Studies on the Mechanism of the Mechanical Enlargement of Root Canals

抄録

As the consumption of reamers is much greater than that of files in Japan [1], it can be safely assumed that most dental clinicians use some kind of reamer for the purpose of root canal enlargement in their daily practice.
In his survey on 659 instruments fractured in root canal HIGAKI [2] reported 592 of them to be reamers with a percentage as high as 89.8%. There are available published research results on the material strength of various root canal enlarging instruments [3, 4, 5], but the author believed that changes in the thickness of blades and edges in root canal enlarging instruments would be intimately concerned with the thickness of dentin to be cut inside the root cavity, when a mechanical enlargement is attempted. Therefore, he conducted a series of investigations into the cutting mechanism, distorsion, its relation to the cutting depth of edge, thickness of cutting chips, shape of cross section of blade and its relation to its cutting efficiency in a selected sample of reamers.