Root canal calcification is a common problem in root canal therapy. It can cause root canal obstruction and even difficulty in finding root canal orifice. Pulp calcification is the pathological change process of pulp under external stimulation. The degree of calcification is related to different stimuli, and the difficulty of clinical treatment is also different.

1. For the curved calcified root canal, the convenient type of pulp opening should be adopted as far as possible. Remove all pulp apices. Sometimes more tooth tissue needs to be sacrificed. The wall of the pulp opening should form a linear channel with the root canal wall.

2. Finding and determining the root canal orifice is the first step in the treatment of calcified root canals. The most important tools are the straight dental tip probe and the root canal mouth probe. The pulp chamber floor is hard dentin, and the probe can enter a little at the root canal mouth under a certain pressure, with a sense of jamming. At this time, X-ray is used to determine whether it is the root canal mouth, and if necessary, a microscope should be used to determine.

Most of the root canal orifices are bent at 1-2 mm, so the dentin of the neck should be removed; If the root canal orifice cannot be found, 2 # long round drill or ultrasonic can be used to enter the root canal orifice for 1-2 mm. The black pulp chamber floor and white restorative dentin are the signs of finding the root canal orifice. Root canal lubricant (including EDTA) is helpful for finding root canal orifice.

(1) The patency and preparation of calcified root canals:

08 # and 10 # files are the most effective tools for expanding the root canal. Pay attention to pre-bend the tip 1mm, mark the bending direction of the file with a stopper, dip the tip of the file with root canal lubricant, and flush with a large amount of irrigating agent. The root canal file is gradually filed in, repeated, and deepened 1~2mm each time. When the file reaches the working length, it shall be determined by X-ray film, and the root canal shall be extended to sufficient working length by lifting up and down. After the root canal is unblocked, various methods can be used for preparation.

(2) Preparation of curved root canals:

First of all, pre-bend the root canal file. The pre-bend root canal file is easy to pass through the bend and can slide through the obstacle point to reach the apical area. There are two kinds of pre-bending, the tip pre-bending and the full file pre-bending, which are prepared in the opposite direction of bending. The pre-expansion and preparation of the root canal orifice and 2/3 of the root canal crown facilitate the smooth entry of the pre-bent root canal file. Select the middle root canal file, such as 12 #, 17 #, 22 #, 27 #, 32 #, 37 #. Replace the small file with the first file after it is fully prepared. When preparing the curved root canal, the working length should be re-determined every 3 # expansion. If the root canal is seriously bent, the initial file can reflect the bending direction and degree of the root canal. It should be carefully observed and the root canal deformation should be noticed at any time.

The primary root canal deformation caused by root canal file is not obvious, but the accumulation of multiple preparation effects will produce larger root canal deformation, resulting in the narrow part of the root canal after preparation is not in the apical region, but a few millimeters away from the apical region, in the form of teardrops. In order to avoid the opening of the apical hole, it is best to remove the cutting ability on the outside of the root canal file tip.

Select the middle root canal file, expand the crown of the root canal first, and use the gradual penetration method or crown down preparation method. Pay attention to sufficient irrigation and use of root canal lubricant; Do not over-rotate the instrument; When the root canal file is difficult to enter, the middle number must be used; Prepare slowly.

When preparing the double-curved root canal, the crown of the root canal should be fully extended, and the crown bending should be removed or straightened as far as possible to obtain a good channel into the apical region; Once the small root canal file reaches the apical area, do not lift the file completely. Instead, use a file to pull up and down a few millimeters until the resistance disappears. Otherwise, it may be difficult to enter the same file again.