Abstract: Mechanical instrumentation of root canal is the key procedure of root canal therapy，the main goals of which are eliminating infection from the root canal system and enlarging root canals to get enough space for chemical irrigation and obturation. However，nickel-titanium instruments are speculated to create dentinal microcracks in the process of mechanical instrumentation，which will cause microleakage and vertical root fracture and may compromise the outcome of root canal therapy. This article aims to provide an overview on the etiology，prevention and controversy of dentinal microcracks during root canal mechanical instrumentation.

Key words: root canal, mechanical instrumentation, nickel-titanium instrument, dentinal microcracks

摘要： 根管机械预备是根管治疗术的关键步骤，在清除感染源和根管成形的同时，为化学冲洗和根管充填创造空间。但有学者认为镍钛器械会在机械预备过程中引起牙本质微裂，继而引发微渗漏、牙根纵裂，对根管治疗的预后产生不利影响。文章就根管机械预备过程中形成牙本质微裂的原因、预防及争议做一介绍。

关键词: 根管, 机械预备, 镍钛器械, 牙本质微裂