In-vitro evaluation of the anti-cariogenic effect of a hybrid coating associated with encapsulated sodium fluoride and stannous chloride in nanoclays on enamel

Objective: The aim of this study is to test, in vitro, the anti-cariogenic effect of experimental hybrid coatings, with nano clays of halloysite or bentonite, loaded with sodium fluoride or with a combination of sodium fluoride and stannous chloride, respectively. Methodology: The varnish Fluor Protector (1,000 ppm of F-) was used as positive control and no treatment was the negative control. Enamel specimens (5 mm × 5 mm) were obtained from bovine teeth. The specimens (n=10) had their surfaces divided into two halves (5 mm × 2.5 mm each), in which one half received one of the treatments (Hybrid; Hybrid + NaF; Hybrid + NaF + SnCl2; Hybrid + NaF Loaded; Hybrid + NaF + SnCl2 Loaded). The specimens were submitted to a cariogenic challenge using a biofilm model (S. mutans UA159, for 5 days). Enamel surfaces both under and adjacent to the treated area were analyzed for mineral loss and lesion depth, by transverse microradiography. The pH of the medium was measured twice a day, and the fluoride release was analyzed. Additional specimens were submitted to confocal analysis. Results: Data were statistically analyzed by two-way ANOVA followed by Tukey test (α=0.05). None of hybrid groups were able to reduce the lesion depth; the Hybrid + NaF group, however, was able to reduce mineral loss differing from the negative control (p=0.008). The groups showed no significant difference in the pH measurement and fluoride release. Confocal analysis confirmed that for all groups the biofilm growth was similar. Conclusion: None of the hybrid groups reduced lesion depth, but the Hybrid + NaF group was able to promote protection against mineral loss

Longitudinal assessment of dental erosion-abrasion by cross-polarization optical coherence tomography in vitro

Abstract: This study tested a novel in vitro dental erosion-abrasion model and the performance of cross-polarization optical coherence tomography (CP-OCT) in longitudinally monitoring the simulated lesions. Thirty human enamel specimens were prepared and randomized to receive three dental erosion-abrasion (EA) protocols: severe (s-EA, lemon juice/pH:2.5/4.25%w/v citric acid), moderate (m-EA, grapefruit juice/pH:3.5/1.03%w/v citric acid) and no-EA (water, control). EA challenge was performed by exposing the specimens to acidic solutions 4x/day and to brushing 2x/day with 1:3 fluoridated toothpaste slurry, for 14 days. Enamel thickness measurements were obtained using CP-OCT at baseline (D0), 7 (D7) and 14 days (D14) and micro-computed tomography (micro-CT) at D14. Enamel surface loss was measured with both CP-OCT and optical profilometry at D0, D7 and D14. Data was analyzed with repeated-measures ANOVA and Pearson's correlation (r) (α = 0.05). CP-OCT enamel thickness decreased over time in the s-EA group (D0 >D7 > D14, p D14, p = 0.019) but did not change in the no-EA group (p = 0.30). Overall, CP-OCT and micro-CT results at D14 correlated moderately (r = 0.73). CP-OCT surface loss was highest for s-EA (p m-EA>s-EA, p < 0.001). D14 surface loss was higher than D7 for both methods except for the no-EA group with profilometry. CP-OCT and profilometry had moderate overall correlation (r = 0.70). Our results revealed that the currently proposed in vitro dental erosion-abrasion model is valid and could simulate lesions of different severities over time. CP-OCT was a suitable method for monitoring the EA lesions

Catálogo Taxonômico da Fauna do Brasil: setting the baseline knowledge on the animal diversity in Brazil

