Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

OBJECTIVES: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. MATERIAL AND METHODS: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For the control groups, the specimens were stored in distilled water for 24 hours at 37º C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05). RESULTS: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (p<0.001) in different solutions (p<0.001). The effect of different solutions on the surface hardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (p<0.001). The compomer was the most affected by an acidic environment, whereas the composite resin materials were the least affected materials. CONCLUSIONS: The effect of sports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material

Surface agents' influence on the flexural strength of bilaminated ceramics

The objective of this study was to evaluate the influence of different surface agents on the flexural strength of a ceramic system. Eighty bar-shaped specimens of zirconia were divided into four groups according to the agent to be used: group Control-to be cleaned with alcohol; group VM9-application of a fluid layer of porcelain; group Effect Bonder-application of a bonding agent; and group Coloring Liquid-application of coloring liquid. All specimens received the porcelain application by the layering technique and were then subjected to thermocycling. The four-point bending test was performed to calculate the strength values (s, MPa) and the failure modes were classified. ANOVA did not detect significant differences among the groups. The Weibull modulus were 5 (Control, VM9 and Effect Bonder) and 6 (Coloring Liquid). The cracking of the porcelain ceramic toward the interface was the predominant failure mode. It was concluded that the surface agents tested had no effect on the flexural strength of the bilaminated ceramic specimens.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Instituto de Ciência e Tecnologia - ICT Univ Estadual Paulista - UNESP, São José dos Campos, SPDepartment of Dental Materials and Prosthodontics Instituto de Ciência e Tecnologia - ICT Univ Estadual Paulista - UNESP, São José dos Campos, SPDepartment of Restorative Dentistry Instituto de Ciência e Tecnologia - ICT Univ Estadual Paulista - UNESP, São José dos Campos, SPInstituto de Ciência e Tecnologia - ICT Univ Estadual Paulista - UNESP, São José dos Campos, SPDepartment of Dental Materials and Prosthodontics Instituto de Ciência e Tecnologia - ICT Univ Estadual Paulista - UNESP, São José dos Campos, SPDepartment of Restorative Dentistry Instituto de Ciência e Tecnologia - ICT Univ Estadual Paulista - UNESP, São José dos Campos, SPFAPESP: 11/13085-

On surface corrosion of dental ceramics in vitro

Purpose: The aims of this thesis were: To assess the effects of in vitro corrosion of various dental ceramic on surface characteristics like topography, surface free energy and protein adsorption materials, but also to study possible differences in surface elemental composition and ion dissolution in an aqueous corrosive media.Materials and methods: Dental ceramic materials ranging from glass-phased to oxide ceramics of equal initial surface conditions were exposed to high- and low intensity in vitro corrosion, as well as contact with saliva and plasma. The 3-D surface - architecture was studied by laser profilometry and SEM, and the surface free energy calculated from the Young-DuprÈ equation after surface contact angle measurements using different probe liquids. The protein adsorption before and after corrosion, and saliva/plasma incubation was analysed by SDS-PAGE and the adsorbed proteins identified by Western blotting technique. The surface elemental composition of the dental ceramics was studied by ESCA, and the effects of different corrosion intensities evaluated. Qualitative and quantitative characteristics of ion-dissolution into a surrounding media were analysed by ICP-OES, and compared to initial elemental composition and corrosive solution intensity.Results: In comparison to oxide ceramics, the glass-phased ceramics displayed a higher susceptibility to surface degradation after high-intensity corrosion, whereas the surface topography of micro crystalline and non-crystalline ceramics were less influenced by corrosion. In spite of surface structural changes taken place at corrosion, the TSFE did not differ significantly between the different ceramics, before or after corrosion. Incubated with saliva or plasma, inter-individual differences in protein adsorption were observed. All plasma proteins, but none of the specific salivary proteins, were surface-bound onto alumina and zirconia ceramics. The permanency of the oxide ceramics manifested through low surface degradation and leaching-out values,while the glass-phased ceramics displayed overall higher values. Increased acidity and temperature of the corrosion media increased ion-leaching.Conclusion: The degree of surface topographical changes due to corrosion was related to the characteristic microstructure and only minor changes occurred. Whereas the TSFE remained virtually unchanged at corrosion (50±5 mN/m), the acid-basic (y+ and y-) component of TSFE, were significantly changed. The differences in protein adsorption among the various ceramics due to corrosion were probably caused by the changes in surface elemental composition, shown to take place at high-intensity corrosion and to a lower extent at low-intensity corrosion. Although traditionally considered as inert materials, the glass-phased ceramics in specific, were found to leach alkali, alkaline-earth, alumina and silicon, and simultaneously display of increased silica content in surface layers. Everything considered, the bioinert concept associated with bio-ceramics should be re-evaluated and given a relative rather than absolute meaning

