Apical seal by customized versus standardized master cones: A comparative study in flat and round canals

Abstract

Master cone adaptation is a crucial step of root canal obturation with the lateral condensation technique. In regular canals such adaptation is facilitated by the use of standardized instruments and master cones, using a “tug-back” sensation as a guide. Standardized master cones are not easily adapted to flat canals and preparation of customized master cones by the chloroform dip technique has been suggested. Thirty-four extracted roots with flat canals and fully formed apices were selected on the basis of buccolingual and mesiodistal radiographs. Roots with regular, round cross-section canals served as controls. Following a clinical-like root canal preparation, half of each group was obturated with a customized master cone, while in the other half standardized cones were used. A single cone was used with AH26 sealer. After the sealer was set, the roots were subjected to dye penetration and a clearing assay. The maximal distance to which the dye penetrated was used as a measure for the quality of the apical seal. In flat canals, customized cones provided a significantly better seal than standardized cones (p<0.05). In round canals, no significant difference could be demonstrated. Master cone adaptation is a crucial step of root canal obturation with the lateral condensation technique. In regular canals such adaptation is facilitated by the use of standardized instruments and master cones, using a “tug-back” sensation as a guide. Standardized master cones are not easily adapted to flat canals and preparation of customized master cones by the chloroform dip technique has been suggested. Thirty-four extracted roots with flat canals and fully formed apices were selected on the basis of buccolingual and mesiodistal radiographs. Roots with regular, round cross-section canals served as controls. Following a clinical-like root canal preparation, half of each group was obturated with a customized master cone, while in the other half standardized cones were used. A single cone was used with AH26 sealer. After the sealer was set, the roots were subjected to dye penetration and a clearing assay. The maximal distance to which the dye penetrated was used as a measure for the quality of the apical seal. In flat canals, customized cones provided a significantly better seal than standardized cones (p<0.05). In round canals, no significant difference could be demonstrated.