In vitro effect of experimental nanocomposites solutions on the prevention of dental caries around orthodontic brackets

Abstract

This study aimed to evaluate the in vitro effect of a single application of experimental nanocomposite solutions on the prevention of dental caries around orthodontic brackets. The specimens were exposed to mesoporous silica (MS) nanocomposites containing fluoride by association with titanium tetrafluoride (TiF4) or sodium fluoride (NaF). Nanocomposites also could contain calcium and groups were described as MSCaTiF4, MSTiF4, MSCaNaF, MSNaF, and controls (TiF4, and NaF). Specimens were subjected to the formation of a multispecies biofilm to generate a cariogenic challenge. After 24h, both pH and total soluble fluoride concentration of the culture medium were assessed. Mineral loss was evaluated by percentage of surface mineral loss (%SML), mineral volume variation (ΔZ) of inner enamel and polarized light microscopy (PL). Linear (Ra) and volumetric (Sa) surface roughness and scanning electronic microscopy (SEM) were used to assess enamel topography. Statistical analyses were conducted considering p<0.05. MSNaF had the highest value of culture medium pH after cariogenic challenge, similarly to MSTiF4. All nanocomposite solutions released less fluoride than their controls NaF and TiF4 (p<0.05). All nanocomposite solutions presented lower %SML compared to their respective control groups (p<0.05). Lower Ra, Sa and ΔZ were observed for experimental groups compared to TiF4 (p<0.05). The results were confirmed by PL and SEM analysis. The experimental nanocomposite solutions contributed for lower enamel demineralization around orthodontic brackets.

In vitro and in situ caries-preventive effect of a new combined fluoride and calcium experimental nanocomposite solution.

“…Mesoporous silica (MS) based nanocomposites were obtained by a nanoprecipitation technique, varying the molar ratio of water/tetraethoxysilane (TEOS), NH3/TEOS and the amount of cetyltrimethylammonium bromide. All characterization analyses are described as previously reported in the literature 11 .…”

“…ICP-AES results were 10.7 ± 0, 8% [w /w] of medium content. The determination of fluoride resulted in 9.3 ± 0.1% [w /w] of medium content 11 .…”

“…The in vitro , randomized, controlled, single-blind study was based on a previous investigation that evaluated the enamel mineral loss reduction resulted from application of nanocomposite solutions containing calcium and fluoride that used a specific sample size (n=13 per group) ( 11 . A 0.8 statistical power was used to detect a 50% significant difference in mean mineral loss in each treatment group compared to the control group (1.36% of NaF, 6135 ppm of F - ), using a one-tailed test with a 5% significance level (BioEstat 5.3 ® , Instituto de Desenvolvimento Sustentável Mamirauá, Tefé, Brazil).…”

“…The images were later reconstructed into cross sections using a dedicated software (NRecon, Bruker) and specific reconstruction parameters. The integrated mineral loss (∆Z) was calculated by drawing a profile across the enamel surface and measuring the integrated area under the curve, corresponding to the mineral density of the carious lesion 11 .…”

“…The search for new dental applications of mesoporous silica nanoparticles (MS), in the scope of the delivering active compounds, has been the focus of nanotechnology and bone tissue engineering, mainly aimed at the development of biocompatible and multifunctional nanocarriers. Previous in vitro studies show that calcium MS was as effective as TiF 4 and NaF to reduce erosive tooth loss 8 , 9 , 10 while others showed that these solutions were able to reduce enamel demineralization around orthodontic brackets 11 . However, no study has yet compared the effect of mesoporous silica nanoparticles with added fluoride in reducing demineralization and enhancing remineralization under in situ cariogenic challenge.…”