A novel endodontic extractor needle for separated instrument retrieval: A new patent technology

Abstract

A novel needle that can be used to retrieve endodontic separated instruments (SIs) from the root canal of a tooth is described in this article. The needle tip is fabricated with a thermomechanically treated NiTi alloy exhibiting both shape memory and super-elasticity. The alloy demonstrates martensitic phase at certain low temperatures (25°C or less) and austenitic phase at certain slightly higher temperatures (35°C or more). These properties facilitate the needle to be straight at room temperature but incorporate a specific snakelike shape when inserted in the root canal of the tooth from which the endodontic SI is to be removed. The suggested lengths for the needles are 21, 25, and 31 mm with five different sizes of the lumina (the internal diameter is 0.25, 0.40, 0.60, 0.80, or 1 mm). The wall thickness of the needle is 0.20 for the last 3 mm of the needle then gradually increases to 0.35 for the coronal aspects. The design of this needle has the US patent application number US 2020/0129268 A1, April 30, 2020.

Keywords

• broken file
• niti alloy
• novel instrument
• root canal preparation
• separated instrument