Evaluation of Ilex guayusa and Piper marginatum Extract Cytotoxicity on Human Dental Pulp Mesenchymal Stem Cells.

BACKGROUND: Amelogenesis imperfecta is a hereditary disorder affecting dental enamel. Among its phenotypes, hypocalcified AI is characterized by mineral deficiency, leading to tissue wear and, consequently, dental sensitivity. Excessive fluoride intake (through drinking water, fluoride supplements, toothpaste, or by ingesting products such as pesticides or insecticides) can lead to a condition known as dental fluorosis, which manifests as stains and teeth discoloration affecting their structure. Our recent studies have shown that extracts from Colombian native plants, Ilex guayusa and Piper marginatum, deposit mineral ions such as phosphate and orthophosphate into the dental enamel structure; however, it is unknown whether these extracts produce toxic effects on the dental pulp. OBJECTIVE: To assess cytotoxicity effects on human dental pulp stem cells (hDPSCs) exposed to extracts isolated from I. guayusa and P. marginatum and, hence, their safety for clinical use. METHODS: Raman spectroscopy, fluorescence microscopy, and flow cytometry techniques were employed. For Raman spectroscopy, hDPSCs were seeded onto nanobiochips designed to provide surface-enhanced Raman spectroscopy (SERS effect), which enhances their Raman signal by several orders of magnitude. After eight days in culture, I. guayusa and P. marginatum extracts at different concentrations (10, 50, and 100 ppm) were added. Raman measurements were performed at 0, 12, and 24 h following extract application. Fluorescence microscopy was conducted using an OLIMPUS fv1000 microscope, a live-dead assay was performed using a kit employing a BD FACS Canto TM II flow cytometer, and data analysis was determined using a FlowJo program. RESULTS: The Raman spectroscopy results showed spectra consistent with viable cells. These findings were corroborated using fluorescence microscopy and flow cytometry techniques, confirming high cellular viability. CONCLUSIONS: The analyzed extracts exhibited low cytotoxicity, suggesting that they could be safely applied on enamel for remineralization purposes. The use of nanobiochips for SERS effect improved the cell viability assessment.

Amorphous calcium phosphate, the lack of order is an abundance of possibilities.

For almost three decades from its discovery, amorphous calcium phosphate (ACP) was not considered a suitable biomaterial due to its structural instability. Thanks to its unique properties in respect to crystalline calcium phosphate phases, nowadays ACP is used in promising devices for hard tissue regeneration. Here we have highlighted the features of ACP that were harnessed to create excellent biomaterials for dental remineralization, self-setting bone cements, drug delivery, and coatings of prostheses. Its current limitations as well as future perspectives of development were concisely described. Despite more research works are needed, we envisage that the future of ACP is bright.

Potencial remineralizante de una saliva sintética: estudio in vitro / Remineralizing potential of synthetic saliva: an in vitro study / Potencial remineralizador de uma saliva sintética: um estudo in vitro

RESUMEN Objetivo : Evaluar el efecto remineralizante de una saliva sintética en el esmalte dental bovino erosionado. Materiales y métodos : Se prepararon 50 bloques de esmalte de dientes de bovino. Las muestras fueron divididas en 5 grupos de estudio según el tratamiento: grupo A (Colgate Total®, pasta de dientes que contiene fluoruro), grupo B (MI Paste Plus®, pasta de dientes que contiene fosfopéptido de caseína-fosfato de calcio amorfo [CPP-ACP] con fluoruro), grupo C (Salival® Solución, saliva sintética), grupo D (agua destilada) y grupo E (sin tratamiento). Todos los especímenes de los grupos A, B, C y D recibieron ataques con ácido cítrico al 0,5 % durante 2 minutos a las 0, 8, 24 y 32 horas. Después de cada ataque ácido, se aplicaron las pastas de dientes correspondientes a cada grupo de tratamiento. Luego se procedió a evaluar el grado de mineralización mediante microscopía Raman y la microdureza superficial mediante microdureza Vickers. Resultados : Respecto al grado de mineralización y la dureza superficial, no se encontraron diferencias significativas (p > 0,05) en el esmalte dental bovino erosionado tratado con Colgate Total®, MI Paste Plus® y Salival® Solución en comparación con las muestras de esmalte sano; sin embargo, todas presentaron un grado de mineralización y dureza superficial significativamente mayor que las muestras de esmalte de dientes bovinos erosionados conservados en agua destilada (p < 0,05). Conclusión : Este estudio in vitro muestra que la saliva sintética Salival® Solución tiene un potencial remineralizante en el esmalte bovino erosionado.

