Assessing the bleaching effect of an experimental stabilized chlorine dioxide agent used for internal bleaching purposes

Aim Assessing the intracoronal bleaching effectiveness of an experimental chlorine dioxide product, based on the walking bleach technique. Methods Extracted bovine incisors were artificially stained with bovine blood and filled with zinc phosphate cement at cementoenamel junction level. Teeth were divided into 3 groups (n=10): (SP) sodium perborate added with distilled water, (CD) chlorine dioxide and (C) control - dry cotton inserted into the pulp chamber. Bleaching agents were used at 0, 7 and 14 days. VITA Easyshadetm (∆Eab) was used to analyze tooth color at the 7th, 14th and 21st days, based on the CIE2000 system. Data were analyzed through ANOVA and Tukey's test. Results There were no statistically significant differences in Δb, ΔE, ΔE00 and ΔWID between CD and the control group. These parameters have shown significant differences between CD and SP, which differed from the control. However, they did not show significant differences either in the control group or in CD at the 7th, 14th and 21st days. Values recorded for SP at the 7th day differed from those recorded at the 14th and 21st days. Δa has shown differences within the same group at the 7th, 14th and 21st days. There was no difference between groups, when they were compared at the same day (7th and 14th). The control group differed from SP at the 21st day. CD did not differ from the other two groups. ΔL did not show differences between groups and times. Conclusion Stabilized chlorine dioxide (0.07%, at pH 3.5) should not be used as intracoronal bleaching agent along with the walking bleach technique.

Effects of glycerol and sodium pentaborate containing new formulation on sleeve gastrectomy model in rats

ABSTRACT Purpose: The development of cutting surface leakage and postoperative peritoneal adhesions (PPA) after sleeve gastrectomy (SG) are the most serious operative complications. We investigated the effectiveness of the newly developed glycerol and sodium pentaborate containing formulation on the prevention of these complications. Methods: Sixteen Sprague Dawley rats (mean weight 310 ± 50 g, mean age 3 months old) were divided into two groups, consisting of eight rats in each. SG and a double-layer suture technique were performed for each group. In study group, there was the mixture of 2 mL 3% glycerol plus 3% sodium pentaborate formulation, and in the control group 2 mL 0.9% NaCl was injected into the peritoneal cavity. Rats were sacrificed after 30 days, then macroscopic adhesion grade scoring and histopathological evaluations were assessed. Results: Macroscopic PPA scores in the control and study groups were 2.75 ± 0.16 and 1.50 ± 0.327, respectively (p = 0.004). Histopatologic fibrosis scores in the control and study groups were 0.87 ± 0.125 and 2.00 ± 0.26, respectively (p = 0.002). Conclusions: In SG operation model, glycerol plus sodium pentaborate compound decreased PPA formation and also increased stomach cut surface line fibrosis. This new formulation is hopeful for more safe SG operations.

Determination of the effective anticandidal concentration of denture cleanser tablets on some denture base resins

Abstract Objective Although the effectiveness of chemical cleansing against Candida albicans biofilm has been shown, the effective concentration of denture cleanser tablets has not been studied. The aim of this study was to assess the effect of three denture materials against Candida albicans biofilm and to determine effective concentrations of denture cleanser tablets. Material and methods The surface-roughness of Acron-hi™, QC-20™ and Deflex™ (n=45 per resin) resins was standardized by using a profilometer and their contact angle or surface free energy was calculated. C. albicans biofilm was formed on all three resins and were treated with Polident 3 min™, Corega™ and Fittydent™ cleanser solutions at various concentrations and both resin-biofilm and cleanser-biofilm interest were determined by using a MTT protocol according to the European Committee on Antimicrobial Susceptibility Testing's antifungal susceptibility testing (AFST-EUCAST). Scanning electron microscopy was used to compare the efficacy of different resin materials against C. albicans biofilm. Anticandidal activity and surface free energy statistical parameters were calculated by using 3-way and 1-way ANOVA, respectively (p<0.05). Results Polident 3 min™ and Corega™ tablets significantly inhibited (p<0.05) the proliferation of C. albicans against all denture resins at 27-37 mg/mL. Scanning electron microscopy results indicated that there was no significant difference among resin specimens regarding biofilm formation on dentures. We failed to find a significant relationship between surface free energy and the anticandidal effect of resin types. However, the polarity value of the resins was statistically associated with their anticandidal activity. Conclusions The polarity of the resins, the concentrations of tablets and the chemical content of the cleanser may directly affect C. albicans biofilm formations. Polident 3 min™ and Corega™ tablets should be suggested for patients who use any denture resin types, whereas the Fittydent™ tablet should only be proposed for those who use Deflex™, when two tablets are dropped into 150 mL water.

