K3 Nickel-Titanium Files
Variable Helical Flute Angle
As previously noted, negative rake angles are inefficient and result in dentin scraping rather than cutting and chip dislodgment. The ideal rake angle is slightly positive, because an overly positive rake angle will result in digging and plowing of the dentin. The K3 features a slightly positive rake angle for optimum cutting efficiently. The chips resulting from the K3 cutting action are easily dislodged from the working area and carried off via the file's unique helical angle as outlined in the next section.
2. Variable Helical Flute Angle
Once the instrument has made its cut into the dentin, the debris needs to move out of the way. This allows for additional debris removal and channeling to occur in the flute space. Compression occurs when debris is caught between the canal wall and instrument flute. Remember that as the file is working, more debris is built-up in the coronal area of the instrument. If there is no more space to channel debris, the instrument becomes clogged and the debris does not flow out of the canal. The chips resulting from the K3 cutting action are easily dislodged from the working area and carried off via the file's unique variable flute design. In short, the degree of taper increases from the tip to the handle.