New instruments for canal retreatment, RetreatAll® files
Gaceta Dental echoes this new clinical case where Zarc’s RetreatAll® files and the new endodontic techniques are key when the aim is to save the tooth and thus avoiding apical surgery when endodontics has not fulfilled its objective.
When it comes to avoiding extraction, endodontics is the key. Despite this, later problems may appear for various reasons and the knowledge of the possibilities that the specialist has is extremely important when saving the tooth.
Retreatment combined with current CBCT, magnification and diagnostic techniques is a viable option to avoid apical surgery and keep the teeth. The success rate is around 77%.
For endodontics to achieve its goal, the filling material contaminated by persistent and failure-causing bacteria, must be removed. To do this, the most effective way is to remove the old gutta-percha using rotary instruments to be able to proceed with disinfection and then give way to the three-dimensional sealing of the canal system, which will ensure that the endodontics is successful in the long term.
Clinical case: case of retreatment through the crown of a 36 of a patient previously treated 6 years ago
The patient reports acute pain on percussion with inflammation of the area and functional impotence. After clinical examination, positive percussion and palpation and physiological probing were seen, thus it is established a definitive diagnosis of a tooth previously treated with symptomatic apical periodontitis.
Prior to treatment, radiological exploration with periapical radiography and CBCT is performed to have a three-dimensional view of the case. (Fig. 1) The images show that the roots have radiolucent images, which is why the existence of missed canals is suspected. The existence of root fissures is ruled out. (Fig. 2)
Figure 1. Radiographic study prior to the start of treatment, where we can observe in 2D and 3D the existence of periapical pathology.
Figure 2. Axial plane of the middle third where the existence of cortex around the roots can be observed, ruling out the presence of vertical cracks or fractures.
It is decided to keep the metal-ceramic crown of the molar, so the entire procedure is carried out through it.
Once anesthetized and isolated, the direction indicated by the CBCT is followed until reaching the chamber and locating the old gutta-percha. For its removal, the RetreatAll® system is used, starting with the file Zr1 (04/30, 21 mm) and Zr2 (25/04 25 mm) at 500 rpm, managing to safely remove the contaminated gutta-percha from the previously treated canals. ( Fig. 3)
Figure 3. Images of the Zr1 and Zr2 files of the RetreatAll® system used during retreatment to remove the contaminated gutta-percha within the canal system.
For the omitted canals, the E-conncect S apex locator and the BlueShaper® dual alloy instrumentation system, it is used the sequence from Z1 to Z4.
Once this process is finished in the five canals of the molar, irrigation is carried out. The 4% sodium hypochlorite used for disinfection and the 17% EDTA are activated with the UltraX system in cycles of 30 seconds the first one and a cycle of one minute the second one.
To achieve a good three-dimensional seal, the continuous heat technique is used with the Fast Pack system. The fluid gutta-percha injection Fast Fill system is used to fill the coronal third. (Fig 4 and 5)
The results of the obturation and its subsequent review at 12 months can be seen in the microscope images. (Fig 6 and 7)
Figure 4. Conometry where we can see the arrangement of the gutta-percha inside the duct system.
Figure 5. Sealing unit used for vertical condensation and filling of the middle and coronal third of the
Figure 6. Images under the light microscope and radiographs, where we can observe the three-dimensional sealing of the root network.
Figure 7. Revision X-ray 12 months later
The success of complex cases depends fundamentally on a good diagnosis of the cause of failure since, if it is a fissure, for example, there is no endodontic solution.
In this specific case, CBCT provides us with a three-dimensional view that is key to determining the cause of this failure, which is the existence of two omitted conduits and lack of condensation in the old fill.
3D allows us to see images that often go unnoticed in periapical radiographs.
To remove the old filling, the fastest and most effective option is the mechanized instrumentation. The activation of the irrigating fluid is crucial to minimize the bacterial load. To conclude, the three-dimensional filling is crucial to ensure success and that a colonization of microorganisms does not occur again, which is what produces a new failure. The more the bacterial load is reduced and a good three-dimensional seal is made, the apical periodontitis will disappear and will not recur.
If you want to know the conclusions and the debate generated by this clinical case, read the full article published by Gaceta Dental here.