Case #1:

• Fig. A: A 23 yrs old lady presented to my attention with a chief complaint of pain during mastication on her left maxilla. The x-ray showed a periapical radiolucency associated to her tooth #14 which was endodontically treated three years before. For tooth #14 the diagnosis was previous root canal treatment (RCT) with symptomatic periapical lesion. Access under the microscope was made and a careful examination (20X) of the pulp chamber floor revealed the presence of the palatal canal and an elongated shape of both the mesiobuccal and distobuccal canals. Even though the three canals were previously treated the presence of necrotic pulp tissue into the mesiobuccal and distobuccal canals demonstrated that they were not properly cleaned during the previous RCT. Necrotic pulp remnants and irritants are probably the reason of the periapical lesion.
  

• Fig. B: Proper cleaning of the pulp chamber using ultrasonic tips was performed. Full instrumentation and adequate obturation of the endodontic system completed the RCT. Two weeks after the treatment the patient presented at the control appointment as symptom free. Permanent restoration was planned to complete the treatment for her tooth #14.
  

Case #2:

• Fig.A. A 38 yrs old man presented to my attention with a chief complaint of spontaneous pain on his upper right quadrant. The x-ray showed periapical radiolucency associated to his tooth #7. The tooth had a previous endodontic treatment with a crown and a post. For the tooth # 7 diagnosis was made of previous root canal treatment with symptomatic periapical lesion. The presence of the long post and the crown with good marginal adaptation let me decide to treat the lesion surgically. Endodontic microsurgery was performed. The tooth was retroprepared using Kis Ultrasonic Tips.
  
• Fig.B. After ultrasonic preparation the microscopic inspection of the root canal using micromirrors revealed dentinal walls smooth and well cleaned and an axial retropreparation. The retrocavity was filled using MTA cement. Microsutures 6.0 were used to close the surgical flap. One week after the treatment the patient presented at the control appointment without any symptoms.