Photoselective Vaporesection of the Prostate with an End-firing Lithium Triborate Crystal Laser / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Photoselective vaporization of the prostate is a technique that is widely used for the treatment of benign prostatic hyperplasia (BPH) and has pronounced advantages compared to the traditional transurethral resection of the prostate. Following the recent introduction of end-firing lithium triborate lasers, we have created a new technique called photoselective vaporesection of the prostate (PVRP). This study described our initial experience using the PVRP technique for the treatment of BPH.</p><p><b>METHODS</b>This prospective study included a total of 35 patients with BPH who underwent PVRP from August 2013 to July 2014. The chief clinical parameters were obtained and evaluated during the perioperative period and follow-up, including the International Prostate Symptom Score (IPSS), quality of life (QoL) score, maximum urinary flow rate, and prostate volume. All variables were evaluated for statistically significant differences compared to baseline values using the analysis of variance.</p><p><b>RESULTS</b>The mean subgroup IPSS and QoL scores significantly improved during follow-up; the respective decreases in IPSS storage score, IPSS voiding score, IPSS nocturia score, and QoL score were 75.3%, 83.6%, 51.4%, and 71.7%, respectively (all P < 0.001 compared with baseline). Three patients were diagnosed with prostate cancer based on postoperative pathological examinations. There were no serious perioperative complications.</p><p><b>CONCLUSION</b>The PVRP technique demonstrates satisfactory short-term clinical outcomes and perioperative safety in the treatment of BPH.</p>

Determinantes da autoavaliação de saúde no Brasil e a influência dos comportamentos saudáveis: resultados da Pesquisa Nacional de Saúde, 2013 / Determinants of self-rated health and the influence of healthy behaviors: results from the National Health Survey, 2013

RESUMO: Objetivo: Investigar os determinantes da autoavaliação de saúde (AAS) no Brasil e a influência dos comportamentos saudáveis. Métodos: Foram usados os dados da Pesquisa Nacional de Saúde (PNS) de 2013. A AAS foi categorizada em muito boa/boa, regular, ruim/muito ruim. Foram testadas diferenças na distribuição da AAS segundo faixa de idade e sexo e foram usados modelos de regressão logística para investigar os efeitos de grau de escolaridade, raça/cor e presença de pelo menos uma doença crônica não transmissível (DCNT) sobre a AAS ruim/muito ruim. Adicionalmente, testou-se a influência dos comportamentos saudáveis, controlando-se os efeitos dos fatores sociodemográficos e presença de pelo menos uma DCNT. Resultados: Foram analisados 60.202 indivíduos, 66,1% avaliaram o seu estado de saúde como muito bom/bom, e 5,9%, como ruim/muito ruim; 47,1% referiram o diagnóstico de pelo menos uma DCNT; e apenas 9,3% disseram ter "estilo de vida saudável" (não usa produtos de tabaco, consome frutas e hortaliças e pratica atividade física no lazer). Entre os fatores sociodemográficos, idade, sexo, grau de escolaridade e raça mostraram associações significativas com a AAS, bem como a presença de pelo menos uma DCNT. Os efeitos de todos os comportamentos saudáveis foram significativos, mesmo após o controle dos demais determinantes. Conclusão: Embora a adoção dos comportamentos saudáveis no Brasil ainda seja insuficiente, a associação dos hábitos saudáveis com a percepção da saúde encontrada neste estudo é um indício de que a população brasileira já começa a relacionar os comportamentos saudáveis ao seu bem-estar e à avaliação melhor da saúde.

