When the pulp is injured or diseased and is unable to repair itself, it becomes inflamed and will eventually become necrotic (i.e., dead). Root Canal Therapy must, therefore, be instituted in order to avoid the spread of inflammation and infection to the tissues surrounding the diseased tooth.
Before proceeding with root canal therapy, it is necessary to take a good quality pre-operative radiograph. Following this, a series of tests must be performed in order to replicate the symptoms that the patient is experiencing.
These are necessary steps that will help to verify the offending tooth and establish an accurate diagnosis.
The tests most commonly performed are:
- The Cold Test,
- The Electric Pulp Tester or EPT test,
- The Heat Test,
- The Percussion Test,
- The Palpation Test, and
- The Tooth Sleuth Test.
All testing should be first performed on a "normal" tooth followed by the "diseased tooth". If the response on the “diseased tooth” is more intense and lingers after the stimulus is applied, this is an indication of inflammatory changes within the pulp. If there is no response it may be an indication of a necrotic pulp.
Following are the steps necessary for successful root canal therapy.
The first step is to achieve complete anesthesia by selecting the appropriate technique according to the tooth type and location. The onset of the anesthesia usually occurs in 3-5 minutes. Before starting the procedure, the operator will verify if complete pulpal anesthesia has been achieved by carefully testing the tooth.
It is of paramount importance to isolate the tooth with a rubber dam. This is necessary to create a sterile environment, to avoid leakage of saliva onto the tooth, and to prevent aspiration or inhalation of instruments and chemicals by the patient.
Access into the core of the tooth, where the pulp is located, is now prepared using a handpiece.
In the following step, the working length should be established in order to determine the end of the preparation. Both an electronic device (ROOT ZX) and a working length radiograph will be taken to confirm this length.
Cleaning and shaping of the root canal can now begin. This can be acheived with the use of hand files and/or rotary instruments. This procedure uses the combined action of both instruments and irrigating solutions. Its final objective is to achieve an apically tapered preparation which will facilitate the progressive access of irrigating solutions into areas within the root canal system. Due to irregularities within the root canal, it is difficult to access these areas by instruments alone. It is important to maintain the original anatomy of the canal, as well as the position, size, and location of the apical foramen.
Once the preparation has been completed, a master apical file radiograph should be taken.
The tooth is now ready to be filled.
A master gutta-percha cone is selected, according to the master apical file, and fitted.
At this stage in the procedure a master cone radiograph is taken.
The obturation of the canal contains a core of gutta-percha as well as a sealer. Sealers can contain resins, zinc-oxide and eugenol or glass ionomer, and calcium hydroxide.
The canal is now dried with sterile paper points which are selected according to the size of the canal. Once dry, the sealer is placed and the filling of the canal is performed. Several gutta-percha points will be placed into the canal space.
A mid-obturation radiograph must be taken to confirm that the filling procedure is being completed with no voids in the apical third.
Once the canal is completely filled, the excess of gutta-percha is seared using a Touch’n Heat unit. A sponge pellet is placed at the orifice level, and a tight double seal should be placed to avoid leakage.
Finally, a post-operative radiograph is taken and the patient is given the final indications.
An appointment for the placement of a permanent restoration MUST be booked, and the patient MUST be aware that only a TEMPORARY restoration has been placed at this time.
Patients should avoid eating on the treated area until the anesthesia has worn-off to avoid biting on the cheek.
Final post-operative indications will be discussed with the patient (date for the next appointment, need for a prescription, etc).