Occupational risk resulting from exposure to mineral wool when installing insulation in buildings.

Mineral wool is widely used for thermal and sound insulation. The subject of the study is to identify hazards for employees resulting from exposure to mineral wool, when it is used to insulate buildings, and to assess the risk arising from this exposure. When installing mineral wool insulation, respirable mineral fibers, dust, and volatile organic compounds may pose a hazard at workplaces. Based on the results of concentration measurements, it was assessed that the probability of adverse health effects related to the work of insulation installers, resulting from exposure to mineral wool fibers, is low, but for dust associated with exposure, an average health risk was estimated. An additional threat may be the sensitizing effect of substances used as binders and additives improving the utility properties of mineral wool, for example, phenol formaldehyde resins. The paper also contains some information on the labeling of mineral wool; this is very important because the label allows downstream users to recognize mineral wools, the composition and properties of which cause that they are not classified as carcinogens. Int J Occup Med Environ Health. 2020;33(6):757-69.

Biological impact of lead from halide perovskites reveals the risk of introducing a safe threshold.

Regulations currently in force enable to claim that the lead content in perovskite solar cells is low enough to be safe, or no more dangerous, than other electronics also containing lead. However, the actual environmental impact of lead from perovskite is unknown. Here we show that the lead from perovskite leaking into the ground can enter plants, and consequently the food cycle, ten times more effectively than other lead contaminants already present as the result of the human activities. We further demonstrate that replacing lead with tin represents an environmentally-safer option. Our data suggest that we need to treat the lead from perovskite with exceptional care. In particular, we point out that the safety level for lead content in perovskite-based needs to be lower than other lead-containing electronics. We encourage replacing lead completely with more inert metals to deliver safe perovskite technologies.

The safety of nanostructured synthetic amorphous silica (SAS) as a food additive (E 551).

KEY MESSAGES: Particle sizes of E 551 products are in the micrometre range. The typical external diameters of the constituent particles (aggregates) are greater than 100 nm. E 551 does not break down under acidic conditions such as in the stomach, but may release dissolved silica in environments with higher pH such as the intestinal tract. E 551 is one of the toxicologically most intensively studied substances and has not shown any relevant systemic or local toxicity after oral exposure. Synthetic amorphous silica (SAS) meeting the specifications for use as a food additive (E 551) is and has always been produced by the same two production methods: the thermal and the wet processes, resulting in E 551 products consisting of particles typically in the micrometre size range. The constituent particles (aggregates) are typically larger than 100 nm and do not contain discernible primary particles. Particle sizes above 100 nm are necessary for E 551 to fulfil its technical function as spacer between food particles, thus avoiding the caking of food particles. Based on an in-depth review of the available toxicological information and intake data, it is concluded that the SAS products specified for use as food additive E 551 do not cause adverse effects in oral repeated-dose studies including doses that exceed current OECD guideline recommendations. In particular, there is no evidence for liver toxicity after oral intake. No adverse effects have been found in oral fertility and developmental toxicity studies, nor are there any indications from in vivo studies for an immunotoxic or neurotoxic effect. SAS is neither mutagenic nor genotoxic in vivo. In intact cells, a direct interaction of unlabelled and unmodified SAS with DNA was never found. Differences in the magnitude of biological responses between pyrogenic and precipitated silica described in some in vitro studies with murine macrophages at exaggerated exposure levels seem to be related to interactions with cell culture proteins and cell membranes. The in vivo studies do not indicate that there is a toxicologically relevant difference between SAS products after oral exposure. It is noted that any silicon dioxide product not meeting established specifications, and/or produced to provide new functionality in food, requires its own specific safety and risk assessment.

Management of hyperphosphataemia in chronic kidney disease: summary of National Institute for Health and Clinical Excellence (NICE) guideline.

Bone disease and ectopic calcification are the two main consequences of hyperphosphataemia of chronic kidney disease (CKD). Observational studies have demonstrated that hyperphosphataemia in CKD is associated with increased mortality. Furthermore, the use of phosphate binders in dialysis patients is associated with significantly lower mortality. The UK Renal Registry data show significant underachievement of phosphate targets in dialysis patients. It is believed to be due to wide variation in how management interventions are used. The National Institute for Health and Clinical Excellence (NICE) has developed a guideline on the management of hyperphosphataemia in CKD. This is based on the evidence currently available using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. This review outlines the recommendations including research recommendations and discusses methodology, rationale and challenges faced in developing this guideline and the health economic model used to assess the cost-effectiveness of different phosphate binders.

Clinical evaluation of the performance and safety of a new dentine substitute, Biodentine, in the restoration of posterior teeth - a prospective study.

