Dr JT (Koos) Marais

The challenge of removing material from root canals during root canal re-treatment

Endodontics is an art as much as it is a science. It requires patience, skill, creativity, and contemplation as much as it requires knowledge, training, understanding and an analytic mind. Add the emotions of pain, empathy, fear, anxiety and the mutual stress of the doctor-patient relationship and one stares into the grim face of a major challenge.

Re-treatment of root canals requires all of the above, but when done properly the success rate is more than 85 percent. The rest of the cases, the 15 percent failures, can often be addressed surgically, so that it should come as a surprise that so many teeth are still extracted every day, to be replaced by implants. The key word is quality. Quality of endodontic treatment, that is. Root canal treatment done to the state of the art standard is all that should be acceptable. It takes dedication and commitment to the principles of the art, science as well as the philosophy of patient centred care to achieve the required level of treatment, in the widest sense.  

Sometimes a case comes around which defies, to a certain extent, even the most sincere and strenuous attempt at re-treatment. And yet, sometimes even then, these cases are successful in the sense of tooth retention, as opposed to radiological perfection. These are the cases where we can only bow our heads humbly, accept our limitations with grace, and say thank you to the Lord, the great Healer. And in the end, in fact, in every case that we treat, there is an element of this side of life.

The patient, a 21 year old lady, was referred for re-treatment of the root canal of the first mandibular molar (46). 

She gave a history of pain from biting and exposure to extreme temperatures for one year, followed by a root canal treatment, three months prior to the present consultation. According to the patient the pain did not dissipate following the root canal treatment.

Examination showed the 46 restored with resin and tender to percussion. The 45, a tooth with a healthy appearance and without any restorations or lesions was tender to heat and cold testing but not to percussion.

Radiologically the 46 showed previous root canal treatment and peri-apical radiolucencies, encircled by areas of radio-opacities, the latter the view of condensing osteitis. (Figure 1)

Figure 1. Note the peri-apical radiolucencies encircled by areas of radio-opacities.

 A diagnosis of chronic peri-radicular periodontitis of endodontic origin of the 46 was made. The differential diagnosis of the 45 was 1. peri-radicular periodontitis of unknown origin  2. anachoresis secondary to the condition of the 46.

The patient was informed of all possible treatment with particular emphasis on re-treatment of the 46 with re-evaluation to establish the diagnosis of the 45. The opinion that spontaneous resolution of the 45 would take was expressed, but the patient was emphatically told that this could not be guaranteed. The patient readily accepted the treatment plan of re-treatment of the 46..

Anaesthesia and isolation were applied and the pulp chamber accessed. Partial removal of the gutta percha allowing penetration of root canal files to the working length was easily accomplished, even resulting in slight extrusion beyond the apical constriction, (Figure 2). It became clear that the apical constricture’s dimension had been negatively impacted by either previous treatment or disease process (resorption) or both. 

 Figure 2. It was a relatively easy task to remove the gutta percha, allowing establishment of the working length. The files were unintentionally placed slightly beyond the apical constricture. It was deemed to be somewhat indicative of difficulty with the eventual obturation procedure.

The canals were re-prepared and irrigated and I then made the “mistake” of opting to place Vitapex, an inter-visit intra-canal calcium hydroxide medicament containing iodine, a product which is notoriously difficult to remove from root canals even though it consists of a soft paste only.

At the obturation appointment, one week later, the patient confirmed that all the symptoms had resolved, including the heat and cold sensitivity of the 45, thereby confirming the diagnosis of anachoresis (see above), and, arguably, the usefulness of Vitapex.

Once again the Vitapex proved extremely difficult to remove, as confirmed by each attempt at trial fit of gutta percha cones (Figure 3). 

Figure 3. Three canals were fitted with master cones of gutta percha. Note the radio-opaque Vitapex in the canals, in the distal canal obscuring the tip of the cone, raising the question of the vertical fit.

In addition, the Vitapex obscured the apical tips of the gutta percha cones, causing me to expose another radiograph without the gutta percha cones in place revealing the extent of the Vitapex remnants (Figure 4). 

This caused me to once again irrigate and clean the canals vigorously and another attempt at trial fit of the gutta percha cone in the distal canal (Figure 5).

 Figure 5. The second attempt at trial fit of the gutta percha cone also did not give an unequivocal confirmation of vertical fit. This was caused by the Vitapex remnants.

This was followed by more instrumentation and irrigation, and another radiograph without gutta percha cones showing again clearly the Vitapex (Figure 6).

Figure 6. Despite the most vigorous attempts at instrumentation and irrigation, some Vitapex remnants in the canals.

The canals were then cleaned again and obturated resulting in a “pleasing” radiograph, in spite of some apical extrusion distally (Figure 7). This extruded material may be gutta percha, sealer or Vitapex. 

Figure 7. The final post-operative radiograph showing good three dimensional obturation, and some apical extrusion distally.

This case will be followed up to confirm long term success.

Every now and then a root canal will come around which will defy all one’s dedication, knowledge, skill, patience and expertise, reminding one of one’s fallibility. In this case the use of Vitapex led to a somewhat less than satisfactory result on the radiograph, that of the slight apical extrusion past the apical constricture of the distal canal. Even though extrusion itself does not present a major problem, and is in fact preferable to under-filling, it is a minor injury to one’s professional pride. Extrusion of Vitapex or sealer presents no real problem, but extra-canal gutta percha prevents the formation of secondary cementum, the ideal result.

 Another potential problem is the eventual dissolution of the Vitapex in the canals and the voids it may leave.

Conclusion

The use of Vitapex is reserved for difficult cases with resistant bacteria. It is difficult to remove from root canals. In this case, it has hurt my professional pride somewhat, not a bad thing to happen once in a blue moon.