Glass-ceramic Flexural Strength after Hydrofluoric Acid and Unfilled Resin Treatment

poster abstractThe use of hydrofluoric (HF) acid is considered one of the most effective methods for achieving durable resin bond to glass-ceramics. Nonetheless, HF acid etching effect on glass-based ceramics strength remains uncertain and only a few contradictory studies have reported the influence of an unfilled resin (UR) application on the ceramic strength. Objectives: To investigate the effect of HF acid etching followed by silane and UR applications on the biaxial flexural strength of a nanofluorapatite glass-ceramic. Methods: 144 disc-shaped (15±1mm in diameter and 0.8±0.1mm in thickness) nanofluorapatite ceramic specimens were allocated into 12 groups: G1-control (no etching), G2-30s, G3-60s, G4-90s, G5-120s, G6-60s+60s. Meanwhile, G7-G12 were treated in the same fashion as G1-G6, but followed by silane and UR applications. Surface morphology of G1-G12 was assessed by scanning electron microscopy/SEM. The flexural strength was determined by biaxial testing per ISO 6872. Statistical analyses were two-way ANOVA and the Sidak multiple comparisons procedure (α=0.05). Additionally, Weibull statistics and finite element analysis (FEA) were carried out. Results: A significant effect of etching time (p=0.0290) on flexural strength was observed. G4 led to a significantly (p=0.0392) higher flexural strength than G1. Correspondingly, G10 revealed a considerably higher flexural strength than G7 (p=0.0392). Furthermore, flexural strength was significantly higher for G7-G12 than for G1-G6 (p<0.0001). For G1-G6, G4 showed the highest Weibull characteristic strength and G10 also presented the highest Weibull characteristic strength among G7-G12. FEA showed lower stress concentration in G7-G12 with the gradient stress supporting the fracture types of the biaxial test. Finally, the SEM data revealed that the HF acid etching affected the surface of ceramic specimens by generating pores and irregularities and more importantly that the UR was able to penetrate into the ceramic microstructure. Conclusions: HF acid etching followed by silane and UR applications enhanced the ceramic biaxial flexural strength

Cyberbullying and adolescent mental health: systematic review

Cyberbullying is a new form of violence that is expressed through electronic media and has given rise to concern for parents, educators and researchers. in this paper, an association between cyberbullying and adolescent mental health will be assessed through a systematic review of two databases: PubMed and Virtual Health Library (BVS). the prevalence of cyberbullying ranged from 6.5% to 35.4%. Previous or current experiences of traditional bullying were associated with victims and perpetrators of cyberbullying. Daily use of three or more hours of Internet, web camera, text messages, posting personal information and harassing others online were associated with cyberbullying. Cybervictims and cyberbullies had more emotional and psychosomatic problems, social difficulties and did not feel safe and cared for in school. Cyberbullying was associated with moderate to severe depressive symptoms, substance use, ideation and suicide attempts. Health professionals should be aware of the violent nature of interactions occurring in the virtual environment and its harm to the mental health of adolescents.Department of Psychiatry at the Federal University of São PauloAcademic League for Violence Prevention and Intervention (LAPIV)Universidade Federal de São Paulo, BR-05414012 São Paulo, BrazilUniv São Paulo, São Paulo, BrazilUniversidade Federal de São Paulo, BR-05414012 São Paulo, BrazilWeb of Scienc

Depressão e câncer

Depression is the most common psychiatric disorder in patients with cancer, with prevalence rates ranging from 22% to 29%. This variability is associated to cancer sites, clinical stages, pain, limited physical functioning, beyond the existence of social support. Depression is associated to poorer prognosis and higher cancer mortality. Depressive syndromes can be a consequence of the antineoplasic therapies, as occurs in 21% to 58% of the patients treated with alfa-interferon. Sadness and desperation can inhibit the search for care by the patients, and difficult depression recognition. Antidepressant treatment is effective, and improve the adherence to cancer treatments, reducing side effects as nausea, pain and fatigue. In cancer patients, pretreatment with antidepressants seems to minimize depressive symptoms induced by interferon-alfa. Psychosocial interventions as relaxing techniques, group and individual psychotherapies can also be applied to reduce depressive and stress symptoms in patients with cancer.A depressão é o transtorno psiquiátrico mais comum em pacientes com câncer, com prevalências variando de 22% a 29%. Essa variabilidade está associada a sítios do tumor, estágio clínico, dor, funcionamento físico limitado, além da existência de suporte social. A depressão associa-se a um pior prognóstico e aumento da mortalidade pelo câncer. Síndromes depressivas podem ser uma consequência das terapias antineoplásicas, como ocorre em 21% a 58% dos pacientes recebendo interferon-alfa. Sentimentos de tristeza e desespero podem inibir a procura de cuidado pelos pacientes, dificultando o reconhecimento da depressão. O tratamento com antidepressivos é efetivo e melhora a adesão aos tratamentos do câncer, reduzindo efeitos adversos como náusea, dor e fadiga. Em pacientes com câncer, tratamento prévio com antidepressivos pode minimizar sintomas depressivos induzidos por interferon-alfa. O tratamento com antidepressivos parece ser uma estratégia efetiva para prevenir o desenvolvimento da depressão induzida por interferon-alfa. Intervenções psicossociais, como técnicas de relaxamento, terapia individual e em grupo, também podem ser utilizadas na redução dos sintomas depressivos e de estresse em pacientes com câncer