ABSTRACT: Objective: To investigate the determinants of self-rated health in Brazil and the influence of healthy lifestyles. Methods: We used data from the National Health Survey (PNS), 2013. The self-rated health was categorized as very good/good, fair, and poor/very poor. Differences in the distribution of self-rated health according to the age group and sex were tested. Logistic regression models were used to test the effects of educational level, race/skin color, and the presence of at least one noncommunicable chronic disease on poor/very poor health perception. In addition, the influence of healthy behaviors was tested controlling for the effects of sociodemographic factors and the presence of at least one chronic disease. Results: We analyzed 60,202 individuals; about 66.1% rated their health as very good/good and 5.9% as poor/very poor; about 47.1% reported the diagnosis of at least one noncommunicable chronic disease; and only 9.3% reported a "healthy lifestyle" (do not use tobacco products, consume fruits and vegetables properly, and do physical activity during leisure time). Among the sociodemographic factors, age, sex, educational level, and race were significantly associated with self-rated health and the presence of at least one chronic disease. The effects of all healthy behaviors were statistically significant even after controlling for the other determinants. Conclusion: Although the adoption of healthy lifestyles in Brazil is still insufficient, the association of healthy practices with self-perception of health found in this study is an indication that the Brazilian population is beginning to relate healthy behaviors to their well-being and better health evaluation.

Determinación de la dureza total en agua con EDTA empleando una solución amortiguadora inodora de borato / Total hardness water determination by EDTA using a olorless buffer borate

La determinación de Dureza Total con EDTA en agua usando una solución amortiguadora de amonio pH 10 tiene la desventaja de generar vapores de gas amoníaco que suelen ser molestos o ser potencialmente dañinos para el sistema respiratorio del operario. El objetivo de este estudio fue utilizar una solución amortiguadora inodora de borato pH 10 en sustitución de una solución amortiguadora de amonio a pH 10 para la determinación de la dureza total en agua por la metodología de la norma COVENIN 2408-86 y determinar si existía diferencia estadísticamente significativa entre ambos procedimientos. Se determinó la Dureza Total usando la solución amortiguadora inodora de borato en 13 muestras de agua con diferentes grados de dureza (suave, dura y muy dura); los resultados obtenidos se compararon con los valores del procedimiento de referencia. La solución amortiguadora permitió una visualización rápida y definida del punto final durante la ejecución de la determinación volumétrica, los resultados mostraron que no existe diferencia estadísticamente significativa (p≤0,05) en los valores de dureza al emplear ambas soluciones amortiguadoras. Se concluyó que el empleo de la solución amortiguadora inodora de borato para la cuantificación de dureza total en agua es una alternativa a la solución amortiguadora de amonio.

Total Hardness determination EDTA in water using ammonium buffer solution pH 10 has the disadvantage of generating ammonia gas vapors are usually upset or be potentially harmful to the respiratory system operator. The aim of this study was to use a buffer solution pH 10 borate odorless replacing ammonium buffer solution at pH 10 for the determination of total water hardness in the methodology of COVENIN 2408-86 standard and determine whether there was difference statistically significant between the two procedures. Total Hardness was determined using borate buffer odorless in 13 water samples with different degrees of hardness (soft, hard and very hard); the results obtained were compared with the reference method values. The buffer allowed rapid and sharp display of the end point during the execution of the volumetric determination, the results showed that there was no statistically significant difference (p≤ 0,05) in hardness values by using two buffers. It was concluded that the use of borate buffer odorless for quantification of total hardness water is an alternative to the ammonium buffer.

Biocompatibility and bioactivity of calcium silicate-based endodontic sealers in human dental pulp cells

