Root canal pre-treatment and adhesive system affect bond strength durability of fiber posts ex vivo

Objectives: To investigate the effect of different pre-treatments on the long-term bond strength of fiberglass posts luted either with dual-curing self-etch adhesives and core build-up composites or with a self-adhesive resin (SAR) cement. Materials and methods: In total, 180 human root-filled teeth received post-space preparations and three different dentin pre-treatments (PTs): PT1, ethanol (99%); PT2, ethanol-tertiary-butanol-water-solution (AH Plus Cleaner, Dentsply Sirona; York, USA); and PT3, distilled water (control). Five luting systems were used: FU, Futurabond U (Voco; Cuxhaven, Germany); CL, Clearfil DC Bond (Kuraray Noritake; Okayama, Japan); GR, Gradia Core SE Bond (GC Europe NV; Leuven, Belgium); LU, LuxaBond Universal (DMG; Hamburg, Germany); and RX, RelyX Unicem 2 (3M; Minnesota, USA). Roots were cut into six slices (1 mm thick). From each root canal region, three slices were submitted to immediate and three to post-storage push-out testing. The latter were subjected to thermocycling (5–55°C, 6.000 cycles) and stored for six months in saline solution (0.9%, 37°C). Data were analysed using repeated measures ANOVA and chi-square tests (MV±SD). Results: Bond strength was significantly affected by material (p<0.0005), pre-treatment (p=0.016), and storage (p<0.0005; repeated-measures ANOVA). LU (18.8±8.1MPa) revealed significantly higher bond strength than RX (16.08±6.4MPa), GR (15.1±4.6MPa), CL (13.95±5.2MPa), and FU (13.7±6.3MPa). PT1 (16.5±6.9MPa) revealed significantly higher bond strength than PT3 (14.5±5.7MPa). Conclusions: A universal adhesive in self-etch mode combined with a core build-up material revealed higher bond strength than a SAR cement, both interacted positively with Ethanol pre-treatment. Clinical relevance statement: Ethanol (99%) rinsing can be recommended as part of post and core pre-treatment for the investigated luting systems

Hard X-ray phase-contrast-enhanced micro-CT for quantifying interfaces within brittle dense root-filling-restored human teeth

Bonding of resin composite fillings, for example following root-canal treatment, is a challenge because remaining gaps grow and lead to failure. Here, phase-contrast-enhanced micro-computed tomography (PCE-CT) is used to explore methods of non-destructive quantification of the problem, so that countermeasures can be devised. Five human central incisors with damaged crowns were root-filled followed by restoration with a dental post. Thereafter, the crowns were rebuilt with a resin composite that was bonded conventionally to the tooth with a dental adhesive system (Futurabond U). Each sample was imaged by PCE-CT in a synchrotron facility (ID19, European Synchrotron Radiation Facility) with a pixel size of 650 nm. The reconstructed datasets from each sample were segmented and analysed in a semi-automated manner using ImageJ. PCE-CT at sub-micrometre resolution provided images with an impressive increased contrast and detail when compared with laboratory micro-computed tomography. The interface between the dental adhesive and the tooth was often strongly disrupted by the presence of large debonded gaps (on average 34% ± 15% on all surfaces). The thickness of the gaps spanned 2 µm to 16 µm. There was a large variability in the distribution of gaps within the bonding area in each sample, with some regions around the canal exhibiting up to 100% discontinuity. Although only several micrometres thick, the extensive wide gaps may serve as gateways to biofilm leakage, leading to failure of the restorations. They can also act as stress-raising `cracks' that are likely to expand over time in response to cyclic mechanical loading as a consequence of mastication. The observations here show how PCE-CT can be used as a non-destructive quantitative tool for understanding and improving the performance of clinically used bonded dental restorations

Uncovering the unique characteristics of the mandible to improve clinical approaches to mandibular regeneration

The mandible (lower jaw) bone is aesthetically responsible for shaping the lower face, physiologically in charge of the masticatory movements, and phonetically accountable for the articulation of different phonemes. Thus, pathologies that result in great damage to the mandible severely impact the lives of patients. Mandibular reconstruction techniques are mainly based on the use of flaps, most notably free vascularized fibula flaps. However, the mandible is a craniofacial bone with unique characteristics. Its morphogenesis, morphology, physiology, biomechanics, genetic profile, and osteoimmune environment are different from any other non-craniofacial bone. This fact is especially important to consider during mandibular reconstruction, as all these differences result in unique clinical traits of the mandible that can impact the results of jaw reconstructions. Furthermore, overall changes in the mandible and the flap post-reconstruction may be dissimilar, and the replacement process of the bone graft tissue during healing can take years, which in some cases can result in postsurgical complications. Therefore, the present review highlights the uniqueness of the jaw and how this factor can influence the outcome of its reconstruction while using an exemplary clinical case of pseudoarthrosis in a free vascularized fibula flap

