Ten-year Clinical Experience and Laboratory Validation of the Modified Tube Technique for Removing Fractured...

Area of Science:

• Endodontics
• Dental Materials Science

Background:

• Separated instruments (SI) in root canals pose a retreatment challenge.
• The modified tube technique (MTT) uses a composite-filled cannula and optical fiber for SI retrieval.
• This study assesses MTT's clinical efficacy and laboratory-to-practice transferability.

Purpose of the Study:

• To evaluate the clinical effectiveness of the modified tube technique (MTT) for retrieving separated instruments (SI).
• To analyze the retention strength and force-to-area ratios of retrieved instruments using MTT.
• To compare laboratory findings with clinical outcomes of the MTT.

Main Methods:

• Retrieved 278 separated instruments (SI) during endodontic retreatment.
• Utilized MTT for 20 SI cases (7.19%) where conventional methods failed.
• Analyzed retrieved cannula-fragment complexes using radiography and tensile strength testing.

Main Results:

• MTT achieved retrieval with a mean fragment exposure of 1.06 mm.
• Tensile strength reached 44.668 N with approximately 1.06 mm overlap.
• A strong positive correlation (ρ = 0.844) existed between lateral surface area (LSA) and applied force.
• Steel instruments showed higher force-to-area ratios (91.38 N/mm²) than NiTi (55.54 N/mm²).

Conclusions:

• The modified tube technique (MTT) is a reliable method for retrieving separated instruments (SI).
• MTT demonstrates high retention forces and minimal invasiveness.
• MTT is a promising microtube technique for challenging endodontic retreatment cases.