Reciprocating Root Canal Technique Induces Greater Debris Accumulation Than a Continuous Rotary Technique as Assessed by 3-Dimensional Micro–Computed Tomography

IntroductionThe ability of single-file, reciprocating instruments to remove inorganic debris is uncertain. By using micro–computed tomography (microCT), this study compared the 3-dimensional distribution, quantity, and density of remaining inorganic debris in the mesial root of mandibular molars after instrumentation. A single reciprocating file was compared with a multifile rotary instrumentation technique.MethodsTeeth were selected for instrumentation using reciprocating or rotary instruments (n = 19). Teeth were scanned using microCT before and after instrumentation. Through shape recognition and superimposition image analysis techniques, remaining inorganic tissue debris was identified, quantified, and visualized 3-dimensionally, mapping debris to its location. The use of a density phantom enabled the debris density to be calculated, giving a measure of compactness.ResultsAfter single-file instrumentation, an average of 19.5% debris remained in the canal compared with 10.6% with the multifile technique (P = .01) and at an average density of 1.60 g/m3 compared with 1.55 g/m3 for the multifile system (P > .05). Isthmuses, protrusions, and irregularities in the canal wall were repeatedly seen at the locations of debris accumulation.ConclusionsIn canals with a high prevalence of isthmuses and protrusions, using multifile rotary systems may be preferred over reciprocating files because it can yield cleaner canals with less debris accumulation.