Influence of canal morphology on the sealing ability of two obturation techniques

Aim The aim of this study was to compare the seal obtained by two obturation techniques: Lateral condensation and Thermafil (Maillefer, Ballaigues, Switzerland) in different root canal shapes. Methodology Fifty extracted permanent human lower premolar teeth were used in this study. All the teeth were instrumented by a ‘crown-down’ technique and allocated randomly into the two groups: Thermafil and lateral condensation. A microleakage study by a 2% aqueous methylene blue dye solution was performed. Six horizontal sections were produced and digitally recorded by a stereomicroscope at 25 × magnification further transferred in NIH-IMAGE software and analysed. Each section was divided into four quadrants, overlapping to each image a cross designed in the centre of the root canal. The degree of infiltration was scored from A (excellent) to E (poor) and the shape of the root canal assigned into three groups: irregular, oval and round. Data were statistically analysed by nonparametric Mann– Whitney U -test. Results Scores of A and B occurred as follows: irregular – 9.4 T vs. 2.9% LC ( P < 0.001); oval – 13.1 T vs. 5.1% LC ( P < 0.001); round – 31.3% T vs. 8.7% LC ( P < 0.0001) Conclusions Under these experimental conditions Thermafil obturation technique demonstrated better results independent of canal section morphology. Round canals were sealed better by both techniques