Effect of propolis added to single-bottle adhesives on water permeation through the hybrid layer.

Water treeing and water droplets are observed within adhesive layers and on the hybridized surface after bonding sound dentin using single-bottle etch-and-rinse adhesives, indicating permeability of the hybrid layer to water. The aim of this study was to assess the efficacy of dentin sealing by adhesives containing propolis by quantifying the area of water transudation from dentinal tubules after dentin hybridization. Brazilian red propolis was added to experimental adhesive and Single Bond (3M/ESPE) adhesive; experimental adhesive and Single Bond without propolis were used as controls. Under simulated pulp pressure, two layers of adhesive were applied to etched human dentin discs. Three minutes after light-curing, the hybridized dentin surface was replicated, and epoxy resin replicas were created to obtain scanning electron microscope images. Data were evaluated using ANOVA and Tukey's test. Single Bond containing propolis significantly decreased water permeation through the hybrid layer compared with the control group. Three minutes after polymerization, the experimental adhesive without propolis had formed a permeable hybrid layer. The addition of Brazilian red propolis significantly reduced surface water on hybridized dentin in a concentration-dependent manner. Two-step etch-and-rinse adhesives containing propolis were effective in reducing water permeation through the hybridized dentin surface.

Brazilian red propolis: phytochemical screening, antioxidant activity and effect against cancer cells.

BACKGROUND: The implementation of new public healthcare models that stimulate the use of natural products from traditional medicine, as a so-called integrated medicine, refers to an approach that use best of both conventional medicine and traditional medicine. Propolis is a widely used natural product by different ancient cultures and known to exhibit biological activities beneficial for health. The large number of studies conducted with propolis had shown that its chemical composition differs as a function of the climate, plant diversity and bee species and plays an important role on its therapeutic properties. The aim of this study was to analyse the phytochemical profile of the ethanolic extract of red propolis (EEP) and its fractionation, antioxidant action of EEP and its fractions hexane, cloroform and ethyl acetate and cytotoxic activity of EEP on human tumour cell lines SF-295 (glioblastoma), OVCAR-8 (ovary) and HCT-116 (colon). METHODS: EEP was obtained by maceration with absolute ethanol, then it was concentrated in rotaevaporator up to complete evaporation of the solvent. The crude extract was fractionated with hexane, ethyl acetate, chloroform and methanol and they were subjected to phytochemical screening and total phenolic compounds. Antioxidant activity of EEP and fractions was done by means of the 2,2-diphenyl-1-picryhydrazyl (DPPH) method. Biomarkers of red propolis were identified by LC-Orbitrap-FTMS. To assess cytotoxic activity of the extract, cells were exposed to EEP over 72 h. Cell viability was assessed by means of MTT assay. The percentage of cell growth inhibition (IC50) was analysed by means of non-linear regression, and the absorbance values of the various investigated concentrations were subjected to one-factor analysis of variance (ANOVA) followed by Tukey's or Tamhane's tests (α = 0.05). RESULTS: The results obtained using phytochemical screening and LC-Orbitrap-FTMS indicated the presence of phlobaphene tannins, catechins, chalcones, aurones, flavonones, flavonols, xanthones, pentacyclic triterpenoids and guttiferones in Brazilian red propolis. EEP and its hexane, chloroform and ethyl acetate fractions obtained by liquid-liquid partitioning exhibited satisfactory antioxidant percentages. EEP (IC50 < 34.27 µg/mL) exhibited high levels of cytotoxicity on all human tumour cell lines tested when compared to negative control. CONCLUSIONS: C-Orbitrap-FTMS was useful to establish the chemical profile of the red propolis. Brazilian red propolis has antioxidant properties and decreases substantially the percentage of cell survival of human tumour cells; thus, it has potential to serve as an anticancer drug.

Propolis in Oral Healthcare: Antibacterial Activity of a Composite Resin Enriched With Brazilian Red Propolis.

