Efeito de diferentes irrigantes finais na resistência união de um cimento de silicato de cálcio: estudo in vitro / Effect of different final irrigants on the bond strength of a calcium silicate cement : in vitro study

Objetivo: Este estudo teve como objetivo avaliar a resistência de união do cimento Biodentine® à dentina radicular após a utilização de diferentes irrigantes finais. Método: Vinte dentes humanos extraídos tiveram seu terço médio radicular cortado em fatias que foram submersas em hipoclorito de sódio 2,5% e posteriormente divididas aleatoriamente em 4 grupos experimentais (n=15) conforme o irrigante final utilizado (1) água destilada (controle), (2) QMixTM, (3) ácido cítrico 10%, (4) EDTA 17%. Após a imersão na substância teste as amostras foram preenchidas com o cimento Biodentine e imersas em solução salina tamponada com fosfato (PBS) por um período de 7 dias. O teste de push out foi realizado e os valores de resistência de união em Mpa foram obtidos. Os dados foram analisados pelos testes de Kruskal Wallis e Studend- Newman-Keuls. Resultados: Os piores valores de união foram obtidos após a utilização do EDTA enquanto a água destilada, o QMix e o ácido cítrico apresentaram resultados estatisticamente semelhantes entre si. Conclusão: A remoção da smear layer não resultou em melhora nos resultados de união do cimento Biodentine.(AU)

Objective: This study aimed to evaluate the bond strength of Biodentine® cement to root dentin after the use of different final irrigants. Method: Twenty extracted human teeth had their middle root third cut into slices that were submerged in 2.5% sodium hypochlorite and then randomly divided into 4 experimental groups (n=15) according to the final irrigant used (1) distilled water (control), (2) QMixTM, (3) 10% citric acid, (4) 17% EDTA. After immersion in the test substance the samples were filled with Biodentine cement and immersed in phosphate buffered saline (PBS) for a period of 7 days. The push out test was performed and the bond strength values in MPa were obtained. The data were analyzed by Kruskal Wallis and Studend- Newman-Keuls tests. Results: The worst bond values were obtained after using EDTA while distilled water, QMix and citric acid showed statistically similar results to each other. Conclusion: Removal of the smear layer did not result in improved bonding results of Biodentine cement.(AU)

Comparison of in vitro erosion protocols in bovine teeth to simulate natural erosion lesion: analysis of mechanical properties and surface gloss

Abstract Objective The aim of this study was to compare two in vitro erosion protocols, in which one simulates in vivo conditions experienced by patients with gastroesophageal disorders or bulimia (HCl-pepsin protocol), and the other simulates the diet of an individual who consumes a high volume of erosive beverages (citric acid protocol). In addition, the mechanical properties and surface gloss of eroded human dentin were compared with those of sound human dentin. Materials and Methods Blocks of cervical dentin were used: sound human dentin (n=10), human dentin with erosive lesions (n=10), and bovine dentin (n=30). Twenty bovine blocks were subjected to either of two erosion protocols (n=10/protocol). In the first protocol, samples were demineralized using HCl-pepsin solution, then treated with trypsin solution. In the second protocol, samples were demineralized with 2% citric acid. Toothbrushing was performed in both protocols using a toothbrushing machine (15 s with a 150 g load). Ten bovine dentin blocks were not subjected to any erosive treatment. All samples of bovine and human dentin were analyzed to obtain Martens hardness values (MH), elastic modulus (Eit*) and surface gloss. One-way ANOVA and Tukey's test were performed to analyze the data (α=0.05). Results Sound human and eroded human dentin groups showed similar MH and Eit* values (p>0.05); however, sound human dentin showed a higher surface gloss value when compared to eroded human dentin (p<0.05). Sound bovine dentin and HCl-pepsin-treated bovine dentin treatments resulted in similar values for both MH and Eit* (p>0.05), but HCl-pepsin-treated bovine dentin and citric acid-treated bovine dentin resulted in lower surface gloss than sound bovine dentin (p<0.05). Conclusions The HCl-pepsin protocol modified bovine dentin properties that could be similar to those that occur on human dentin surfaces with erosive lesions.

Non-contact profilometry of eroded and abraded enamel irradiated with an Er: YAG laser

Abstract Literature has reported positive results regarding the use of lasers in the control of erosive lesions; however, evaluating whether they are effective in the control of the progression of erosive/abrasive lesions is important. Objectives This study aimed to evaluate the effect of the Er:YAG laser irradiation in controlling the progression of erosion associated with abrasive lesions in enamel. Material and methods Bovine incisors were sectioned, flattened and polished. Forty-eight enamel slabs were subjected to treatment in an intraoral phase. Twelve volunteers used an intraoral appliance containing one slab that was irradiated with an Er:YAG laser (5.2 J/cm2, 85 mJ, 2 Hz) and another non-irradiated slab on each side of the appliance, during one phase of 5 d, under a split-mouth design. Devices were subjected to erosive challenges (1% citric acid, 5 min, 3 times a day) and abrasive challenges one h after (brushing force of 1.5 N for 15 s) randomly and independently on each side of the device. Measurements of enamel loss were performed via 3D optical profilometry (μm). We analyzed data using the Kruskal-Wallis and Mann-Whitney tests and morphological characteristics via scanning electron microscopy. Results Following erosive and abrasive challenges, the group that was irradiated with the Er:YAG laser presented less loss of structure than the non-irradiated group. The group that underwent erosion and irradiation did not exhibit a significant difference from the non-irradiated group. Conclusion Irradiation with the Er:YAG laser did not control the loss of structure of enamel subjected to erosion but did control abrasion after erosion.

