Endodontic retreatment remains one of the greatest challenges in daily clinical practice, especially when factors such as inadequate obturations or complex anatomies are involved.
This clinical case addresses the management of a previously treated maxillary first molar (2.6), in which planning and the choice of instrumentation were key to achieving a predictable outcome.
A patient attended the clinic of Dr. Carlos González (Clínica EME) reporting persistent discomfort in the upper first molar, which had previously undergone root canal treatment and had been restored with a crown.
During the clinical examination, the patient experienced pain on percussion and palpation, and a clear misfit of the crown was observed.
Radiographic evaluation revealed several key findings:
- A threaded post in the palatal canal.
- Poor obturation in all canals, particularly the buccal ones.
- Severe curvature in the mesiobuccal canal below the level of obturation.
- Suspicion of a ledge compromising access to the apical third.
These factors create a complex scenario requiring a carefully planned retreatment strategy.
Removal phase to gain access to the canals
The first step consisted of removing the crown and the post. As it was a threaded metal post, it was easily removed using friction with an Endo-Z bur.
Once access was achieved:
- The pulp chamber was cleaned.
- Visualization was enhanced to locate the MV2 canal, which had not been identified previously.
After locating the MV2 canal, Dr. González used a ZXS file (Zarc) to slightly enlarge the access. Canal negotiation was then performed using a pre-curved size 10 K-file.
This step proved challenging due to the presence of a ledge before the curvature, requiring particularly delicate handling.
Subsequently, a mechanical glide path was established using the Excalibur Glider PRO File (Zarc)
Canal treatment with reciprocating files
For the treatment of previously obturated canals, the Excalibur PRO E25 system (Zarc), was used both for removing the filling material and for complete canal preparation, as none of the canals had been fully shaped. This decision was based on the file’s characteristics: S-shaped cross-section, reduced taper, and reciprocating motion.
Excalibur PRO® offers excellent penetration ability and efficient removal of old filling material while closely following the original canal anatomy.
It is essential to allow the instrument to progress without excessive pressure, using gentle pecking motions to avoid blockage and ensure smooth advancement within the canal.
Throughout the procedure, abundant irrigation is crucial. In this case, the clinician used sodium hypochlorite delivered with a syringe and IrriFlex tip (Zarc)which adapts better to curved anatomies due to its flexibility, along with apical patency using a size 10 K-file. The palatal canal was the only one in which the apical diameter was enlarged, using the ApicalShaper Z30 file (Zarc).
After completing the mechanical preparation, a cone fit test was performed, followed by the final irrigation protocol with NaOCl, EDTA, and NaOCl, ending with a saline rinse.
Obturation with bioceramic sealer
Obturation was carried out using the bioceramic sealer NeoSEALER Flo (Zarc) with a single-cone technique, combined with slight heat condensation in the coronal portion of the canals, as this sealer allows both cold and warm techniques without alteration.
Finally, a temporary restoration was placed, and the patient was referred back for definitive restoration.
This clinical case by Dr. Carlos González highlights the importance of accurate diagnosis and the appropriate selection of instrumentation systems to achieve predictable outcomes in endodontic retreatment.