CBCT-Aided Microscopic and Ultrasonic Treatment for Upper or Middle Thirds Calcified Root Canals

Figure 1

Determination of Parameters. (a1)–(a4) Locate calcified root canal orifice. On cross-sectional plane, canal managed by ultrasonic instrument before CBCT scanning (red arrows) and real canal below calcified orifice (yellow arrow) could be visible. Then, the distance between the calcified orifice and other references (usually orifices of other canals) could be measured to help locate the calcified orifice. (b1)–(b4) Adjust the cross-sectional plane, by moving the red line, to make clear root canal image under the calcification visible. Then, move blue line and green line until their intersection locates on the canal under the calcification, which made the canal appear on buccolingual and mesiodistal planes. (c1)–(c4) Determine the depth of calcification. Rotate the mesiodistal plane to make the blue line in accordance with the same trend of the root canal and overlap the canal resulting in the maximum exposure of root canal on buccolingual plane. Then, the depth of calcification (DOC) in buccolingual direction was determined. In the same way, DOC in mesiodistal direction could be measured (not shown). (d1)–(d4) Determine the direction of calcification. On cross-sectional plane, move the blue line parallel to the mesial or distal wall of pulp chamber (distal wall in this figure) to make the measurement plane in buccolingual direction parallel to distal wall of pulp chamber. Then, the buccolingual instrument angle (BLIA) was determined. In the same way, mesiodistal instrument angle (MDIA) could be measured (not shown).