ABSTRACT Objective : To evaluate the remineralizing effect of synthetic saliva on eroded bovine dental enamel. Materials and methods : 50 enamel blocks were prepared from bovine teeth. The specimens were divided into 5 study groups according to treatment: group A (Colgate Total®, toothpaste containing fluoride), group B (MI Paste Plus®, toothpaste containing casein phosphopeptide, amorphous calcium phosphate [CPP-ACP] with fluoride), group C (Salival® Solution, synthetic saliva), group D (distilled water) and group E (no treatment). All specimens in groups A, B, C and D received 0.5% citric acid attacks for 2 minutes at 0, 8, 24 and 32 hours. After each acid attack, toothpastes corresponding to each treatment group were applied. The degree of mineralization was then evaluated by Raman microscopy and surface microhardness by Vickers microhardness. Results : Regarding the degree of mineralization and surface hardness, no significant differences (p > 0.05) were found in the eroded bovine tooth enamel treated with Colgate Total®, Mi Paste Plus® and Salival® Solution in comparison with the healthy enamel samples. But all presented a significantly higher degree of mineralization and surface hardness than the eroded bovine tooth enamel samples preserved in distilled water (p < 0.05). Conclusion : This in vitro study shows that the synthetic saliva Salival® Solution has a remineralizing potential on eroded bovine enamel.

RESUMO Objetivo : Avaliar o efeito remineralizante de uma saliva sintética no esmalte dentário bovino erodido. Materiais e métodos : Foram preparados 50 blocos de esmalte de dentes de bovinos. As amostras foram divididas em 5 grupos de estudo de acordo com o tratamento: grupo A (Colgate Total®, pasta dentífrica contendo flúor), grupo B (MI Paste Plus®, pasta dentífrica contendo fosfopeptídeo de caseína, fosfato de cálcio amorfo [CPP-ACP] com flúor), grupo C (Salival® Solution, saliva sintética), grupo D (água destilada) e grupo E (sem tratamento). Todos os espécimes dos grupos A, B, C e D receberam um ataque ácido cítrico a 0,5% durante 2 minutos às 0, 8, 24 e 32 horas. Após cada ataque ácido, foram aplicadas as pastas dentífricas correspondentes a cada grupo de tratamento. O grau de mineralização foi então avaliado por microscopia Raman e a microdureza superficial por microdureza Vickers. Resultados : Relativamente ao grau de mineralização e à dureza da superfície, não foram encontradas diferenças significativas (p > 0,05) no esmalte dentário bovino erodido tratado com Colgate Total®, Mi Paste Plus® e Salival® Solution em comparação com as amostras de esmalte saudável. Mas todos mostraram um grau significativamente mais elevado de mineralização e dureza superficial do que as amostras de esmalte de dentes de bovinos erodidos preservados em água destilada (p < 0,05). Conclusão : Este estudo in vitro mostra que a saliva sintética Salival® Solution tem um potencial remineralizante no esmalte bovino erodido.

Biomimetic Tooth Repair: Amelogenin-Derived Peptide Enables in Vitro Remineralization of Human Enamel.