Interaction of dental pulp stem cells with Biodentine and MTA after exposure to different environments

ABSTRACT Objective: The aim of the present study was to evaluate and compare the cytotoxic effects of Biodentine and MTA on dental pulp stem cells (DPSCs) and to assess cell viability and adherence after material exposure to an acidic environment. Material and Methods: DPSCs were cultured either alone or in contact with either: Biodentine; MTA set for 1 hour; or MTA set for 24 hours. After 4 and 7 days, cell viability was measured using the MTT assay. Biodentine and MTA were also prepared and packed into standardized bovine dentin disks and divided into three groups according to the storage media (n=6/group): freshly mixed materials without storage medium (Group A); materials stored in saline (Group B); materials stored in citric acid buffered at pH 5.4 (Group C). After 24 hours, DPSCs were introduced in the wells and cell adherence, viability, and cellular morphology were observed via confocal microscopy after three days of culture. Cell viability was analyzed using repeated-measures analysis of variance test with Tukey's post hoc tests (α=0.05). Results: Biodentine expressed significantly higher cell viability compared with all other groups after 4 days, with no differences after 7 days. Notably, cell viability was significantly greater in 24-hour set MTA compared with 1-hour set MTA and control groups after 7 days. Material exposure to an acidic environment showed an increase in cell adherence and viability in both groups. Conclusions: Biodentine induced a significantly accelerated cell proliferation compared with MTA. Setting of these materials in the presence of citric acid enhanced DPSC viability and adherence.

Avaliação dos efeitos de diferentes agentes condicionadores na descontaminação da superfície de titânio: estudo in vitro / Evaluation of the effects of different conditioning agents in the decontamination of the implant surface: in vitro study

O uso de implantes osseointegrados vem crescendo nas ultimas decadas e, juntamente com eles, suas complicacoes. A periimplantite se apresenta como uma infeccao bacteriana que afeta os tecidos moles e duros ao redor do implante, promovendo perda da osseointegracao. Assim, o objetivo primario deste estudo foi analisar a efetividade da remocao de bacterias, atraves do software ImageJ, aderidas as superficies de titanio por diferentes agentes quimicos condicionantes, por meio de analise em microscopia eletronica de varredura (MEV). Juntamente foi analisado a alteracao da rugosidade de superficie apos a utilizacao dos agentes. Foi realizado estudo in vitro, no qual 70 covers (prototipos de implantes) passaram por preparo das superficies para adequacao do meio a cultura bacteriana, fixacao das bacterias; e em seguida, foram divididos em 7 grupos (n=10), de acordo com o tratamento: AF180– aplicacao de acido fosforico (AF) por 180 segundos; AF90- AF por 90 segundos; EDTA180 – EDTA por 180 segundos; EDTA90 – EDTA por 90 segundos; AC180 – acido citrico por 180 segundos; AC90 –AC por 90 segundos; Controle – RAR. A analise comparativa do grau de contaminacao bacteriana observado antes e depois do tratamento entre os diferentes grupos foi realizada por meio do teste nao parametrico de Kruskal-Wallis; e as alteracoes da rugosidade superficial foram analisadas por meio do teste ANOVA a dois criterios, pos-teste de Dunnett. Atraves desta metodologia, este trabalho sugere que o tratamento de superficies de titanio contaminadas por meio do emprego de solucao em gel de EDTA a 24% por 90 e 180 segundos e acido citrico a 50% por 180 segundos e efetiva para remocao de A. atinomycetencomitans. Alem disso, o tratamento por meio de EDTA por 90 e 180 segundos promove alteracao significativa dos parametros de rugosidade superficial, especialmente quando comparado aos grupos controle e AF180, indicando que este tratamento pode resultar em subtracao acida adicional.

The use of dental implants has grown in recent decades and, with them, their complications. The periimplantitis is presented as a bacterial infection that affects the soft and hard tissue around the implant, promoting loss of osseointegration. Thus, the primary objective of this study was to analyze the effectiveness of removal of bacteria tby means of the ImageJ software, adhered to the titanium surfaces by different chemical conditions, through analysis in scanning electron microscopy (SEM). The change of surface roughness was also analyzed after using the chemical agents. An in vitro study in which 70 covers (implant prototypes) was prepared for the bacteria culture, fixation of the bacterias; and then they were divided into 7 groups (n = 10), according to the surface treatment: AF180- application of phosphoric acid (FA) for 180 seconds; AF90- AF for 90 seconds; EDTA180 - EDTA for 180 seconds; EDTA90 - EDTA for 90 seconds; AC180 - citric acid for 180 seconds; AC90 -AC for 90 seconds; Control - RAR. The comparative analysis of the degree of bacterial contamination was performed using Kruskal-Wallis non parametric test; and changes of surface roughness were analyzed by ANOVA two criteria, post-test Dunnett. Through this method, this work suggests that treatment of titanium contaminated surfaces by means of EDTA gel solution employing 24% for 90 and 180 seconds and citric acid 50% for 180 seconds is effective for removing A. atinomycetencomitans. Moreover, treatment using EDTA for 90 to 180 seconds promotes significant change of surface roughness parameters, especially when compared to control groups and AF180, indicating that this treatment can result in additional acidic subtraction.