Influence of substrate design for in vitro mechanical testing

The goal of this study was to evaluate the influence of dental substrate simulator material, and the presence of root and periodontal ligament on the stress distribution in an adhesively-cemented monolithic crown. Five (5) 3D models according to the substrate simulator material and shape were modeled with CAD software for conducting non-linear finite element analysis (FEA): Tooth with and without periodontal ligament - subgroup ?pl? (groups Tooth+pl and Tooth-pl), machined tooth in epoxy-resin with and without pulp chamber - subgroup ?pc? (ER+pc and ER-pc) and simplified epoxy-resin substrate without pulp chamber and roots (SiER). Next, adhesively-cemented monolithic crowns in zirconia reinforced lithium silicate were modeled over each substrate. The solids were then imported in STEP format to the analysis software and the contact between teeth and cylinder was considered perfectly bonded; whereas, the contacts involving the resin cement were considered as non-separated. The materials were considered isotropic, linearly elastic, and homogeneous. An axial load (600 N) was applied to the occlusal surface and results of maximum principal stress (MPa) on the restoration were required. FEA revealed that all evaluated subtracts showed the crown intaglio surface as the most stressed region. The average stress and stress peaks were similar for restorations cemented onto Tooth+pl, Tooth-pl and ER+pc substrates, but, 13% higher in comparison to ER-pc and SiER substrates. Simplified substrates can be used to evaluate posterior full crown behavior without periodontal ligaments and roots, since the rigidity of the specimen is taken into account

The influence of custom-milled framework design for an implant-supported full-arch fixed dental prosthesis: 3D-FEA sudy

The current study aimed to evaluate the mechanical behavior of two different maxillary prosthetic rehabilitations according to the framework design using the Finite Element Analysis. An implant-supported full-arch fixed dental prosthesis was developed using a modeling software. Two conditions were modeled: a conventional casted framework and an experimental prosthesis with customized milled framework. The geometries of bone, prostheses, implants and abutments were modeled. The mechanical properties and friction coefficient for each isotropic and homogeneous material were simulated. A load of 100 N load was applied on the external surface of the prosthesis at 30° and the results were analyzed in terms of von Mises stress, microstrains and displacements. In the experimental design, a decrease of prosthesis displacement, bone strain and stresses in the metallic structures was observed, except for the abutment screw that showed a stress increase of 19.01%. The conventional design exhibited the highest stress values located on the prosthesis framework (29.65 MPa) between the anterior implants, in comparison with the experimental design (13.27 MPa in the same region). An alternative design of a stronger framework with lower stress concentration was reported. The current study represents an important step in the design and analysis of implant-supported full-arch fixed dental prosthesis with limited occlusal vertical dimension

Binge eating disorders and psychotherapy: is it possible to systematize a psychodynamic formulation case?

The Core Conflictual Relationship Theme (CCRT) method establishes psychotherapeutic guidelines for a patient's relational patterns. The CCRT was used in the analysis of narratives coming from psychodynamic psychotherapy sessions (taped and transcribed) from a patient suffering from Binge Eating Episodes. The CCRT method made it possible to systematize the connection between psychological conflicts and symptoms, not always an easy task for psychiatrists and psychologists in training.O método Tema Central de Conflito nos Relacionamentos - CCRT sistematiza as inferências feitas por psicoterapeutas dos padrões de relacionamento de pacientes submetidos à psicoterapia. O CCRT foi utilizado na análise das narrativas de uma paciente com Compulsão Alimentar Periódica, submetida a sessões de psicoterapia (gravadas e transcritas). Com o método CCRT foi possível sistematizar a relação entre os conflitos psíquicos e o aparecimento de sintomas, uma tarefa nem sempre fácil para psiquiatras e psicólogos em formação.Universidade Federal de São Paulo (UNIFESP)Universidade de São Paulo Instituto de PsicologiaUniversidade de São Paulo Faculdade de Filosofia, Ciência e Letras de Ribeirão PretoUniversidade de São Paulo Faculdade de Medicina Hospital das ClínicasUNIFESPSciEL

Biaxial flexural strength and Weilbull characteristics of adhesively luted hybrid and reinforced CAD/CAM materials to dentin: effect of self-etching ceramic primer versus hydrofluoric acid etching

This study evaluated the influence of the surface treatment and aging on the biaxial flexural strength of ceramic materials cemented to a dentin analogue. One hundred twenty disc-shaped specimens were allocated into 12 groups considering three study factors: ceramic material (lithium disilicate, leucite-based ceramic and hybrid ceramic), surface treatment (10% hydrofluoric acid etching + silane or self-etching glass-ceramic primer) and Aging (with 10,000 thermocycles of 5–37–55 °C or without). A tri-layer assembly was designed to mimic a cemented restoration (Variolink N) into a dentin analogue. All samples were submitted to the biaxial flexural strength assay. The flexural strength in MPa was calculated using the finite element method for each sample considering thickness, material properties, and the load to fracture during the in vitro test. Fractographic analysis was also performed. The data was evaluated using three-way ANOVA and Tukey test (α = 5%). ANOVA showed influence for the Material*Treatment*Aging interaction on the flexural strength (p = 0.011). The highest strength was calculated for lithium disilicate ceramic + self-etching ceramic primer without aging (499 ± 17 MPa)A and the lowest value for hybrid ceramic material + acid etching with aging (424 ± 48 MPa)E. According to the Weibull modulus, the most predictable strength was calculated for lithium disilicate + acid etching after aging. Acid etching or self-etching ceramic primer promotes similar immediate biaxial flexural strength for each evaluated ceramic. In the long-term, superior strength was observed using acid etching for lithium disilicate and the self-etching ceramic primer for the hybrid ceramic while no difference was observed for leucite-based ceramic