White spot lesions (WSL) and incipient caries on enamel surfaces are the earliest clinical outcomes for demineralization and caries. If left untreated, the caries can progress and may cause complex restorative procedures or even tooth extraction which destroys soft and hard tissue architecture as a consequence of connective tissue and bone loss. Current clinical practices are insufficient in treating dental caries. A long-standing practical challenge associated with demineralization related to dental diseases is incorporating a functional mineral microlayer which is fully integrated into the molecular structure of the tooth in repairing damaged enamel. This study demonstrates that small peptide domains derived from native protein amelogenin can be utilized to construct a mineral layer on damaged human enamel in vitro. Six groups were prepared to carry out remineralization on artificially created lesions on enamel: (1) no treatment, (2) Ca2+ and PO43- only, (3) 1100 ppm fluoride (F), (4) 20 000 ppm F, (5) 1100 ppm F and peptide, and (6) peptide alone. While the 1100 ppm F sample (indicative of common F content of toothpaste for homecare) did not deliver F to the thinly deposited mineral layer, high F test sample (indicative of clinical varnish treatment) formed mainly CaF2 nanoparticles on the surface. Fluoride, however, was deposited in the presence of the peptide, which also formed a thin mineral layer which was partially crystallized as fluorapatite. Among the test groups, only the peptide-alone sample resulted in remineralization of fairly thick (10 µm) dense mineralized layer containing HAp mineral, resembling the structure of the healthy enamel. The newly formed mineralized layer exhibited integration with the underlying enamel as evident by cross-sectional imaging. The peptide-guided remineralization approach sets the foundation for future development of biomimetic products and treatments for dental health care.

Efeito de dentifrícios com alta concentração de flúor na remineralização de substrato dentário com cárie artificial / Effect of toothpaste with high fluoride concentration on remineralization of dental substrate with artificial caries

Introduction: fluoride toothpaste is widely used by the population. Objective: dentifrices with a high concentration of sodium fluoride and the presence of tricalcium phosphate were developed, providing additional protection to patients vulnerable to the development of caries. This study aimed to evaluate the influence of different dentifrices on the surface and internal hardness and enamel wear after artificial caries, pH cycling, and toothbrushing. Material and method: enamel blocks (4x4 mm) were obtained from 20 bovine teeth. The specimens were submitted to artificial caries lesion and then to pH cycling and brushing according to the dentifrice: Colgate Total 12 and Clinpro + Tricalcium Phosphate. Result: after this period, they were submitted to analysis of superficial and internal hardness and profilometry. Scanning Electron Microscopy (SEM) was performed. The data obtained were evaluated by one-way Analysis of Variance (ANOVA) to evaluate the mineral recovery and profilometry, and two-way repeated measures ANOVA to evaluate the superficial and internal hardness. Conclusion: analyzing the surface hardness, after caries induction, there was a significant reduction in hardness that was partially recovered regardless of the dentifrice used. For internal hardness, Clinpro obtained lower values on the control side and up to 90 micrometers on the test side. As for profilometry, Colgate Total 12 showed greater wear when compared to Clinpro. It was concluded that Clinpro promoted lower internal hardness, however, Colgate Total 12 resulted in greater surface wear of tooth enamel.

Introdução: dentifrícios fluoretados são amplamente utilizados pela população. Foram desenvolvidos dentifrícios com alta concentração de fluoreto de sódio e presença de tricálcio fosfato, fornecendo proteção adicional a pacientes vulneráveis ao desenvolvimento da cárie. Objetivo: o objetivo deste estudo foi avaliar a influência de diferentes dentifrícios na dureza superficial, interna e desgaste do esmalte após cárie artificial, ciclagem de pH e escovação. Material e método: blocos de esmalte (4x4 mm) foram obtidos a partir de 20 dentes bovinos. Os espécimes foram submetidos à lesão de cárie artificial e, em seguida, à ciclagem de pH e escovação de acordo com o dentifrício: Colgate Total 12 e Clinpro + Tricálcio Fosfato. Após este período, foram submetidos à análise de dureza superficial e interna e perfilometria. Foi realizada microscopia eletrônica de varredura. Resultado: os dados obtidos foram avaliados por ANOVA um critério para avaliar a recuperação mineral e perfilometria, ANOVA dois critérios medidas repetidas para avaliar a dureza superficial e interna. Conclusão: analisando a dureza superficial, após a indução da cárie houve uma redução significativa na dureza que foi parcialmente recuperada independente do dentifrício utilizado. Para dureza interna, Clinpro obteve valores menores no lado controle e até 90 micrômetros no lado teste. Quanto à perfilometria, o Colgate Total 12 apresentou maior desgaste quando comparado ao Clinpro. Concluiu-se que Clinpro promoveu menor dureza interna, porém, o Colgate Total 12 resultou em maior desgaste superficial do esmalte dentário.

Effect of xylitol varnishes on remineralization of artificial enamel caries lesions in situ.