The aim of this study was to obtain a Brazilian red propolis (BRP) enriched composite resin and to perform the characterization of its antibacterial activity, mechanical, and physical-chemical properties. Brazilian red propolis ethyl acetate extract (EABRP) was characterized by LC-ESI-Orbitrap-FTMS, UPLC-DAD, antibacterial activity, total flavonoids content, and radical scavenging capacity. BRP was incorporated to a commercial composite resin (RC) to obtain BRP enriched composite at 0.1, 0.15 and 0.25% (RP10, RP15 and RP25, respectively). The antibacterial activity RPs was evaluated against Streptococcus mutans by contact direct test and expressed by antibacterial ratio. The RPs were characterized as its cytotoxicity against 3T3 fibroblasts, flexural strength (FS), Knoop microhardness (KHN), post-cure depth (CD), degree of conversion (DC%), water sorption (Wsp), water solubility (Wsl), average roughness (Ra), and thermal analysis. Were identified 50 chemical compounds from BRP extract by LC-ESI-Orbitrap-FTMS. EABRP was bacteriostatic and bactericide at 125 and 500 µg/ml, respectively. The RP25 exhibited antibacterial ratio of 90.76% after 1 h of direct contact with S. mutans (p < 0.0001) while RC no showed significative antibacterial activity (p = 0.1865), both compared with cell control group. RPs and RC no showed cytotoxicity. RPs exhibited CD from 2.74 to 4.48 mm, DC% from 80.70 to 83.96%, Wsp from 17.15 to 21.67 µg/mm3, Wsl from 3.66 to 4.20 µg/mm3, Ra from 14.48 to 20.76 nm. RPs showed thermal resistance between 448-455°C. The results support that propolis can be used on development of modified composite resins that show antibacterial activity and that have compatible mechanical and physical-chemical properties to the indicate for composite resins.

Layered double hydroxides for controlled fluoride release.

This study aims to develop a nano-sized fluoridated layered double hydroxide (LDH)-based release system via hydrothermal treatment for the controlled delivery of fluoride (F-) ions in the oral environment. The synthesis of conventional LDH-type (C-LDH) precursor nanomaterials was conducted using a co-precipitation method at constant pH, and the nanoparticulate-LDH (N-LDH) was synthesized by a hydrothermal procedure. Fluoride LDH (F-LDH) products were obtained through indirect synthesis using the precursor ion-exchange technique by varying the agitation time (2 and 24 h) and temperature (25 and 40 °C) to produce 12 material samples. The materials were characterized by energy dispersive x-ray, hexamethyldisilazane, digital radiography x-ray, Fourier-transform infrared, thermogravimetric analysis, and scanning electron microscopy. Additionally, the F-release kinetic profile was evaluated for 21 d in neutral and acid media with mathematical model analysis. Products with varying F-quantities were obtained, revealing specific release profiles. In general, there was a higher F-release in the acid medium, with emphasis on F-LDH-8. Fluoride-LDH and controlled fluoride delivery was successfully obtained, proving the potential of these nanomaterials as alternative anti-caries agents.

Polyphenols and Brazilian red propolis incorporated into a total-etching adhesive system help in maintaining bonding durability.

OBJECTIVES: The aim of this study was to evaluate the degree of conversion and bond strength of a commercial dental adhesive modified by the incorporation of quercetin, resveratrol (RES), and Brazilian red propolis (BRP). METHODS: BRP markers were identified using ultra-performance liquid chromatography coupled with a diode array detector, and the antioxidant activity (AAO) of the three substances was analyzed. Single Bond 2 adhesive (3M ESPE) was modified by adding BRP, quercetin, and RES, separately, at 20 µg/mL, 250 µg/mL, and 500 µg/mL, respectively. The degree of conversion (DC) was measured using near-infrared spectroscopy 24 h after photopolymerization. Measurements of the resin-dentin microtensile bond strength (µTBS) were carried out after 1 day and 1 year. Student's t test and ANOVA with Tukey's test were used for data analysis (α = 0.05). RESULTS: The markers daidzein, liquiritigenin, pinobanksin, isoliquiritigenin, formononetin, pinocembrin, and biochanin A were found in the ethanolic extract of BRP. Quercetin, RES, and BRP showed high AAO. The DC of the tested adhesives remained adequate for this category of material, with a slight increase in the DC of adhesives with quercetin and BRP (P > 0.05). Comparisons between µTBS measurements made at 1 day and 1 year showed that, contrary to the control group, µTBS values for all modified adhesives were maintained after 1 year in distilled water (P > 0.05). CONCLUSIONS: These findings suggest that quercetin, RES, or BRP might be useful in adhesive dentistry to help improve hybrid layer resistance. CLINICAL SIGNIFICANCE: Dentin bonding agents with quercetin, RES, and BRP have potential to increase the longevity of composite restorations.