Avaliação dos efeitos de diferentes agentes condicionadores na descontaminação da superfície de titânio: estudo in vitro / Evaluation of the effects of different conditioning agents in the decontamination of the implant surface: in vitro study

O uso de implantes osseointegrados vem crescendo nas ultimas decadas e, juntamente com eles, suas complicacoes. A periimplantite se apresenta como uma infeccao bacteriana que afeta os tecidos moles e duros ao redor do implante, promovendo perda da osseointegracao. Assim, o objetivo primario deste estudo foi analisar a efetividade da remocao de bacterias, atraves do software ImageJ, aderidas as superficies de titanio por diferentes agentes quimicos condicionantes, por meio de analise em microscopia eletronica de varredura (MEV). Juntamente foi analisado a alteracao da rugosidade de superficie apos a utilizacao dos agentes. Foi realizado estudo in vitro, no qual 70 covers (prototipos de implantes) passaram por preparo das superficies para adequacao do meio a cultura bacteriana, fixacao das bacterias; e em seguida, foram divididos em 7 grupos (n=10), de acordo com o tratamento: AF180– aplicacao de acido fosforico (AF) por 180 segundos; AF90- AF por 90 segundos; EDTA180 – EDTA por 180 segundos; EDTA90 – EDTA por 90 segundos; AC180 – acido citrico por 180 segundos; AC90 –AC por 90 segundos; Controle – RAR. A analise comparativa do grau de contaminacao bacteriana observado antes e depois do tratamento entre os diferentes grupos foi realizada por meio do teste nao parametrico de Kruskal-Wallis; e as alteracoes da rugosidade superficial foram analisadas por meio do teste ANOVA a dois criterios, pos-teste de Dunnett. Atraves desta metodologia, este trabalho sugere que o tratamento de superficies de titanio contaminadas por meio do emprego de solucao em gel de EDTA a 24% por 90 e 180 segundos e acido citrico a 50% por 180 segundos e efetiva para remocao de A. atinomycetencomitans. Alem disso, o tratamento por meio de EDTA por 90 e 180 segundos promove alteracao significativa dos parametros de rugosidade superficial, especialmente quando comparado aos grupos controle e AF180, indicando que este tratamento pode resultar em subtracao acida adicional.

The use of dental implants has grown in recent decades and, with them, their complications. The periimplantitis is presented as a bacterial infection that affects the soft and hard tissue around the implant, promoting loss of osseointegration. Thus, the primary objective of this study was to analyze the effectiveness of removal of bacteria tby means of the ImageJ software, adhered to the titanium surfaces by different chemical conditions, through analysis in scanning electron microscopy (SEM). The change of surface roughness was also analyzed after using the chemical agents. An in vitro study in which 70 covers (implant prototypes) was prepared for the bacteria culture, fixation of the bacterias; and then they were divided into 7 groups (n = 10), according to the surface treatment: AF180- application of phosphoric acid (FA) for 180 seconds; AF90- AF for 90 seconds; EDTA180 - EDTA for 180 seconds; EDTA90 - EDTA for 90 seconds; AC180 - citric acid for 180 seconds; AC90 -AC for 90 seconds; Control - RAR. The comparative analysis of the degree of bacterial contamination was performed using Kruskal-Wallis non parametric test; and changes of surface roughness were analyzed by ANOVA two criteria, post-test Dunnett. Through this method, this work suggests that treatment of titanium contaminated surfaces by means of EDTA gel solution employing 24% for 90 and 180 seconds and citric acid 50% for 180 seconds is effective for removing A. atinomycetencomitans. Moreover, treatment using EDTA for 90 to 180 seconds promotes significant change of surface roughness parameters, especially when compared to control groups and AF180, indicating that this treatment can result in additional acidic subtraction.

Effect of different salivary exposure times on the rehardening of acid-softened enamel

Abstract This in situ study assessed the effect of different times of salivary exposure on the rehardening of acid-softened enamel. Bovine enamel blocks were subjected in vitro to a short-term acidic exposure by immersion in 0.05 M (pH 2.5) citric acid for 30 s, resulting in surface softening. Then, 40 selected eroded enamel blocks were randomly assigned to 10 volunteers. Intraoral palatal appliances containing 4 enamel blocks were constructed for each volunteer, who wore the appliance for 12 nonconsecutive hours: initial 30 min, followed by an additional 30, and then by an additional 1 hour. For the last additional 10 hours the appliances were used at night, during the volunteers' sleep. Surface hardness was analyzed in the same blocks at baseline, after erosion and after each period of salivary exposure, enabling percentage of surface hardness recovery calculation (%SHR). The data were tested using repeated measures ANOVA and Tukey's test (α = 0.05). Increasing periods of salivary action promoted a progressive increase in the surface hardness (p < 0.001). However a similar degree of enamel rehardening (p = 0.641) was observed between 2 hours (49.9%) and 12 hours (53.3%) of salivary exposure. Two hours of salivary exposure seems to be appropriate for partial rehardening of the softened enamel surface. The use of the intraoral appliance during sleep did not improve the enamel rehardening after erosion.

Changes in pH of irrigating solutions after contact with human root dentin / Variaciones del ph de soluciones de irrigación endodónticas en contacto con dentina radicular humana

El objetivo de este trabajo fue estudiar in vitro el comportamiento del pH de diferentes soluciones de irrigación endodónticas, usadas solas o en forma consecutiva, después del contacto con dientes humanos extraídos. Se seleccionaron premolares inferiores. El tercio medio radicular se dividió en 6 partes. Los especímenes obtenidos se dividieron en 6 grupos,de acuerdo a la solución de irrigación empleada: 1) agua destilada; 2) NaClO 1 por ciento; 3) Ácido Cítrico 1 por ciento (AC); 4) EDTA 17 por ciento; 5) AC 1 por ciento + NaClO 1 por ciento ; 6) EDTA 17 por ciento + NaClO 1 por ciento. Los especímenes fueron sumergidos en 1 mL de cada solucióna 37°C. Aquellos del grupo 1, 2 y 3 durante 5 minutos, y el resto, consecutivamente 2,5 minutos. Se determinaron pH inicial y final para cada solución. Los datos fueron analizados utilizando Test T, ANOVA y Test de comparaciones múltiples de Tukey. A los 2,5 y 5 minutos de exposición hubo diferencias estadísticamente significativas entre el pH inicial y final en todas las soluciones. El pH disminuyó en el caso de agua destilada e NaClO, mientras que aumentó en AC y EDTA. In vitro, el pH de todas las soluciones se modificó después del contacto con dentina radicular humana en ambos períodos de tiempo (2,5 y 5 minutos).

