The use of different adhesive filling material and mass combinations to restore class II cavities under loading and shrinkage effects: a 3D-FEA

3D tooth models were virtually restored: flowable composite resin + bulk-fill composite (A), glass ionomer cement + bulk-fill composite (B) or adhesive + bulk-fill composite (C). Polymerization shrinkage and masticatory loads were simulated. All models exhibited the highest stress concentration at the enamel–restoration interfaces. A and C showed similar pattern with lower magnitude in A in comparison to C. B showed lower stress in dentine and C the highest cusps displacement. The use of glass ionomer cement or flowable composite resin in combination with a bulk-fill composite improved the biomechanical behavior of deep class II MO cavities

The use of different adhesive filling material and mass combinations to restore class II cavities under loading and shrinkage effects: a 3D-FEA

3D tooth models were virtually restored: flowable composite resin + bulk-fill composite (A), glass ionomer cement + bulk-fill composite (B) or adhesive + bulk-fill composite (C). Polymerization shrinkage and masticatory loads were simulated. All models exhibited the highest stress concentration at the enamel-restoration interfaces. A and C showed similar pattern with lower magnitude in A in comparison to C. B showed lower stress in dentine and C the highest cusps displacement. The use of glass ionomer cement or flowable composite resin in combination with a bulk-fill composite improved the biomechanical behavior of deep class II MO cavities

Effects Of High Pressure Homogenization On The Activity, Stability, Kinetics And Three-dimensional Conformation Of A Glucose Oxidase Produced By Aspergillus Niger