OBJECTIVES: Analyze the effect of varnishes containing xylitol compared to commercial fluoridated varnishes on the remineralization of artificial enamel caries lesions in situ. METHODS: Twenty subjects took part in this crossover, double-blind study performed in four phases of 5days each. Each subject worn palatal appliances containing four predemineralized bovine enamel specimens. Artificial caries lesions were produced by immersion in 30ml of lactic acid buffer containing 3mM CaCl2·2H2O, 3mM KH2PO4, 6µM tetraetil metil diphosphanate (pH 5.0) for 6days. The specimens in each subject were treated once with the following varnishes: 20% xylitol (experimental); Duofluorid™ (6% NaF, 6% CaF2), Duraphat™ (5% NaF, positive control) and placebo (no-F/xylitol, negative control). The varnishes were applied in a thin layer and removed after 6h. Fifteen subjects were able to finish all phases. The enamel alterations were quantified by surface hardness and transversal microradiography. The percentage of surface hardness recovery (%SHR), the integrated mineral loss and lesion depth were statistically analyzed by Friedmann and Dunn's tests test (p<0.05). RESULTS: Enamel surface remineralization was significantly increased by Duraphat™, Duofluorid™ and 20% xylitol formulations. Significant subsurface mineral remineralization could also be seen for the experimental and commercial varnishes, except for Duraphat™, when the parameter "lesion depth" was considered. CONCLUSIONS: 20% xylitol varnish seem to be a promising alternative to increase surface and subsurface remineralization of artificial caries lesions in situ. CLINICAL SIGNIFICANCE: effective vehicles are desirable for caries control. Xylitol varnishes seem to be promising alternatives to increase enamel remineralization in situ, which should be confirmed by clinical studies.

Effect of xylitol varnishes on remineralization of artificial enamel caries lesions in vitro.

OBJECTIVES: Analyse the effect of varnishes containing xylitol alone or combined with fluoride on the remineralization of artificial enamel caries lesions in vitro. METHODS: Bovine enamel specimens were randomly allocated to 7 groups (n=15/group). Artificial caries lesions were produced by immersion in 30 mL of lactic acid buffer containing 3mM CaCl2·2H2O, 3mM KH2PO4, 6 µM tetraetil metil diphosphanate (pH 5.0) for 6 days. The enamel blocks were treated with the following varnishes: 10% xylitol; 20% xylitol; 10% xylitol plus F (5% NaF); 20% xylitol plus F (5% NaF); Duofluorid™ (6% NaF, 2.71% F+6% CaF2), Duraphat™ (5% NaF, positive control) and placebo (no-F/xylitol, negative control). The varnishes were applied in a thin layer and removed after 6h. The blocks were subjected to pH-cycles (demineralization-2h/remineralization-22 h during 8 days) and enamel alterations were quantified by surface hardness and transversal microradiography. The percentage of surface hardness recovery (%SHR), the integrated mineral loss and lesion depth were statistically analysed by ANOVA/Tukey's test or Kruskal-Wallis/Dunn's test (p<0.05). RESULTS: Enamel surface remineralization was significantly increased by Duraphat™, 10% xylitol plus F and 20% xylitol plus F formulations, while significant subsurface mineral remineralization could be seen only for enamel treated with Duraphat™, Duofluorid™ and 20% xylitol formulations. CONCLUSIONS: 20% xylitol varnishes seem to be promising alternatives to increase remineralization of artificial caries lesions. CLINICAL SIGNIFICANCE: effective vehicles are desirable for caries control. Xylitol varnishes seem to be promising alternatives to increase enamel remineralization in vitro, which should be confirmed by in situ and clinical studies.

Casein phosphopeptide-amorphous calcium phosphate nanocomplex (CPP-ACP) in dentistry: state of the art / Nanocomplejo de fosfopéptido de caseína-fosfato de calcio amorfo (CPP-ACP) en Odontología: estado del arte

