Root canal filling steps

Root canal filling is usually done at the tooth site. If there is a problem with the tooth, this step of root canal filling is required. If there is inflammation, try not to have the root canal filled. Wait until the inflammation is gone before doing this step. During the root canal filling process, we must pay attention to the patient's mentality and try to calm his emotions before treatment. Otherwise, if the patient is uncooperative, the entire operation will be difficult to carry out.

1. Prepare the root canal and open the pulp, thoroughly remove the diseased and necrotic pulp tissue, measure the root canal length, and expand the root canal.

2. Root canal flushing is a repeated operation during root canal treatment to flush out the infection sources such as small fragments of organic matter in the root canal and small fragments of hard tissue cut off.

3. Root canal disinfection: Drug disinfection is most commonly used. A cotton swab is dipped in a small amount of liquid medicine and placed inside the root canal. The hole is sealed with a temporary sealing material.

4. Root canal filling is the last step of root canal treatment and also the most important step in root canal treatment. Currently, the most common clinical practice is to use root canal filling agent plus gutta-percha to fill the root canal so that the root canal system can be tightly closed.

Although root canal treatment requires multiple sessions, it can save you the trouble of tooth extraction and dentures. Many people often equate root canal treatment with "nerve extraction", but in fact they are not exactly the same, because the dental pulp contains not only nerves, but also blood vessels and other tissues. Complete root canal treatment is not just about extracting nerves, but also includes complex and detailed steps such as root canal expansion and filling, so multiple sessions are required.

1. Timing of root canal filling

The patient's symptoms and signs, the condition of the pulp and periradicular tissues, and the complexity of the treatment determine the number of root canal treatments and the timing of root filling. It is generally believed that when a patient is diagnosed with acute apical periodontitis and has acute symptoms, it is a contraindication for root canal filling. In cases of pulpitis, regardless of the state of inflammation, after complete removal of the infected pulp and perfect root canal preparation during treatment, root filling can be completed in one go if time permits. For cases of pulp necrosis and chronic apical periodontitis, root filling can also be completed in one go. However, most studies have shown that root canal sealing with Ca(OH)2 paste for one week before root canal filling is beneficial to the healing of apical lesions and long-term efficacy. The prerequisite for root filling is that there is no exudation in the root canal and the root canal is completely dried with paper twist. For apical periodontitis or apical cyst, if there is continuous exudation in the root canal, root filling cannot be performed immediately. Ca(OH)2 paste should be sealed in the root canal for 1 week to reduce or control the exudation before root filling. The absence of abnormal clinical findings in the affected tooth is another condition for feasible root filling.

2. Standards that root canal filling should meet

The ideal root filling material should tightly fill the three-dimensional space of the root canal above the junction of the apical dentin and cementum. The quality of root filling can only be clinically judged by periapical X-rays as "adequate filling", "poor filling" or "overfilling". The evaluation criteria include two aspects: ① the root filling material should fit tightly with the canal wall (only the mesial and distal walls can be displayed), and there should be no X-ray transmission image of the canal wall; ② the root filling material should reach the junction of dentin and cementum in the apical area. Based on the measurement of a large number of ex vivo teeth, it was found that the junction of dentin and cementum is about 0.15 to 1.10 mm away from the outer edge of the apical foramen; the location of the apical foramen is not necessarily at the top of the root, and the outer edge of the apical foramen is about 0.15 to 1.10 mm away from the top of the root (i.e. the apex of the X-ray film). Therefore, the clinical standard is that the root filling should be 0.15 to 2.10 mm away from the X-ray apex. When both of the above two criteria are met, it is called "adequate filling"; when the first and/or second criteria are not met, it is called "poor filling"; when the first criterion is met but the root filling exceeds the apical foramen, it is called "overfilling"; when the X-ray shows that the root filling is only 1mm or 115mm away from the X-ray apex, and the apex shows the transmission image of the unfilled root canal, it is called "poor filling"; when the root filling is flush with the X-ray apex, it is overfilling. Clinical studies have confirmed that the efficacy of "appropriate filling" of teeth with root filling is better than that of "poor filling" and "overfilling". However, despite the lack of sufficient evidence, some scholars are willing to fill the root filling material to the level with the X-ray apex or slightly overfill (apical puff) when using the vertical pressure technique of hot gutta-percha as an indication of tight filling of the apical area and lateral root canals.