High pressure homogenization (HPH) is a non-thermal method, which has been employed to change the activity and stability of biotechnologically relevant enzymes. This work investigated how HPH affects the structural and functional characteristics of a glucose oxidase (GO) from Aspergillus niger. The enzyme was homogenized at 75 and 150 MPa and the effects were evaluated with respect to the enzyme activity, stability, kinetic parameters and molecular structure. The enzyme showed a pH-dependent response to the HPH treatment, with reduction or maintenance of activity at pH 4.5-6.0 and a remarkable activity increase (30-300%) at pH 6.5 in all tested temperatures (15, 50 and 75°C). The enzyme thermal tolerance was reduced due to HPH treatment and the storage for 24 h at high temperatures (50 and 75°C) also caused a reduction of activity. Interestingly, at lower temperatures (15°C) the activity levels were slightly higher than that observed for native enzyme or at least maintained. These effects of HPH treatment on function and stability of GO were further investigated by spectroscopic methods. Both fluorescence and circular dichroism revealed conformational changes in the molecular structure of the enzyme that might be associated with the distinct functional and stability behavior of GO. © 2014 Tribst et al.97Bankar, S.B., Bule, M.V., Singhal, R.S., Ananthanarayan, L., Glucose oxidase - An overview (2009) Biotechnol Adv, 27 (4), pp. 489-501Whitaker, J.R., (2003) Handbook of Food Enzymology, p. 1108. , New York: Marcel Dekker IncorporatedWohlfahrt, G., Witt, S., Hendle, J., Schomburg, D., Kalisz, H.M., Hecht, H.-J., 1.8 and 1.9 Â resolution structures of the Penicillium amagasakiense and Aspergillus niger glucose oxidases as a basis for modelling substrate complexes (1999) Acta Crystallographica Section D: Biological Crystallography, 55 (5), pp. 969-977. , DOI 10.1107/S0907444999003431Leskovac, V., Trivic, S., Wohlfahrt, G., Kandrac, J., Pericin, D., Glucose oxidase from Aspergillus niger: The mechanism of action with molecular oxygen, quinones, and one-electron acceptors (2005) International Journal of Biochemistry and Cell Biology, 37 (4), pp. 731-750. , DOI 10.1016/j.biocel.2004.10.014Fiedurek, J., Gromada, A., Screening and mutagenesis of molds for improvement of the simultaneous production of catalase and glucose oxidase (1997) Enzyme and Microbial Technology, 20 (5), pp. 344-347. , DOI 10.1016/S0141-0229(96)00148-2, PII S0141022996001482Pluschkell, S., Hellmuth, K., Rinas, U., Kinetics of glucose oxidase excretion by recombinant Aspergillus niger (1996) Biotechnology and Bioengineering, 51 (2), pp. 215-220. , DOI 10.1002/(SICI)1097-0290(19960720)51:2<215::AIDLacroix, N., Fliss, I., Makhlouf, J., Inactivation of pectin methylesterase and stabilization of opalescence in orange juice by dynamic high pressure (2005) Food Research International, 38 (5), pp. 569-576. , DOI 10.1016/j.foodres.2004.11.010, PII S0963996904002716Tribst, A.A.L., Franchi, M.A., Cristianini, M., Ultra-high pressure homogenization treatment combined with lysozyme for controlling Lactobacillus brevis contamination in model system (2008) Innov Food Sci Emerg Technol, 9 (3), pp. 265-271Tribst, A.A.L., Franchi, M.A., De Massaguer, P.R., Cristianini, M., Quality of mango nectar processed by high-pressure homogenization with optimized heat treatment (2011) J Food Sci, 76 (2), pp. M106-M110Franchi, M.A., Tribst, A.A.L., Cristianini, M., Effects of High Pressure Homogenization on Beer Quality Attributes (2011) J Inst Brew, 117 (2), pp. 195-198Tribst, A.A.L., Franchi, M.A., Cristianini, M., De Massaguer, P.R., Inactivation of Aspergillus niger in mango nectar by high-pressure homogenization combined with heat shock (2009) J Food Sci, 74 (9), pp. M509-M514Augusto, P.E.D., Ibarz, A., Cristianini, M., Effect of high pressure homogenization (HPH) on the rheological properties of a fruit juice serum model (2012) J. Food Eng, 111 (2), pp. 474-477Augusto, P.E.D., Ibarz, A., Cristianini, M., Effect of high pressure homogenization (HPH) on the rheological properties of tomato juice: Time-dependent and steady-state shear (2012) J Food Eng, 111 (4), pp. 570-579Welti-Chanes, J., Ochoa-Velasco, C.E., Guerrero-Béltran, J.A., High-pressure homogenization of orange juice to inactivate pectinmethylesterase (2009) Innov Food Sci Emerg Technol, 10 (4), pp. 457-462Liu, W., Liu, J., Liu, C., Zhong, Y., Liu, W., Activation and conformational changes of mushroom polyphenoloxidase by high pressure microfluidization treatment (2009) Innov Food Sci Emerg Technol, 10 (2), pp. 142-147Liu, W., Liu, J., Xie, M., Liu, C., Liu, W., Characterization and high-pressure microfluidization-induced activation of polyphenoloxidase from Chinese pear (Pyrus pyrifolia Nakai) (2009) J Agric Food Chem, 57, pp. 5376-5380Tribst, A.A.L., Cristianini, M., High pressure homogenization of a fungi α-amylase (2012) Innov Food Sci Emerg Technol, 3, pp. 107-111Tribst, A.A.L., Cristianini, M., Increasing fungi amyloglucosidase activity by high pressure homogenization (2012) Innov Food Sci Emerg Technol, 16, pp. 21-25Tribst, A.A.L., Cristianini, M., Changes in Commercial Glucose Oxidase Activity by High Pressure Homogenization (2012) Innov Food Sci Emerg Technol, 16, pp. 355-360Tribst, A.A.L., Augusto, P.E.D., Cristianini, M., The effect of the high pressure homogenisation on the activity and stability of a commercial neutral protease from Bacillus subtilis (2012) Int J Food Sci Technol, 47 (4), pp. 716-722Tribst, A.A.L., Augusto, P.E.D., Cristianini, M., The effect of high pressure homogenization on the activity of a commercial β-Galactosidase (2012) J Ind Microbiol Biotechnol, 39 (11), pp. 1587-1596Tribst, A.A.L., Augusto, P.E.D., Cristianini, M., Changes in enzyme activity by multiple passes on high pressure homogenizer (2013) Innov Food Sci Emerg Technol, 18, pp. 83-88Leite Jr., B.R.D.C., Tribst, A.A.L., Cristianini, M., Proteolytic and milk-clotting activities of calf rennet processed by high pressure homogenization and the influence on the rheological behavior of the milk coagulation process (2014) Innov Food Sci Emerg Technol, 21, pp. 44-49Liu, W., Zhang, Z.-Q., Liu, C., Xie, M., Tu, Z., The effect of dynamic high-pressure microfluidization on the activity, stability and conformation of trypsin (2010) Food Chem, 123, pp. 616-621Miller, G.L., Use of dinitro salicylic acid reagent for determination of reducing sugar (1959) Anal Chem, 31, pp. 426-428Takács, E., Grolmusz, V.K., Vértessy, B.G., A tradeoff between protein stability and conformational mobility in homotrimeric dUTPases (2004) FEBS Letters, 566 (1-3), pp. 48-54Whitmore, L., Wallace, B.A., Protein secondary structure analyses from circular dichroism spectroscopy: Methods and reference databases (2008) Biopolymers, 89 (5), pp. 392-400Vertessy, B.G., Flexible glycine rich motif of Escherichia coli deoxyuridine triphosphate nucleotidohydrolase is important for functional but not for structural integrity of the enzyme (1997) Proteins: Structure, Function and Genetics, 28 (4), pp. 568-579Yanari, S., Bovey, F.A., Interpretation of the ultraviolet spectral changes of proteins (1960) J Biol Chem, 235 (10), pp. 2828-12825Vivian, J.T., Callis, P.R., Mechanisms of tryptophan fluorescence shifts in proteins (2001) Biophysical Journal, 80 (5), pp. 2093-2109Hecht, H.J., Kalisz, H.M., Hendle, J., Schmid, R.D., Schomburg, D., Crystal structure of glucose oxidase from Aspergillus niger refined at 2.3 A reslution (1993) Journal of Molecular Biology, 229 (1), pp. 153-172. , DOI 10.1006/jmbi.1993.1015Woody, R.W., Theory of Circular dichroism of Proteins (1996) Circular Dichroism and the Conformational Analysis of Biomolecules, pp. 25-30. , Fasman GD (ed) New York: Plenum Press PublisherLuo, D.H., Zhao, Q.Z., Zhao, M.M., Yang, B., Long, X.T., Effects of limited proteolysis and high-pressure homogenisation on structural and functional characteristics of glycinin (2010) Food Chem, 122, pp. 25-3