Energy consumption of programming languages in machine learning : Comparing compiled and interpreted languages in the context of training machine learning models

As machine learning is seeing increased adoption, it is important to consider the sustainability of the technology. Training machine learning models can be resource-intensive, which may lead to high energy consumption. In order to achieve sustainable use, ways of reducing the energy consumption of machine learning is needed. In this study, a quasi-experiment was conducted to compare the energy consumption of the interpreted language Python, and the compiled language C++, in the context of training machine learning models. The energy consumption of both execution and compilation was measured, while also considering the impact of compiler optimization levels.The results showed that there were differences between interpreted and compiled languages in machine learning, however, the differences were smaller than found in previous research. There were also differences between compiler optimization levels, but some levels were more consistent than others. While certain patterns in energy consumption were seen, determining the most energy efficient programming language or optimization level was difficult. The study concluded that the energy consumption can be attributed to factors other than the programming language itself and varies between use-cases

Det oförutsägbara vårdandet : En integrativ litteraturstudie om hotfulla och våldsamma vårdmöten prehospitalt

Ambulanssjukvård bedrivs i ett samhällsklimat där hot och våld har blivit både en vardaglig del i vårdarbetet och ett arbetsmiljöproblem för ambulanspersonalen. Internationella studier tyder på att hot och våld mot ambulanspersonal är ett omfattande problem. Studiens syfte är att granska samlad kunskap angående ambulanspersonalens erfarenheter av hotfulla och våldsamma vårdmöten. En integrativ litteraturstudie valdes som metod och 27 artiklar och studier inkluderades. Den tematiska innehållsanalysen resulterade i två teman; Utsatthet och Säkerhetsmedvetenhet. Resultatet visar att hot och våld påverkar ambulanspersonalen känslomässigt, skapar distans mellan vårdare och patient och gör att omvårdnaden påverkas eller uteblir. Tidigare erfarenheter av hot och våld höjer ambulanspersonalens säkerhetsmedvetenhet men tycks även leda till en ökad acceptans, att hotfulla och våldsamma vårdmöten är en del av arbetet. Ibland måste ambulanspersonalen tillkalla polis och resultatet visar att det både möjliggör och hindrar omvårdad av patienter i hotfulla och våldsamma situationer. Utvecklingen inom ambulansen går mot mer ensamarbete och det finns en diskussion kring om ambulanspersonalen ska bära skyddsutrustning. Hotfulla och våldsamma vårdmöten kan därför både ses som ett arbetsmiljöproblem och en fråga om patientsäkerhet

Det oförutsägbara vårdandet : En integrativ litteraturstudie om hotfulla och våldsamma vårdmöten prehospitalt

Ambulanssjukvård bedrivs i ett samhällsklimat där hot och våld har blivit både en vardaglig del i vårdarbetet och ett arbetsmiljöproblem för ambulanspersonalen. Internationella studier tyder på att hot och våld mot ambulanspersonal är ett omfattande problem. Studiens syfte är att granska samlad kunskap angående ambulanspersonalens erfarenheter av hotfulla och våldsamma vårdmöten. En integrativ litteraturstudie valdes som metod och 27 artiklar och studier inkluderades. Den tematiska innehållsanalysen resulterade i två teman; Utsatthet och Säkerhetsmedvetenhet. Resultatet visar att hot och våld påverkar ambulanspersonalen känslomässigt, skapar distans mellan vårdare och patient och gör att omvårdnaden påverkas eller uteblir. Tidigare erfarenheter av hot och våld höjer ambulanspersonalens säkerhetsmedvetenhet men tycks även leda till en ökad acceptans, att hotfulla och våldsamma vårdmöten är en del av arbetet. Ibland måste ambulanspersonalen tillkalla polis och resultatet visar att det både möjliggör och hindrar omvårdad av patienter i hotfulla och våldsamma situationer. Utvecklingen inom ambulansen går mot mer ensamarbete och det finns en diskussion kring om ambulanspersonalen ska bära skyddsutrustning. Hotfulla och våldsamma vårdmöten kan därför både ses som ett arbetsmiljöproblem och en fråga om patientsäkerhet