IADR Abstract Archives
Characteristics and Biological Considerations of Newly Developed NanoFA-Based Dental Composite.
Objectives: The objectives of this project were to develop fluoride releasing model dental composites incorporating nano-fluorapatite (nanoFA) as secondary fillers and to measure their degree of conversion (DC) as well as fluoride ion release. Moreover, the toxicity of the monomers UDMA, HEMA was investigated. The overall effect of the new composite material on gingival fibroblasts was assessed by RNA-Seq analysis.
Methods: Composites containing UDMA: HEMA (4:1) as resin (37.9% vol) with silica glass (62.1% vol) and nanoFA as filler part (20% weight) were made. G-ænial Anterior (GC Europe) was used as comparator. The DC was recorded by FTIR, and an ion-selective electrode was used to measure fluoride release for a period of one month storage. Monomer toxicity was tested by colorimetric XTT viability assay. The underlying cellular mechanisms were characterised by gene expression analysis using RT-qPCR and RNA-Seq analysis with gingival fibroblasts exposed for 24 hours to the dental composites.
Results: The DC for the new material was 84 % and after 28 days 2.5 µg/(cm2.day) fluoride was released compared to the comparator. The toxicity studies revealed a significant reduction in the cell viability at 2 mM of HEMA and 1 mM of UDMA. RT-qPCR showed a dose dependent expression increase of DNA repair genes (DDX11, IPPK, XRCC2 and RAD50) in gingival fibroblasts treated with HEMA. RNA-Seq analysis identified an early stress response and disturbed cellular redox balance manifested by an increased expression of cellular signalling pathways such as oxidoreductase activity, NADPH activity, ferroptosis in response to composite materials.
Conclusions: The new materials achieved high degree of conversion. The amount of fluoride released was comparable to G-ænial dental composites. However, dental composite material induced signs of chemical toxicity such as impaired redox balance in oral tissues.
Methods: Composites containing UDMA: HEMA (4:1) as resin (37.9% vol) with silica glass (62.1% vol) and nanoFA as filler part (20% weight) were made. G-ænial Anterior (GC Europe) was used as comparator. The DC was recorded by FTIR, and an ion-selective electrode was used to measure fluoride release for a period of one month storage. Monomer toxicity was tested by colorimetric XTT viability assay. The underlying cellular mechanisms were characterised by gene expression analysis using RT-qPCR and RNA-Seq analysis with gingival fibroblasts exposed for 24 hours to the dental composites.
Results: The DC for the new material was 84 % and after 28 days 2.5 µg/(cm2.day) fluoride was released compared to the comparator. The toxicity studies revealed a significant reduction in the cell viability at 2 mM of HEMA and 1 mM of UDMA. RT-qPCR showed a dose dependent expression increase of DNA repair genes (DDX11, IPPK, XRCC2 and RAD50) in gingival fibroblasts treated with HEMA. RNA-Seq analysis identified an early stress response and disturbed cellular redox balance manifested by an increased expression of cellular signalling pathways such as oxidoreductase activity, NADPH activity, ferroptosis in response to composite materials.
Conclusions: The new materials achieved high degree of conversion. The amount of fluoride released was comparable to G-ænial dental composites. However, dental composite material induced signs of chemical toxicity such as impaired redox balance in oral tissues.