Análise comparativa da resistência flexural de duas resinas indiretas

Purpose: The system of indirect composite resins is an alternative esthetics treatment aiming to solve some of the problems present in the ceramic restorations and conventional resins. The aim of this study was to evaluate and compare the flexural strength in three points, of two indirect restorative materials, Sinfony® (3M-ESPE) and Ceramage® (Shofu). Materials and Methods: Twelve samples were made of each material with 15 mm diameter and 2 mm thick. After 24 hours of preparation, the discs were subjected to flexural strength test at three points in a universal testing machine EMIC, at constant speed of 0.5 mm/min and load cell of 50 Kgf. The data were analyzed by Student T test, the significance level of 5%. Results: The Ceramage had the highest average (98.90 MPa) of resistance to bending by the method biaxial compared to Sinfony (86.90 MPa), the difference had being statistically significant. Conclusion: Within the limitations of this study, we conclude that the Ceramage showed higher values of flexural strength than Sinfony, being an excellent option of indirect restorative material for the clinician.Objetivos: O sistema de resinas compostas indiretas constitui uma alternativa de tratamento estético com o objetivo de solucionar alguns dos problemas presentes nas restaurações das cerâmicas e das resinas convencionais. O presente estudo teve o objetivo de avaliar e comparar a resistência flexural, em três pontos, de dois materiais restauradores indiretos, Sinfony® (3M-ESPE) e Ceramage® (Shofu). Materiais e Métodos: Foram confeccionados 12 corpos de prova de cada material com 15 mm de diâmetro e 2 mm de espessura. Decorridas 24 horas após a confecção, os discos foram submetidos ao teste de resistência flexural em três pontos em uma máquina de ensaio universal EMIC, a uma velocidade constante de 0,5 mm/min e com célula de carga de 50 Kgf. Os dados foram avaliados estatisticamente pelo Teste t de Student, ao nível de significância de 5%. Resultados: A resina Ceramage apresentou a maior média (98,90 MPa) de resistência à flexão pelo método biaxial comparado ao grupo Sinfony (86,90 MPa), sendo esta diferença estatisticamente significante. Conclusão: Dentro das limitações deste estudo, podemos concluir que a resina Ceramage apresentou maior resistência flexural que a resina Sinfony, sendo uma excelente indicação de material restaurador indireto para o clínico

Stress distribution in fixed mandibular prostheses fabricated by CAD/CAM and conventional techniques : photoelastic and strain gauge analyses

The aim of this study was to evaluate the distribution of stress in complete fixed mandibular prostheses with infrastructures (IE) fabricated with different materials and techniques, under compressive force. A model of an edentulous mandible, which received five 4x11 mm external hexagon implants between the mental foramens, was fabricated. The groups were divided into: Group I - IE in nickel-chromium with an acrylic resin occlusal coating; Group II ? IE in nickel-chromium with a ceramic occlusal coating; Group III ? IE milled in zirconia with a ceramic coating. For the photoelastic methodology, 70 N axial loads were applied in three regions. Photographic images were taken and analyzed according to the number of high-intensity fringes. For the strain gauge methodology, the measurement of stresses was performed in two distinct regions. The same compression tests described earlier were then performed. The registered stress values were grouped in tables and submitted to two-factor variance analysis (ANOVA) and the Tukey test with 5% significance. The results of the two methodologies demonstrated smaller stress values for Group I, when compared to the other groups. It was possible to conclude that the complete fixed prostheses, with infrastructures cast in metal and acrylic occlusal coating, demonstrated better biomechanical results

Masticatory efficiency, bite force and electrical activity of the masseter and temporalis muscles in bodybuilders

This study aimed to compare the masticatory efficiency, the maximum voluntary occlusal bite force (MVOBF) and the electrical activity (EMG) of masticatory muscles of practitioners of upper limb bodybuilding before and after physical activity. Twenty he

Prevalence of symptoms of temporomandibular disorders, oral behaviors, anxiety, and depression in Dentistry students during the period of social isolation due to COVID-19