Mineral Trioxide Aggregate (MTA) is a calcium silicate-based material. New sealers have been developed based on calcium silicate as MTA Fillapex and MTA Plus.Objective The aim of this study was to evaluate biocompatibility and bioactivity of these two calcium silicate-based sealers in culture of human dental pulp cells (hDPCs).Material and Methods The cells were isolated from third molars extracted from a 16-year-old patient. Pulp tissue was sectioned into fragments with approximately 1 mm3 and kept in supplemented medium to obtain hDPCs adherent cultures. Cell characterization assays were performed to prove the osteogenic potential. The evaluated materials were: MTA Plus (MTAP); MTA Fillapex (MTAF) and FillCanal (FC). Biocompatibility was evaluated with MTT and Neutral Red (NR) assays, after hDPCs exposure for 24 h to different dilutions of each sealer extract (1:2, 1:3 and 1:4). Unexposed cells were the positive control (CT). Bioactivity was assessed by alkaline phosphatase (ALP) enzymatic assay in cells exposed for one and three days to sealer extracts (1:4 dilution). All data were analyzed by ANOVA and Tukey post-test (p≤0.05%).Results MTT and NR results showed suitable cell viability rates for MTAP at all dilutions (90-135%). Cells exposed to MTAF and FC (1:2 and 1:4 dilutions) showed significant low viability rate when compared to CT in MTT. The NR results demonstrated cell viability for all materials tested. In MTAP group, the cells ALP activity was similar to CT in one and three days of exposure to the material. MTAF and FC groups demonstrated a decrease in ALP activity when compared to CT at both periods of cell exposure.Conclusions The hDPCs were suitable for the evaluation of new endodontic materialsin vitro. MTAP may be considered a promising material for endodontic treatments.

Does prostate size impact upon perioperative outcomes associated with photoselective vaporization of the prostate using the 180W lithium triborate laser?

Photoselective vaporization of the prostate [PVP] has been widely adopted as a surgical treatment for lower urinary tract symptoms due to benign prostatic hyperplasia [BPH]. Recently, a high-powered 180 W lithium triborate [LBO] laser has become commercially available and there is relatively little information on the impact of this very high-powered laser on perioperative outcomes. Even more so is the impact of the laser on outcomes according to prostate size. The objective of this study was to evaluate perioperative outcomes after PVP with the 180W laser, relative to prostate size. A prospectively maintained institutional ethics approved database was retrospectively reviewed. Subjects were analyzed according to transrectal ultrasound and categorized into groups namely 0-39 mL, 40-79 mL, 80-120 mL and >120 mL. Perioperative measures included energy utilized, length of operation, duration catheterization, post operative length of stay [POLOS], Clavien-Dindo adverse events and number discharged home within 24 hours catheter free. With increasing prostate size, there was a statistically significant increase in energy utilization and operation time [P < 0.01 between groups]. Duration of catheterization, POLOS, incidence of Grade 3 and above Clavien-Dindo adverse events and discharge home catheter free within 24 hours was not statistically significant across groups. Prostate volume impacts upon energy utilized with PVP surgery. Prostate volume does not influence duration of catheterization or POLOS. Clavien-Dindo Grade 3 or greater adverse events were low and do not appear to be influenced by prostate size. The ability to be discharged home catheter free within 24 hours likewise does not appear to be influenced by prostate size

Preparation and characterization of uricase in uricase-catalase liposomes prepared using borate buffer / 南方医科大学学报

<p><b>OBJECTIVE</b>To characterize the property of uricase loaded in uricase-catalase liposomes (BUCLPs) prepared using borate buffer.</p><p><b>METHODS</b>BUCLPs were prepared using reverse-phase evaporation, and the physicochemical properties of uricase in the prepared BUCLPs were examined.</p><p><b>RESULTS</b>The optimal temperature of BUCLP and URI was 40 degrees celsius, their optimal pH values were 8.0 and 8.5, and their Michaelis-Menten constants were 14.207 µmol/L and 13.623 µmol/L, respectively. Fluorescence intensity of nanoliposome-loaded uricase-catalase that bound to FITC was higher than that of uricase-catalase binding directly with FITC; the fluorescence intensity of BUCLP was higher than that of free uricase-catalase at 280 nm.</p><p><b>CONCLUSION</b>Uricase activity is enhanced after loading in uricase and catalase liposomes.</p>

Comparison of different methods for total RNA extraction from sclerotia of Rhizoctonia solani