ABSTRACT Saliva and external agents containing different concentrations of sodium fluoride (NaF) promote the dental remineralization process. However, these resources may not be sufficient to counteract the multiple factors involved in the process of dental caries, especially in high-risk patients. There are alternatives that have been extensively researched, such as casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) which provides essential ions, like phosphate and calcium, acting as an adjuvant in the remineralization process. Manufacturers of CPP-ACP-based products also suggest that it can produce desensitizing effects. This nanocomplex has been used experimentally with some dental cements and adhesive systems, but it is important to clarify the effects of this procedure, and the remineralizing/desensitizing advantages it offers. The objective of this topic review was to present the state of the art on CPP-ACP nanocomplex. In terms of dental caries prevention, this remineralizing option is not better than NaF. CPP-ACP provides a dental desensitizing action, but it is temporary, similar or less effective than other alternatives such as potassium nitrate or NaF. The experimental incorporation of CPP-ACP into dental cements should be controlled for not to compromise the physico-chemical properties of the material. The use of dental products based on this nanocomplex as dental surface pretreatment may decrease the bond strength of adhesive materials, but this effect is material dependent.

RESUMEN La saliva y agentes externos que contienen diferentes concentraciones de fluoruro de sodio (NaF) favorecen el proceso de remineralización dental. No obstante, estos recursos podrían no ser suficientes para contrarrestar los múltiples factores involucrados en el proceso de caries dental, especialmente en pacientes con alto riesgo. Existen alternativas que han sido ampliamente investigadas, como el fosfopéptido de caseína-fosfato de calcio amorfo (CPP-ACP) que aporta iones esenciales como fosfato y calcio, actuando como coadyuvante en el proceso de remineralización. Los fabricantes de productos basados en CPP-ACP también sugieren que este es capaz de generar efectos desensibilizantes. Este nanocomplejo ha sido utilizado de forma experimental con algunos cementos dentales y sistemas adhesivos, pero es importante esclarecer los efectos de dicha incorporación y las ventajas remineralizantes/desensibilizantes que ofrece esta alternativa. El objetivo del presente artículo de revisión de tema consistió en presentar el estado del arte sobre el nanocomplejo CPP-ACP. En términos de prevención de caries dental, esta opción remineralizante no es superior al NaF. El nanocomplejo ejerce acción desensibilizante dental, pero esta es transitoria, similar o inferior a otras alternativas como nitrato de potasio o NaF. La incorporación experimental de CPP-ACP en cementos dentales debe ser controlada para no comprometer las propiedades fisicoquímicas del material. La utilización de productos dentales a base de este nanocomplejo como pretratamiento de la superficie dental puede disminuir la resistencia de unión de materiales adhesivos, pero este efecto es material-dependiente.

Generalidades sobre la mínima intervención en cariología / General remarks about minimal intervention dentistry

Introducción: los tratamientos de la caries dental con mínima intervención incorporan a la ciencia estomatológica: detección, diagnóstico y tratamientos a niveles microscópicos. Objetivo: caracterizar, a través de una revisión bibliográfica, la mínima intervención en el tratamiento de la caries dental.Métodos: se realizó una revisión de la literatura científica sobre mínima intervención en cariología, a través de los buscadores de información y plataformas: SciELO, Hinari, y Medline. Se revisaron 25 revistas de impacto. Se incluyó artículos en idioma inglés y español. Los descriptores empleados para la búsqueda fueron: mínima intervención, odontología/ estomatología mínimamente invasiva, cariología, mínima intervención en cariología, tratamiento actual de la caries dental, filosofía mínima intervención, las combinaciones entre ellos y su equivalente en inglés. Se obtuvo 204 artículos; luego de ser filtrados quedaron 32 publicaciones científicas y un libro, que enfocaban esta temática de manera más integral. El 97 por ciento de la bibliografía correspondía a publicaciones realizadas durante los últimos 5 años. Integración de la información: se realiza análisis sobre la prevención, remineralización y tratamientos con técnicas de mínima intervención para la remoción de la caries dental. Conclusiones: la mínima intervención propicia el actuar científicamente de acuerdo a la etapa del proceso caries dental. Es una concepción teórica con herramientas para la práctica encaminada a preservar la mayor cantidad posible de tejido dental de manera que los dientes tengan mayor funcionabilidad(AU)

