A laboratory study comparing two methods for removing plastic carrier obturators from severely curved root canals

Area of Science:

• Endodontics
• Dental Materials Science

Background:

• Removing plastic carrier obturators in root canal retreatment is a significant clinical challenge.
• Existing methods are often time-consuming and difficult, particularly in curved canals.

Purpose of the Study:

• To compare the efficiency and safety of a novel indirect, two-stage technique versus a conventional direct technique for removing plastic carriers.
• To evaluate intra-operative complications and procedural time for both retreatment methods.

Main Methods:

• A laboratory study using 36 extracted mandibular premolars filled with plastic carriers and endodontic cement.
• Teeth were randomly assigned to either a direct technique (carriers removed with gutta-percha) or an indirect technique (carriers removed first, then gutta-percha).
• Evaluated parameters included retreatment duration, instrument/carrier fractures, ledge formation, apical transportation, and remaining filling material.

Main Results:

• The indirect technique (Group 1) demonstrated significantly faster root filling removal compared to the direct technique (Group 0).
• Significantly fewer instances of carrier fracture, ledge creation, and apical transportation were observed with the indirect technique.
• No root canal perforations occurred in either group, and other variables showed no significant differences.

Conclusions:

• The indirect, two-stage technique for removing plastic carriers is more rapid and associated with fewer intra-operative complications.
• This technique offers improved safety and efficiency for plastic carrier removal during root canal retreatment in curved canals.