Purpose: to assess the influence of retreatment procedure on the appearance of defects on the root canal walls
Materials and Methods:
•N = 200 extracted mandibular premolars were standardized.
•4 groups (n= 50, average diameter was 0.7 mm)
•Teeth were examined to exclude presence of cracks.
•Group (1): left unprepared. Group (2-4): C/S with ProTaper to F4. Passive Ultrasonic was used at the end. All groups (2-4) were filled with lateral condensation (MAF= 40, spreader with controlled load 2 kg, AH26 sealer). oGroup (1): unprepared and no obturation.
oGroup (2): Prepared, obturated but no retreatment.
oGroup (3): Retreated with ProTaper retreatment files (D1, D2, D3) with chloroform.
oGroup (4): Retreated with H-files + chloroform.
•Part One: Evaluation under operating microscope. Part II: roots were sectioned horizontally and examined under stereomicroscope.
Most highlighted Results:
- Group (1): unprepared and no obturation: No defects
- Group (2): prepared and obturated: almost 30% defects were found
- Group (3): prepared and obturated, then retreated with ProTaper: almost 38 % defects were found
- Group (4): prepared and obturated, then retreated with H-file: almost 55% defects were found üGroups 3 and 4 were compared to group 2. No difference between groups 3 and 4
Clinical significance: The lower success noted in retreatment may be attributed to further damage to roots resulted from the procedure.