Temporomandibular dysfunction (TMD), anxiety, and depression are disorders that, due to the current lifestyle, are affecting an increasing portion of the population. Investigating the prevalence of the symptoms of these disorders during the quarantine due to the coronavirus 2019 pandemic (COVID-19) is important to outline clinical strategies for patient care. Objective: This study assessed the prevalence of TMD symptoms, anxiety, depression, and oral behaviors and their associations during the social isolation due to COVID-19. Methodology: Questionnaires were used to assess TMD symptoms in accordance with the Diagnostic Criteria for Temporomandibular Disorders: clinical protocol and assessment instruments, a questionnaire to verify oral behaviors and Hospital Anxiety and Depression Scale to assess symptoms of anxiety and depression in students of dentistry at the Faculty of Health Sciences of the University of Brasília in May 2020. Qualitative data were subjected to descriptive statistics and chi-squared analysis (p<0.05). The relationship between quantitative and qualitative data was evaluated using Spearman's rho correlation (p<0.05). Results: There was a high prevalence of TMD symptoms, anxiety, and depression in the participants, resulting in association between gender and anxiety symptoms (p=0.029). There was a positive correlation between oral behaviors and TMD symptoms (r=0.364; p<0.001), between oral behaviors and anxiety symptoms (r=0.312; p=0.001), and between oral behaviors and symptoms of depression (r=0.216; p=0.021). Conclusion: Social isolation due to the COVID-19 pandemic has an impact on the prevalence of TMD symptoms, anxiety, and depression

Dynamic UCLA for single tilted implant in an aesthetic region

AbstractIntroductionThe aim of this paper was to present a rehabilitation of a patient with a dynamic universal castable long abutment (UCLA) for a single tilted implant in the anterior maxillary area.Presentation of caseA 57-year-old male patient attended the dentistry college clinic complaining of a vertical fracture of a residual root of the dental element 22. The tooth extraction was indicated for the implant installation. Due to the socket buccal wall thickness, the implant was installed with an inclination to the palate. It was done in a two-stage surgical protocol, and an external hexagon implant (3.75×11.5mm) was placed. After a six-month healing period to correct the implant position, a dynamic UCLA was set in place, rectifying the implant emergence profile at 20°. The ceramic structure fitting was performed and, after the patient’s consent, the prosthesis was finalized and installed.DiscussionAfter a follow-up period of twenty months, no complications were observed.ConclusionThe installation of tilted implants with a dynamic UCLA may be a viable option, faster and less invasive than bone grafts

Bond strength of lithium disilicate after cleaning methods of the remaining hydrofluoric acid

Different ceramic surface cleaning methods have been suggested after the acid conditioning. The aim was to evaluate the effect of different protocols used to remove the remaining hydrofluoric acid on the shear bond strength (SBS) between lithium disilicate and resin cement. Forty-four specimens of lithium disilicate (IPS e.max Press) were divided in 4 groups (n=11): group C (control, no treatment); group HF+S (5% hydrofluoric acid + silane); group HF+US+S (5% hydrofluoric acid + ultrasound cleaning + silane); group HF+PH+S (5% hydrofluoric acid + 37% phosphoric acid + silane). Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were performed to characterize the surface morphology. The SBS test was performed on the resin/ceramic interface, and the failure mode was characterized. SBS values were submitted to 1-way ANOVA and the Tukey test (?=.05). The relation between surface treatment and failure modes was analyzed using the chi-squared test (?=.05). The surface treatment type interfered in the shear strength (p<.001) and higher SBS values were observed for the groups HF+US+S (17.87 MPa) and HF+PH+S (16.37 MPa). The surface treatment did not influence the failure mode (p=.713). No fluorsilicate salts were observed after ultrasound cleaning. The utilization of ultrasound cleaning was an effective procedure to remove remaining fluorsilicate salts, promoting the highest SBS values

Prevalence of symptoms of temporomandibular disorders, oral behaviors, anxiety, and depression in dentistry students during the period of social isolation due to COVID-19