Spinning of Endless Bioactive Silicate Glass Fibres for Fibre Reinforcement Applications

Bioactive glasses have been used for many years in the human body as bone substitute. Since bioactive glasses are not readily available in the form of endless thin fibres with diameters below 20 µm, their use is limited to mainly non-load-bearing applications in the form of particles or granules. In this study, the spinnability of four bioactive silicate glasses was evaluated in terms of crystallisation behaviour, characteristic processing temperatures and viscosity determined by thermal analysis. The glass melts were drawn into fibres and their mechanical strength was measured by single fibre tensile tests before and after the surface treatment with different silanes. The degradation of the bioactive glasses was observed in simulated body fluid and pure water by recording the changes of the pH value and the ion concentration by inductively coupled plasma optical emission spectrometry; further, the glass degradation process was monitored by scanning electron microscopy. Additionally, first in vitro experiments using murine pre-osteoblast cell line MC3T3E1 were carried out in order to evaluate the interaction with the glass fibre surface. The results achieved in this work show up the potential of the manufacturing of endless bioactive glass fibres with appropriate mechanical strength to be applied as reinforcing fibres in new innovative medical implants

Inhibition of ovine in vitro fertilization by anti-Prt antibody: hypothetical model for Prt/ZP interaction

BACKGROUND: The impact of prion proteins in the rules that dictate biological reproduction is still poorly understood. Likewise, the role of prnt gene, encoding the prion-like protein testis specific (Prt), in ram reproductive physiology remains largely unknown. In this study, we assessed the effect of Prt in ovine fertilization by using an anti-Prt antibody (APPA) in fertilization medium incubated with spermatozoa and oocytes. Moreover, a computational model was constructed to infer how the results obtained could be related to a hypothetical role for Prt in sperm-zona pellucida (ZP) binding. METHODS: Mature ovine oocytes were transferred to fertilization medium alone (control) or supplemented with APPA, or pre-immune serum (CSerum). Oocytes were inseminated with ovine spermatozoa and after 18 h, presumptive zygotes (n = 142) were fixed to evaluate fertilization rates or transferred (n = 374) for embryo culture until D6-7. Predicted ovine Prt tertiary structure was compared with data obtained by circular dichroism spectroscopy (CD) and a protein-protein computational docking model was estimated for a hypothetical Prt/ZP interaction. RESULTS: The fertilizing rate was lower (P = 0.006) in APPA group (46.0+/−6.79%) when compared to control (78.5+/−7.47%) and CSerum (64.5+/−6.65%) groups. In addition, the cleavage rate was higher (P < 0.0001) in control (44.1+/−4.15%) than in APPA group (19.7+/−4.22%). Prt CD spectroscopy showed a 22% alpha-helical structure in 30% (m/v) aqueous trifluoroethanol (TFE) and 17% alpha in 0.6% (m/v) TFE. The predominant alpha-helical secondary structure detected correlates with the predicted three dimensional structure for ovine Prt, which was subsequently used to test Prt/ZP docking. Computational analyses predicted a favorable Prt-binding activity towards ZP domains. CONCLUSIONS: Our data indicates that the presence of APPA reduces the number of fertilized oocytes and of cleaved embryos. Moreover, the CD analysis data reinforces the predicted ovine Prt trend towards an alpha-helical structure. Predicted protein-protein docking suggests a possible interaction between Prt and ZP, thus supporting an important role for Prt in ovine fertilization

Spinning of Endless Bioactive Silicate Glass Fibres for Fibre Reinforcement Applications

Bioactive glasses have been used for many years in the human body as bone substitute. Since bioactive glasses are not readily available in the form of endless thin fibres with diameters below 20 mu m, their use is limited to mainly non-load-bearing applications in the form of particles or granules. In this study, the spinnability of four bioactive silicate glasses was evaluated in terms of crystallisation behaviour, characteristic processing temperatures and viscosity determined by thermal analysis. The glass melts were drawn into fibres and their mechanical strength was measured by single fibre tensile tests before and after the surface treatment with different silanes. The degradation of the bioactive glasses was observed in simulated body fluid and pure water by recording the changes of the pH value and the ion concentration by inductively coupled plasma optical emission spectrometry; further, the glass degradation process was monitored by scanning electron microscopy. Additionally, first in vitro experiments using murine pre-osteoblast cell line MC3T3E1 were carried out in order to evaluate the interaction with the glass fibre surface. The results achieved in this work show up the potential of the manufacturing of endless bioactive glass fibres with appropriate mechanical strength to be applied as reinforcing fibres in new innovative medical implants

