Cytotoxic effects of cyanoacrylates used as retrograde filling materials: an in vitro analysis

Os cianoacrilatos tem encontrado aplicabilidade tanto na Medicina como na Odontologia há muitos anos. Têm sido usados como curativo após exodontias, bem como para obturação retrógrada em cirurgia parendodôntica. O objetivo deste estudo foi o de avaliar o efeito citotóxico do Histoacryl e outros dois homólogos etil cianoacrilatos: SuperBonder e Ultrabond, em cultura de fibroblastos, empregando ensaios de viabilidade pela exclusão de células coradas pelo azul de Trypan. Os cianoacrilatos foram aplicados em lamínulas de vidro circulares, que foram colocadas sobre cultura de fibroblastos NIH - 3T3. Após 0, 6, 12 e 24 horas (resposta celular imediata - curto prazo) e 1, 3, 5 e 7 dias (sobrevivência celular - longo prazo), foram efetuadas contagens celulares em microscópio de fase. Os dados obtidos foram analisados valendo-se do teste estatístico de Kruskal-Wallis. No experimento de curto prazo, somente as culturas do grupo Ultrabond (GIV) apresentaram porcentagens de viabilidade celular significantemente menores que a dos outros grupos (GI: controle; GII: Super Bonder; GIII: Histoacryl). Embora as culturas do grupo Super Bonder (GII) apresentassem porcentagens de viabilidade celular menores que as dos outros grupos (GI, GIII, GIV) no experimento de longo prazo, esse grupo foi o único que mostrou crescimento celular progressivo e contínuo. Nossos resultados mostraram biocompatibilidade in vitro tanto do Histoacryl como dos outros dois homólogos etil cianoacrilatos. Esses cianoacrilatos podem ser importantes para finalidades biológicas.Cyanoacrylate has been used in medicine and dentistry for many years. It has been used as a postextraction dressing and retrograde filling material in endodontic surgery. The aim of this study was to evaluate the cytotoxic effects of Histoacryl and other two homologue ethyl cyanoacrylates, Super Bonder and Ultrabond, on cultured fibroblasts, using the Trypan blue dye exclusion assay. The cyanoacrylates were applied to round glass coverslips, which were placed in contact with NIH 3T3 cells. After 0, 6, 12 and 24 h (short-term assay; viability) and 1, 3, 5 and 7 days (long-term assay; survival), the cells were examined under phase light microscopy and counted. The data were compared by the Kruskal-Wallis test. In the short-term experiments, only the cultures of the Ultrabond group (GIV) presented significant smaller percentages of cell viability than the cultures of the other groups (GI: control; GII: Super Bonder; GIII: Histoacryl). Although the cultures of the Super Bonder group (GII) presented smaller percentages of cell viability than cultures of the other groups (GI, GIII, GIV) at the long-term assay, this group was the only experimental group presenting a continuous and progressive cell growth. Our results have shown an in vitro biocompatibility of Histoacryl and ethyl cyanoacrylate homologues. These cyanoacrylates could therefore be of importance for endodontic purposes

Micromorphological and hardness analyses of human and bovine sclerotic dentin: a comparative study

The purpose of this study was to test the hypothesis that both human and bovine sclerotic dentin have similar hardness properties, in addition to similar micromorphological characteristics. Sixteen teeth (8 human and 8 bovine) exhibiting exposed dentin in the incisal edge and showing characteristics typical of sclerosis were used. Vickers surface microhardness testing was conducted. Three areas of the dentin surface of each specimen were selected. All teeth were processed for scanning electron microscopy in order to estimate the amount (in percentage) of solid dentin on the sclerotic dentin surface. The data were compared by Student's t test (α = 0.05). The micromorphological and microhardness data were compared by Pearson's linear correlation test (α = 0.05). The mean percentages of solid dentin of human and bovine sclerotic dentin were similar (human 90.71 ± 0.83 and bovine 89.08 ± 0.81, p = 0.18). The mean microhardness value (VHN) of human sclerotic dentin was significantly higher than that of bovine sclerotic dentin (human 45.26 ± 2.92 and bovine 29.93 ± 3.83, p = 0.006). No correlation was found between the microhardness values and the amount of solid dentin in the sclerotic dentin, irrespective of the species considered (human R² = 0.0240, p = 0.714; bovine R² = 0.0017, p = 0.923; and combined R² = 0.038, p = 0.46). We concluded that although both bovine and human sclerotic dentin present a similar amount of solid tissue, human sclerotic dentin presents higher microhardness than bovine sclerotic dentin.(FAPESP) São Paulo Research Foundation(CAPES) Coordination for the Improvement of Higher Education Personne