Temporomandibular dysfunction (TMD), anxiety, and depression are disorders that, due to the current lifestyle, are affecting an increasing portion of the population. Investigating the prevalence of the symptoms of these disorders during the quarantine due to the coronavirus 2019 pandemic (COVID-19) is important to outline clinical strategies for patient care. Objective: This study assessed the prevalence of TMD symptoms, anxiety, depression, and oral behaviors and their associations during the social isolation due to COVID-19. Methodology: Questionnaires were used to assess TMD symptoms in accordance with the Diagnostic Criteria for Temporomandibular Disorders: clinical protocol and assessment instruments, a questionnaire to verify oral behaviors and Hospital Anxiety and Depression Scale to assess symptoms of anxiety and depression in students of dentistry at the Faculty of Health Sciences of the University of Brasília in May 2020. Qualitative data were subjected to descriptive statistics and chi-squared analysis (p<0.05). The relationship between quantitative and qualitative data was evaluated using Spearman's rho correlation (p<0.05). Results: There was a high prevalence of TMD symptoms, anxiety, and depression in the participants, resulting in association between gender and anxiety symptoms (p=0.029). There was a positive correlation between oral behaviors and TMD symptoms (r=0.364; p<0.001), between oral behaviors and anxiety symptoms (r=0.312; p=0.001), and between oral behaviors and symptoms of depression (r=0.216; p=0.021). Conclusion: Social isolation due to the COVID-19 pandemic has an impact on the prevalence of TMD symptoms, anxiety, and depression

Relationship between self-reported pain, pain threshold, pain catastrophization and quality of life in patients with TMD

The aim of this study was to verify if there is a relationship between self-reported pain, PPT (pressure pain threshold) of the masseter, temporal and sternocleidomastoid muscles, pain catastrophizing and quality of life in patients with TMD (temporomand

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Análise in vitro da proliferação celular e produção de mediadores inflamatórios por células da conjuntiva estimuladas por materiais utilizados na confecção de próteses oculares

Ocular prosthesis is a treatment option for esthetical and functional rehabilitation of ocular absence. The knowledge of ocular prosthesis material's biocompatibility is important to ensure a safe use in patients. The aim of this study was to evaluate the cytotoxic effect of ocular prosthesis materials, through the analysis of the cell proliferation, and the production of proinflammatory cytokines and extracellular matrix proteins by a human conjunctival cell line. Initially, the influence of different preparation and exposition periods of eluates from heat-polymerized ocular prosthesis N1 color acrylic resin in human conjunctival cell line was evaluated. A total of 24 acrylic resin samples were manufactured and divided into 2 groups, according to the eluate exposition period to conjunctival cell line (24 and 72 hours). Eluates corresponding to 24, 48 and 72 hours of resin sample immersion in medium and, 24 hours of resin sample immersion in water followed by 24 hours of immersion in medium, were prepared (n=3) for the proposed tests. Then, the cytotoxic effect of different polymerization methods of ocular prosthesis N1 color acrylic resin was analyzed. A total of 9 acrylic resin samples were manufactured (n=3), according to the polymerization method: heat-polymerization in water bath, polymerization by microwave energy and auto-polymerization. Eluates corresponding to 72 hours of resin sample immersion in medium were prepared for proposed tests and exposed to conjunctival cell line for 72 hours. Additionally, the influence of pigment incorporation on the cytotoxicity of heat-polymerized ocular prosthesis N1 color acrylic resin was evaluated...A prótese ocular é utilizada para a reabilitação estética e funcional da ausência ocular. O conhecimento da sua biocompatibilidade é importante para a utilização sem reações danosas aos usuários. O objetivo neste estudo foi avaliar a citotoxicidade de materiais utilizados na confecção de próteses oculares, por meio da análise da proliferação celular e da produção de citocinas pró-inflamatórias e de proteínas de matriz extracelular por células da conjuntiva humana. Inicialmente, foi analisada a influência de diferentes períodos de formação e de exposição dos extratos de resina acrílica branca (N1), termopolimerizada em água aquecida, sobre culturas de células da conjuntiva. Foram confeccionados 24 corpos de prova em resina, sendo 12 para cada período de exposição de células da conjuntiva aos extratos da resina testada (24 e 72 horas). Após a formação dos extratos por 24, 48 e 72 horas de imersão em meio de cultura e, 24 horas em água seguido de 24 horas de imersão em meio, os ensaios propostos foram realizados (n=3). Em seguida, foi avaliado o efeito citotóxico de diferentes métodos de polimerização de resina acrílica N1 em células da conjuntiva. Foram confeccionados 9 corpos de prova em resina (n=3), termopolimerizados em água aquecida, por energia de microondas ou ativados quimicamente, utilizados para a formação dos extratos dessas resinas. Os extratos foram obtidos após 72 horas de imersão dos corpos de prova em meio de cultura e, então, expostos às células da conjuntiva por 72 horas para a realização dos ensaios propostos. Adicionalmente, foi analisada a influência da presença do pigmento acrílico na confecção da prótese de resina acrílica N1, termopolimerizada em água aquecida...Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP