Separation of Nickel-Titanium Rotary and Reciprocating Instruments: A Mini-Review of Clinical Studies

Area of Science:

• Endodontics
• Dental Materials Science
• Clinical Dentistry

Background:

• Nickel-titanium (NiTi) instruments are widely used in endodontic treatments.
• Understanding instrument separation incidence is crucial for procedural safety and predictability.
• Previous research has focused on various NiTi instrument systems and their clinical performance.

Purpose of the Study:

• To systematically review and evaluate clinical studies on the separation incidence of NiTi rotary and reciprocating instruments.
• To assess the impact of instrument type, usage (single vs. multiple), and operator experience on separation rates.
• To analyze the current status of instrument separation as a clinical challenge in endodontics.

Main Methods:

• A comprehensive review of clinical studies was conducted.
• Studies involving undergraduate students, graduate students, and endodontic specialists were included.
• Data on separation incidence for rotary, reciprocating, and hybrid NiTi systems were extracted and analyzed.
• The number of uses for different NiTi systems was also assessed.

Main Results:

• Separation incidence for rotary NiTi instruments ranged from 0% to 23%, with lower rates observed with hybrid techniques by undergraduate students.
• Rotary instruments were used between 1 to 50 times, varying by instrument and tooth type.
• Separation incidence for reciprocating NiTi instruments was significantly lower, ranging from 0% to 1.71%.
• Reciprocating instruments were predominantly single-used, with a low separation rate (0.2%) even with multiple uses.

Conclusions:

• Instrument separation appears to be a diminishing concern in contemporary endodontics.
• Multiple uses of NiTi rotary instruments can be safely implemented without a substantial increase in separation risk.
• Both single and multiple uses of NiTi reciprocating instruments are associated with a low incidence of separation.
• Careful consideration is advised when attempting to retrieve separated instruments.