The aim of this study was to analyze the in vitro behavior of the pH of different irrigating solutions, used alone or consecutively, after contact with extracted human teeth. Mandibular human premolars were selected. The middle thirds were divided into 6 parts. The specimens obtained were divided into 6 groups and treated with irrigating solutions: 1) distilled water; 2) 1% NaOCl; 3) 1% Citric Acid (CA); 4) 17% EDTA; 5) 1% CA + 1% NaOCl; 6) 17% EDTA + 1% NaOCl. Specimens were immersed in 1 mL of each solution at 37ºC, those of groups 1, 2, 3 and 4, for 5 minutes, and the rest, consecutively for 2.5 minutes in each solution. Initial and final pH of the solutions were determined. Data were analyzed by the T Test, one-way analysis of variance (ANOVA) and Tukey multiple comparison Test. At 2.5 and 5 minutes there were significant differences between the initial and final pH for all solutions. The pH values decreased for distilled water and NaOCl, while they increased for CA and EDTA. In vitro, the pH of all solutions was modified after contact with root dentin at both test times (2.5 and 5 min).

Titratable acidity of beverages influences salivary pH recovery

A low pH and a high titratable acidity of juices and cola-based beverages are relevant factors that contribute to dental erosion, but the relative importance of these properties to maintain salivary pH at demineralizing levels for long periods of time after drinking is unknown. In this crossover study conductedin vivo, orange juice, a cola-based soft drink, and a 10% sucrose solution (negative control) were tested. These drinks differ in terms of their pH (3.5 ± 0.04, 2.5 ± 0.05, and 5.9 ± 0.1, respectively) and titratable acidity (3.17 ± 0.06, 0.57 ± 0.04 and < 0.005 mmols OH- to reach pH 5.5, respectively). Eight volunteers with a normal salivary flow rate and buffering capacity kept 15 mL of each beverage in their mouth for 10 s, expectorated it, and their saliva was collected after 15, 30, 45, 60, 90, and 120 s. The salivary pH, determined using a mini pH electrode, returned to the baseline value at 30 s after expectoration of the cola-based soft drink, but only at 90 s after expectoration of the orange juice. The salivary pH increased to greater than 5.5 at 15 s after expectoration of the cola drink and at 30 s after expectoration of the orange juice. These findings suggest that the titratable acidity of a beverage influences salivary pH values after drinking acidic beverages more than the beverage pH.

Adsorption of Cd[II] from aqueous solution by modified and chelated cellulose

The preparation of modified and chelated cellulose adsorbents and its biosorption behaviors of Cd[II] have been studied. Effect of different chemical modifications and its adsorbent properties including different alkalis saponification [NaOH, NH40H] and different acids [citric and oxalic acids] modification after saponification with NaOH were investigated. The infrared spectra showed that there are different functional groups in biosorbents which are able to react with metal ion in aqueous solution. In addition, influences of pH, contact time, and initial concentration of Cd [II] on sorption of Cd [II] were discussed. Different models are used to fit experimental data. Results showed that experimental data follows Langmuir and Freundlich models, and pseudo-second order model. The maximum adsorption capacities obtained from Langmuir model are 76.92 and 122.50 mg g-1 by using control [non modified] and modified biosorbents as an average, respectively. Equilibrium time was obtained at 105 mm, and was accelerated to reach 90 mm. by using the modified treatments. The optimum pH value was 6. Therefore, cellulose can be used as an effective biosorbent for removing Cd [II] from aqueous solution

Effect of denture cleansers on metal ion release and surface roughness of denture base materials

Chemical disinfectants are usually associated with mechanical methods to remove stains and reduce biofilm formation. This study evaluated the effect of disinfectants on release of metal ions and surface roughness of commercially pure titanium, metal alloys, and heat-polymerized acrylic resin, simulating 180 immersion trials. Disk-shaped specimens were fabricated with commercially pure titanium (Tritan), nickel-chromium-molybdenum-titanium (Vi-Star), nickel-chromium (Fit Cast-SB Plus), and nickel-chromium-beryllium (Fit Cast-V) alloys. Each cast disk was invested in the flasks, incorporating the metal disk to the heat-polymerized acrylic resin. The specimens (n=5) were immersed in these solutions: sodium hypochlorite 0.05%, Periogard, Cepacol, Corega Tabs, Medical Interporous, and Polident. Deionized water was used as a control. The quantitative analysis of metal ion release was performed using inductively coupled plasma mass spectrometry (ELAN DRC II). A surface analyzer (Surftest SJ-201P) was used to measure the surface roughness (µm). Data were recorded before and after the immersions and evaluated by two-way ANOVA and Tukey's test (α=0.05). The nickel release proved most significant with the Vi-Star and Fit Cast-V alloys after immersion in Medical Interporous. There was a significant difference in surface roughness of the resin (p=0.011) after immersion. Cepacol caused significantly higher resin roughness. The immersion products had no influence on metal roughness (p=0.388). It could be concluded that the tested alloys can be considered safe for removable denture fabrication, but disinfectant solutions as Cepacol and Medical Interporous tablet for daily denture immersion should be used with caution because it caused greater resin surface roughness and greater ion release, respectively.