Effect of QMix irrigant in removal of smear layer in root canal system: a systematic review of in vitro studies.

OBJECTIVES: To evaluate the outcome of in vitro studies comparing the effectiveness of QMix irrigant in removing the smear layer in the root canal system compared with other irrigants. MATERIALS AND METHODS: The research question was developed by using Population, Intervention, Comparison, Outcome and Study design framework. Literature search was performed using 3 electronic databases PubMed, Scopus, and EBSCOhost until October 2019. Two reviewers were independently involved in the selection of the articles and data extraction process. Risk of bias of the studies was independently appraised using revised Cochrane Risk of Bias tool (RoB 2.0) based on 5 domains. RESULTS: Thirteen studies fulfilled the selection criteria. The overall risk of bias was moderate. QMix was found to have better smear layer removal ability than mixture of tetracycline isonomer, an acid and a detergent (MTAD), sodium hypochlorite (NaOCl), and phytic acid. The efficacy was less effective than 7% maleic acid and 10% citric acid. No conclusive results could be drawn between QMix and 17% ethylenediaminetetraacetic acid due to conflicting results. QMix was more effective when used for 3 minutes than 1 minute. CONCLUSIONS: QMix has better smear layer removal ability compared to MTAD, NaOCl, Tubulicid Plus, and Phytic acid. In order to remove the smear layer more effectively with QMix, it is recommended to use it for a longer duration.

Inhibition of matrix metalloproteinases: a troubleshooting for dentin adhesion.

Matrix metalloproteinases (MMPs) are enzymes that can degrade collagen in hybrid layer and reduce the longevity of adhesive restorations. As scientific understanding of the MMPs has advanced, useful strategies focusing on preventing these enzymes' actions by MMP inhibitors have quickly developed in many medical fields. However, in restorative dentistry, it is still not well established. This paper is an overview of the strategies to inhibit MMPs that can achieve a long-lasting material-tooth adhesion. Literature search was performed comprehensively using the electronic databases: PubMed, ScienceDirect and Scopus including articles from May 2007 to December 2019 and the main search terms were "matrix metalloproteinases", "collagen", and "dentin" and "hybrid layer". MMPs typical structure consists of several distinct domains. MMP inhibitors can be divided into 2 main groups: synthetic (synthetic-peptides, non-peptide molecules and compounds, tetracyclines, metallic ions, and others) and natural bioactive inhibitors mainly flavonoids. Selective inhibitors of MMPs promise to be the future for specific targeting of preventing dentin proteolysis. The knowledge about MMPs functionality should be considered to synthesize drugs capable to efficiently and selectively block MMPs chemical routes targeting their inactivation in order to overcome the current limitations of the therapeutic use of MMPs inhibitors, i.e., easy clinical application and long-lasting effect.

Layered double hydroxides for controlled fluoride release

Abstract This study aims to develop a nano-sized fluoridated layered double hydroxide (LDH)-based release system via hydrothermal treatment for the controlled delivery of fluoride (F-) ions in the oral environment. The synthesis of conventional LDH-type (C-LDH) precursor nanomaterials was conducted using a co-precipitation method at constant pH, and the nanoparticulate-LDH (N-LDH) was synthesized by a hydrothermal procedure. Fluoride LDH (F-LDH) products were obtained through indirect synthesis using the precursor ion-exchange technique by varying the agitation time (2 and 24 h) and temperature (25 and 40 °C) to produce 12 material samples. The materials were characterized by energy dispersive x-ray, hexamethyldisilazane, digital radiography x-ray, Fourier-transform infrared, thermogravimetric analysis, and scanning electron microscopy. Additionally, the F-release kinetic profile was evaluated for 21 d in neutral and acid media with mathematical model analysis. Products with varying F-quantities were obtained, revealing specific release profiles. In general, there was a higher F-release in the acid medium, with emphasis on F-LDH-8. Fluoride-LDH and controlled fluoride delivery was successfully obtained, proving the potential of these nanomaterials as alternative anti-caries agents.