SEVERE CHRONIC PERIODONTITIS AND C-REACTIVE PROTEIN LEVELS

This study aims to analyze the relationship between chronic periodontitis and C-reactive protein (CRP), taking certain associated factors into consideration. A cross-sectional study was conducted on a sample of 75 adults of both sexes. After the participants had been interviewed, they underwent physical and dental examinations and blood collection. CRP levels were evaluated by means of nephelometry. A periodontal clinical examination was conducted by trained examiners and the diagnosis of chronic periodontitis was established when at least 30% of the individual’s teeth presented clinical attachment loss ≥ 5 mm. The analysis procedures consisted of descriptive analysis and linear regression. The results showed that there was no statistically significant difference in CRP levels between the groups with and without periodontitis. The median CRP level in the group with periodontitis was 2.3 mg/l (25-75% interquartile range, IQR = 0.74-5.4) and in the group without periodontitis, 1.8 mg/l (25-75% IQR = 0.79-4.54) (p = 0.417). Log CRP was significantly correlated only with the individual’s body mass index (BMI). The main findings from this study indicate that there is no association between severe chronic periodontitis and CRP, and factors like BMI need to be analyzed carefully in studies on this topic

Reação de resistência de genótipos de quiabeiro ao Meloidogyne incognita raça 1 / Reaction of resistance of okra genotypes to Meloidogyne incognita race 1

A cultura do quiabeiro se mostra sensível a doenças como oídio, podridões e tombamento de pré e pós-emergência, murchas e aos nematoides das galhas. Dentre as medidas de controle recomendadas para os nematoides das galhas, a utilização de cultivares resistentes é um dos métodos mais eficazes. Com isso, o objetivo foi avaliar a reação de resistência de genótipos de quiabeiro à Meloidogyne incognita raça 1. O delineamento experimental utilizado foi o inteiramente casualizado, com oito tratamentos e três repetições, totalizando 24 parcelas experimentais com cinco plantas. As variáveis analisadas foram: incidência de galhas no torrão, número de galhas no sistema radicular, número de ovos e fator de reprodução. Considerando o fator de reprodução, o híbrido experimental TPX-49 apresentou reação de resistência ao Meloidogyne incognita raça 1, sendo um genótipo promissor. O genótipo TPX-59 apresentou maior fator de reprodução dentre os genótipos avaliados

Palivizumabe: a importância da imunização do prematuro contra o vírus sincicial respiratório - Revisão integrativa / Palivizumab: the importance of immunization of preterm infants against respiratory syncytial virus - Integrative reviewod

Introdução: O vírus sincicial respiratório (VSR) que acomete o trato respiratório inferior é responsável por doenças graves nos primeiros meses de vida, sendo uma causa importante de mortalidade nesta faixa etária. A prematuridade é fator de risco para hospitalização e agravamento de doenças pelo VSR. Objetivo: Analisar as produções científicas acerca do uso da imunoglobulina palivizumabe em recém-nascidos prematuros e sua importância. Método: Trata-se de uma revisão integrativa da literatura, onde foram coletadas informações das bases de dados Scielo (Scientific Electronic Library Online), MEDLINE (Medical Literature Analysis and Retrieval System Online) e Lilacs (Literatura Latino-Americana e do Caribe em Ciências da Saúde). Selecionados 11 artigos após adequação aos critérios de inclusão. Resultados: 27,3% dos artigos avaliados obtiveram em seus resultados a redução da taxa de hospitalização por VSR nas crianças que receberam a imunoprofilaxia, 36,6% consideram o custo benefício positivo, 18,2% consideraram que os critérios de elegibilidade são exíguos devido à quantidade de doenças que tornam bebês e crianças imunocomprometidas, especialmente as nascidas prematuras. Conclusão: A imunoprofilaxia é de extrema importância na sobrevida de prematuros acometidos pelo VSR. Os critérios de elegibilidade da imunoglobulina palivizumabe devem ser rediscutidos e reavaliados, a fim de ampliar seu acesso, objetivando queda de morbimortalidade por uma doença imunoprevenível.