Effect of Hexagonal Boron Nitride Nanoparticles on the Push-Out Bond Strength of a Bioceramic Root Canal Sealer

This in vitro study evaluated the effect of hexagonal boron nitride (HBN) nanoparticles on the push-out bond strength of a bioceramic root canal sealer. Sixty-eight extracted human maxillary central incisors were prepared using Reciproc R40 instruments and assigned to four groups: Adseal, unmodified BioRoot RCS, and BioRoot RCS containing 5% or 20% HBN by volume. Following obturation with gutta-percha and the respective sealers, specimens were stored at 37 °C and 100% humidity for 14 days. One-millimeter-thick slices from the coronal, middle, and apical thirds underwent push-out testing. Data were analyzed using a linear mixed-effects model, with sealer type, root region, and their interaction as fixed effects and tooth identity as a random effect (p < 0.05). BioRoot RCS containing 20% HBN showed significantly higher bond strength than Adseal in the coronal region, no significant difference in the middle region, and significantly lower bond strength in the apical region. Unmodified BioRoot RCS showed the lowest bond strength in all regions. Regional variations differed according to sealer type. Within the limitations of this study, incorporating 20% HBN increased the push-out bond strength of BioRoot RCS. Further investigation of the physicochemical, biological, and long-term properties of HBN-modified sealers is required.