The limited temporal completeness and taxonomic accuracy of species lists, made available in a traditional manner in scientific publications, has always represented a problem. These lists are invariably limited to a few taxonomic groups and do not represent up-to-date knowledge of all species and classifications. In this context, the Brazilian megadiverse fauna is no exception, and the Catálogo Taxonômico da Fauna do Brasil (CTFB) (http://fauna.jbrj.gov.br/), made public in 2015, represents a database on biodiversity anchored on a list of valid and expertly recognized scientific names of animals in Brazil. The CTFB is updated in near real time by a team of more than 800 specialists. By January 1, 2024, the CTFB compiled 133,691 nominal species, with 125,138 that were considered valid. Most of the valid species were arthropods (82.3%, with more than 102,000 species) and chordates (7.69%, with over 11,000 species). These taxa were followed by a cluster composed of Mollusca (3,567 species), Platyhelminthes (2,292 species), Annelida (1,833 species), and Nematoda (1,447 species). All remaining groups had less than 1,000 species reported in Brazil, with Cnidaria (831 species), Porifera (628 species), Rotifera (606 species), and Bryozoa (520 species) representing those with more than 500 species. Analysis of the CTFB database can facilitate and direct efforts towards the discovery of new species in Brazil, but it is also fundamental in providing the best available list of valid nominal species to users, including those in science, health, conservation efforts, and any initiative involving animals. The importance of the CTFB is evidenced by the elevated number of citations in the scientific literature in diverse areas of biology, law, anthropology, education, forensic science, and veterinary science, among others

Relação maxilomandibular em desdentado total : aspectos neurofisiológicos

Para a confecção de uma prótese total dentro de princípios neurofisiológicos, diversos fatores são determinantes. Dentre estes, um dos principais e que necessita da maior atenção do profissional é a obtenção de uma dimensão vertical de oclusão correta, pois é esta medida que ditará o restabelecimento correto e satisfatório do sistema estomatognático e consequentemente, das funções de fonação, mastigação e deglutição, além de proporcionar uma estética agradável. A musculatura exerce uma grande influência na relação entre maxila e a mandíbula tanto no que concerne ao plano vertical, como ao sagital e horizontal. Assim o aparelho oclusal plano é essencial para definir a correta relação maxilo mandibular, já que além de aumentar a dimensão da face e eliminar interferências oclusais, esse dispositivo promove uma leve distensão dos músculos que estão em sobrecarga funcional. Para se determinar a dimensão vertical, tanto em dentados como em desdentados, existem diferentes técnicas. Antigamente o que se preconizava na reabilitação de pacientes com perda de DVO era a reabilitação seguindo a DVR já que se acreditava que essa era imutável, mas estudos atuais mostram que essa distancia é mutável. A reprodução inadequada da dimensão vertical provoca diversas alterações morfológicas e funcionais nas articulações, dor, entre outras. Assim sendo, é extremamente importante o correto restabelecimento da relação maxilomandibular, onde o melhor método é a associação entre no mínimo duas técnicas, sempre respeitando a individualidade de cada paciente. E sendo ideal em desdentados totais, a utilização de aparelho oclusal liso e plano, pois ele definirá uma relação maxilomandibular mais adequada.For making a denture within neurophysiological principles, several factors are decisive. Among these, one of the leading and needs the most attention of the professional is to obtain a correct vertical dimension of occlusion, it is this measure that will dictate the correct and satisfactory restoration of stomatognathic system and consequently the functions of speech, mastication and swallowing, and provide a pleasing esthetic. The musculature exerts a great influence on the relationship between maxilla and mandible both in relation to the vertical plane as the sagittal and horizontal. So the plan occlusal appliance is essential to define the correct maxillomandibular relationship, as well as increasing the size of the face and eliminate occlusal interference, this device promotes a slight stretching of muscles that are functional overload. To determine the vertical dimension, both toothed and toothless in, different techniques. Previously what is advocated in the rehabilitation of patients with loss of OVD was rehabilitation following the VDR since it was believed that this was immutable, but current studies show that this distance is changeable. Inadequate reproduction of the vertical dimension causes morphological and functional changes in the joints, pain, among others. Therefore, it is extremely important to the correct restoration of maxillomandibular relationship, where the best method is the combination of at least two techniques, always respecting the individuality of each patient. And being perfect edentulous, the use of smooth, flat occlusal appliance, because it sets a more appropriate maxillomandibular relationship

Evaluation of the anti-erosive effect of solutions containing sodium fluoride, tin chloride and some film-forming copolymers