Desinfetantes químicos são normalmente associados a métodos mecânicos para remover manchas e reduzir a formação do biofilme. Este estudo avaliou o efeito de desinfetantes na liberação de íons metálicos e na rugosidade superficial do titânio comercialmente puro, ligas metálicas e resina acrílica termopolimerizável, simulando 180 ensaios de imersões. Espécimes em formato de discos foram confeccionados com titânio comercialmente puro (Tritan), liga de níquel-cromo-molibdênio-titânio (Vi-Star), liga de níquel-cromo (Fit Cast-SB Plus) e liga de níquel-cromo-berílio (Fit Cast-V). Os espécimes (n=5) foram imersos nestas soluções: hipoclorito de sódio a 0,05%, Periogard, Cepacol, Corega Tabs, Medical Interporous e Polident. Como controle, foi utilizada a água deionizada. A análise quantitativa de liberação de íons metálicos foi realizada por meio de espectrometria de massa com plasma indutivamente acoplado (ELAN DRC II). O rugosímetro (Surftest SJ-201P) foi utilizado para medir a rugosidade superficial (µm). Os dados foram registrados antes e depois das imersões e avaliados por ANOVA com dois fatores e teste de Tukey (α=0,05). A liberação de níquel provou ser mais expressiva nas ligas Vi-Star e Fit Cast-V após a imersão em Medical Interporous. Houve diferença significante na rugosidade superficial da resina (p=0,011) após a imersão. O Cepacol causou maior rugosidade superficial de forma significativa. Os produtos de imersão não influenciaram nos resultados da rugosidade do metal (p=0,388). Pode-se concluir que as ligas metálicas testadas podem ser consideradas seguras para a fabricação de próteses removíveis, mas as soluções desinfetantes como o Cepacol e a pastilha Medical Interporous para a imersão diária da prótese devem ser utilizados com cautela, pois causaram maior rugosidade superficial da resina e maior liberação de íons, respectivamente.

Effect of different cleansers on the surface of removable partial denture

Removable partial dentures (RPD) demand specific hygienic cleaning and the combination of brushing with immersion in chemical solutions has been the most recommended method for control of biofilm. However, the effect of the cleansers on metallic components has not been widely investigated. This study evaluated the effect of different cleansers on the surface of RPD. Five disc specimens (12 mm x 3 mm metallic disc centered in a 38 x 18 x 4 mm mould filled with resin) were obtained for each experimental situation: 6 solutions [Periogard (PE), Cepacol (CE), Corega Tabs (CT), Medical Interporous (MI), Polident (PO), 0.05 percent sodium hypochlorite (NaOCl), and distilled water (DW) control] and 2 Co-Cr alloys [DeguDent (DD) and VeraPDI (VPDI)] were used for each experimental situation. A 180-day immersion was simulated and the measurements of roughness (Ra, µm) of metal and resin were analyzed using 2-way ANOVA and Tukey’s test. The surface changes and tarnishes were examined with a scanning electronic microscopy (SEM). In addition, energy dispersive x-ray spectrometry (EDS) analysis was carried out at representative areas. Visually, NaOCl and MI specimens presented surface tarnishes. The roughness of materials was not affected by the solutions (p>0.05). SEM images showed that NaOCl and MI provided surface changes. EDS analysis revealed the presence of oxygen for specimens in contact with both MI and NaOCl solutions, which might suggest that the two solutions promoted the oxidation of the surfaces, thus leading to spot corrosion. Within the limitations of this study, it may be concluded that the NaOCl and MI may not be suitable for cleaning of RPD.

As próteses parciais removíveis (PPR) exigem higienização específica e a associação da escovação com imersão em soluções químicas tem sido o método mais recomendado para controle do biofilme. Entretanto, os efeitos destas soluções não são amplamente reportados em componentes metálicos. Este estudo avaliou o efeito de diferentes agentes de higienização na superfície dos componentes de uma PPR. Foram confeccionados 5 espécimes (disco metálico de 12 x 3 mm centralizado em uma tira de resina com 38 x 18 x 4 mm) para cada situação experimental: 6 soluções [Periogard (PE), Cepacol (CE), Corega Tabs (CT), Medical Interporous (MI), Polident (PO), hipoclorito de sódio 0,05 por cento (HS) e água destilada (AD) como controle)] e 2 ligas de cobalto-cromo [DeguDent (DD) e Vera PDI (VPDI)] foram utilizadas para cada situação experimental. Foram simuladas imersões de 180 dias. As aferições de rugosidade (Ra, μm) tanto em porção metálica quanto em resina acrílica termopolimerizável foram submetidos ao ANOVA e ao teste de Tukey. As alterações superficiais e manchas foram examinadas por meio de microscopia eletrônica de varredura (MEV). Áreas de interesse foram submetidas à espectrometria por energia dispersiva por raios X (EDS). Visualmente, puderam ser verificadas manchas nas superfícies metálicas quando utilizados HS e MI. A rugosidade dos materiais não foi afetada pelas soluções (p>0,05). As fotomicrografias evidenciaram que HS e MI ocasionaram alterações superficiais. As análises de EDS revelaram a presença de oxigênio nos grupos HS e MI, o que pode sugerir que estas duas soluções causaram oxidação das superfícies, provocando pontos de corrosão. Dentre as limitações do presente estudo, pode-se concluir que estas soluções não são apropriadas para a higienização das PPR.

