Dislodgement resistance of calcium silicate-based materials from root canals with varying thickness of dentine

To evaluate the dislodgement resistance of DiaRoot BioAggregate and Biodentine from canals in roots with varying amounts of remaining dentine thickness.

A total of 90 maxillary incisor teeth with similar dimensions were used. The teeth were extracted for periodontal reasons from adult subjects aged between 52 and 61 years. They were decoronated at the cemento-enamel junction. Simulated internal cavities with a depth of 3 mm were performed by widening the canals on the coronal thirds of the roots, leaving varying amounts of remaining dentine thickness. The canals were enlarged progressively using round diamond burs until the desired dentine wall thickness was obtained. The samples were divided into three main groups (n = 30 each) according to the dentine thickness as follows: group 1: dentine thickness of 0.75 mm, group 2: dentine thickness of 1.50 mm and group 3: dentine thickness of 2.25 mm. Then, these main groups were further divided into two subgroups (n = 15 each) according to the filling material (DiaRoot BioAggregate or Biodentine). Horizontal root slices of 1 mm were obtained from each specimen. Vertical loading was applied to the filling materials at a cross-head speed of 1 mm min^-1 using a universal testing machine. The force that led to dislodgement of the filling was recorded in Newtons. The resistance to dislodgement was calculated in megapascals (MPa) by dividing the load in Newtons by the area of the bonded interface. The data were statistically analysed with two-way anova with Tukey's honestly significant difference (HSD) test.

Biodentine had significantly higher resistance to dislodgement than DiaRoot BioAggregate (P < 0.001). The specimens with thinner remaining dentine had lower dislodgement resistance compared to those with dentine thicknesses of 1.50 and 2.25 mm (P < 0.001). The lowest mean value for dislodgement resistance was obtained from the DiaRoot BioAggregate group with 0.75 mm dentine thickness (2.72 ± 0.90 MPa).

The dislodgement resistance of Biodentine and DiaRoot BioAggregate from root dentine was influenced by remaining dentine thickness, which determines dentinal tubular density.