Clinical Evaluation of Endodontic Re-treatment Using LSTR 3Mix-MP

Objective: Periradicular lesions generated after previous endodontic treatment are not so rare, and one of the causative factors is bacterial residue in root canal systems. 3Mix-MP, a combination of metronidazole, minocycline and ciprofloxacin (3Mix), and macrogol and propylene glycol (MP), has been proved to penetrate efficiently through root canal systems and disinfect lesions. This study aimed to evaluate the therapy for cases with radiolucent periapical lesions, which had been generated after the previous endodontic treatment. Methods: Without removal of previous obturation, 3Mix-MP was placed at orifices of root canals of 101 permanent teeth, and then sealed with glass-ionomer cement and further reinforced with resin/metal inlay cemented with resin. Root canal preparation/obturation was not done, and the treatment finished with 1-2 visits. Using X-ray photographs taken more than 3 months after the treatment, changes of radiolucent lesions were clinically evaluated. The treatment was designated as LSTR 3Mix-MP NIET, LSTR: Lesion Sterilization and Tissue Repair; NIET: Non-Instrumentation Endodontic Treatment. Result: Clinical symptoms, such as pain on bite, swelling, abscess and sinus tract, if any, were improved soon after the treatment in all cases. Root fracture and post-treatment disorders were not observed, probably because of no mechanical instrumentation to avoid weakening root structure and damaging apical foramen and periapical membrane. Radiolucent lesions were completely disappeared in 69 cases, and, thus, evaluated as clinically successful. In 28 cases, lesions were apparently reduced in size, and, thus, evaluated as cases in the process of lesion repair. Thus, 97 cases (96%) were clinically good. However, the lesions were not changing in size in 4 cases, being under observation. Conclusion: Radiolucent lesions were efficiently and successfully re-treated using LSTR 3Mix-MP NIET.