Most general dental practitioners leave dental school without much exposure to more complex aspects of endodontic treatment. In the first of a three part series, Stephen Martin gives his top tips on endodontics, starting with a discussion on the importance of pre-operative assessment and accessing the tooth.
The primary aim for any dentist undertaking endodontic treatment is to make the process as easy and predictable as possible, thus increasing the chances of success. The first important step is to take your time from the start of the treatment to make a thorough pre-operative assessment. I recommend using the following checklist when analysing the radiograph:
- Assess the anatomy of the tooth; check for any rotation, assess the root length and curvature
- Assess the size and position of the pulp chamber; check for any obstructions such as pulp stones
- Assess the angle at which the canals leave the pulp chamber and check for any calcification of the canals
- Assess the restorability of the tooth and plan the permanent restoration. Bear in mind this may require some work to fully assess.
I would advise, in the vast majority of cases, complete removal of any existing restorations. This will allow full examination for any caries or cracks and make accessing the tooth easier. Often, removal of a large restoration can be carried out reasonably quickly and, after inspection, a temporary glass ionomer core (such as Chemfil Rock) easily placed.
Once you are confident you have collated all the information you need for a full pre-operative assessment you need to effectively communicate this back to the patient. Keep them updated from the very start explaining clearly what you have identified and any potential problems that you may encounter.
Access the tooth
Now that you have carried out a thorough assessment, the next step is to access the tooth. Time spent accessing the pulp chamber and refining the access carefully will make the treatment easier and more predictable. The aims of the access cavity are to:
- Allow visualisation of the entire pulpal floor
- Allow straight line access of the preparation instruments to the canals
- Provide a reservoir for canal irrigant
- Provide retention for an adequate thickness of interim restoration to provide a good seal in a multiple visit treatment.
Important points to remember are to always remove the entire roof of the pulp chamber. It is surprising how often large parts of the roof are intact in re-treatment cases, thus making it impossible to visualise the entire pulpal floor. Also, remember the pulpal floor will be darker in colour than the walls. The canal orifices are at the junction of the floor and the walls, and if there are root developmental fusion lines then the canals will be located at the end of these.
This information and further rules that can be followed with accessing canals can be found in Krasner and Rankow’s (2004) Anatomy of the Pulp Chamber – an excellent paper that is well worth reading.
The correct equipment
To carry out high quality endodontic treatment you need to have the correct equipment. I consider the following essential:
- Good isolation ie rubber dam at all times
- Good lighting
- Loupes for magnification
- Flat fissure bur for cutting the initial access
- Non end cutting bur for removing the roof of the pulp chamber
- Front surface reflecting mirror
- DG 16 endodontic probe.
After the initial pulp chamber access, it is worth spending time refining the access to allow thorough checking for additional canals and to fulfil the above requirements of the access cavity.
In particular, I find that long neck burs, which can be high or low speed, are very useful to remove overhanging dentine and reparative dentine. The advantage of these is that they allow the operator to see the area they are removing dentine in, so they can be used safely.
Further refinement using a piezo-electric ultrasonic scaler, together with tips designed for endodontic access and refinement, can make cleaning and shaping the canals much easier, even in very difficult cases. Ultrasonics have multiple applications in endodontics, such as pulp stone removal, removal of reparative dentine, and other obstructions such as posts or fractured instruments, and therefore are a very worthwhile investment. The Dentsply Start-X series of endodontic tips is a robust and versatile collection of instruments with each tip designed with a specific use in mind.
Having spent time on properly accessing the tooth, the operator can then move on to canal preparation and cleaning with confidence, as they have located all the canals and made the cleaning of these as easy and predictable as possible.
Krasner P and Rankow H (2004) Anatomy of the Pulp-Chamber Floor Journal of Endodontics 30 (1): 5-16