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Effect of titanium tetrafluoride (TiF4) and sodium fluoride (NaF) varnishes on the dental biofilm microbiome in vivo

Grant number: 22/07980-0
Support Opportunities:Scholarships abroad - Research Internship - Doctorate (Direct)
Effective date (Start): February 01, 2023
Effective date (End): January 31, 2024
Field of knowledge:Health Sciences - Dentistry - Social and Preventive Dentistry
Principal Investigator:Marília Afonso Rabelo Buzalaf
Grantee:Samanta Mascarenhas Moraes
Supervisor: Ramiro Mendonça Murata
Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil
Research place: East Carolina University (ECU), United States  
Associated to the scholarship:18/18147-1 - Prevention and remineralization of white spot lesions in orthodontics: comparison of sodium fluoride varnish and titanium tetrafluoride varnish (TiF4), BP.DD


The formation of a white spot lesion (WSL) around orthodontic accessories is considered a reversible iatrogenesis, with a high frequency of occurrence. The presence of different bacteria and their degrees of pathogenicity in dysbiotic biofilm related to dental caries is recent. In addition, no studies relate the action of a high fluoride concentration on the cariogenic biofilm in vivo. Identifying the main differences in the biofilm microbiome after exposure to high fluoride concentrations (titanium tetrafluoride TiF4 and sodium fluoride NaF) is not elucidated in the literature, and microbiome studies have never been performed in an experimental model like the one we propose. Thus, this Research Internship Abroad Grant aims to describe the different types of microbial biofilms involved in dental caries after treatment with fluoride varnishes by performing a comprehensive 16S rDNA profiling of the dental plaque microbiome. The mentioned experiment is an in vivo crossover study with 12 participants selected from the ongoing clinical trial. Inclusion criteria: six-monthly attendance at the clinical study, 12 and 18 years old, to be in the 18 or 24-month follow-up stage of the clinical study, presence of fixed orthodontic appliance, and at least one active white spot lesion (non-cavitated). Exclusion criteria: absence from the clinical study, having removed the fixed orthodontic appliance, non WSL, and presence of cavitated caries. The participants will go through 4 groups: G1 - negative control (non treatment), G2 - negative control (placebo varnish), G3 - positive control (5.42% NaF varnish, containing 2.45% F, pH 5.0); G4 - test varnish (4% TiF4 varnish, containing 2.45% F, native pH 1.0). Participants will be seen at the end of the first day; professional prophylaxis will be performed on all volunteers, and clinical analyses will be performed (ICDAS and Nyvad). The varnish will be applied according to the following schedule: first, the placebo varnish, one month later, the NaF varnish will be used, and after three months of washout, the TiF4 varnish will be applied. After the application, the participant will be instructed not to eat anything for 3 to 4 hours, not to brush their teeth until the return, and to fast for at least 6 hours before returning the following day to collect the biofilm. Supragingival plaque samples will be collected and immersed in RNAlaterTM Stabilization Solution. Samples will be stored in a -20°C refrigerator until shipping to the USA. At East Carolina University, the bacterial DNA will be extracted, quantified, and amplified. The sequencing will be performed on the Nanopore MinION sequencing platform (Oxford Nanopore Technologies, Oxford, UK). Afterward, the statistical analysis will be performed, and microbial identification will be carried out using the WIMP analysis tool. (AU)

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