A novel root canal preparation technique hybridizing heat-treated nickel-titanium rotary instruments

Aim: This study aimed to assess the potential of the hybrid heat treatment (HHT) technique for shaping severely curved canals. Background: This innovative HHT technique combines the use of both Ni-Ti austenitic and martensitic Ni-Ti files, with a simplified sequence, to properly utilize the different files’ properties. Case description: The operative technique started with canal scouting and determination of working length using a size 10 SS K-file. Then, a specific sequence was applied using the F1 20.06v Ni-Ti austenitic file (EdgeTaper) for the preparation of the coronal and middle parts of the canal. This step was followed by S2 20.04 and F1 20.06v martensitic Ni-Ti files (EdgeTaper Platinum) to enlarge the canal until the apex reached. No intracanal breakage of any instruments or deformation of flutes was recorded. Conclusion: The present study describes a new HHT technique aiming at simplifying procedures and taking most of the different characteristics of the different heat treatment; the clinical cases seem to show its potentialities in terms of safety, speediness, effectiveness, and preservation of original anatomy. Clinical significance: The cases show the advantages of the newly proposed technique over a traditional approach to properly shape complex anatomies with only a few Ni-Ti rotary instruments number.