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.
Imagine the following scenario:
A busy day in practice! A patient comes in with tooth #2-6 (upper left first maxillary molar) being extremely sensitive to cold (a.k.a. a “hot tooth”). You notice a very old, large amalgam filling on the tooth which had been done over 2o years ago. No recent restorative changes in the area is reported by the patient. Breathing in air, blowing air on this tooth with an air-water syringe or applying ice to the tooth sends the patient through the roof. All other teeth in this quadrant are responding normally to cold test. Quickly and confidently, a pulpal diagnosis is reached (irreversible pulpitis), endodontic treatment is recommended, and the need for a full coverage crown is also emphasized after root canal treatment. Simple, right?
Well, not so fast!
You may miss a more serious issue with this innocent-looking tooth in need of JUST a root canal and a crown, you may lose the opportunity to properly inform your patient of possible outcomes of your treatment and you may end up performing unnecessary treatments for a tooth with no hope.
Just imagine the final conversation with the patient after a quick exploratory/pulpectomy procedure:
Me – “Ms. Black, unfortunately your tooth cannot be saved as I had suspected and warned you before we started the root canal procedure today.”
Ms. Black – “I am amazed Dr. E! [with a smile] You knew exactly what was wrong with my tooth. You called it.”
Some of you may wonder how a long root with moderate to severe curvature should be instrumented. Some clinicians may also be hesitant to use rotary instruments in such roots and therefore resort to using handfiles.
Here are some pearls that I learned during my training:
1. The first step in staying out of trouble is to scrutinize the x-ray really well before starting the treatment. I find myself guilty of not doing what I preach sometimes and I realize mid-treatment how severe the curvature was or the fact that the canal was not completely instrumented with the rotary files to length at the end of treatment (i.e. the second case presented above shows sealer in the last 2mm of this long canal).
2. We only see curvature in 2-D. Canals are almost always curved in bucco-lingual direction as well (i.e. usually MB canals of upper and lower molars have a buccal curvature in the cervical 1/3 , the ML canals of the lower molars are curved buccally in the middle or apical 1/3, the DB canals of upper molars and D canals of lower molars are curved buccally and distally to mention a few).
3. The shaping stage of root canal treatment should be done in 1/3‘s: coronal 1/3, middle 1/3, apical 1/3. I always start by preparing access cavity, locating canals, scouting the coronal 1/3 with sizes 8 and 10 SS files, coronal shaping with rotaries, redefining the access (to achieve straight line access), working length determination with EAL (trust the apex locator more than the x-ray if it is reading well), middle and apical shaping.
4. Why do I not bother establishing the actual working length until the straight line access and coronal shaping are completed? Calcification always starts coronal to apical. If you are careful with the instrumentation of the cervical 1/3, you will never lose or block the canal (be patient when negotiating tight canals!). If you see the canals in the middle and apical 1/3 of the root pre-operatively but your files are struggling, you are dealing with narrow canals, deep splits or curvatures. Go back to your last file and by using filing motion make enough room for the next one. Use lots of irrigation.
5. Follow steps 3 and 4. Use a set of fresh rotary files. In teeth with long curvy roots, use smaller tapered instruments (0.04 or 0.02 tapers).
And remember: “Chance favors only the prepared mind. –Louis Pasteur”