A erosão é um processo que resulta na perda superficial dos tecidos duros dentários pela ação de ácidos não bacterianos. A associação de copolímeros formadores de filme com produtos fluoretados pode ser uma estratégia promissora na prevenção da erosão. O objetivo deste estudo foi avaliar o efeito anti-erosivo de soluções contendo fluoreto de sódio (F: 225 ppm F-), cloreto de estanho (Sn: 800 ppm Sn2+), copolímeros formadores de filme (Gantrez, PGA, Plasdone e CMC) e algumas de suas combinações. A água deionizada foi utilizada como controle negativo. As soluções foram testadas em um modelo de erosão-remineralização, utilizando espécimes de esmalte e dentina, obtidos de incisivos bovinos (n=10 para cada substrato). A ciclagem consistia de imersão em saliva humana por 2 h, para permitir a formação da película adquirida, imersão em solução de ácido cítrico a 0,3% (pH=2,6), por 5 min, seguida de 120 min de exposição em saliva humana clarificada. Esse procedimento foi repetido 4 vezes ao dia, por 5 dias. O tratamento com as soluções teste foi realizado 2 vezes ao dia, 60 min após o primeiro e o último desafios erosivos, por 2 min. A perda superficial dos espécimes (PS, em ?m) foi avaliada com um perfilômetro ótico e dados submetidos aos testes de ANOVA a 2 fatores e Tukey (?=0,05). Em esmalte, todos os copolímeros isoladamente exibiram uma menor PS quando comparados com a água, com exceção do PGA. Todas as soluções contendo F apresentaram menor PS em relação ao controle. O PGA foi o único copolímero capaz de melhorar o efeito protetor do F. Nenhum dos copolímeros foi capaz de melhorar o efeito protetor do F+Sn. Para dentina, isoladamente, apenas o Gantrez reduziu significativamente a PS quando comparado ao controle. Apesar de todas as soluções contendo F apresentarem menor PS em relação a água, nenhum copolímero foi capaz de potencializar o efeito das soluções contendo F ou F+Sn.Erosive tooth wear is a process that results in the loss of dental hard tissues, caused by non-bacterial acids. The association between film-forming agents with fluoride products can be a promising strategy to prevent erosion. The aim of this study is to evaluate the anti-erosive effect of solutions containing sodium fluoride (225 ppm F-), stannous chloride (800 ppm Sn2+), film-forming copolymers (Gantrez, PGA, Plasdone and CMC), and combinations thereof. Deionized water was used as a negative control. The solutions were tested in an erosion-remineralization cycling model, using enamel and dentin specimens obtained from bovine incisors (n=10 for each substrate). Cycling consisted of 2 h immersion in human saliva to allow the formation of the salivary acquired pellicle, immersion in 0.3% citric acid solution (pH = 2.6) for 5 min, followed by 120 min of exposure to clarified human saliva. This procedure was repeated 4 times a day, for 5 days. Treatment with test solutions was carried out 2 times a day, 60 min after the first and last erosive challenges, for 2 min. Surface loss (SL, in ?m) was evaluated with an optical profilometer, and data were submitted to 2-way Anova and Tukey tests (? = 0.05). In enamel, all copolymers alone showed lower SL than water, except for PGA. All solutions containing F presented less SL in relation to the control. PGA was the only copolymer capable of improving the protective effect of F. None of the copolymers was able to increase the protection of F + Sn. For dentin, only Gantrez significantly reduced SL when compared to the water. Although all solutions containing F demonstrated less SL compared to control, no copolymer was able to enhance the effect of the solutions containing F or F+Sn

Effect of experimental coating with sodium fluoride and stannous chloride on erosive tooth wear