Introduction: minimal intervention treatments for dental caries enrich dental practice by incorporating detection, diagnosis and microscopic techniques into it. Objective: characterize minimal intervention in the treatment of dental caries by means of a bibliographic review about the subject. Methods: a review was conducted of the literature about minimal intervention in dentistry, using the search engines and platforms SciELO, Hinari and Medline. Twenty-five high impact journals were reviewed. The papers included were in English or Spanish. The descriptors used in the search wereminimal intervention, minimally invasive dentistry, cariology, minimal intervention dentistry, current treatments for dental caries and minimal intervention philosophy, as well as combinations thereof and their counterparts in Spanish. 204 papers were obtained. After being filtered, the sample was composed of 32 scientific journals and one book, i.e. the materials that approached the topic in a more comprehensive manner. 97 percent of the bibliography reviewed had been published in the last five years. Data integration: an analysis was conducted about prevention, remineralization and minimal intervention techniques for the removal of dental caries.Conclusions: Minimal intervention dentistry is characterized by adopting a position in which intervention or preparation of dental tissue is the last choice of therapy resorted to after applying a whole set of prevention and remineralization techniques(AU)

Generalidades sobre la mínima intervención en cariología / General remarks about minimal intervention dentistry

Introducción: los tratamientos de la caries dental con mínima intervención incorporan a la ciencia estomatológica: detección, diagnóstico y tratamientos a niveles microscópicos. Objetivo: caracterizar, a través de una revisión bibliográfica, la mínima intervención en el tratamiento de la caries dental. Métodos: se realizó una revisión de la literatura científica sobre mínima intervención en cariología, a través de los buscadores de información y plataformas: SciELO, Hinari, y Medline. Se revisaron 25 revistas de impacto. Se incluyó artículos en idioma inglés y español. Los descriptores empleados para la búsqueda fueron: mínima intervención,odontología/estomatología mínimamente invasiva, cariología, mínima intervención en cariología, tratamiento actual de la caries dental, filosofía mínima intervención, las combinaciones entre ellos y su equivalente en inglés. Se obtuvo 204 artículos; luego de ser filtrados quedaron 32 publicaciones científicas y un libro, que enfocaban esta temática de manera más integral. El 97 por ciento de la bibliografía correspondía a publicaciones realizadas durante los últimos 5 años. Integración de la información: se realiza análisis sobre la prevención, remineralización y tratamientos con técnicas de mínima intervención para la remoción de la caries dental. Conclusiones: la mínima intervención propicia el actuar científicamente de acuerdo a la etapa del proceso caries dental. Es una concepción teórica con herramientas para la práctica encaminada a preservar la mayor cantidad posible de tejido dental de manera que los dientes tengan mayor funcionabilidad(AU)

Introduction: minimal intervention treatments for dental caries enrich dental practice by incorporating detection, diagnosis and microscopic techniques into it. Objective: characterize minimal intervention in the treatment of dental caries by means of a bibliographic review about the subject. Methods: a review was conducted of the literature about minimal intervention in dentistry, using the search engines and platforms SciELO, Hinari and Medline. Twenty-five high impact journals were reviewed. The papers included were in English or Spanish. The descriptors used in the search wereminimal intervention, minimally invasive dentistry, cariology, minimal intervention dentistry, current treatments for dental caries and minimal intervention philosophy, as well as combinations thereof and their counterparts in Spanish. 204 papers were obtained. After being filtered, the sample was composed of 32 scientific journals and one book, i.e. the materials that approached the topic in a more comprehensive manner. 97 percent of the bibliography reviewed had been published in the last five years. Data integration: an analysis was conducted about prevention, remineralization and minimal intervention techniques for the removal of dental caries. Conclusions: Minimal intervention dentistry is characterized by adopting a position in which intervention or preparation of dental tissue is the last choice of therapy resorted to after applying a whole set of prevention and remineralization techniques(AU)

Comparação de diferentes pré-tratamentos de superfície na remineralização de esmalte com flúor em tratamento de lesões com mancha branca e sua resistência após desafio ácido / Comparison of different pretreatments on remineralization of enamel white spot lesions with fluoride and its resistance after new acidic challenge