OBJECTIVES: A multicentric randomized, 3-year prospective study was conducted to determine for how long Biodentine, a new biocompatible dentine substitute, can remain as a posterior restoration. MATERIALS AND METHODS: First, Biodentine was compared to the composite Z100®, to evaluate whether and for how long it could be used as a posterior restoration according to selected United States Public Health Service (USPHS)' criteria (mean ± SD). Second, when abrasion occurred, Biodentine was evaluated as a dentine substitute combined with Z100®. RESULTS: A total of 397 cases were included. This interim analysis was conducted on 212 cases that were seen for the 1-year recall. On the day of restoration placement, both materials obtained good scores for material handling, anatomic form (0.12 ± 0.33), marginal adaptation (0.01 ± 0.10) and interproximal contact (0.11 ± 0.39). During the follow-up, both materials scored well in surface roughness (≤1) without secondary decay and post-operative pain. Biodentine kept acceptable surface properties regarding anatomic form score (≤1), marginal adaptation score (≤2) and interproximal contact score (≤1) for up to 6 months after placement. Resistance to marginal discoloration was superior with Biodentine compared to Z100®. When Biodentine was retained as a dentine substitute after pulp vitality control, it was covered systematically with the composite Z100®. This procedure yielded restorations that were clinically sound and symptom free. CONCLUSIONS: Biodentine is able to restore posterior teeth for up to 6 months. When subsequently covered with Z100®, it is a convenient, efficient and well tolerated dentine substitute. CLINICAL RELEVANCE: Biodentine as a dentine substitute can be used under a composite for posterior restorations.

Comparative assessment of sacral screw loosening augmented with PMMA versus a calcium triglyceride bone cement.

STUDY DESIGN: A calcium triglyceride bone cement (CTBC) was compared with the gold-standard polymethylmethacrylate (PMMA) to assess the stability of augmented sacral screw fixation under cyclic loading. OBJECTIVE: To determine whether CTBC augmentation of a pedicle screw would provide a similar level of fixation in the S1 pedicles compared with PMMA augmentation. SUMMARY OF BACKGROUND DATA: Numerous studies have shown the advantages of using PMMA to augment screw fixation; however, its biomechanical properties are not ideal. CTBC offers potential benefits such as being low exothermic, a modulus of elasticity closer to bone, and the potential for osteoconductivity, but its comparative performance in this situation has not been previously evaluated. METHODS: Six cadaveric sacra were used in this study; 3.0 mL volumes of PMMA (Simplex P) and CTBC (Kryptonite™ Bone Cement) were injected into contralateral screw tracts, with the screw immediately inserted after cement injection. After a 12-hour setting period, the sacrum was potted in a custom fixture and mounted to the frame of a materials testing machine. Alternating flexion and extension bending moments were applied at 1 Hz. Flexion moments were applied starting at 0.5 Nm and increased by 1 Nm after every 1000 cycles until the screw had reached 6° of rotation relative to its starting position. Extension moments were maintained at 0.5 Nm. Screw rotation relative to bone was determined in real time by a custom optical tracking system and was analyzed using two-way repeated-measures analyses of variance (ANOVAs) and post hoc Student-Newman-Keuls tests (α = 0.05). RESULTS: To reach 6° of screw rotation, the PMMA-augmented screw required more loading cycles (15,464 ± 2526 vs. 10,277 ± 1762 cycles; P = 0.006) and a larger applied moment (15.3 ± 2.2 vs. 10.5 ± 1.7 Nm; P = 0.010) than CTBC-augmented screw. CONCLUSION: The PMMA augmentation provided increased resistance to cyclic loading compared with the CTBC augmentation for sacral pedicle screw fixation, but both augmentations well exceeded previously published findings for nonaugmented screws.

Effect of diode laser irradiation on the apical sealing of MTA retrofillings.

Apical sealing is essential for the success of paraendodontic surgery, so any procedure that may favor an adequate sealing of the apical remainder should be performed. The purpose of this study was to evaluate the influence of diode laser irradiation on the apical sealing of root-end cavities with MTA retrofillings. Root canals in twenty extracted human teeth were shaped with K-files and filled with gutta-percha. The apexes were cut off and root-end preparations were performed. The roots were divided randomly in 2 groups. Group 1 (ten specimens) was retrofilled with MTA. Group 2 was irradiated with diode laser, with 1 W for 20 seconds, on the apical surface and root end cavity before retrofilling with MTA. The specimens had their external surfaces impermeabilized with cyanoacrylate, except for the apical surface, and were then immersed in 1% rhodamine B dye for 72 h and placed in plaster stone. After that, the specimens were submitted to longitudinal abrasion until half of the root remained. The linear dye leakage was observed in these mid-roots between the root canal wall and retrofilling. The linear dye leakage was measured with Image Lab software, and the results were statistically analyzed with Student's t test. There were no statistically significant differences between the two groups (p > 0.05). The diode laser irradiation did not improve the apical sealing of MTA retrofillings under the conditions of this in vitro study.

Effect of diode laser irradiation on the apical sealing of MTA retrofillings / Efeito da irradiação de laser de diodo no selamento apical em retrobturações com MTA

Apical sealing is essential for the success of paraendodontic surgery, so any procedure that may favor an adequate sealing of the apical remainder should be performed. The purpose of this study was to evaluate the influence of diode laser irradiation on the apical sealing of root-end cavities with MTA retrofillings. Root canals in twenty extracted human teeth were shaped with K-files and filled with gutta-percha. The apexes were cut off and root-end preparations were performed. The roots were divided randomly in 2 groups. Group 1 (ten specimens) was retrofilled with MTA. Group 2 was irradiated with diode laser, with 1 W for 20 seconds, on the apical surface and root end cavity before retrofilling with MTA. The specimens had their external surfaces impermeabilized with cyanoacrylate, except for the apical surface, and were then immersed in 1 percent rhodamine B dye for 72 h and placed in plaster stone. After that, the specimens were submitted to longitudinal abrasion until half of the root remained. The linear dye leakage was observed in these mid-roots between the root canal wall and retrofilling. The linear dye leakage was measured with Image Lab software, and the results were statistically analyzed with Student's t test. There were no statistically significant differences between the two groups (p > 0.05). The diode laser irradiation did not improve the apical sealing of MTA retrofillings under the conditions of this in vitro study.

O selamento apical é fundamental para o sucesso da cirurgia parendodôntica. Assim, procedimentos que melhorem o selamento do remanescente apical devem ser utilizados. O objetivo deste estudo foi verificar se a irradiação de laser de diodo poderia aumentar o selamento apical em cavidades retrógradas obturadas com MTA. Foram utilizadas 20 raízes de dentes humanos extraídos que, após preparo com lima tipo K, tiveram seus canais obturados com guta-percha. Os ápices foram cortados e sofreram preparo de cavidades retrógradas. As raízes foram divididas aleatoriamente em 2 grupos. O grupo 1 (dez espécimes) foi retrobturado com MTA, e o grupo 2 sofreu irradiação de laser de diodo na potência de 1 W por 20 s na superfície apical e na cavidade retrógrada antes da obturação com MTA. Os espécimes foram impermeabilizados externamente com cianoacrilato, com exceção da superfície apical, imersos em corante rodamina B a 1 por cento por 72 h, incluídos em gesso e posteriormente desgastados no sentido longitudinal até obter-se metade da raiz. Foi feita a leitura da infiltração linear do corante nessas hemi-raízes, entre a parede do canal radicular e a retroobturação, com auxílio do programa de computação Image Lab. Os resultados foram analisados estatisticamente pelo Teste t de Student. Não houve diferença estatística significante entre os dois grupos (p > 0,05). A irradiação com laser de diodo não proporcionou aumento do selamento apical em retrobturações com MTA sob as condições do presente estudo in vitro.

Effect of different dye solutions on the evaluation of the sealing ability of Mineral Trioxide Aggregate.

Alkaline materials have shown incompatibility with methylene blue dye in leakage experiments. The goal of the present study was to analyze the effect of different dyes on the evaluation of the apical sealing ability of Mineral Trioxide Aggregate root-end fillings. Fifty-six extracted human canines were submitted to root canal instrumentation and obturation. After apical resection, retrograde cavities were prepared and teeth were randomly divided into four experimental (n = 13) and two control groups (n = 2). The following root-end filling materials were used: groups 1 and 2--Pro Root MTA (Dentsply), groups 3 and 4--zinc oxide-eugenol cement (ZOE). Teeth in groups 1 and 3 were immersed in 2% methylene blue solution, while teeth in groups 2 and 4 were immersed in 0.2% rhodamine B in a reduced pressure environment for 48 hours. Teeth were then longitudinally sectioned and leakage was evaluated. Results were submitted to statistical analysis (ANOVA and Tukey's test). Group 1 presented the least leakage (p < 0.05). It was concluded that the evaluation of the sealing ability of MTA is influenced by the dye used, since this material presented better sealing ability when evaluated with Methylene Blue, but was similar to ZOE when evaluated with rhodamine B.

Effect of different dye solutions on the evaluation of the sealing ability of mineral trioxide aggregate

Tem sido demonstrada a incompatibilidade de materiais alcalinos com a solucão corante de azul de metileno utilizada em testes de infiltracão marginal. O objetivo do presente estudo foi analisar a influência de diferentes solucões corantes na avaliacão do selamento apical proporcionado pelo agregado de trióxido mineral. Cinqüenta e seis caninos humanos extraídos tiveram seus canais radiculares instrumentados e obturados. Após a seccão da porcão apical, cavidades retrógradas foram preparadas e os dentes divididos aleatoriamente em quatro grupos experimentais (n = 13) e dois controles (n = 2). Foram utilizados os seguintes materiais retrobturadores: grupos 1 e 2 - Pro Root MTA (Dentsply); grupos 3 e 4 - cimento de óxido de zinco e eugenol (OZE). Em seguida, os dentes dos grupos 1 e 3 foram imersos em solucão de Azul de Metileno a 2% e dos grupos 2 e 4 em solucão de Rodamina B a 0,2% por 48 horas em ambiente com vácuo. Decorrido este período, os dentes foram seccionados longitudinalmente, e a infiltracão marginal foi analisada. Os dados obtidos foram submetidos à análise estatística (Análise de variância e teste de Tukey). Os resultados demonstraram que o Grupo 1 apresentou menor infiltracão apical que os demais (p < 0,05). Conclui-se que a avaliacão da capacidade seladora do MTA é influenciada pela solucão corante, uma vez que o mesmo apresentou melhores resultados com o Azul de Metileno e infiltracão marginal semelhante à do OZE quando avaliado em solucão de Rodamina B.