Incorporation of Hydroxyapatite and Calcium Triphosphate in the Epoxy Resin-Based Sealer

Objective This study aims to assess and compare the influence of hydroxyapatite (HA) and tricalcium phosphate (TCP) nanoparticles on a commercially available epoxy resinbased sealer, focusing on porosity and push-out bond strength.

Materials and Methods This work was classified into a control group and two experimental groups. In each experimental group, the sealer was mixed with 2.5 wt.% of HA and TCP nanoparticles. Thirty extracted single-rooted teeth were utilized. After sectioning the crowns, the remaining roots of 15 teeth were used, up to 40 to 0.06, using a K3 rotary system. Smear layers were removed with 3 mL of 17% EDTA applied for 60 seconds. Then, the canals were irrigated with 3 mL of 2.25% NaOCl and 5 mL of distilled water. The strength of push-out bonds was tested via an Instron universal testing machine on a 2 mm section acquired from obturated canals. Data were assessed using one-way ANOVA and post hoc tests at a significance level of p < 0.05.

Results A nonsignificant difference (p > 0.05) was evident when the three groups were crosschecked in terms of void volume and bond strength. Micro-CT evaluations revealed the lowest volume of voids to be 0.1152 mm3 (2.69%) for the HA group compared with the control group 0.1818 mm3 (3.9%) and the TCP group 0.2194 mm3 (4.33%). Mean bond strength values were 4.18 ± 1.77 MPa for group 1 (control), 4.19 ± 1.54 MPa for group 2 (HA 2.5%) and 3.76 ± 1.95 MPa for group 3 (TCP 2.5%). Groups 1 and 3 showed both cohesive and a mixed type of failure, while group 2 showed adhesive and a mixed type of bond failure.

Conclusion Within the limitations of the study, incorporation of 2.5 wt% HA and TCP nanoparticles into AH Plus did not significantly affect the percentage volume of voids and the bond strength negatively.