The aim of the study was to analyze the chemical–physical properties and bioactivity (apatite-forming ability) of three recently introduced premixed bioceramic root canal sealers containing varied amounts of different calcium silicates (CaSi): a dicalcium and tricalcium silicate (1–10% and 20–30%)-containing sealer with zirconium dioxide and tricalcium aluminate (CERASEAL); a tricalcium silicate (5–15%)-containing sealer with zirconium dioxide, dimethyl sulfoxide and lithium carbonate (AH PLUS BIOCERAMIC) and a dicalcium and tricalcium silicate (10% and 25%)-containing sealer with calcium aluminate, tricalcium aluminate and tantalite (NEOSEALER FLO). An epoxy resin-based sealer (AH PLUS) was used as control. The initial and final setting times, radiopacity, flowability, film thickness, open pore volume, water absorption, solubility, calcium release and alkalizing activity were tested. The nucleation of calcium phosphates and/or apatite after 28 days aging in Hanks balanced salt solution (HBSS) was evaluated by ESEM-EDX, vibrational IR and micro-Raman spectroscopy. The analyses showed for NeoSealer Flo and AH Plus the longest final setting times (1344 ± 60 and 1300 ± 60 min, respectively), while shorter times for AH Plus Bioceramic and Ceraseal (660 ± 60 and 720 ± 60 min, respectively). Radiopacity, flowability and film thickness complied with ISO 6876/12 for all tested materials. A significantly higher open pore volume was observed for NeoSealer Flo, AH Plus Bioceramic and Ceraseal when compared to AH Plus (p < 0.05), significantly higher values were observed for NeoSealer Flo and AH Plus Bioceramic (p < 0.05). Ceraseal and AH Plus revealed the lowest solubility. All CaSi-containing sealers released calcium and alkalized the soaking water. After 28 days immersion in HBSS, ESEM-EDX analyses revealed the formation of a mineral layer that covered the surface of all bioceramic sealers, with a lower detection of radiopacifiers (Zirconium for Ceraseal and AH Plus Bioceramic, Tantalum for NeoSealer Flo) and an increase in calcium, phosphorous and carbon. The calcium phosphate (CaP) layer was more evident on NeoSealer Flo and AH Plus Bioceramic. IR and micro-Raman revealed the formation of calcium carbonate on the surface of all set materials. A thin layer of a CaP phase was detected only on AH Plus Bioceramic and NeoSealer Flo. Ceraseal did not show CaP deposit despite its highest calcium release among all the tested CaSi-containing sealers. In conclusion, CaSi-containing sealers met the required chemical and physical standards and released biologically relevant ions. Slight/limited apatite nucleation was observed in relation to the high carbonation processes.

The most common leguminous plants’ diseases are caused by soil-borne pathogens leading to important economic losses worldwide. Strains L1 and L8, belonging to Aureobasidium pullulans species, were tested in vitro and in vivo as biocontrol agents (BCAs) against Rhizoctonia solani (Rs1) (AG-4) and as plant growth promoters (PGPs). The non-volatile metabolites produced by L1 and L8 strains inhibited the pathogen mycelial growth by 87.9% on average, with no significant differences between the two strains. The lower pathogen diametric growth inhibition was displayed by both yeasts’ volatile metabolites (VOCs) that significantly reduced the colony growth of R. solani, and similarly to the control, with an average of 10.5%. By in vivo assay, L1 and L8 strains showed the ability to control the pathogen virulence probably through the biofilm formation around the bean and soybean plant roots, as confirmed by scanning electron microscope (SEM) analysis. The spectroscopic analysis highlighted the composition of non-volatile compounds: complex carbohydrates (pullulan), degrading enzymes, siderophores and antifungals (aureobasidins). Moreover, the ability of L1 and L8 strains to stimulate the bean and soybean plant roots, stems, and leaves growth was investigated, showing that these yeasts could have an application not only as BCAs but also as plant growth biostimulator.