Effect of in-office bleaching with 35% hydrogen peroxide with and without addition of calcium on the enamel surface.

This study aimed to evaluate effectiveness and effects of bleaching with 35% hydrogen peroxide with and without calcium on color, micromorphology, and the replacement of calcium and phosphate on the enamel surface. Thirty bovine enamel blocks (5.0 × 5.0 mm) were placed into the following groups: G1: artificial saliva (control); G2: 35% hydrogen peroxide gel without calcium (Whiteness HP Maxx-FGM); and G3: 35% hydrogen peroxide gel with calcium (Whiteness HP Blue-FGM). Three color measurements were performed with a spectrophotometer: untreated (baseline), after performing staining, and after application of bleaching agents. Calcium deposition on the enamel was evaluated before and after the application of bleaching agents using energy-dispersive X-ray spectrometry. The enamel surface micromorphology was observed under scanning electron microscopy. The pH of each product was measured. The data were subjected to one-factor analysis of variance (ANOVA), and any differences were analyzed using Tukey's test (P < 0.05). G3 showed greater variation in total color after the experiment than G2 and G1; there was no significant difference in calcium or phosphorus concentration before and after the experimental procedures; morphological changes were observed only in G2 and G3; and the pH values of the Whiteness HP Maxx and Whiteness HP Blue bleaching agents were 5.77 and 7.79, respectively. The 35% hydrogen peroxide with calcium showed greater bleaching potential, but the addition of calcium had no effect in terms of reducing morphological changes or increasing the calcium concentration on the enamel surface.

Mechanical and physical properties of silorane and methacrylate-based composites.

OBJECTIVES: This study measured the degree of conversion (DC), sorption, solubility and microhardness of methacrylate (Filtek Z250 and Filtek Z350XT) and silorane-based composites (Filtek P90). METHODS: DC was measured using near infrared spectroscopy immediately and 24h after the photoactivation. Sorption and solubility measurements were performed after 24h, 4 weeks and 12 weeks of storage in water. Knoop microhardness was measured after 24h and after thermal cycling. The data were statistically analyzed using ANOVA followed by Tukey's, Tamhane or paired t-tests (α=0.05). RESULTS: The DC for P90 (37.22±1.46) was significantly lower than the Z250 (71.44±1.66) and Z350 (71.76±2.84). Water sorption was highest in the Z250 and lowest in the P90. All the tested composites exhibited similar values after 24h of immersion, and no significant differences were observed. No significant differences were observed between the solubilities of the P90 composite (12 weeks) and the Z250 or Z350 composites (4 weeks). KHN values were less elevated for the P90 composite and similar for the Z250 and Z350 composites. An effect of thermal cycling on KHN values was observed for all the composites (p<0.001). CONCLUSIONS: Silorane produced the lowest DC and KHN values and exhibited lower water sorption and solubility compared to methacrylate-based composites. These differences suggest that silorane composites exhibit better hydrolytic stability after 3 months of water immersion compared to conventional methacrylate-based composites. CLINICAL SIGNIFICANCE: Silorane had higher hydrolytic stability after 3 months of water immersion than the methacrylate-based resins, despite the lower values of DC and KHN recorded.

Influence of the photoinitiator system and light photoactivation units on the degree of conversion of dental composites.

The aim of this study was to observe the influence of two light polymerization units (LED or halogen light) on the degree of conversion (DC) of three dental composites with lighter shades and a different photoinitiator system. The top (T) and bottom (B) surfaces of 60 discs of composite resin (Filtek™ Supreme, Filtek™ Z250, Tetric™ Ceram Bleach) cured either by LED or by halogen lamp (HL) were studied using an FT-Raman spectrometer. The degree of conversion (DC) was evaluated by following the changes in the intensity of the methacrylate C=C stretching mode at 1640 cm⁻¹. The calculated DC ranged from 54.2% (B) to 73.4% (T) and from 60.2% (B) to 76.6% (T) for the LED and HL, respectively. LED and halogen devices were able to produce an adequate DC for all the resins tested.

In vitro potential cytotoxicity of an adhesive system to alveolar macrophages.

