding thermal damage.

4. The working tip with heater should stay in the root canal less than 3 seconds. It should be heating with continuous movement and never stay at a fixed position in the root canal.

5. The root canal should be thoroughly dried before gutta-percha filling. Or The heating up of working tip and the softening of gutta-percha will be seriously affected by the residual liquid in the root canal.

6. Select the suitable heating temperature of the heat carrier. Select the appropriate heating temperature according to the material properties of the gutta-percha tip. The heating temperature of the heat carrier is usually set to 200°C ± 10°C. If the temperature is too low, the root canal thermal gutta-percha cannot be softened. If the temperature is too high, the gutta-percha softens too much and the three-dimensional filling material will be lost. The required back pressure, and the temperature is too high can cause periodontal ligament burns.

7. After the working tip of the heat carrier reaches the position and suspends heating, the filling pressure should be maintained until the apical gutta-percha is solid, usually for 5-10 seconds, which can make up for the shrinkage of the material during the cooling process.

8. During the slow cooling of the gutta-percha, gently shake the heat-carrying device to cut off the gutta-percha tip. After the root canal hot gutta-percha is completely cooled, heat it again for 1 second, so that the working tip of the heat-carrying device is separated from the gutta-percha below to prevent removal. Take out the main gutta-percha tip when carrying the heat-carrying tip.

9. Select the suitable heating temperature of the injection device according to the different components of the gutta-percha filling. At this stage, the components of the bullet-shaped gutta-percha injected on the market are different, and the corresponding heating temperature can be set according to the requirements of the manufacturer’s instructions (150℃, 180℃, 200°C, etc.).

10. Before the injection of the injector, the needle should be in contact with the gutta-percha at the tip of the root for 2-3 seconds to soften the hot gutta-percha of the root canal and fully fuse with the injected gutta-percha to prevent the formation of air bubbles. During the injection process, excessive pressure should be prevented to prevent the vertical extrusion of the gutta-percha to the dentin wall and cause a cavity in the root canal. The main apex of the test tip is about 1mm away from the root apex, and the root pressure formed in the vertical pressure section can make the gutta-percha tip descend to seal the apical foramen and prevent overfilling.