Background Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) is one of the most important pathogens of rice (Oryza sativa L.) that causes severe yield losses in all rice-growing regions. Sclerotia, formed from the aggregation of hyphae, are important structures in the life cycles of R. solani and contain a large quantity of polysaccharides, lipids, proteins and pigments. In order to extract high-quality total RNA from the sclerotia of R. solani, five methods, including E.Z.N.A.™ Fungal RNA Kit, sodium dodecyl sulfate (SDS)-sodium borate, SDS-polyvinylpyrrolidone (PVP), guanidinium thiocyanate (GTC) and modified Trizol, were compared in this study. Results The electrophoresis results showed that it failed to extract total RNA from the sclerotia using modified Trizol method, whereas it could extract total RNA from the sclerotia using other four methods. Further experiments confirmed that the total RNA extracted using SDS-sodium borate, SDS-PVP and E.Z.N.A.™ Fungal RNA Kit methods could be used for RT-PCR of the specific amplification of GAPDH gene fragments, and that extracted using GTC method did not fulfill the requirement for above-mentioned RT-PCR experiment. Conclusion It is concluded that SDS-sodium borate and SDS-PVP methods were the better ones for the extraction of high-quality total RNA that could be used for future gene cloning and expression studies, whereas E.Z.N.A.™ Fungal RNA Kit was not taken into consideration when deal with a large quantity of samples because it is expensive and relatively low yield.

Effect of endodontic irrigation and dressing procedures on the shear bond strength of composite to coronal dentin

This study aimed to evaluate the effects of three sodium hypochlorite [NaOCl]-endodontic irrigation procedures used alone or in combinations with two intermediate dressing materials on bond strengths of two adhesive composite systems to coronal dentin. Surfaces were treated with NaOCl or NaOCl-Glyde-File-Prep [H[2]O[2] and EDTA] with or without chlorhexidine [CHX] as a final rinse. Intermediate dressing materials of calcium hydroxide [Ca[OH][2]] and sodium perborate [SP] were combined with surface treatments. Surface treatment groups [n = 10/group] included [1] distilled water [control], [2] 5.25% NaOCl [30 min], [3] NaOCl/Glyde [30 min], [4] NaOCl/Glyde [30 min] + CHX [2 min], [5] NaOCl/Glyde [30 min]+ Ca[OH][2] [5 days] + CHX [2 min], and [6] NaOCl/Glyde [30 min] + SP [9 days] + CHX [2 min]. For each surface treatment group, dentin shear bond strengths of two different composite systems [Excite/Tetric Flow Chroma, [EX/TFC], and Clearfil Protect Bond/Protect Liner F [PB/PLF]] were evaluated. Median shear bond strengths [EX/TFC, PB/PLF] for each surface treatment group in MPa were [1] 21, 18; [2] 26, 18; [3] 21, 17; [4] 22, 16; [5] 17, 11; and [6] 14, 11, respectively. NaOCl significantly increased the bond strength of EX/TFC [p < 0.05], but did not significantly affect that of PB/PLF. The use of NaOCl/Glyde with CHX did not significantly affect EX/TFC [p > 0.05] whereas it significantly decreased PB/PLF [p < 0.05]. Ca[OH][2] and SP significantly decreased the bond strengths of both adhesive systems [p < 0.05]. Adhesion to coronal dentin is dependent upon the irrigation regimen and the type of adhesive

Effective application duration of sodium ascorbate antioxidant in reducing microleakage of bonded composite restoration in intracoronally-bleached teeth

OBJECTIVES: The aim of this study was to determine an appropriate application duration of sodium ascorbate (SA) antioxidant gel in reducing microleakage of bonded composite restoration in intracoronally-bleached teeth. MATERIALS AND METHODS: Eighty endodontically-treated human incisors were randomly divided into eight groups: control, no bleaching; IB and DB, immediate and delayed bonding after bleaching, respectively; S10m, S60m, S24h, S3d and S7d, bleaching + SA gel for 10 min, 60 min, 24 hr, 3 day and 7 day, respectively. For bleaching, a mixture of 30% hydrogen peroxide and sodium perborate was applied for 7 day. All access cavities were restored using One-Step adhesive (Bisco Inc.) and then Aelite LS Packable composite (Bisco Inc.). The bonded specimens were subjected to 500 thermal cycles, immersed in 1% methylene blue for 8 hr, and longitudinally sectioned. Microleakage was assessed with a 0 - 4 scoring system and analyzed using nonparametric statistical methods (alpha = 0.05). RESULTS: Group IB showed a significantly higher microleakge than the control group (p = 0.006) and group DB a statistically similar score to the control group (p > 0.999). Although groups S10m, S60m, and S24h exhibited significantly higher scores than group DB (p 0.999). CONCLUSIONS: Application of SA gel for 3 day after nonvital bleaching was effective in reducing microleakage of composite restoration in intracoronally-bleached teeth.

