Biomechanical tooth preparation is the most time consuming procedure in root canal treatment, which is also most important step in therapy. Conventional technique of instrumentation is the benchmark over hand instrumentation, which makes procedure time consuming and hectic for both patients and dentists. Using rotary instruments for primary tooth pulpectomies is cost effective and results in fills that are consistently uniform and predictable. The purpose of this article is to review the rotary instrument in primary root canal procedure.