Root canal treatment may be necessary when the blood supply system of the tooth nerves or the tooth may be compromised due to dental caries, inflammation or injury, and inflammation may spread to the jaws where it may cause cysts. Root canal treatment is therefore aimed at saving the teeth and preventing the infection from reaching the root tip, thereby protecting the jaw. The tooth is fixed to the bone through periodontal fibres. Outside the cement, inside the dentin, and deep inside the root canal are located. It contains the blood vessels and nerves that supply the teeth with nutrients (tooth tissue). Nerves also have a signalling role, as if something happens to the tooth, the nerves indicate to the brain with pain that something is wrong (decayed tooth, too hot, too cold, etc.). After removing the Pulpa dentis, the roots can be used to wear dental crown with the perfect filling of the root, which is very beneficial for conservative dentistry. Root canal treatment needs to be done perfectly because faulty root canal treatment can cause additional unpleasant problems or cause inflammation at the root tip. It had been very difficult to do the root canal treatment in the old days since the length of root filling should be the same as the length of the root canal. The filling material should not be longer (because it irritates the root-tip tissue) or shorter than the root length (because bacteria can multiply in the cavity causing inflammation). Nowadays, there is a state-of-art instrument that can be used to precisely apply the correct length of root canal filling. The root should be prepared by thoroughly removing the Pulpa dentis, then taking the medicine into the root canal and let it work for a few days. After removing the medicine, the doctor decides whether to use additional medication or to fill the root permanently with root canal filling. If everything is fine, the root canals are permanently closed, and the resulting tooth can also be used for prosthesis or dental bridge maintenance. Only an inflammation-free tooth with perfectly cleaned root canals can be permanently filled. In the case of prosthesis, the damaged, broken teeth may be rescued if, after root canal treatment, a pin-tooth is inserted, but it is necessary for the tooth to be root canal treated. If the fixed crown is pasted to live tooth, it is still possible the follow-up root canal treatment through the dental crown. In this case, we remove the Pulpa dentis through the crown and place the medicine, and then we fill permanently the non-inflammatory tooth root through the crown. Treatment is performed by anesthetizing Ultracain Forte, so our patients feel nothing during root canal treatment, and the whole procedure is perfectly painless.