Effect of TiF4 varnish on microbiological changes and caries prevention: in situ and in vivo models
The aim of this study was to evaluate microbiological changes, oral soft tissue toxicity, and caries-preventive effect of an experimental titanium tetrafluoride (TiF4) varnish compared with a commercially available fluoride varnish (NaF), using in situ and in vivo models.
Materials and methods
The treatment groups were the following: TiF4 varnish (experimental varnish), Duraphat® (fluoride positive control), placebo varnish (no fluoride), and no treatment (negative control). The varnishes were applied once over the enamel surface using a microbrush. For the in vivo study, 48 Wistar rats were infected with Streptococcus sobrinus 6715, received a treatment, and were submitted to a cariogenic challenge. After 4 weeks, S. sobrinus, oral soft tissue toxicity, presence, and severity of caries were evaluated. For the in situ study, 12 volunteers took part in this randomized crossover, double-blind study performed in four phases of 14 days each. They used intraoral appliances containing four enamel specimens that received the varnish according treatment group. After 24 h, the varnish was removed and plaque accumulation was allowed. A 20% sucrose solution was dripped over the enamel blocks (10×/day for 5 min each). Total streptococci, S. mutans, Lactobacillus, Candida spp. counts, and presence of white spot lesions were evaluated. Lesion depth was also quantified by micro-CT.
For the in vivo study, the fluoride (F-varnishes) showed a statistically significant reduction in the percentage of S. sobrinus compared to the negative control (p < 0.05). Toxicological analysis revealed no abnormalities in oral tissues of rats from all groups, and both F-varnishes reduced the number and severity of caries lesions, without significant differences (p < 0.05). No statistical differences in microbiological counts were seen for the in situ experiment (p > 0.05). However, the specimens treated with TiF4 exhibited lower percentage of white spot lesions and the lesion depth was significantly reduced by F-varnishes (p < 0.05).
F-varnishes showed reduction in the percentage of S. sobrinus in vivo, no oral soft tissue toxicity, and a caries-preventive effect in vivo and in situ.
NaF varnish is largely used due its capacity to form CaF2-like layer on enamel. Therefore, development of studies focused on other fluoride compounds such as a TiF4 varnish, which may have greater efficacy than NaF against tooth demineralization, is important.
KeywordsCaries Titanium tetrafluoride Mutans streptococci Fluoride varnish Oral biofilm
The authors thank J.A. Cury, R.C. Evangelista, and F.Y. Fujiwara for the scientific support during the varnish development and analytical process; E. Campagnoli for the toxicological analysis; V.S.S. Pierro, M.P. Barbosa, and T.C. França for their support during this experiments; and J.M. Granjeiro, E. Calvano, and T. Vieira for their support during genetic analysis. The authors gratefully thank all the volunteers who participated in the in situ study.
This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil - (CAPES) - finance code 001 and from FAPERJ E-26/202.924/2017 and CNPQ 303535/2016-4. This study is part of the PhD thesis of the first author. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted.
Informed consent was obtained from all individual participants included in the study.
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