A aplicação de flúor tópico é a principal estratégia de natureza química para a remineralização de lesões incipientes (LI) clinicamente visíveis como manchas brancas (MB) por cárie. Abordagens para aumentar a retenção de F no substrato pode favorecer sua ação e para isso, tratamentos prévios da superfície do esmalte podem ser usados. O objetivo deste trabalho foi comparar a capacidade de remineralização do flúor sem e com pré-tratamento do esmalte com ácido fosfórico e nitrato de alumínio e a sua resistência após novo desafio. Sessenta espécimes de esmalte bovino foram preparados (6mm x 4mm) e selecionados por meio de análise de microdureza de superfície (MS). LI foram produzidas através de ciclagem Desmineralização-Remineralização (DES-RE) e os espécimes divididos aleatoriamente em cinco grupos, de acordo com o tratamento (n=12): V- controle (verniz de fluoreto de sódio 5% por 4 horas), F (sem pré-tratamento); P-F(condicionamento ácido com ácido fosfórico por 30s); Al-F (nitrato de alumínio a 0,05M por 1min); P-Al-F (condicionamento com ácido fosfórico a 37% + nitrato de alumínio a 0,05M). Os tratamentos foram repetidos semanalmente durante quatro semanas. Após o tratamento, os espécimes foram submetidos à nova ciclagem ácida. Após cada etapa, nova MS foi realizada e ao final das análises, um corte transversal dos espécimes foi realizado. Uma das metades foi submetida à análise da microdureza longitudinal (ML) e a outra preparada para realização da microrradiografia transversal (TMR) para a análise de conteúdo mineral perdido. O percentual de perda de dureza de superfície (%PDS) foi analisado por ANOVA a 2 critérios de medidas repetidas e Tukey e o percentual de perda de dureza longitudinal (%PDL) por ANOVA a 3 critérios de medidas repetidas e Tukey (p<0,05). Os dados de TMR no parâmetro LD (profundidade da lesão) foram analisados por ANOVA a dois critérios (p<0,05). Os resultados mostraram que a ciclagem DES-RE resultou em significante %PDS e %PDL em todos os grupos. Grupo F revelou menor perda de MS após tratamento e, F, Al-F e P-Al-F, mostraram menor perda de dureza final, após o novo desafio ácido. Na análise de %PDL, o grupo V apresentou menor perda de dureza final quando comparado com os demais grupos, nas diferentes profundidades. A análise do conteúdo mineral não revelou nenhuma diferença entre os tratamentos e fases. Nenhum dos pré tratamentos propostos foram capazes de otimizar a atuação do gel APF na remineralização de MB.(AU)

The topical fluoride is the main chemical strategy to remineralize incipient caries lesions (ICL) visible as carious white spot lesions (WSL). Approaches to increase the fluoride retention may favor its action and therefore, enamel pretreatments can be used for this purpose. The aim of this study was to compare the potential of fluoride remineralization with and without previous enamel pretreatment with aluminum nitrate and phosphoric acid as well as their resistance after a new acid challenge. Sixty bovine enamel specimens were prepared (6mm x 4mm) and selected by the surface hardness (SH) analysis. The ICL were produced using DE-RE cycling and the specimens were randomized in five groups, according to the treatment (n=12): Vcontrol (5% sodium fluoride varnish during 4h), and four groups previously preatreated with topical application of acidulated phosphate fluoride (APF) during 4min: F (without pretreatment), P-F (phosphoric acid etching during 30s), Al-F (0.05M aluminum nitrate during 1min); P-Al-F (phosphoric acid etching + aluminum nitrate). The treatments were performed weekly during four weeks. After the treatment, the specimens were submitted to the new acid challenge. After each step, a new SH analysis was performed followed by the transversal cut of the specimens. A half was submitted to the longitudinal cross-sectional hardness analysis (LH) and the other half was prepared to transverse microradiography assessments (TMR) to determine the loss of mineral content. The percentage of surface mineral loss (%SH) was analyzed using two-way repeated-measures ANOVA and the percentage of crosssectional mineral loss (%LH) by the three-way repeated-measures ANOVA and Tukey (p<0.05). Data of TMR analysis by LD (lesion depth) parameter was analyzed with two-way ANOVA (p<0.05). The results showed significant %SH and %LH after DE-RE cycling for all groups. F group showed the lowest %SH after treatment, with no significant difference to Al-F and P-Al-F after the new acid challenge. V group showed the lowest %LH compared to the other groups, in the different depths, suggesting more resistance. Mineral content assessment did not reveal any difference among treatments and phases. None pretreatments were able to increase the potential of fluoride remineralization.(AU)