The main reason of instrument breaking:
1, the root canal file itself quality is not qualified, or file in disinfectant, soaking time is too long, corrosion;
2 、 when the root canal is prepared, the root canal file is improperly used, jump number is used, or excessive force is reversed;
3, because the tooth aging changes, too small, curved root canal;
4, the root canal file repeatedly used, leading to metal fatigue; nickel titanium instruments fatigue generally without visible damage.
Equipment and operation technique for breaking out instrument in different root canal
(1) pathway establishment: clinical operation, X-ray clear broken needle position, microscope in root canal (up to 10 ~ 20 times) observation, first with a shank root canal file into the root canal, until the broken needle coronal section, marked with a moving plate, to determine the depth of the broken needle. Then use the K file or H file will be broken needle upper root canal to 30 ~ 40, GG No. 2 and No. 3 drill tip down to GG plane is larger than the diameter of the drill tip needle diameter, with 2 or 3 after grinding GG drill from root canal preparation to establish channel the broken needle position, the needle part above the root canal was smooth, easy operation and intraoperative microscope.
(2): the use of ultrasound, ultrasonic extraction method can replace the file handle with ET20/ET40 and endodontic instruments. In the clinical operation, first with a cotton ball to block the root canal orifice, then there will be a pathway under the microscope needle after root canal, the ultrasonic power setting file in the root canal treatment, ultrasonic K file in the coronal gently downward pressure, ultrasonic or ET20/ET40 file into the broken needle and root canal wall in between the upper until the broken needle, counterclockwise around the needle vibration, in most cases, the broken needle often with the washing liquid floated out, or with a file.
(3) H file out method: to establish the pathway after the formation of a certain gap in the broken needle around by ultrasonic method, using the 3 H file is inserted into the needle around the counter clockwise, 3 H file intertwined, bite the broken needle, the needle broken out. It is suitable for the removal of broken screw filling device and H file.
(4): establish a pathway after casing removal, root canal needle coronal 1/3 with ultrasound exposure, outer tube for trapping the broken needle, the wedges inserted into the casing in place, the needle head will be the tip of the wedge sleeve side window, at this time of casing and the wedge is taken out with the broken needle.
(5) forceps removal method: if the broken needle is located on the root canal, 1/3, after the establishment of access, you can use the broken needle removal forceps out alone, or use ultrasound to break the needle after loosening, use a broken needle to remove the forceps, remove the broken needle.
(6) auxiliary broach out method: when the broken instruments when the broach or spiral plugger, with barbed broaches, for the broken needle test check.
Although there are many ways to remove the broken instruments, there are still a lot of broken instruments that are difficult to remove.
Two, the main reason for the removal of broken instruments, there are two
First, the depth of the root canal, the diameter of the cross section and the curvature of the root canal. In general, if the length of the 1/3 exposure of broken instruments, often can be removed; if the broken instruments in root canal straight are easily removed; if the broken instruments in root canal curvature, and dentin thickness from root canal instruments to allow the establishment of coronal channels are also likely to be out of the broken needle but if the broken needle in curved root canal below to root zone, it is difficult to establish a secure channel, it is difficult to remove broken instruments.
Secondly, the type of broken instrument is also an important factor affecting the removal. The instrument such as screw filling device can be removed easily, while the nickel and titanium can be broken again under the action of ultrasonic heat, which is difficult to remove.
The following points should be noted when taking off the instrument:
1. in the use of ultrasound to take multiple tooth broken needle, broken needle from a root canal outflow may flow into another root canal, in order to prevent its occurrence, should advance in other place or other cotton root canal obturation in advance;
2., under the ultrasonic heat, nickel titanium instruments may break again and fall deeper into the root canal, so ultrasound should be taken to avoid excessive power, in case of excessive heat production;
3., in order to avoid side wear or break the needle out of the root tip hole, remove the dentin around the broken needle, the vision should be clear, to avoid stressing on the broken needle.
Prognosis and observation: not all the broken instruments will affect the effect of root canal treatment. The preparation, cleaning and filling of the deep root canals can be completed by the needle breakage removal method and the broken needle technique. If the broken instruments located in the apical root canal could not wedge out, root canal basic clean teeth without clinical symptoms, not out of the instrument also plays the role of filling material. Preparation and root filling should be carried out, and regular observation should be performed. If necessary, the root canal surgery will be performed. If the broken instrument exceeds the apical foramen and the inflammation of the teeth is removed, a feasible apical operation can be performed. Preparation and root filling can be carried out, and regular observation is performed. If necessary, the apical operation is performed.