Calcium Hydroxide Dressing Influences the Obturation of Simulated Lateral Canals

The aim of this study was to investigate the influence of calcium hydroxide dressing on the filling of simulated lateral canals by different obturation techniques. Sixty single-root-premolars were instrumented. Simulated lateral canals were drilled on each third of the roots. The teeth were divided into four groups: no dressing and obturation by lateral condensation technique (G1), dressing with calcium hydroxide and obturation by lateral condensation technique (G2), no dressing and obturation by hybrid technique (G3) and, dressing with calcium hydroxide and obturation by hybrid technique (G4). The teeth were maintained at 37°C in 100% humidity for 7 days, and obturation techniques were performed. Radiographs were taken and filled or unfilled lateral canals were counted. Data were analyzed using analysis of variance (ANOVA) followed by Tukey's test (a = 5%). The hybrid technique filled large number of lateral canals as compared to lateral condensation technique, regardless the use of intracanal medication (p < 0.05). Calcium hydroxide decreased the number of lateral canals filled for both lateral and hybrid techniques (p < 0.05). Significant differences were observed when comparing the number of filled and unfilled lateral canals in the same root third of each group (p < 0.05). Regardless the obturation technique, calcium hydroxide dressing reduced the penetration of filling material in simulated lateral canals. The persistence of calcium hydroxide residues reduces the penetration of filling material in simulated lateral canals, possibly representing a potential cause of failure in the future.