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Background To investigate the effects of adding ZrO₂, TiO₂, and two sizes of hydroxyapatite (HAP) nanoparticles on the physicochemical and bioactivity properties of calcium silicate-based cement (CSC). Methods MTA, PC, and nanoparticle-modified groups (5% and 10% n-ZrO₂, n-TiO₂, n-HAP1, n-HAP2) were evaluated for setting time, compressive strength (1, 7, 14 days), solubility (14 days), and bioactivity. Setting time and compressive strength followed ISO 9917–1:2007, solubility followed a modified ISO 6876:2012, and bioactivity was analyzed using SEM–EDS. Results All groups showed significantly reduced setting times (p < 0.001) compared to MTA and PC, with 10% n-HAP1 showing the greatest reduction. Compressive strength increased over time in all groups except 5% and 10% n-ZrO₂, which remained stable (p > 0.05). MTA had the highest strength at 14 days. MTA’s solubility was higher than PC’s (p < 0.001). All groups, except 10% n-TiO₂, 5% and 10% n-HAP1, showed increased solubility vs. MTA (p < 0.003); all exceeded PC (p < 0.001). SEM after 1 day showed spherical apatite structures, which thickened by days 7 and 14. EDS confirmed Ca/P ratios similar to controls. Conclusions All nanoparticles accelerated the setting time, and only ZrO₂ nanoparticles enhanced early strength. Despite increased solubility, all values remained within acceptable limits. All groups demonstrated bioactivity potential.

Background Resin-based pit and fissure sealants, used to prevent dental caries, can experience abrasive wear. This study aimed to assess the abrasive wear of experimental pit and fissure sealants (DIF) compared with the other commercial pit and fissure sealants by measuring surface roughness, volume loss, and ultrastructure after chewing simulation at different time points. Methods Specimens were divided into five groups ( n  = 10): Clinpro ™ (CP), Teethmate ™ White (TW), Teethmate ™ Natural (TN), experimental sealant (DIF), and Filtek ™ Supreme Flowable Restorative (FC). They underwent chewing simulation with 120,000, 240,000, and 360,000 strokes. Surface roughness and volume loss were measured with a profilometer, and ultrastructures were assessed using scanning electron microscope (SEM). Results All specimens showed a significant increase in surface roughness after chewing simulation. FC had the highest roughness ( p  < 0.001) whereas DIF did not differ from other groups ( p  > 0.05). All materials experienced significant volume loss. Sealant types and chewing cycles affected volume loss, with CP showing the highest and TW the lowest ( p  < 0.001). SEM analysis revealed worn areas with circular or oval shapes, with CP and TN having larger diameters and TW the smallest. Conclusions DIF showed acceptable surface roughness and wear resistance compared to other commercial products after chewing simulation.

Objective This study aimed to develop enamel substitute material using a mechanochemical technique. Materials and Methods Hydroxyapatite was synthesized with and without tricalcium phosphate under uniaxial pressing of 10 and 17 MPa (HA10, HA17, BCP10, and BCP17), followed by sintering at 1250 °C for 2 h. Human enamel and dentin blocks were used as control groups. The mechanical properties were determined by compressive strength test and Vickers microhardness. The data were analyzed with one-way ANOVA and LSD post-hoc test ( α  = 0.05). The phase formation and morphology of the specimens were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results HA17 and HA10 had compressive strength values comparable to enamel and dentin, respectively ( p  > 0.05). The microhardness of all synthesized groups was significantly higher than that of tooth structures ( p  < 0.05). From the XRD graphs, only the hydroxyapatite peak was observed in the control and HA groups. SEM images showed homogeneous hydroxyapatite grains in all groups, while the BCP groups contained higher porosities. Conclusions Both HA10 and HA17 are suitable for use as the inorganic part of dentin and enamel substitutes.

ObjectivesThis study aimed to evaluate the effect of fractional radiation on the mechanical properties of fluoride-releasing materials.Materials and methodsHigh-viscosity glass ionomer cement (F9), resin-modified glass ionomer cement (F2), glass hybrid restoration (EQ), and bioactive composite (AC) were divided into 3 subgroups: 0, 35, and 70 Gy fractional radiation doses. The specimens were subjected to surface roughness, Vickers microhardness, and compressive strength tests. The chemical components and morphology of the tested specimens were observed via energy dispersive spectroscopy and scanning electron microscopy. The data were analyzed using two–way ANOVA with Bonferroni post hoc analysis.ResultsAfter exposure to fractional radiation, the surface roughness increased in all the groups. F9 had the highest surface roughness, while AC had the lowest surface roughness within the same radiation dose. The Vickers microhardness decreased in F9 and EQ. The AC had the highest compressive strength among all the groups, followed by F2. More cracks and voids were inspected, and no substantial differences in the chemical components were observed.ConclusionsAfter fractional radiation, the surface roughness of all fluoride-releasing materials increased, while the Vickers microhardness of F9 and EQ decreased. However, the compressive strength increased only in F2 and AC.