Effect of silver diamine fluoride on adhesion and microleakage of a pit and fissure sealant to tooth enamel: in vitro trial.

AIM: To identify the effect of silver diamine fluoride in adhesion and microleakage of a pit and fissure sealant to tooth enamel. METHODS: An in vitro study including 120 human molars without caries, and caries grade 1 was performed. Molars were randomly divided into four groups. Occlusal surfaces of groups 2 and 4 were sealed. In groups 1 and 3 silver diamine fluoride (SDF) was placed in the occlusal surface and then molars were sealed according to manufacturer's instructions. Afterwards, all groups were submitted to the adhesion test. Groups 1 and 2 were placed in a forming cylinder and their roots were submerged in polymethyl methacrylate after that they were stored in deionised water (37 °C ± 1). Subsequently, they were tested by applying a tractional load (Instron machine, speed cross of 1 mm/min). Sealant adhesion was evaluated through: Resistance to the detachment (MPa), residues of sealant area (mm2) and adhesive remaining index (ARI) (0-3 interval). Microleakage test: Groups 3 and 4 were placed in a plastic container and subjected to 2000 cycles at different temperatures one at 6 °C ± 1 and the other at 60 °C ± 1. Later the occlusal surface was immersed for 24 h in 1% toluidine blue. Microleakage was observed by optical microscopy (10×) and was interpreted in micrometres. RESULTS: Of the samples without SDF 18.1 and 23.0% of the sealant remaining and of the samples with SDF present 100% of sealant remaining on enamel. Samples with SDF obtained an average in the test of detachment of 6.89 ± 3.09 MPa, whereas in the group without SDF the average obtained was 6.42 ± 3.35 MPa. Differences were not statistically significant (p = 0.579). Most of the samples not treated with SDF (81.6%) showed microleakage than those treated with SDF in which 47% presented microleakage. CONCLUSIONS: There is an improvement in the retention properties of a fissure sealant applied after treatment with silver diamine fluoride. The application of fissure sealant to improve the aesthetics of teeth treated with SDF is recommended.

Colloidal synthesis of biocompatible iron disulphide nanocrystals.

The aim of this research was to synthesis biocompatible iron disulphide nanocrystals at different reaction temperatures using the colloidal synthesis methodology. Synthesis was conducted at the 220-240 °C range of reaction temperatures at intervals of 5 °C in an inert argon atmosphere. The toxicity of iron disulphide nanocrystals was evaluated in vitro using mouse fibroblast cell line. Two complementary assays were conducted: the first to evaluate cell viability of the fibroblast via an MTT assay and the second to determine the preservation of fibroblast nuclei integrity through DAPI staining, which labels nuclear DNA in fluorescence microscopes. Through TEM and HRTEM, we observed a cubic morphology of pyrite iron disulphide nanocrystals ranging in sizes 25-50 nm (225 °C), 50-70 nm (230 °C) and >70 nm (235 °C). Through X-ray diffraction, we observed a mixture of pyrite and pyrrohotite in the samples synthesized at 225 °C and 240 °C, showing the best photocatalytic activity at 80% and 65%, respectively, for the degradation of methylene blue after 120 minutes. In all experimental groups, iron disulphide nanocrystals were biocompatible, i.e. no statistically significant differences were observed between experimental groups as shown in a one-way ANOVA and Tukey's test. Based on all of these results, we recommend non-cytotoxic semiconductor iron sulphide nanocrystals for biomedical applications.

Nanomaterials made of non-toxic metallic sulfides: A systematic review of their potential biomedical applications.

Metallic sulfides involve the chemical bonding of one or more sulfur atoms to a metal. Metallic sulfides are cheap, abundant semiconductor materials that can be used for several applications. However, an important and emerging use for non-toxic metallic sulfides in biomedical applications has arisen quickly in the medical field. In this systematic review, the available data from electronic databases were collected according to PRISMA alignments for systematic reviews. This review shows that these metallic sulfides could be promising for biomedical uses and applications. This systematic review is focused primarily on the following compounds: silver sulfide, copper sulfide, and iron sulfide. The aim of this review was to provide a quick reference on synthesis methods, biocompatibility, recent advances and perspectives, with remarks on future improvements. The toxicity of metallic sulfides depends directly on the cytotoxicity of their interactions with cells and tissues. Metallic sulfides have potential biomedical applications due to their antibacterial properties, uses in imaging and diagnostics, therapies such as photothermal therapy and chemotherapy in tumors and cancer cells, drug delivery and the fabrication of biosensors for the sensitive and selective detection of moieties, among others. Although current evidence about metallic sulfide NPs is promising, there are still several issues to be addressed before these NPs can be used in biomedicine. The current review is a brief but significant guide to metallic sulfides and their potential uses in the biomedical field.

Mothers' self-efficacy and children's oral health.

OBJECTIVES: To (i) test the validity of the Spanish Self-Efficacy Scale for Maternal Oral Care (SESMO), (ii) compare SESMO scores among socio-demographic groups and (iii) relate mothers' SESMO to children's dental status. METHODS: A limited census sample included 130 children and their mothers. The SESMO was applied through an interview, and the children's DMFT/dmft (number of decayed, missing and filled teeth) and OHI-S (oral hygiene score) were assessed through clinical examinations. To test the internal consistency and validity, the Spanish and English SESMO versions were compared. Dental status and oral hygiene were examined in different socio-demographic groups. RESULTS: Most of the families were from the middle socio-economic class, and the majority of children (65%) were ≤6 years of age. Cronbach's α was 0.82 for the English SESMO and 0.86 for the Spanish SESMO; both versions had a three-factor structure (one for each self-efficacy subscale). Overall, the factor loadings of the total and its subscale items were similar between the two SESMO versions. There was a correlation between the mothers' self-efficacy and the children's dental health status in deciduous dentition. CONCLUSIONS: The Spanish SESMO scale had similar internal consistency and validity as the previously validated English SESMO scale. Mothers' self-efficacy was associated with children's dental status in deciduous dentition but not with children's status in permanent dentition.