Efeito da desmineralização óssea superficial na migração, adesão e diferenciação de pré-osteoblastos / The effect of surface bone demineralization on the migration, adhesion and differentiation of pre-osteoblasts

Resultados de pesquisas prévias tem encontrado potencial aumentado para a consolidação de enxertos ósseos mediante desmineralização do material enxertado e/ou das superfícies de consolidação. Entretanto há carência de embasamento apoiado em evidências biológicas do benefício de tal procedimento. Para testar esta hipótese, o tecido ósseo da calvária de cobaias (Cavia porcellus) foi exposto ao condicionamento por ácido cítrico durante 15, 30, 90 e 180 segundos (grupos teste). Quarenta e cinco discos ósseos de três milímetros de diâmetro foram removidos dos animais, dos quais 36 foram condicionados com ácido cítrico pH 1 a 50% e nove não receberam condicionamento (grupo controle). Sobre nove discos de cada grupo foram cultivados pré-osteoblastos MC3T3-E1 durante 24, 48 e 72 horas (três discos de cada grupo em cada tempo). Análises da morfologia celular, do número de células aderidas sobre as superfícies e da área de cobertura destas superfícies por préosteoblastos foram realizadas à microscopia eletrônica de varredura. Observou-se aumento do número de células aderidas às superfícies com o tempo, independentemente de haver condicionamento ou de seu tempo de aplicação. Entretanto, essa diferença só foi estatisticamente significante intragrupos (p<0,05) e quando comparados os períodos de 24 e 72 horas de incubação. A área de cobertura das superfícies por células aumentou significantemente com o tempo somente nos grupos teste, também entre os períodos de incubação de 24 e 72 horas (p<0,01). O grupo controle apresentou-se com 50% ou menos de área de cobertura superficial em relação aos demais. A duração de aplicação do ácido não interferiu significantemente nesse parâmetro de avaliação, mas nos grupos 15 e 30, a área de recobrimento ósseo mais do que triplicou às 72 horas em relação às 24 horas (p<0,01), com cerca de 70% das superfícies cobertas por células, contra 30% no grupo controle. Conclui-se que a desmineralização óssea...

Results of previous research has found increased potential for the consolidation of bone grafts by demineralization of the graft material and / or areas of consolidation. However there is a lack of foundation supported by biological evidence of benefits from such procedures. To test this hypothesis, the bone tissue of the calvaria of guinea pigs (Cavia porcellus) were exposed to conditioning by citric acid for 15, 30, 90 and 180 seconds (test group). Forty-five bone disks measuring three millimeters in diameter were removed from the animals, of which 36 were conditioned with citric acid pH 1 to 50% and nine did not receive conditioning (control group). About nine disks in each group were pre-cultured with MC3T3- E1 osteoblasts for 24, 48 and 72 hours (three discs of each group at each time point). Analysis of cell morphology, number of cells attached on the surface and the coverage area of these surfaces by pre-osteoblasts were performed on scanning electron microscopy. There was na increase in the number of cells attached to surfaces over time, regardless of conditioning or application time. However, this difference was not statistically significant intra-group (p <0.05) when comparing the periods of 24 and 72 hours of incubation. The coverage area of the surfaces of cells increased significantly with time only in the test groups, also among the incubation periods of 24 and 72 hours (p <0.01). The control group presented with 50% or less of surface area coverage compared to the other. The duration of application of the acid did not affect significantly this parameter of evaluation, but in groups 15 and 30, the bonearea covered more than tripled from 24 to 72 hours (p <0.01), with about 70 % of the area covered by cells, versus 30% in the control group. It was concluded that bone demineralization in the studied conditioning times provides a substrate on which cells acquire pre-osteoblastic morphology compatible with...

Effect of chemical degradation followed by toothbrushing on the surface roughness of restorative composites

OBJECTIVES: The aim of the present study was to assess the effect of the exposure to food-simulating liquids prior to brushing simulation on the surface roughness of five composite materials (Quixfil, Filtek Supreme, Esthet-X, Filtek Z250, Tetric Ceram). Material and METHODS: Twenty cylinders (5 mm diameter and 4 mm height) of each composite were randomly allocated to 4 groups (n=5), according to the food-simulating liquid in which they were immersed for 7 days at 37°C: artificial saliva, heptane, citric acid, and ethanol. After this period, the top surface of composite cylinders was submitted to 7,500 brushing cycles (200 g load). Measurements of the surface roughness (Ra, »m) were carried out before and after the exposure to the chemicals/brushing simulation. Changes on the morphology of composite surfaces were observed through scanning electron microscopy (SEM). RESULTS: The statistical analysis (ANOVA with cofactor / Tukey's test, α=5 percent) detected a significant interaction between solutions and composite resins. Esthet-X, Filtek Z250 and Tetric Ceram were not affected by the food-simulating liquids/toothbrushing. Citric acid and ethanol increased the surface roughness of Quixfil and Filtek Supreme, respectively. SEM images corroborate the surface roughness findings, demonstrating the negative effect from chemical solutions and mechanical abrasion. CONCLUSIONS: The surface roughness of composite resin materials are differently affected by the food-simulating solutions, depending on the immersion media.

The effect of irrigation solutions on the apical sealing ability in different root canal sealers

The aim of this study was to assess the effect of three root canal irrigation solutions on the apical sealing ability of three root canal obturation materials: gutta-percha/AH plus or MM-seal and Resilon/Epiphany SE. A total of 100 teeth with single straight root canals were randomly divided into three equal groups of 30 samples each, with the other 10 teeth (5 positive and 5 negative) used as controls. Each irrigation group was divided into three groups according to the use of three different root canal obturation materials (n = 10): Gutta-percha with AH plus or MM-seal, Resilon with Epiphany SE. The crowns were removed at the cementoenamel junction with a diamond disc under water coolant. The root canals were prepared using step-back technique and irrigation with either sodium hypochlorite (2.5 percent), chlorhexidine (2 percent), or MTAD solutions. The roots were obturated with lateral condensation technique using one of the obturation materials. The root surfaces was coated with two layer nail varnish (except apex), placed in 2 percent methylene blue dye solution, and centrifuged at 3,000 rpm for 5 minutes. Irrigation solutions affected the apical sealing ability of all the sealers. The chlorhexidine irrigation solution exhibited higher apical leakage values than did MTAD and NaOCl in all canal sealers, although the MTAD irrigation solution groups showed the least leakage values. The apical sealing ability of AH plus, Epiphany SE and MM-seal root canal sealers decreased when the chlorhexidine was used as an irrigation solution.

