A dental instrument for the treatment of the root canals

摘要

A dental instrument for root canal therapy having a shaft portion and an operational portion extended from such shaft portion, wherein at least a region from the tip of the operational portion down to a predetermined distant position has a sectional form surrounded by an arc and a chord, and a length of a line segment along a vertical bisector of the chord sectioned between such chord and such arc equals to or longer than five-eighths of the diameter of a virtual circle composed by such arc was disclosed. IMAGE