Effect of denture cleansers on surface hardness of resilient denture liners at various time intervals- an in vitro study

PURPOSE: This study was aimed to determine the effect of two chemically distinct denture cleansers and water on the surface hardness of acrylic and silicone based soft denture liners at various time intervals. MATERIALS AND METHODS: Two commonly used commercial resilient liner material were selected based on their chemical composition (silicone- and acrylic-based soft liners) for this investigation. 120 cylindrical specimens were made of 15 mm x 10 mm dimensions (according to ASTM: D-2240-64T) in a custom made metal mold. All specimens were stored in artificial saliva throughout the study. Forty specimens were cleansed daily in 0.5% sodium hypochlorite solution; forty were cleansed in sodium perborate and remaining forty specimens were daily rinsed in water. Testing was done at 1 week, 1 month, 3 months and 6 months for surface hardness using a Shore A Durometer. A mean of 3 reading for each sample was subjected to one-way ANOVA, Post Hoc test and pair-t test for statistical analysis. P values of less than 0.05 were taken as statistically significant. RESULTS: Surface hardness of all the samples was significantly higher after a period of 6 months irrespective of the cleansing treatment. Minor changes were observed between control, sodium hypochlorite and sodium perborate groups with time. Greater change was observed in surface hardness of acrylic-based soft denture liners as compared to silicone-based soft liners for all groups, as time progressed. CONCLUSION: Silicone-based soft denture liners performed significantly better in all cleansing treatments than acrylic-based soft denture liners.

The effect of some boron derivatives on kanamycin resistance and survival of E. coli and P. aeruginosa in lake water / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study MIC value of 7 boron derivatives namely [Boric acid (H(3)BO(3)), Anhydrous Borax (Na(2)B(4)O(7)), Sodium Borate (NaBO(2)), Diammonium Tetraborate (NH(4))(2)B(4)O(7), Sodium Perborate (NaBO(3)), Boron Trioxide (B(2)O(3)), Potassium Tetraborate (K(2)B(4)O(7))] on E. coli and P. aeruginosa and their effects on survival of bacteria in lake water and resistance against kanamycin antibiotic.</p><p><b>METHODS</b>MIC values of Boron derivatives and antibiotic were studied by broth microdilution method. The effect of boron derivatives on survival of bacteria in lake water were also determined with plate count.</p><p><b>RESULTS</b>Sodium perborate was determined as the most effective substance among the studied substances. Effectiveness increased as temperature increased. E. coli was more affected from P. aeruginosa in 8 mg/mL sodium perborate concentration in lake water. Moreover, it was determined that MIC value of kanamycin antibiotic decreased 200 times by especially treating P. aeruginosa with sodium perborate in lake water. However, it can be stated that this change in resistance did not arise from microorganisms.</p><p><b>CONCLUSION</b>Sodium perborate solution can be used supportedly in kanamycin antibiotic applications for P. aeruginosa. Future studies are necessary to explore the relation between sodium perborate and kanamycin which is effective on P. aeruginosa in lake water.</p>

Mini-Photoselective Vaporization of the Prostate for Difficult Intermittent Self-Catheterization

Bladder neck incision or transurethral incision of the prostate is a procedure described for men with bladder outflow obstruction associated with a gland size of less than 30 ml. We report a case of a man with detrusor dysfunction who was having increasing difficulty performing clean intermittent self-catheterization of the bladder. The successful use of the 120 W lithium triborate laser to perform a "mini-photoselective vaporization of the prostate" ("mini-PVP") enabled discharge of the patient on the same day as well as resolution of the patient's difficulties in performing self-catheterization. Mini-PVP has proven to be a simple and effective approach to resolution of a prostate configuration impeding the process of clean intermittent self-catheterization.

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.

