If you are interested in an endodontic refresher lecture, come and join me next Thursday at the Pacific Dental Conference (PDC 2019). Two and a half hours lecture filled with pictures and videos demonstrating the initial endodontic treatment.
The following is an excerpt from #vanendo lecture series at this year’s Pacific Dental Conference.
The apical 3mm of an infected root canal system is considered to be the “Critical Zone” when it comes to the chemomechanical preparation. Mechanical instrumentation and chemical disinfection of the root canal system to its full length significantly affect the outcome of treatment. All endodontists agree that the irrigation phase of the root canal treatment must be accompanied by an agitation technique. These techniques include: sonic agitation (EndoActivator), ultrasonic agitation, multi-sonic agitation (promising area of research currently), and the cheapest and simplest of all, Manual Dynamic Agitation (MDA).
The following video demonstrates how the MDA technique (repeated insertion of a well-fitting gutta-percha cone to the WL at a frequency of 100 strokes/min) significantly facilitates debris removal from the apical portion of a root canal system that appears to be fully shaped and cleaned.
Patient presented with #1.3 pulp necrosis and chronic apical abscess. Due to missing #1.2, mesially tilted tooth #1.3 had been restored as #13-#1.4 splinted crowns in the place of #1.2 and #1.3. The clinical picture shows a ceramic interdental papilla which covers the root of tooth #1.3.
The key aspects in treating such a case are as follows:
In my previous post “The Little Devil Horn,” I showed a case of fractured Dens Evaginatus (DE) that had resulted in pulpal necrosis in an 11 years old girl. In almost all cases the tubercles fracture off as soon as the teeth come into occlusion. The resultant pulp exposure goes unnoticed until patient develops pain and symptoms and a combined endodontic-restorative procedures would then be necessary. Therefore, just observing what does not belong to a proper occlusion is not a good choice.
The endodontic treatment for necrotic teeth with immature roots is either regenerative endodontics or MTA apexogenesis depending on many factors. The latter was used to treat the case of fractured DE with pulpal necrosis.
So, what should we do if we face a vital tooth with an intact tubercle?
Some evidence suggest a gradual shaving off the tubercle over a period of few months in order to allow tertiary dentin formation is the treatment of choice. However, tertiary dentinogenesis may not provide a complete seal of the pulp chamber as this process lays down an irregularly formed dentinal structure.
Another approach would be to remove the tubercle mechanically under RD isolation and to seal off the resultant mechanical exposure, if any, with bonding material. This approach was performed for the same young patient for tooth #3-5.
The only non-precious stone that I know is the pulp stone. One of the factors contributing to root canal failure is remaining infected pulp tissue and the pulp stones, if left behind unnoticed, are the main reason for trapping tissue and retaining infection. Pulp stone removal is therefore a crucial factor in achieving a successful result in endodontic treatment. The following case shows how a large pulp stone can result in failure of a reasonably well done root canal treatment by trapping infected tissue, hiding the MB2 canal and retaining infection.
Proper access cavity (i.e. adequately large and at the level of the CEJ) in order to visualize the outline of the pulp stone/chamber floor is the key in removing it completely. In the above example the pulp stone is easily dislodged by troughing around it using a large diamond-coated ultrasonic tip and applying the energy directly to the calcified tissue. For demonstration and documentation purposes, no water was used in this case; however, it is highly recommended to use water for its cooling effect and in order to facilitate the debris removal.
If you attended my lecture at the Pacific Dental Conference last month, I mentioned “The Laws” that allow us to safely and predictably locate canals without being worried about mishaps (i.e. perforations, over-enlarged access cavities, etc.). One of the scenarios that we have to always be prepared for is accessing through a crown that is placed on a rotated tooth. One of the key elements discussed was the use of a probe to gain a better appreciation of the root outline at the CEJ level. The “Law of Concentricity” then allows us to start our access cavity preparation in the right direction.
The case below shows a rotated tooth #1-4 under a PFM crown. Preparing a typical access cavity in the Buccal-Lingual direction would definitely result in mishaps. Understanding the orientation of the tooth prior to the start of root canal treatment can result in achieving a safe and a conservative access prep. Note that even the rubber dam clamp wings are not good guides for the orientation of the chamber floor and for locating canals.
Sometimes when the conventional endodontic access is not possible, the unconventional approach can save the day.
A clinician should always aim at establishing a straight line access (SLA) in order to properly instrument, irrigate and obturate the canal system. Depending on the initial challenges, establishing a SLA could mean accessing an anterior tooth through its buccal surface [example below], accessing an anterior tooth through its incisal edge, or accessing a molar tooth through its mesial marginal ridge or its MB cusp.