The purpose of this study was to compare ultrasonic and bur root end cavity preparations with regard to retention, cleanliness, and root canal parallelism. Twenty anterior teeth from human cadavers were instrumented and obturated with gutta-percha and sealer. After raising a full-thickness flap, the apices of the roots were exposed and beveled at a 45-degree angle. Half of the apical cavities w...

Table 1 Correlation of vertex and edge frontier sizes with execution time for three randomly selected roots of different graph structures. The size of the vertex frontier correlates positively with execution time regardless of the root or structure of the graph.. Figure 1 Evolution of vertex frontiers (as a percentage of total vertices) for differ-Figure 4 Power consumption for various betweenn...