Use of Aspergillus niger in the bioleaching of colemanite for the production of boric acid

Colemanite is one of the most important underground riches of Turkey, having approximately 60 percent of the world boron deposits, and it has a large portion in the deposits. In this study, chemical leaching and biological leaching methods were used for production of boric acid from colemanite (2CaO · 3B3O3 · 5H2O) (Emet-Kütahya, Turkey). Oxalic acid concentration, temperature, stirring time and solid-to-liquid ratio were taken as parameters in the chemical leaching process. It was found that the dissolution rate increases with increasing oxalic acid concentration and temperature but it decreases at higher solid-to-liquid ratios in the chemical leaching process. Using optimum conditions (d100 = 0.075 mm; 5 percent solids by weight; 0.55 M oxalic acid; 80 +/- 2 ºC leaching temperature; 150 rpm stirring speed; 90 min leaching time) for colemanite sample (28.05 percent B2O3) on chemical leaching with oxalic acid experiments, the calculated boric acid extraction efficiency from colemanite ore was 97.89 percent. Optimum conditions on bioleaching of Emet-Kütahya, Turkey colemanite ores using the fungus Aspergillus niger were found to be as follows: reaction temperature 25 +/- 2ºC; solid-to-liquid ratio 5 percent solids by weight; d100 = 0.075 mm; stirring speed 150 rpm; initial the fungus populations in the inocula about 3 x 10(7) cells/ml and reaction time 21 days. The calculated boric acid extraction efficiency from colemanite ore was 90.18 percent under the optimum conditions. Bioleachate contained 12.95 g/l B2O3, 6.60 g/l Ca and 0.087 g/l Mg. Compared with chemical leaching at 5 percent pulp density, the fungus was less efficient in the extraction of B2O3 from colemanite but the difference in the extraction yields between the two processes was less than 10 percent. Although bioleaching generally requires a longer period of operation compared to chemical leaching, these results suggest that bioleaching by A...

Influence of nano-silica content on flexural properties of the aluminum borate whisker and silica filler composite resins / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To discuss the influence of nano-silica content which was hydrolyzed by tetraethyl orthosioate (TEOS) on the aluminum borate whisker (AlBw) and silica filler composite resins on flexural properties.</p><p><b>METHODS</b>The nanometer-size silicon dioxide (SiO2) particles were prepared by sol-gel method based on tetraethyl orthosioate. Different proportion of AlBw and SiO2 were fused and attached onto the surface of AlBw through high temperature, then polymerized with resin matrix after surface siliconization and their flexural strength and flexural modulus were determined. The effects of heat treatment to the surface morphology of AlBw and the shapes of the mixture at various proportions were characterized by TEM.</p><p><b>RESULTS</b>The flexural properties of dental composite resins with AlBw-SiO2 compound as inorganic fillers were significantly improved. The flexural property of a new type of dental composite resins was(130.29 +/- 8.38) MPa, when the mass ratio of AlBw and nano-SiO2 particle was 3:1.</p><p><b>CONCLUSION</b>Nano-silica content which was hydrolyzed by tetraethyl orthosioate improved flexural properties of the aluminum borate whisker and silica filler composite resins.</p>

Effects of cleaners on the color stability of prosthesis silicone rubbers / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of different cleaners on the color stability of two silicone rubbers used for maxillofacial prosthesis, and to provide recommendations for clinical use.</p><p><b>METHODS</b>Thirty skin-color columniform specimens (12 mm diameter, 10 mm height) of two silicone rubber (A:A-2000; Z:ZY-1) were prepared, randomly divided into 6 groups according to the table of random number, and cleaned with the following solutions: isopropyl alcohol (I), three kinds of denture cleaners (P: Polident, S: Steradent, C: Cleansoft) and distilled water (D), simulating the total immersion time of 1 year (1, 15, 10, 3 and 10 min each time respectively). Control group was kept in dark place without treatment. The L(*), a(*), b(*) value were tested before and after immersion. Then color difference value was calculated.</p><p><b>RESULTS</b>Color differences were different among groups. Color difference in group I (A: 2.15, Z: 2.00) were significantly greater than that in any other group. There were no significant differences between groups using denture cleaner P (A: 0.36, Z: 0.36), C (A: 0.42, Z: 0.37) and S (A: 0.33, Z: 0.38), and group D (A: 0.22, Z: 0.23).</p><p><b>CONCLUSIONS</b>Isopropyl alcohol causes the most severe fading, and denture cleaners and distilled water cause obscure fading.</p>