Can Cleansing Regimens Effectively Eliminate Saliva Contamination from Lithium Disilicate Ceramic Surface?

This study evaluated the effect of cleaning protocols on the bond strength of resin cement to glass-ceramic. Ceramic specimens (N=120, n=12 per group) were etched with hydrofluoric acid and rinsed with water. After saliva contamination, specimens were cleaned as follows: water, 37% H3PO4, cleaning-paste (Ivoclean), or isopropanol. Non-contaminated specimens acted as the control. Resin cement was bonded to the specimens, and tested either after 24 h or x5000 thermocycling. Both the cleaning method (p=0.001) and the storage conditions (p=0.005) significantly affected the bond strength results. In dry conditions, the groups PA and IV showed no significant difference, being also similar to the non-saliva contaminated control group (p⟩0.05). In dry conditions, no significant difference was observed between the mean DW and IS being significantly lower than those of other groups (p⟨0.05). Except for the group IV, thermocycling decreased the results significantly in all groups (p⟨0.05). Predominantly mixed failure type was observed in both dry and aged conditions. SEM micrographs of ceramic surfaces after cleaning agents showed no major differences but on the specimens from the IV group, small, rounded-zirconia particles were observed. In case of saliva contamination of acid-etched glass-ceramics, mechanical cleaning can restore adhesion to the baseline situation

3D

© 2021 Wiley Periodicals LLC.Fabrication of scaffolds using polymers and then cell seeding is a routine protocol of tissue engineering applications. Synthetic polymers have adequate mechanical properties to substitute for some bone tissue, but they are generally hydrophobic and have no specific cell recognition sites, which leads to poor cell affinity and adhesion. Some natural polymers, have high cell affinity but are mechanically weak and do not have the strength required as a bone supporting material. In the present study, 3D printed hybrid scaffolds were fabricated using PCL and GelMA carrying dental pulp stem cells (DPSCs), which is printed in the gaps between the PCL struts. This cell loaded GelMA was shown to support osteoinductivity, while the PCL provided mechanical strength needed to mimic the bone tissue. 3D printed PCL/GelMA and GelMA scaffolds were highly stable during 21 days of incubation in PBS. The compressive moduli of the hybrid scaffolds were in the range of the compressive moduli of trabecular bone. DPSCs were homogeneously distributed throughout the entire hydrogel component and exhibited high cell viability in both scaffolds during 21 days of incubation. Upon osteogenic differentiation DPSCs expressed two key matrix proteins, osteopontin and osteocalcin. Alizarin red staining showed mineralized nodules, which demonstrates osteogenic differentiation of DPSCs within GelMA. This construct yielded a very high cell viability, osteogenic differentiation and mineralization comparable to cell culture without compromising mechanical strength suitable for bone tissue engineering applications. Thus, 3D printed, cell loaded PCL/GelMA hybrid scaffolds have a great potential for use in bone tissue engineering applications