Pulp capping materials exert an effect on the secretion of IL-1β and IL-8 by migrating human neutrophils

Pulp repair is a complex process whose mechanisms are not yet fully understood. The first immune cells to reach the damaged pulp are neutrophils that play an important role in releasing cytokines and in phagocytosis. The objective of this study was to analyze the effect of different pulp-capping materials on the secretion of interleukin-1 beta (IL-1&#946;) and interleukin-8 (IL-8) by migrating human neutrophils. Neutrophils were obtained from the blood of three healthy donors. The experimental groups were calcium hydroxide [Ca(OH)2], an adhesive system (Single Bond), and mineral trioxide aggregate (MTA). Untreated cells were used as control. Transwell chambers were used in performing the assays to mimic an in vivo situation of neutrophil chemotaxis. The pulp-capping materials were placed in the lower chamber and the human neutrophils, in the upper chamber. The cells were counted and the culture medium was assayed using ELISA kits for detecting and quantifying IL-1&#946; and IL8. The data were compared by ANOVA followed by Tukey's test (p < 0.05). The secretion of IL-8 was significantly higher in all groups in comparison to the control group (p < 0.05). The adhesive system group showed higher IL-8 than the MTA group (p < 0.05). The secretion of IL-1&#946; was significantly greater only in the MTA group (p < 0.001). It was concluded that only MTA is able to improve the secretion of IL-1&#946;, and all materials tested increased IL-8 secretion. These results combined with all the other biological advantages of MTA indicate that it could be considered the material of choice for dental pulp capping.(FAPESP) São Paulo Research Foundatio

Tricho-rhino-phalangeal syndrome type I as a “cis-ruption disorder” caused by a translocation

Tricho-rhino-phalangeal syndrome type I (TRPS I; OMIM 190350) and type II (OMIM 150230) are two forms of the rare autosomal-dominant TRP malformation syndrome localised in 8q23.3–24.1. TRPS I is generally caused by point mutations or deletions of the TRPS1 gene, whereas type II is characterised by the presence of multiple cartilage exostoses (EXT) and deletions comprising the TRPS1 and EXT1 genes. In the present study, we have mapped and sequenced the breakpoints of a balanced familial translocation [t(8;13)(q23.3;q21.32)] segregating with mild TRPS I and analysed the TRPS1 candidate gene. The proband, in addition to features compatible with TRPS I, also presented developmental delay and severe mental retardation. The pathogenic chromosome 8 breakpoint was localised within a transposon type I element at 116.768 Mb, 87 kb from the TRPS1 5′ end. The breakpoint on chromosome 13 was localised within a gene-poor region at 65.101 Mb, and the nearest gene, 1.5 Mb distal from the breakpoint, is protocadherin 9 (PCDH9). Analysis of the three affected relatives by the 33K tiling BAC array and of the proband by 2.7-M high-resolution oligonucleotide array painting did not reveal additional genomic variation. Furthermore, mutation screening of the TRPS1 also did not reveal any alteration. Finally, expression studies of TRPS1 performed from LCLs indicate that inter-individual variation is higher than the expected gene expression changes induced by the translocation. Although the reason underlying the severe mental retardation observed in the proband is unknown, the available data indicate that this is not associated with the translocation. As far as we know, this is the first reported case of position effect or “cis-ruption” causing TRPS I. Finally, further studies are necessary to unveil the molecular pathogenic mechanisms of this “cis-ruption disorder” triggered by chromosometranslocation

Fragile X syndrome: intergenerational allele instability and associated phenotypes in families