The purpose of this study was to evaluate the potential cytotoxicity of Adper Single Bond 2 (SB) simplified etch-and-rinse adhesive system in alveolar macrophage cultures, as a function of the post-polymerization time and duration of immersion in the culture medium for preparation of extracts, by observing the levels of nitric oxide (NO) release and cell survival rate (MTT assay). Wistar rat alveolar macrophages were exposed to 200 microL of extracts obtained from 24- or 72-h immersion of adhesive samples in culture medium (RPMI), immediately or 24 h after polymerization. Fresh RPMI and E. coli lipopolysaccharides were used as negative and positive controls, respectively. The cells were placed in a humidified incubator for 24 h. The results were analyzed by the Student's-t test (alpha=5%). The amount of NO produced and viable cells were significantly different (p<0.05) between the experimental and the control groups, showing that, irrespective of the post-polymerization time and duration of immersion in the culture medium, the adhesive system caused intense cytotoxicity to the macrophages. The cytotoxic effects were not statistically different (p<0.05) among the experimental groups. In conclusion, chemical components released from SB in aqueous environment were highly toxic to cell culture and thus an inflammatory pulpal response should be considered during the clinical application of dental adhesives.

Avaliação em curto e médio prazo da sorção e da solubilidade de resinas compostas à base de metacrilato e de silorano em saliva artificial / Evaluation of short- and medium-term sorption and solubility of methacrylate or silorane-based composite resins in artificial saliva

Introdução: A absorção/adsorção de moléculas de água por monômeros hidrofílicos dentro de materiais resinosos expostos à umidade da boca pode resultar em degradação. Objetivo: Este estudo avaliou sorção e solubilidade de resinas compostas à base de metacrilato e silorano em contato com saliva artificial, nos períodos de um dia (curto prazo), e 30 e 90 dias (médio prazo). Material e Método: Sessenta corpos de prova foram confeccionados com as resinas Filtek® Z250 e Filtek® P90 Silorano (3M/ESPE), e depois imersos em saliva artificial a 37 ± 1 ºC durante um, 30 e 90 dias. Os dados foram analisados usando-se ANOVA um fator/dois fatores seguido dos testes Tukey ou Tamhane (α = 0,05). Resultado: As médias de sorção das duas resinas aumentaram com o tempo (p = 0,001). A sorção de Z250 (1 e 90 d) foi significativamente maior do que de P90 (p = 0,008), com valores semelhantes após 30 dias. A solubilidade das resinas também aumentou com o tempo, com diferença significativa entre todos os períodos (p = 0,001), exceto para a resina P90 (entre 1 e 30 d). Não houve diferença estatística significante entre os grupos Z250 (1 d) e P90 (1 dia), Z250 (1 d) e P90 (30 d), e Z250 (30 d) e P90 (90 d). Para os demais pares, comprovaram-se diferenças significativas (p < 0,001). Conclusão: As propriedades de sorção e solubilidade das resinas compostas testadas foram influenciadas pelo tempo de exposição à saliva artificial. O silorano teve desempenho ora melhor ora semelhante à resina de metacrilato.

Introduction: The absorption/adsorption of water molecules by hydrophilic monomers within the resinous material exposed to the humid environment of the mouth may result in degradation. Objective: This study evaluated the sorption and solubility of methacrylate-based resin and silorane in contact with artificial saliva after 1 day (short-term), 30 days and 90 days (medium-term). Material and Method: Sixty samples were prepared with Filtek® Z250 and Filtek® P90 Silorano (3M/ESPE) and then immersed in artificial saliva at 37 ± 1 ºC for 1, 30 and 90 days. Data were analyzed using one-way/two-way ANOVA followed by the Tukey or Tamhane tests (α = 0,05). Result: The sorption and solubility of two resins increased with the evaluation time (p = 0.001). Sorption of Z250 (at 1 and 90 days) was significantly higher than that of P90 ( p = 0.008), and similar values were registered at 30 days. Resin solubility also increased with time and there were significant differences for all time periods (p = 0.001), except for P90 at 1 and 30 days. There were no significant differences between Z250 (1 day) and P90 (1 day), Z250 (1 day) and P90 (30 day), and Z250 (30 days) and P90 (90 days). Significant differences were shown for other pairings (p < 0.001). Conclusion: The solubility and sorption properties of the composites tested were influenced by time of exposure to artificial saliva. Silorane performed better than or similar results to methacrylate-based resin.

