The potential use of glycosyl-transferase inhibitors for targeted reduction of S. mutans biofilms in dental materials.

Streptococcus mutans is the primary oral caries-forming bacteria, adept at producing "sticky" biofilms via the synthesis of insoluble extracellular polysaccharides (EPS), catalyzed by glucosyltransferases (GTFs). To circumvent the use of broad-spectrum antibiotics to combat these bacteria, this study sought to modify existing EPS-targeting small molecules with the ultimate goal of producing anti-biofilm polymer surfaces specifically targeting S. mutans. To achieve this, a known GTF inhibitor (G43) was modified with methoxy or tetraethyleneglycol substitutions in different positions (nine derivatives, tested at 50-µM) to pinpoint potential sites for future methacrylate functionalization, and then assessed against single-species S. mutans biofilms. As expected, the compounds did not diminish the bacterial viability. In general, the compounds with methoxy substitution were not effective in reducing EPS formation, whereas the tetraethyleneglycol substitution (G43-C3-TEG) led to a decrease in the concentration of insoluble EPS, although the effect is less pronounced than for the parent G43. This aligns with the reduced GTF-C activity observed at different concentrations of G43-C3-TEG, as well as the consequent decrease in EPS formation, and notable structural changes. In summary, this study determined that G43-C3-TEG is non-bactericidal and can selectively reduce the biofilm formation, by decreasing the production of EPS. This molecule will serve to functionalize surfaces of materials to be tested in future research.

Erratum: Single-center developing country analysis of radium-223 therapy in prostate cancer-preliminary results.

[This corrects the article on p. 352 in vol. 11, PMID: 34754606.].

Single-center developing country analysis of radium-223 therapy in prostate cancer-preliminary results.

We reviewed the records of mCRPC patients treated with off-label use of Ra-223. Ra-223 efficiency in this non-study population was correlated to outcome measures overall survival (OS), progression-free survival (PFS), bone event-free survival, bone marrow failure (BMF), and disease-related biomarkers. There were no limits regarding the number of prior hormonal agents or chemotherapy received before or during Ra-223. Exclusion criteria consisted of baseline platelet counts below 50,000/mm3 and/or absolute neutrophil counts below 1,500/mm3. Twenty-eight patients received 130 cycles of Ra-223 between 2017 and 2018. The overall median OS was 15.6 months. However, in patients submitted to 4 or fewer cycles, the median OS was 9.1 months; in contrast, the median OS was 18.5 months in patients submitted to 5 or 6 cycles. There was a significant inverse correlation between the number of cycles and the occurrence of bone events (76.2% of the patients that completed 6 cycles did not present bone events, while 71.4% of the patients that had skeletal-related events were submitted to less than 6 cycles). 82.1% of the patients were submitted to concomitant therapies with no significant side effects. There was also a decrease in ALP and LDH levels throughout treatment. Radium-223 increased OS and decreased bone events, especially when patients were able to complete 5-6 cycles. The proper selection of patients is crucial to improve outcomes.

Associação terapêutica conservadora para o tratamento das manchas de fluorose dental / Conservative treatment therapy for dental fluorosis staining

O excesso de ingestão de flúor durante o desenvolvimento do órgão dental pode resultar em alterações estruturais tanto em esmalte quanto em dentina. No esmalte, observa-se um aumento de porosidades causadas pela interação do flúor com os prismas em desenvolvimento, tanto na superfície quanto em profundidade. Clinicamente essas alterações são visíveis como manchas com aspecto que vai do branco opaco ao amarelo amarronzado. A presença de manchas no esmalte dental leva ao comprometimento estético do sorriso tão valorizado atualmente. Para a homogeinização de cor, nos casos mais brandos, recomenda-se a realização do tratamento clareador com agentes oxidantes de baixa concentração (clareamento caseiro). Em casos mais severos a associação do clareamento caseiro com o procedimento de microabrasão é indicada para remoção das manchas de fluorose. Na microabrasão, o uso simultâneo da abrasão e da erosão ácida é capaz de remover as manchas decorrentes de alterações superficiais em esmalte. Portanto, utilizando tratamentos conservadores é possível devolver a autoestima do paciente de forma bastante satisfatória.

The excess fluoride intake during dental organ development may result structural changes in enamel and dentin. Increase porosity was observed by fluorine interaction with enamel prisms development, both on surface and in depth. Clinically these changes are visible as spots with aspect that goes from opaque white to brownish yellow. The enamel spots leads to unpleasant smile. In mild cases, for color homogenization, it is recommended bleaching treatment with low concentration oxidizing agents (home bleaching). In more severe cases, the home bleaching and microabrasion procedure association are indicated for fluorosis stains removal. In microabrasion, the association of abrasion and acid erosion remove stains from changes on enamel surface. Thus conservative treatments can successfully restore patient's self- esteem.

Polymerization development of "low-shrink" resin composites: Reaction kinetics, polymerization stress and quality of network.

OBJECTIVES: To evaluate "low-shrink" composites in terms of polymerization kinetics, stress development and mechanical properties. METHODS: "Low-shrink" materials (Kalore/KAL, N'Durance/NDUR, and Filtek P90/P90) and one control (Esthet X HD/EHD) were tested. Polymerization stress (PS) was measured using the Instron 5565 tensometer. Volumetric shrinkage (VS) was determined by the ACTA linometer. Elastic modulus (E) and flexural strength (FS) were obtained by a three-point bending test. Degree of conversion (DC) and polymerization rate (Rp) were determined by NIR spectroscopy (6165cm(-1) for dimethacrylates; 4156 and 4071cm(-1) for P90). Photopolymerization was performed at 740mW/cm(2)×27s. Glass transition temperature (Tg), degree of heterogeneity and crosslink density were obtained in a DMA for the fully cured specimens. Analysis of extracts was done by (1)H NMR. Data were analyzed with one-way ANOVA/Tukey's test (α=0.05). RESULTS: The control presented the highest shrinkage and Tg. P90 showed the highest modulus, and NDUR demonstrated the highest conversion. The polymerization rates were comparable for all materials. NDUR and KAL had the highest and the lowest network homogeneity, respectively. The multifunctional P90 had the highest crosslink density, with no difference between other composites. The control had the greatest stress development, similar to NDUR. Crosslinking density and polymer network homogeneity were influenced by degree of conversion and monomer structure. SIGNIFICANCE: Not all "low-shrink" composites reduced polymerization stress. P90 and NDUR had no leachable monomers, which was also a function of high crosslinking (P90) and high conversion (NDUR).