Fragile X syndrome (FXS) is the most common hereditary form of intellectual disability with an estimated frequency of 1/4000 males and 1/8000 females. This disease is caused by a (CGG)n expansion in the 5’UTR of the FMR1 gene, which as a result is methylated and gene silenced. Four classes of alleles can be found based on CGG repeat length: normal (5-44), intermediate (45-54), premutation (55-200) and full mutation (>200). In premutation carriers, both FMR1-related primary ovarian insufficiency (FXPOI) and fragile-X associated tremor/ataxia syndrome (FXTAS) have been described. To gain insights into instability of FMR1 CGG repeats and associated phenotypes, we studied 541 individuals from 128 FXS Portuguese families. DNA samples were genotyped by PCR and Southern blot analysis. Additional clinical evaluation was performed in premutation carriers. Among FXS families, 5.3% intermediate, 29.9% premutation and 26.6% full mutation alleles were found. Normal and intermediate alleles were stable upon transmission. For 115 maternal premutation transmissions, 26 (23%) with alleles ranging 60-98 CGGs remained in premutation size with an average expansion of 17 repeat units, whereas 89 (77%) with alleles ranging from 66-199 CGGs expanded to full mutation. In 44 transmissions of maternal full mutation, the offspring inherited alleles in the full mutation range. For 10 paternal transmissions of premutations, ranging 56-120 CGGs, all daughters inherited a premutation allele, with an average expansion of 7 repeat units. After clinical evaluation of 7 premutation carriers, 1 male with FXTAS and 2 females with FXPOI were identified; however the remaining premutation individuals were not yet examined. In Portuguese FXS families, allele instability upon transmission is in agreement with previous reports. The risk of premutation to full mutation expansion increases with maternal premutation size.FCT Fundação para a Ciência e a Tecnologi

Programa de secagem para a madeira de seringueira (Hevea brasiliensis Muell. Arg.)

The rubber tree (Hevea brasiliensis Muell. Arg.) has been cultivated for tapping purposes and it is considered as wood supply in the end of the productive cycle of latex. Drying is one of the most important steps in the mechanical processing of wood. As far as rubberwood is concerned, kiln-drying is particularly an essential step due to its high susceptibility to decay and mold fungi attacks mainly when the wood moisture content is high. Thus, this study aimed to develop and evaluate a conventional drying schedule for four clones of Hevea brasiliensis (IAN-873, IAN-717, GT-711 and AVROS-1301) planted in Ituberá and Grapiúna counties in the Bahia state, Brazil. The conventional drying schedule applied, with minimum and maximum drying temperatures, respectively, of 50°C and 75°C in a Hildebrand test dryer kiln with a Gann automatic control, was efficient, producing a very fast drying (less than 4 days for clones IAN-873, IAN-717 and GT-711) and fast (4,5 days to clone AVROS-1301) with low drying defects development.A seringueira (Hevea brasiliensis Muell. Arg.) tem sido cultivada para extração de látex e utilizada para produção de madeira ao fim do ciclo produtivo do látex. A secagem é uma etapa fundamental no processamento mecânico da madeira. No caso da madeira de seringueira, faz-se particularmente necessária a secagem artificial em estufa para a sua utilização, devido à alta susceptibilidade ao ataque de fungos emboloradores e apodrecedores quando úmida. Dessa maneira, este trabalho teve como objetivo elaborar e avaliar programa de secagem convencional para quatro clones de Hevea brasiliensis (IAN-873, IAN-717, GT-711 e AVROS-1301) plantados nos municípios de Ituberá e Grapiúna, no Estado da Bahia, Brasil. O programa de secagem convencional utilizado, com temperatura inicial de 50°C e final de 75°C, aplicado em uma estufa Hildebrand tipo “Test Dryer” com controle automático Gann, foi eficiente, produzindo uma secagem muito rápida (menos de 4 dias para os clones IAN-873, IAN-717 e GT-711) e rápida (4,5 dias para o clone AVROS-1301), observando-se uma baixa incidência de defeitos de secagem

A novel insertion from chromosome 18 to chromosome 15 with a 183Kb 18q deletion

Chromosome 18q- syndrome is a rare chromosomal disorder with an incidence of 1 in 40 000 live births. The phenotype is highly variable, depending on the amount of deleted genetic material, and is characterized by mental retardation, developmental delay, hypotonia, seizures, obesity, abnormal behavior, short stature and craniofacial dysmorphisms. We report a patient with mental retardation, dysmorphic features, hypotonia, growth retardation, severe expressive speech delay and Duane syndrome, with an insertion of 18q in 15q causing a 183Kb deletion in18q. Cytogenetic and SNP array analysis showed a female karyotype presenting a de novo rare chromosome rearrangement: an insertion of the 18q21q23 on the 15q22 region, with deletion 18q12.3 (chr18:42,484,980-42,667,966, [GRCh37]), involving only the MIR4319 and SETBP1 genes. There are few reports of 18q12.3 deletion associated with mild dysmorphic features, mental retardation and impairment of expressive language. To our knowledge this is the smallest deletion described, involving two genes: SETBP1 and a microRNA (MIR4319). SETBP1 gene is associated to expressive speech delay. The authors present a literature review of 18q12.3 deletion.info:eu-repo/semantics/publishedVersio