Erosive effect of an antihistamine liquid formulation on bovine teeth: influence of exposure time

Aim: To evaluate, in vitro, the effect of an oral antihistamine liquid formulation on roughness and topography of bovine enamel and the influence of exposure time on its erosive effect. Methods: Forty-one bovine enamel blocks were prepared leaving an exposed window of 0.8 mm2 Thirtynine blocks were divided into three treatment groups according to media immersion: antihistamine. formulation (Histamin ®), 0.6% citric acid (positive control), and distilled water (negative control). Before immersion of the samples, pH, titratable acidity, calcium, phosphate and fluoride contents of all media were verified. Enamel roughness was evaluated at baseline, and after 5, 15, and 30 min of immersion (9 samples per group). Two specimens from each group and exposure time, and 2 additional specimens representing baseline, were analyzed by scanning electron microscopy (SEM). Data were analyzed by the Kruskal-Wallis test, and the Mann-Whitney test using the Bonferroni correction (á=0.017). Results: Specimens immersed in citric acid showed the highest roughness (P<.001). SEM images showed a progressive erosion pattern in samples immersed in citric acid and in antihistamine formulation. Conclusions: The antihistamine liquid formulation did not promote significant alterations of enamel roughness. Nevertheless, SEM demonstrated that the antihistamine eroded bovine enamel, and the erosion pattern was influenced by exposure time.

Ação do EDTA e do ácido cítrico sobre a dentina radicular / Action of EDTA and citric acid on the root dentin

Objetivo: Avaliar a ação quelante do EDTA a 17% e do ácido cítrico a 10% sobre a microdureza da dentina radicular. Método: Utilizou-se 6 caninos superiores humanos. Os dentes foram seccionados longitudinalmente e incluídos em resina epóxi fornecendo assim doze corpos de prova. As amostras foram divididas em três grupos: Grupo 1 - cinco amostras tratadas com ácido cítrico a 10% por 30 segundos; Grupo 2 - cinco amostras tratadas com EDTA a 17% por cinco minutos e Grupo 3 - controle que não recebeu nenhum tratamento com substância quelante. Para avaliar a microdureza da dentina, utilizou-se um aparelho para medição de microdureza na escala Vickers calibrado com 50 gramas de carga e 15 segundos de aplicação. Foram medidas as microdurezas da dentina no terço médio em toda a extensão da luz do canal até a parte periférica próximo ao cemento. Os valores da microdureza dentináriaforam analisados por meio do teste de Aderência e do teste Kruskal-Wallis (p<0,05). Resultados: O EDTA a 17% e o ácido cítrico a 10% afetaram de forma significante a microdureza da dentina radicular, sendo que a ação do EDTA foi significantemente superior que a ação do ácido cítrico. Conclusão: O EDTA a 17% no tempo preconizado para o uso afeta mais a microdureza radicular do que o ácido cítrico a 10% no respectivo tempo ideal de utilização. O ácido cítrico a 10% por 30 segundos é a solução quelante mais indicada para se utilizar na terapia endodôntica, pois remove "smear layer" efetivamente e afeta menos a microdureza dentinária.

Objective: To evaluate the chelating action of 17% EDTA and 10% citric acid on the root dentin microhardness. Method: Six human maxillary canines were used. The teeth were sectioned longitudinally and embedded in epoxy resin, thus providing 12 specimens that were divided in three groups: Group 1 - five specimens treated with 10% citric acid for 30 seconds; Group 2 - five specimens treated with 17% EDTA for 5 minutes; and Group 3 - control (no treatment with any chelating substance). Dentin microhardness was measured using a Vickers microhardness tester with load of 50 g for 15 seconds. Dentin microhardness was measured at the middle root third along the entire canal lumen extension up to the peripheral region close to the cementum. The dentin microhardness values were analyzed statistically by the Adherence test and Kruskal-Wallis test. Significance level was set at 5%. Results: Both chelating solutions affected significantly the root dentin microhardness, but the action of 17% EDTA was significantly greater than that of 10% citric acid. Conclusion: The 17% EDTA affects more the root microhardness than the 10% citric acid, when both chelating agents are used for the recommended clinical time. These results suggest that 10% citric acid for 30 seconds is the most indicated chelating solution for use in endodontic therapy because it removes the smear layer effectively and affects less the root dentin microhardness.

Antimicrobial effect of MTAD, Tetraclean, Cloreximid, and sodium hypochlorite on three common endodontic pathogens.

Objectives: The aim of this in vitro study was to evaluate the antimicrobial action of BioPure MTAD (Dentsply Tulsa Dental, Johnson City, TN), Tetraclean, Cloreximid (a mixture of Chlorhexidine (CHX) digluconate and Cetrimide), and 5.25% NaOCl (Ogna Laboratori Farmaceutici, Milano, Italy) against selected endodontic pathogens (Enterococcus faecalis, Porphyromonas gingivalis, and Prevotella intermedia). Materials and Methods: The agar plate diffusion procedure was used to observe the antimibrobial activity of irrigants. Results: Statistical analysis revealed significant effects of the different irrigants on the bacteria colonies. Treatment with 5.25% NaOCl induced a larger zone of microbial inhibition in Prevotella intermedia and Porphyromonas gingivalis (Tukey HSD post-test, P = 0.0001) when compare to MTAD, Tetraclean and CHX. Anyway, MTAD and Tetraclean were more effective to inhibit bacterial growth compared to CHX (P < 0.0001, Tukey HSD post-test). Furthermore, post hoc analysis revealed that MTAD and Tetraclean induced the largest zone of microbial inhibition of Enterococcus faecalis cultured under both aerobic and anaerobic conditions, when compared with 2% CHX and NaOCl (P < 0.0001, Tukey HSD post-test). The control group showed no microbial inhibition. Conclusion: 5.25% NaOCl showed a high antimicrobial activity against anaerobic bacteria. MTAD and Tetraclean showed a high action against both, strictly anaerobic and facultative anaerobic bacteria. Chlorexidine + Cetrimide (Cloreximid) showed the lowest antibacterial activity against both, facultative and strictly anaerobic bacteria tested.

