Safe Mechanical Preparation with Reciprocation Movement without Glide Path Creation: Result from a Pool of 673 Root Canals. This MTA+ (by Cerkamed) i.. One file endoLength: 31mm 6 x R40Ref: V 04 0212 031 040Reciprocating Files. In most cases, the R25 will be suitable in size for the root canal treatment. Cyclic Fatigue Resistance of Reciproc Blue and Reciproc Files in an S-shaped Canal. If the instrument was not able to reach the full WL, the case was classified as "not reaching the full working length" (NRFWL).