Esse estudo teve os seguintes objetivos: 1. Formular uma película híbrida e testar o seu efeito contra erosão e erosão-abrasão em esmalte e dentina; 2. Modificar essa película com a adição de fluoreto e estanho, encapsulados ou não, e testar os seus efeitos no desgaste dental erosivo. A retenção da película híbrida ao substrato dentário foi testada e sua presença avaliada em Microscopia Eletrônica de Varredura (MEV). Depois, foi realizada a aditivação dessa película com fluoreto de sódio (15.000 ppm de F-) ou fluoreto de sódio mais cloreto de estanho (10.000 ppm de Sn2+). A aditivação foi realizada de maneira direta ou encapsulada. A quantidade de fluoreto e de estanho liberada pelas nano cápsulas (argilas haloisita e bentonita, respectivamente), em meio ácido (ácido cítrico 0,3%, pH=2,6) e meio neutro (saliva artificial), foi avaliada por meio de eletrodo seletivo de F- e espectrometria de emissão atômica, respectivamente, após imersão por 1, 3, 5, 12, 24 e 48 h. Em seguida, espécimes de esmalte e dentina, obtidos de incisivos bovinos, foram submetidos aos tratamentos e testados em uma ciclagem erosão e erosão-abrasão (n=10 para cada substrato, para cada ciclagem). A água deionizada foi utilizada como controle negativo e um verniz fluoretado (Flúor Protector, 1000 ppm F-) como positivo. A ciclagem erosiva consistiu em 5 min de imersão em ácido cítrico a 0,3%, seguido de 60 min de remineralização em saliva artificial, 4 vezes ao dia, por 5 dias. Para a ciclagem de erosão-abrasão, o mesmo protocolo foi seguido, porém, os espécimes foram escovados em uma máquina de escovação, após o primeiro e último desafios erosivos, com uma suspensão de dentifrício fluoretado e água (1:3), por 15 s (45 movimentos), com 2 min de exposição total à suspensão. Ao final do experimento, a perda superficial dos espécimes (em µm) foi avaliada em perfilômetro ótico. Os dados foram submetidos aos testes de Kruskal-Wallis, Dunn e Mann-Whitney (?=0,05). Na MEV, foi possível observar a presença da película sobre os substratos dentários. As argilas conseguiram armazenar os compostos, apresentando uma maior liberação de F- e Sn2+ em meio ácido em relação ao meio neutro em todos os tempos. No modelo de erosão, para o esmalte, os grupos película híbrida sem aditivos e o controle positivo, apresentaram significativamente menor perda superficial do que o controle negativo (p0,05). Para dentina, todos os as películas híbridas testadas e o controle positivo apresentaram significativamente menor perda superficial do que o controle negativo (p0,05). Para o modelo de erosão-abrasão, nenhum grupo apresentou perda superficial significativamente menor do que controle negativo, para ambos substratos. A película híbrida foi capaz de se aderir aos substratos dentários e de protegê-los contra erosão, independente da sua aditivação. Entretanto, nenhum dos aditivos testados foi eficaz no controle do desgaste dental erosivo no esmalte e na dentina.The aims of this study were: 1. To formulate a hybrid coating and test its effect against enamel and dentin erosion and erosion-abrasion; 2. To modify the hybrid coating with the addition of fluoride and stannous, encapsulated or not, and thereafter test their effects against erosion and erosion-abrasion. The retention of the hybrid film to the dental substrate was evaluated by Scanning Electron Microscopy (SEM). Then, sodium fluoride (15,000 ppm F) or sodium fluoride plus tin chloride (10,000 ppm Sn) were added on the polymeric film. The addition of the agents was performed by direct or encapsulated means. The amounts of fluorine and tin chloride released by the nanocapsules (halloysite and bentonite, respectively), in acidic (citric acid 0.3%, pH=2.6) and neutral media, were evaluated by an ion selective electrode and atomic emission spectrometry, respectively, 1, 3, 5, 12, 24 and 48 h after immersion. Then, the enamel and dentin specimens, obtained from bovine incisors, were subjected to the treatments and tested in erosion and erosion-abrasion cycling models (n = 10 for each substrate, for each model). Deionized water was used as a negative control and a fluoride varnish (Fluor Protector, 1000 ppm F-) was used as positive control. Erosive cycling consisted of 5 min of immersion in 0.3% citric acid (pH = 2.6), followed by 60 min of remineralization in artificial saliva, 4 times a day for 5 consecutive days. For the erosion-abrasion cycling, the same protocol was used, however, the specimens were brushed on a brushing machine after the first and last erosive challenges with a fluoridated toothpaste and water slurry (1:3) for 15 sec (45 strokes), with 2 min total suspension exposure. At the end of the cycling, the tooth surface loss (in µm) was evaluated by optical profilometry. Data were analyzed by Kruskall-Wallis, Dunn and Mann-Whitney tests (?=0.05). The SEM analysis showed the presence of the hybrid coating as a film over the dental substrates. The clays were able to store the antierosive agents, presenting a greater release of F- and Sn2+ in acid medium in relation to the neutral one, at all times. For enamel, in the erosion model, the hybrid coating and positive control showed significantly less SL than negative control (p0.05). For dentin, all the hybrid coatings tested and the positive control showed significantly less surface loss than the negative control (p 0.05). For the erosion-abrasion model, none of the groups showed significantly lower SL than negative control, for both substrates. The hybrid coating was able to adhere to dental substrate and protect them from erosion, regardless of the addition of the agents. However, none of the treatments tested was effective on protection of erosive tooth wear on enamel and dentin