Endodontic management of dilacerated and bayonet shaped roots / Tratamento endodôntico de raízes dilaceradas e em forma de baioneta

Successful root canal therapy requires a thorough knowledge of root anatomy and root canal morphology which may be quiet variable. The significance of internal root canal morphology has been emphasized by studies demonstrating that variations in canal morphology may affect the endodontic outcome. Consequently, in treating each tooth the clinician must assume that complex anatomy occurs often enough to be considered normal. Root dilaceration is one of the variations that may complicate the endodontic therapy. It is important for a clinician to have complete knowledge of internal anatomy relationships, careful interpretation of radiographs; proper access preparationand a detailed exploration of the interior of the tooth to achieve a successful treatment outcome. This paper reports successful endodontictherapy of severe dilaceration of the root of mandibular first molar and bayonet shaped root of maxillary first premolar and highlights theclinical considerations to be followed during the endodontic procedures to get the successful outcome.

Um tratamento de canal bem sucedido requer conhecimento profundo da anatomia da raiz dentária e morfologia do canal radicular, que pode ser variável. A importância da morfologia interna do canal radicular tem sido enfatizada por estudos que demonstram que as variações na morfologia do canal podem afetar o resultado do tratamento endodôntico. Consequentemente, no tratamento de cada dente, o clínico deve assumir que uma anatomia complexa ocorre com frequência suficiente para ser considerada normal. A dilaceração da raiz dentária é uma das variações que podem complicar o tratamento endodôntico. É importante para o clínico ter conhecimento completo das relações da anatomia interna, fazer uma interpretação cuidadosa de radiografias; preparar adequadamente o acesso e realizar uma exploração detalhada do interior do dente para conseguir um resultado de tratamento bem sucedido. Este artigo relata casos de terapia endodôntica bem sucedida de dilaceração severa da raiz do primeiro molar inferior e de raiz em forma de baioneta de um primeiro pré-molar superior e destaca as considerações clínicas a serem seguidas durante os procedimentos endodônticos para se obter êxito no tratamento.

In vitro evaluation of incompatibility between simplified adhesive systems and dual-cure resin cement / Avaliação in vitro da incompatibilidade entre sistemas adesivos e cimento resinoso dual

Objective: The aim of this study was to evaluate the incompatibility between simplified adhesive systems and dual-cure resin cement by means of marginal micro-leakage testing. Methods: Standardized cavity preparations were performed in 30 bovine teeth. The adhesive systems Adper Scotchbond Multipurpose Plus (3M ESPE, St. Paul, MN, USA) - Group A, Excite (Ivoclar/Vivadent, AG, Liechtenstein) - Group B, and Adper Prompt L-Pop (3M ESPE, St. Paul, MN, USA) - Group C, were applied and the cavities were filled with dual-cure resin cement (Enforce - Denstply, Milford, DE, USA). The samples were submitted to five hundred thermal cycles, after which they were immersed in 2% buffered methylene blue. Results: Group A presented the lowest mean percentage of micro-leakage (3.34%), followed by Group B (13.60%) and Group C (48.33%). Significant differences were found among the groups after the application of the Kruskal-Wallis statistical test (P=0.00). Conclusion: The highest mean marginal micro-leakage values were shown with the use of the one-bottle etch-and-rinse adhesive system and the all-in-one self-etch system, which demonstrates the incompatibility between these materials.

