RESUMO
The primary purposes of this study were to compare the quality (length and density) and efficiency (time to completion) of obturation when single- or multiple-cone obturation techniques were used by graduating dental school students on previously instrumented single-canalled teeth using simulated clinical conditions in vitro. Five students took part in the study, each of whom obturated thirty-six teeth using six obturation techniques. The multiple-cone techniques included lateral condensation of gutta-percha, the technique the students had used in their laboratory and clinical courses, and two similar variations: lateral condensation of Epiphany and mechanical lateral condensation of gutta-percha. These three methods were compared to three single-cone techniques: Thermafil, Activ GP, and GuttaFlow. The students had no experience with single-cone techniques except for a brief introduction and demonstration. All obturations were timed, and post-obturation radiographs were taken in the clinical and proximal views (CV and PV). The radiographs were read by two endodontic faculty members who were blinded to technique, student, and fellow faculty member's results. Data were also separated by operator experience with individual techniques: the first three obturations/techniques were compared to the final three obturations/techniques. Data were analyzed using chi-square tests. The quality produced or time required rarely differed within multiple-cone or single-cone groups, but statistical differences did occur between the two groups. Multiple-cone obturation was more likely to produce adequate length (p=0.0042), density in the CV (p=0.0056), and density in the PV (p=0.0003). Conversely, the single-cone techniques were significantly faster (mean 350 seconds) than the multiple-cone techniques (mean 464 seconds) (p=0.0020). Quality did not improve significantly with the experienced groups versus the inexperienced with any of the six techniques, but the mean time for obturation decreased from 449 seconds to 362 seconds. These preliminary findings suggest that further training and experience are needed to improve the quality of obturation produced when single-cone techniques are used. Further research is needed to determine how much training and/or experience will be needed.