Calcified root canal system provide an endodontic treatment challenge. The introduction of new technologies has increased the predictability of these treatments and, consequently, their success rates. This article describes one case with a clinical treatment strategy using high technology for this second mandibular molar with pulp canal obliteration (PCO) using digital radiography (DR), dental operating microscopy (DOM), cone-beam computed tomography (CBCT), and ultrasonic tips (US).
Patient presented with an irreversible pulpitis most likely due to a crack on its distal marginal ridge.
This is a unique root canal morphology were pulp chamber has two superimposed floors.
DR was analyzed with different filters. Subsequently, the access cavity was performed without the aid of DOM using Krasner and Rankow laws of symmetry and centrality. When the first (most coronal) pulp chamber floor has been reached with a 330 long shank bur the root canal entries were still obscured by reparative dentine and could not be located despite the high magnification (OPMI PRO ergo from Zeiss).
At this point, the search for the distal canal begun as it was more coronally positioned. Sclerotic dentine was thoroughly removed with a ultrasonic tip (Buc 3, Spartan) coupled to a piezo Varios 370 unit (Nakanishi) set at low power. After location of the distal root canal entry, Krasner and Rankow law of symmetry helped in locating the mesio lingual canal entriy (but not the mesio buccal one), the two canals were then negotiated and instrumented with Mani K hand files to create a glide path. Shaping completed with ProTaper Universal.
Mesio vestibular canal was much deeper and could not be located under the DOM, Krasner and Rankow laws were not sufficient since Mesio vestibular began at the deepest pulp chamber floo, thus, in order to limit the risk of perforation, patient was rescheduled as a CBCT was requested and more chair side time needed.
Sagittal and axial slices guided the direction of our ultrasonic tips. Mesio vestibular was finally located, an angulated X ray was taken
The mesio buccal canal has then been shaped, cleaned and filled with an interim Ca(OH)2 dressing.
Final obturation: Canals were irrigated with 5% heated NaOCl , PUI activation. Root canal sealer used Neo MTA Plus (Avalon Biomed) cold lateral condensation.
The second more apical floor could not have been cleaned by mechanical means without having to destroy a huge amount of tooth structure and without taking a risk of perforating the tooth since its filled with sclerotic dentine. Furthermore scattering was creating a lot of noise making the reading of the slices very difficult. Thus it was left alone.