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Modern endodontic techniques in treatment and retreatment of periapical lesions

Numerous authors have reported mechanical advantages of preparation with Ni-Ti files over preparations with stainless steel files. However, not only the instrumentation and disinfection of the endodontic space but also a good obturation is mandatory to avoid treatment fail. Apical leakage is still considered as a factor in the failure of endodontic treatment, but in the recent years, more attention has been paid to coronal leakage. Despite the effort of the dentist and a modern endodontic treatment, still a number of cases need a retreatment. Paradoxically, studies carried out on various population groups have shown that root-filled teeth have a greater prevalence of apical periodontitis than non-treated teeth. Unfortunately, some dentist referred the patient to the endo surgery without any pretreatment. It should be pointed out that in any case when primary endodontic treatment fails the classic retreatment of a root canal filling is a first method of choice and should be performed. A convenient ways is to use an organic solvent such as eucalyptol and one of the motor drive techniques such as Profile or Quantec or even laser device. Use of an Nd:YAG laser alone is capable of softening gutta-percha and in laser techniques, the addition of solvents did not improve the retreatment, either in terms of the time or in terms of the area of remaining gutta-percha on root-canal walls. The Ni-Ti instruments due to its elasticity and the fact that can be rotated in the much curved canal by 250 to 350 rpm are capable to remove dentin as well as the old root canal filling very fast. In the same time the possibility of breaking the instruments is very low. The techniques mentioned above save the time and can be performed even by inexperienced dentists. Following the retreatment, the root canal should be disinfected by the 1.0 - 5.25% solution of the sodium hypochlorite or the 0.6 - 1.6% of the chlorhexidine solution. After that the canal sealer should be introduced into the canal and the canal should be obturated by gutta-percha. For this purpose, among the numbered techniques, the thermoplasticized techniques such as System B , Microseal, Obtura II or Thermafile could be used. The complete sealing of the root canal is necessary to prevent penetration of the bacteria and yeast from oral cavity towards apical region. If the good obturation of the canal is achieved the complete healing of the periapical region could be obtained. When the retreatment fails, and only than, the endo surgery is indicated. Studies on the outcome of periapical surgery have reported variable results ranging from a 30-90% success rate. In some cases, before surgery, the decompression of the periapical lesions could decrease the lesions and in this way make the surgery less extensive. On the other hand, the decompression technique associated with good obturation of the root canal, in some cases may allow a favorable outcome without classical. Persistent extra-radicular infection is not affected by the action of antimicrobial agents such as irrigants and medicaments used during root canal treatment. In this case, apical surgery may be the only method for definitive removal of infection, promoting repair in therapy-resistant cases. Following the endo-surgery, the sutures should be removed after 48 to 72 hours. The accumulation of the bacteria and the inflammation could be a consequence if removing of the sutures is postponed.

instrumentation; obturation; laser

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