Purpose: to study the effects of over-instrumentation and overfilling on the results of the re-treatments performed in a previous study.
N= 344 patients (566 roots) – endo re-treatment during 2 years
•The reason for retreatment was either technically incomplete root filling without PA lesion (technical group), or PA lesion present radiographically (osteitis group).
•Retreatment procedures were done by students under supervision.
•New root filling was made by using gutta-percha and resin in chloroform as an adhesive in the canal, according to the multi-cone technique. •Treatment factors including: over-instrumentation through the apex or if complete mechanical cleansing of the root canal was impossible to perform, were recorded.
•Within 2 years, the cases were followed up, clinical and radiographical examinations done.
•Overfills were registered through radiographs taken before, during, and after re-treatment. Also recorded, was the status of periapical area (whether the original PA lesion had healed completely, was reduced in size, was unchanged, or had increased in size).
Most highlighted Results:
- In cases with original PA lesions and no overfilling à 62% of the lesions healed & 22% reduced in size.
- The rate of healing of PA significantly reduced in cases of overfilling (36%) and in cases where the canals were cleaned through the apex (over instrumentation): 41%.
to create favorable healing conditions when re-treating endodontic cases, a combination of over-instrumentation and overfilling should be avoided.