Objetivo: Avaliar a incompatibilidade entre sistemas adesivos e cimento resinoso dual através de teste de microinfiltração marginal. Métodos: Foram realizados preparos cavitários padronizados em 30 dentes bovinos divididos em 3 grupos: A) Adper Scotchbond Multipurpose (3M ESPE, St. Paul, MN, USA); B) Excite (Ivoclar/Vivadent, AG, Liechtenstein) e C) Adper Prompt L-Pop (3M ESPE, St. Paul, MN, USA). Após aplicação dos adesivos, as cavidades foram preenchidas com cimento resinoso dual Enforce (Denstply, Milford, DE, USA), submetidos à ciclagem térmica (500 ciclos) e imersos em azul de metileno 2% tamponado. Resultados: O grupo A apresentou os menores percentuais de microinfiltração (3,34%), seguido pelo grupo B (13,60%) e pelo grupo C (48,33%). Após aplicação do teste estatístico Kruskal-Wallis, foram detectadas diferenças estatisticamente significativas entre os três grupos (P=0.00). Conclusão: Houve incompatibilidade na associação entre os sistemas adesivos, convencional de dois passos (Excite, Ivoclar/Vivadent, AG, Liechtenstein) e autocondicionante de passo único (Adper Prompt L-Pop (3M ESPE, St. Paul, MN, USA), e o cimento resinoso dual Enforce (Denstply, Milford, DE, USA).

Influence of the photoinitiator system and light photoactivation units on the degree of conversion of dental composites

The aim of this study was to observe the influence of two light polymerization units (LED or halogen light) on the degree of conversion (DC) of three dental composites with lighter shades and a different photoinitiator system. The top (T) and bottom (B) surfaces of 60 discs of composite resin (Filtek™ Supreme, Filtek™ Z250, Tetric™ Ceram Bleach) cured either by LED or by halogen lamp (HL) were studied using an FT-Raman spectrometer. The degree of conversion (DC) was evaluated by following the changes in the intensity of the methacrylate C=C stretching mode at 1640 cm-1. The calculated DC ranged from 54.2 percent (B) to 73.4 percent (T) and from 60.2 percent (B) to 76.6 percent (T) for the LED and HL, respectively. LED and halogen devices were able to produce an adequate DC for all the resins tested.

In vitro potential cytotoxicity of an adhesive system to alveolar macrophages

The purpose of this study was to evaluate the potential cytotoxicity of Adper Single Bond 2 (SB) simplified etch-and-rinse adhesive system in alveolar macrophage cultures, as a function of the post-polymerization time and duration of immersion in the culture medium for preparation of extracts, by observing the levels of nitric oxide (NO) release and cell survival rate (MTT assay). Wistar rat alveolar macrophages were exposed to 200 μL of extracts obtained from 24- or 72-h immersion of adhesive samples in culture medium (RPMI), immediately or 24 h after polymerization. Fresh RPMI and E. coli lipopolysaccharides were used as negative and positive controls, respectively. The cells were placed in a humidified incubator for 24 h. The results were analyzed by the Student's-t test (α=5 percent). The amount of NO produced and viable cells were significantly different (p<0.05) between the experimental and the control groups, showing that, irrespective of the post-polymerization time and duration of immersion in the culture medium, the adhesive system caused intense cytotoxicity to the macrophages. The cytotoxic effects were not statistically different (p<0.05) among the experimental groups. In conclusion, chemical components released from SB in aqueous environment were highly toxic to cell culture and thus an inflammatory pulpal response should be considered during the clinical application of dental adhesives.

O objetivo deste estudo foi avaliar o potencial de citotoxicidade do sistema adesivo Adper Single Bond 2 (SB), em função dos tempos pós-polimerização e imersão no meio de cultura para preparação dos extratos, observando-se os níveis de liberação de óxido nítrico (NO) e taxa de sobrevivência celular (MTT assay). Macrófagos alveolares de ratos Wistar foram expostos a 200 μL de extratos obtidos a partir da imersão de amostras do adesivo em meio de cultura (RPMI), imediatamente ou 24 h após sua polimerização, onde permaneceram durante 24 ou 72 h. RPMI puro e lipopolissacarídeos de E. coli foram utilizados como controles negativo e positivo, respectivamente. As células foram levadas à incubadora umidificada por 24 h. Os resultados foram submetidos ao teste "t" de Student (α=5 por cento). As quantidades de NO produzido e células sobreviventes foram significativamente diferentes entre os grupos experimentais e grupos controle, mostrando que, independente do tempo pós-polimerização e tempo de elaboração dos extratos, o sistema adesivo causou uma intensa citotoxicidade sobre os macrófagos. Os efeitos citotóxicos não foram estatisticamente diferentes entre os grupos experimentais. Componentes químicos do SB liberados em meio aquoso podem ser altamente citotóxicos para as células em cultura e, portanto, uma resposta inflamatória pulpar deve ser considerada durante a aplicação clínica de adesivos dentinários.