Process of rock phosphate solubilization by Aspergillus sp PS 104 in soil amended medium.

Aspergillus sp PS 104, a soil isolate had excellent potential to solubilize rock phosphate in vitro. The process was influenced by the presence of various concentrations of local loess (red soil). The simultaneous occurrence, in our experiment, of high levels of solubilized phosphate and synthesized citric acid, together with the lowest reached pH values, confirmed the role of citric acid in the phosphate solubilization mechanism. When the soil was present, phosphate release was better correlated than citrate synthesis with H+ concentration. Changes in soluble phosphate concentration did not follow a sigmoid pattern. The ability of organism to release phosphatase was also studied. An interesting relationship was observed between the two processes of phosphate mobilization: citric acid synthesis and phosphatase production.

Análisis de la acción del ácido cítrico en la remoción del ligamento periodontal necrosado de dientes de ratón / Análise da ação do ácido cítrico na remoção do ligamento periodontal necrosado de dentes de rato / Analysis of the action of citric acid in the removal of mouse necrotized periodontal ligament

El mantenimiento del ligamento periodontal sin vitalidad en la superficie radicular puede influenciar en el proceso de reparación en el reimplante dental, por lo tanto puede ser sustituido por tejido óseo o comenzar un proceso de reabsorción inflamatória. Por lo tanto, muchas formas de retiro de este ligamento se han estudiado. Es propuesta de ese trabajo evaluar, por medio de cortes histológicos, los resultados del tratamiento de la superficie de los dientes sometidos a exodoncias y mantenerlo en medio ambiente por 6 horas. Para la realización del experimiento, se utilizaron 15 ratones, divididos en tres grupos, con 5 dientes cada uno: Grupo I, suero fisiológico por tres minutos; Grupo II, ácido cítrico (pH 1.0) por tres minutos; Grupo III, fricción de la superficie radicular con gaza esteril humedecida con ácido cítrico (pH1.0) por um minuto. Después del procesamiento laboratorial de rutina los cortes fueron sometidos a análisis cuantitativo y cualitativo (Software ImageLab - Diracom 3). En todos los grupos fueron observados restos del ligamento periodontal en toda la extensión palatina de la superfície radicular. El grupo III tuvo la mayor área de tejido con diferencia estadisticamente significante (p> 0.001). Fue posible concluir que el ácido cítrico no fue capaz de remover el ligamento periodontal necrosado de dientes de ratón después de seis horas de resequedad, en ninguna de las formas de aplicación utilizada.

The maintenance of the periodontal ligament without vitality on the root surface can influence in the process of repair in the dental replantation, therefore it can be substituted by bone tissue or to give beginning to a process of inflammatory resorption. Therefore, many forms of removal of this ligament have been studied. It is intention of this work to evaluate, by means of histological study, the results of the treatment of the tooth surface in dental extraction and left in environment for 6 hours. For the accomplishment of the experiment 15 mouse, divided in three groups will be used, with 5 teeth in each: Group I, salt solution per three minutes; Group II, acid citric (pH 1,0) per three minutes e; Group III, friction of the root surface with acid humidified barren gauze with citric (pH 1,0) per one minute. After the laboratorial processing of routine the cuts had been submitted to the qualitative and quantitative analysis (Software ImageLab - Diracom 3). In all the groups had been observed remaining of the periodontal ligament in all palatal extension of the root s surface. Group III showed to greater tissue area with statistic significant difference (p > 0.001). It was possible to conclude that acid the citric one was not capable to after remove the rat periodontal tooth ligament necrosis six hours of drying, in none of the forms of used application.

A manutenção do ligamento periodontal sem vitalidade sobre a superfície radicular pode influenciar no processo de reparo no reimplante dentário, pois pode ser substituído por tecido ósseo ou dar início a um processo de reabsorção inflamatória. Por isso, muitas formas de remoção desse ligamento têm sido estudadas. É propósito de este trabalho avaliar, por meio de cortes histológicos, os resultados do tratamento da superfície de dentes avulsionados cirurgicamente e deixados em meio ambiente por 6 horas com soro fisiológico e ácido cítrico (pH 1.0). Para a realização do experimento serão empregados 15 ratos, divididos em três grupos, com 5 dentes em cada: Grupo I, soro fisiológico por três minutos; Grupo II, ácido cítrico (pH 1.0) por três minutos e; Grupo III, fricção da superfície radicular com gaze estéril umedecida com ácido cítrico (pH 1.0) por um minuto. Após o processamento laboratorial de rotina os cortes foram submetidos à análise qualitativa e quantitativa (Software ImageLab - Diracom 3). Em todos os grupos foram observados remanescentes do ligamento periodontal em toda extensão palatina da superfície radicular. O grupo III mostrou maior área de tecido com diferença estatisticamente significante (p> 0.001). Foi possível concluir que o ácido cítrico não foi capaz de remover o ligamento periodontal necrosado de dentes de rato após seis horas de ressecamento, em nenhuma das formas de aplicação utilizada.