Produtos clareadores de venda livre: : uma revisão de literatura

Aim: To review the literature regarding the effects of over-the-counter (OTC) dental whitening products available in the Brazilian market. Literature review: PubMed, Scielo, and Google Scholar databases were consulted, along with a manual reference search. The relentless pursuit of the perfect smile has led to an increased demand for aesthetic procedures, such as dental whitening, recommended by dentists due to their proven safety and efficacy. However, amid the demand for more affordable alternatives that do not require professional supervision, over-the-counter whitening products have emerged in the market as alternative options to professional whitening. Discussion: The prevalence of laboratory studies highlights that the efficacy of OTC products differs from professional treatments. Whitening toothpaste containing peroxide demonstrates effectiveness in reducing extrinsic stains, with wear similar to or lower than regular toothpaste, depending on the evaluated substrate. On the other hand, whitening mouthwashes show limited evidence of efficacy compared to products with higher concentrations of peroxide. Home remedies and natural whitening products have proven ineffective compared to professional treatments, raising concerns about their safety due to the potential for causing irreversible damage to dental structure. Activated charcoal lacks whitening effects, has potential abrasiveness, and causes staining on the oral mucosa. Conclusion: Although OTC whitening products may be appealing for their autonomy, they generally do not demonstrate significant efficacy. Their use should be recommended with caution, preferably under professional guidance. Emphasizing the importance of continuous education, dentists should stay abreast of trends in this field.Objetivo: Revisar a literatura quanto aos efeitos dos produtos de venda livre destinados ao clareamento dental disponíveis no mercado brasileiro. Revisão de literatura: Foram consultadas as bases de dados PubMed, Scielo e Google Scholar, além de busca manual de referências. A incessante busca pelo sorriso perfeito aumenta a procura por procedimentos estéticos, como o clareamento dental, recomendado por cirurgiões-dentistas devido à sua segurança e eficácia comprovadas. Contudo, em meio à demanda por alternativas mais acessíveis e que dispensem o acompanhamento profissional, surgiram no mercado os produtos clareadores de venda livre ou OTC (do inglês over-the-counter), que são opções alternativas ao clareamento profissional. Discussão: A predominância de estudos laboratoriais destaca que a eficácia dos produtos OTC difere dos tratamentos profissionais. Os dentifrícios branqueadores contendo peróxido demonstram eficácia na redução de manchas extrínsecas, com desgaste semelhante ou inferior aos dentifrícios regulares, dependendo do substrato avaliado. Já os enxaguatórios clareadores apresentam evidências limitadas de eficácia em comparação aos produtos de concentrações mais elevadas de peróxido. As receitas caseiras e produtos naturais para clareamento dental mostraram-se ineficazes em comparação aos tratamentos profissionais, levantando preocupações sobre sua segurança devido ao potencial de causar danos irreversíveis à estrutura dental. O carvão ativado não possui efeito clareador, apresenta potencial abrasivo e causa manchamento em mucosa bucal. Conclusão: Produtos clareadores OTC, embora atrativos pela autonomia oferecida, não demonstram, em sua maioria, eficácia significativa, devendo seu uso ser recomendando com cautela, preferencialmente com orientação profissional. Salienta-se a importância da educação contínua para que cirurgiões-dentistas acompanhem as tendências nesse campo

The Addition of Propylene Glycol Alginate to a Fluoride Solution to Control Enamel Wear: An in situ Study.