Uso do laser de baixa intensidade na hipersensibilidade dentinária / The use of low intensity laser in dentin hypersensitivity

A dor é, indubitalvemente, o sintoma mas comum que leva o paciente a procurar o dentista. Dentre os principais motivos desta visita, destaca-se a hipersensibilidade dentinária, uma sensação negativa e que requer tratamento específico. A etiologia é multifuncional, sendo que a dor se instala principalmente quando a dentina localizada na região cervical do dente fica exposta ao meio bucal. O tratamento eficaz da patologia tem sido motivo de várias pesquisas durante os últimos anos, e sem alguma, o advento do uso do laser na odontologia torna-se uma nova opção de tratamento, destacando-se devido à rapidez e conforto ao paciente. Assim, com base nestas colocações, fez-se um levantamento da literatura pertinente, objetivando a constatação da eficácia da aplicação do laser de baixa intensidade no tratamento da hipersensibilidade dentinária.

The pain is the most common symptom that brings the patiet to seek the dentist. Together with other important factors, which we may highlight the hypersensitivity, a negative feeling that requires an adequate treatment. The etiology is multifatorial, and the pain appears especially when the carvical region dentine is exposed to the oral environment. In order to find the effectiveness treatment for this pathology many researches have been conducted in this (dentistry) during the last years, and undoubtedly, the advent of the use of laser in dentistry opens a new and remarkable option of treatment, which proves to be outstanding due to its fastness and comfort for the patients. Thus, this paper will discuss, according the literature, aiming the effectiveness application of low intensivity laser in dentine hypersensitivity treatment.

Remoção de dentina cariada: abordagem atual / Carious dentine removal: current approach

A odontologia se renova a cada dia mediante os resultados de pesquisas qualificadas. A abordagem quanto à remoção da dentina cariada está passando por questionamentos e inovações. O escopo desse trabalho foi realizar uma revisão literária no sentido de elucidar questões pertinentes à problemática da necessidade ou não de remover completamente a dentina cariada e da possibilidade de restaurar em sessão única, além de discutir a respeito de qual material deve ser aplicado nesse tipo de substrato. Após a análise dos artigos referenciados, concluiu-se que o tratamento expectante controla a progressão da cárie, há uma tendência na literatura de remover a dentina cariada parcialmente em lesões profundas e restaurar de forma definitiva. O cimento de hidróxido de cálcio é um forrador clássico nessas situações, enquanto o cimento de ionômero de vidro e os materiais resinosos representam outras possibilidades de materiais que podem estar em íntimo contato com a dentina remanescente.

Dentistry is renewed day after day through the results of qualified researches. The approach as regards carious dentin removal is going through questioning and innovation. The scope of this study was to perform a literature review in the sense of elucidating questions pertaining to the problem of whether or not it is necessary to completely remove carious dentin, and the possibility of performing restoration in a single session, in addition to a discussion about which type of material should be applied in this type of substrate. After analyzing the referenced articles, it was concluded that the stepwise treatment controls caries progression; there is a trend in the literature to partially remove the carious dentin in deep lesions and perform definitive restoration; Calcium hydroxide cement is a classical liner in these situations, while glass ionomer cement and resinous materials are other possibilities of materials that can be in close contact with the remaining dentin.

Citotoxidade de sistemas adesivos contemporâneos: testes in vitro sobre cultura de macrófagos murinos primários / Cytotoxicity of contemporary adhesive systems: in vitro tests on cultured primary murine macrophages

Este estudo, apresentado na forma de três artigos científicos, teve como objetivo geral avaliar o potencial de citotoxidade dos adesivos Adper Single Bond Plus (SB), Clearfil SE Bond (CF) e Xeno V (XE), observando-se a produção de óxido nítrico (NO) e taxa de sobrevivência celular (MTT assay) de macrófagos alveolares de ratos Wistar.

The main goal of this study, presented as three papers, was to evaluate the potencytotoxicity of Adper Plus Single Bond (SB), Clearfil SE Bond (CF), and Xeno V (XE) adhesives, by observing the production of nitric oxide (NO) and rate of cell survival (MTT assay) of aveolar macrophages from rats...