To evaluate the mechanical properties and metallurgical characteristics of the M3 Rotary and M3 Pro Gold files (United Dental).
One hundred and sixty new M3 Rotary and M3 Pro Gold files (sizes 20/0.04 and 25/0.04) were used. Torque and angle of rotation at failure (
Comparing the same size of the 2 different instruments, cyclic fatigue resistance was significantly higher in the M3 Pro Gold files than in the M3 Rotary files (
The M3 Pro Gold files showed greater flexibility and angular rotation than the M3 Rotary files, without decrement of their torque resistance. The superior flexibility of M3 Pro Gold files can be attributed to their martensite phase.
The purpose of this study was to observe the change in the viscoelastic properties of thermoplasticized injectable root canal filling materials as a function of temperature and to compare the handling characteristics of these materials.
Three commercial gutta perchas and Resilon (Pentron Clinical Technologies) in a pellet form were heated in the Obtura-II system (Obtura Spartan) at 140℃ and 200℃, and the extrusion temperature of the thermoplasticized materials was measured. The viscoelastic properties of the materials as a function of temperature were evaluated using a rheometer. The elastic modulus
The three gutta perchas had dissimilar profiles in viscoelastic properties with varying temperature. The phase transition of softened materials into solidification occurred at 40℃ to 50℃, and the onset temperatures obtained by a rheometer and a DSC were similar to each other. The onset temperature of phase transition and the consistency upon compaction pressure were different among the materials (
The rheological characteristics of the thermoplasticized root canal filling materials changed under a cooling process. The dissimilar viscoelastic properties among the materials require different handling characteristics during an injecting and compacting procedure.