The aim of this study was to evaluate the protective effect of propylene glycol alginate (PGA) associated with sodium fluoride (NaF) against enamel erosion and erosion-abrasion. A 4-phase, split-mouth, double-blind, crossover in situ trial was conducted with the following solutions: F + PGA (225 ppm F- + 0.1% PGA), F (225 ppm F-), F + Sn (225 ppm F- + SnCl2, 800 ppm Sn2+), and negative control (distilled water). In each phase, 12 subjects wore removable mandibular appliances containing 4 enamel specimens, which were submitted either to erosion or to erosion-abrasion challenges for 5 days. Acquired salivary pellicle was formed in situ for 2 h. Erosion-abrasion consisted of acid challenge (1% citric acid solution, pH 2.3, 5 min, 4×/day), exposure to saliva in situ (2 h, 4×/day), brushing (5 s, total 2 min exposure to the slurry), and treatment with the solutions (2 min, 2×/day). For erosion, the same procedures were performed, without brushing. At the end, surface loss (SL; in μm) was evaluated by means of optical profilometry. KOH-soluble fluoride was quantified for erosion-only groups using extra specimens. For both challenges, the SL values found for F + PGA did not differ significantly from those of F and the negative control, and the SL value shown for F + Sn was significantly the lowest. Erosion-abrasion promoted significantly higher SL values than erosion. KOH-soluble fluoride analysis showed that F + Sn had a higher fluoride concentration in comparison with the negative control and F, while F + PGA did not differ from any of the other groups. In conclusion, PGA was not able to improve the protective effect of NaF against erosive enamel wear

Film-Forming Polymers for Inhibition of Hydroxyapatite Dissolution: A Screening Study.

The aim of this study was to evaluate the effect of film-forming polymer solutions of different concentrations and pH values, either associated or not with sodium fluoride (F; 225 ppm F-), when applied during the initial stage of salivary pellicle formation, to prevent the dissolution of hydroxyapatite (HA), which was determined by the pH-stat method. Polyacrylic acid (PA), chitosan, sodium linear polyphosphate (LPP), polyvinyl methyl ether/maleic anhydride (PVM/MA), and propylene glycol alginate (PGA) were tested in three concentrations (lower, medium, and higher), two pH values (native or adjusted), and either associated or not with F. Distilled water, F, and stannous ion+fluoride (Sn/F; 225 ppm F- and 800 ppm Sn2+, as SnCl2) solutions were the controls, totalizing 63 groups. HA crystals were pretreated with human saliva for 1 min to allow pellicle formation, then immersed in the experimental solutions (1 min), and exposed to saliva for another 28 min. Subsequently, they were added to a 0.3% citric acid solution (pH = 3.8), connected to a pH-stat system that added aliquots of 28 μL 0.1 N HCl for a total reaction time of 5 min. Data were analyzed with one-way ANOVA and Tukey's tests (α = 0.05). For PA alone, the concentrations of 0.1% (native pH), 0.06%, and 0.08% (both pH adjusted) showed significantly lower HA dissolution than the negative control. PA concentrations of 0.1% and 0.08%, of both pH values, improved the effect of F against HA dissolution to a near-identical value as Sn/F. All solutions containing chitosan and LPP significantly reduced HA dissolution in comparison with the control. For chitosan, the concentration of 0.5% (in both pH values) improved the effect of F. LPP at 0.5% (native pH) and all associations of LPP with F outperformed the effect of F. Some PVM/MA solutions significantly reduced HA dissolution but PVM/MA could not improve the protection of F. PGA was incapable of reducing HA dissolution or improving F effect. It was concluded that chitosan, LPP, and some PA and PVM/MA solutions used alone were capable of reducing HA dissolution. Only PA, chitosan, and LPP were able to enhance fluoride protection, but for PA and chitosan, this was influenced by the polymer concentration