Characterization of bone cells obtained from the calvaria of neonatal rats (osteo-1) after serial subculture

The objective of the present study was to characterize bone cells grown in two culture media, and to determine the effective concentration of OP-1 on the growth of osteo-1 cells. Subcultured rat bone cells (osteo-1) were grown in alpha-modified Eagle's minimal essential medium (alpha-MEM) and Dulbecco's modified Eagle's medium (DMEM) and total protein content, alkaline phosphatase activity and the formation of mineralized nodules were evaluated after 7, 14 and 21 days. Cells were exposed to different concentrations of rhOP-1 for 1, 3, 5 and 7 days and compared with an untreated control. Osteo-1 cells presented a significant increase in alkaline phosphatase activity and calcium deposits were observed at 21 days. Cells treated with 10 and 20 ng/mL rhOP-1 for 24 h showed a significant increase in cell viability when compared to control. Osteo-1 cells cultured on DMEM demonstrated an osteoblastic phenotype as indicated by high alkaline phosphatase activity and the presence of calcified nodules. The results suggest that low concentrations of OP-1 may promote an osteogenic effect on osteo-1 cells

Cytotoxicity of substances leached from a root canal sealer based on mineral trioxide aggregate

Objetivo: Com base nas características biológicas e físico-químicas do agregado de trióxido mineral (MTA), este seria o material mais adequado para a obturação do canal radicular. No entanto, esse material apresenta baixo escoamento e, consequentemente, difícil manipulação. O MTA Fillapex (MTA-F) foi criado na tentativa de combinar as propriedades físico-químicas do cimento endodôntico com as propriedades biológicas do MTA. No entanto, os estudos sobre as características biológicas do MTA-F ainda são controversos. Dessa forma, este estudo teve como objetivo analisar in vitro a citotoxicidade do MTA-F. Materiais e Métodos: fi broblastos gengivais foram cultivados em Dulbecco’s modifi ed Eagle Medium (DMEM) e submetidos ao meio de cultura condicionado pelo MTA ou MTA-F. Esse meio condicionado continha substâncias liberadas pelos cimentos endodônticos. Células cultivadas em meio fresco serviram como controle positivo. A viabilidade celular foi avaliada por ensaio do MTT após 1, 3, 5 e 7 dias. Os dados obtidos foram comparados por análise de variância (ANOVA) seguida pelo teste de Tukey (p &lt; 0,05). Resultados: As células submetidas ao meio condicionado pelo MTA apresentaram curva de crescimento celular semelhante à das células do grupo controle. Para o grupo MTA-F, não houve crescimento celular e foi observado um número de células viáveis significativamente menor do que o dos demais grupos durante todo o experimento. Conclusão: Substâncias liberadas a partir de MTA-F não permitiram o crescimento celular, mostrando que esse cimento endodôntico à base de MTA é altamente citotóxico. A característica de biocompatibilidade do MTA pode ser perdida com o MTA-F e comprometer o sucesso do tratamento endodôntico.Aim: Based on its biological and physicochemical characteristics, mineral trioxide aggregate (MTA) could be considered the most appropriate material for root canal obturation; nevertheless, handling of MTA is not easy. The MTA Fillapex (MTA-F) was created in an attempt to combine the physicochemical properties of a root canal sealer with the biological properties of MTA. However, the studies on the biological characteristics of MTA-F are still controversial. Thus, this study aimed to analyze the cytotoxicity of MTA-F. Materials and Methods: Cultured human gingival fi broblasts were grown in Dulbecco’s modifi ed Eagle Medium (DMEM) and submitted to a cell culture medium conditioned by MTA or MTA-F. The conditioned medium contained substances leached from the root canal sealers. Cells grown on a fresh medium served as a positive control. Cell viability was assessed by MTT assay at 1, 3, 5 and 7 days. Data was compared by ANOVA followed by Tukey’s test (p &lt; 0.05). Results: Cells submitted to media conditioned by MTA presented a cell growth curve similar to that of the control cells. For the MTA-F group, cell growth was not observed and cell viability was signifi cantly lower than for the other groups during the entire experiment. Conclusion: Substances leached from MTA-F did not allow cell growth, indicating that this MTA-based root sealer is highly cytotoxic. The biocompatibility characteristic of MTA can be lost with MTA-F, and may compromise the endodontic treatment outcome