Effects of sonic instrumentation on the apical preparation of curved canals

This study compared apical transportation produced in curved (45- to 60-degree) molar canals instrumented with two MM-3000 Sonic Air test files (Rispi-Sonic and Trio-Sonic) with apical transportation from instrumentation with conventional K-type files. Seventy-five extracted human permanent mandibular molars were equally divided into three groups. Results showed that 92 (61%) of 150 measurements demonstrated no transportation, and only 7 (5%) had transportation between 0.25 and 0.5 mm. Most of the transportation was 0.25 mm or less, and no file produced transportation greater than 0.5 mm in a buccolingual or mesiodistal direction. Statistical analysis (chi-square test and analysis of variance) showed no significant difference (p greater than 0.05) in the amount of apical transportation in canals prepared with the Kerr K-type, Rispi-Sonic, or Trio-Sonic files.