Pit and Fissure sealants fortified with nanobiofillers for remineralization

Objectives: 1.) To formulate Pit and fissure sealants (PFS) containing nano-Hydroxyapatite (nHAP) filler; nHAP filler and silica co- filler; nHAP and nano-Amorphous Calcium Phosphate (nACP) co- filler.
2.) To evaluate and compare physical properties like degree of conversion (DOC), curing depth (CD) and mechanical properties like microshear bond strength (MBS) of fortified PFS with commercially available fluoride and ACP containing sealants.
3.) To evaluate remineralization potential of fortified PFS
Methods: In present pilot laboratory study four PFS were prepared using monomers with mixture of 35.5 wt % BisGMA, 35.5 wt % TEGDMA and 28 wt % HEMA. Bioactive nano fillers (n-HAP and n-ACP) were added in various concentrations: 1) Unfilled 0% filler 2) 30% nHAP filler; 3) 10% nHAP + 20% silica filler; 4) 10% nHAP + 20% nACP filler. Commercial unfilled PFS served as negative control and Fluoride releasing PFS served as positive control. Commercially available ACP containing PFS was another test material. The samples (n=21,3/gp) were tested for MBS, DOC (Fourier Transform Infrared Spectroscopy) and CD (ISO standards for dental resin 4049 using the scrapping technique). Remineralization of permanent teeth enamel was assessed by Scanning Electron Microscopy (SEM). Data obtained was statistically analysed. (Kruskal-Wallis Test, Chi-square test, p<0.05)
Results: There were statistically significant differences in MBS (p=0.006), DOC (p= 0.004) and CD (p=0.004) between different experimental and control groups. 10% nHAP and 20% nACP filled PFS showed the highest MBS. Amongst the different experiment groups, DOC was highest for 30% nHAP filled sealant. However CD was lowest of 30% nHAP filled sealant although higher than the ISO 4049 CD requirement. A remineralized region on the surface between fissure sealant and tooth enamel was observed by SEM in bioactive sealants.
Conclusions: The addition of nanoscale bioactive fillers to PFS showed remineralizing capability without declining their physical and mechanical properties.