In vitro study of needle deflection: a linear insertion technique versus a bidirectional rotation insertion technique

Area of Science:

• Dental Anesthesiology
• Biomedical Engineering
• Materials Science

Background:

• Needle deflection during dental anesthesia administration can lead to failed procedures.
• Understanding factors influencing needle path is crucial for improving injection techniques.

Purpose of the Study:

• To evaluate the efficacy of a bidirectional rotation insertion technique in minimizing dental needle deflection.
• To compare needle deflection across different needle gauges and tissue-like substances.

Main Methods:

• In vitro deflection tests using three tissuelike substances of varying densities.
• Testing of 30-, 27-, and 25-gauge needles with both linear and bidirectional rotation insertion techniques.
• Standardized needle insertion depth (20 mm) using a customized dental surveyor and radiographic analysis.

Main Results:

• The bidirectional rotation insertion technique significantly minimized needle shaft deflection for all tested needle gauges (30-, 27-, and 25-gauge).
• This reduction in deflection was consistently observed across all three tissuelike substances.
• Force vectors acting on the needle's bevel are the primary determinant of needle path.

Conclusions:

• The bidirectional rotation insertion technique offers a superior method for achieving a straighter needle path during dental procedures.
• This technique effectively minimizes deflection, potentially improving the success rate of dental anesthesia.
• Findings are applicable across multiple needle sizes and simulated tissue densities.