An in vitro study of the quality of root fillings in teeth obturated by lateral condensation of gutta-percha or Thermafil obturators.

The aim of this in vitro study was to assess the quality of root canal obturation and degree of linear apical dye penetration in teeth root filled with either laterally condensed gutta-percha or Thermafil obturators. A total of 150 teeth with single roots were included in the study. All canals were prepared using a standard step-back technique with anticurvature filing. Radiographs taken of the teeth to show the maximum degree of canal curvature were then exposed and the angle, radius and position of curvature determined. This information about the canals, together with their working length and diameter at end-point, was used to divide the teeth into two experimental and two control groups. A total of eight teeth were excluded because of technical difficulties, 65 were filled with Thermafil obturators, 63 were filled with laterally condensed gutta-percha whilst 14 teeth remained unfilled and acted as controls. Following obturation, the teeth were radiographed in two planes and the technical quality of fill assessed on a four-point scale. All access cavities were then sealed and the teeth immersed in dye for 48 h before being split longitudinally. Linear dye penetration via the apical foramen was then assessed. Canal obturation with Thermafil obturators (0.7 min) was significantly quicker (P < 0.001) than lateral condensation (6.4 min). Apical extrusion of sealer and gutta-percha occurred significantly more often with Thermafil obturators but there was little difference in the technical quality of the fillings and no significant difference in dye penetration. Under the conditions of this study. Thermafil obturators proved a satisfactory alternative to lateral condensation of gutta-percha.