COVID-19 and the impact on the cranio-oro-facial trauma care in Italy: An epidemiological retrospective cohort study

The coronavirus disease 2019 (COVID-19) has deeply modified the organization of hospitals, health care centers, and the patient’s behavior. The aim of this epidemiological retrospective cohort study is to evaluate if and how the COVID-19 pandemic has determined a modification in cranio-oro-facial traumatology service. Methods: The dataset included hospital emergency room access of a six-month pre-pandemic period and six months into pandemic outbreak. The variables collected were: patient age, gender, type of emergency access with relative color code, Glasgow Coma Scale Score, type of discharge. Results: 537 vs 237 (pre-pandemic vs pandemic) patients accessed the hospital emergency room and the mean age decreased from 60.79 ± 25.34 to 56.75 ± 24.50 year. Yellow and green code access went from 28.9% and 66.1% to 37.5% and 57.7% (pre-pandemic vs pandemic). Glasgow Coma Scale (GCS) shows an increase of 16.6% vs 27.8% of 15 grade score, a 28.7% vs 28.5% of the 14 grade score and reduction of 13 and 12 grade 40.2% and 14.5% vs 37.1 and 9.7% (pre-pandemic vs pandemic). Conclusions: Since the COVID-19 outbreak continues, epidemiological data are still necessary to perform public health intervention strategies and to appropriately predict the population needs, in order to properly manage the COVID-19 related to oral pathologies as well as the most common health problems

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

Loading stress distribution in posterior teeth restored by different core materials under fixed zirconia partial denture: A 3d-fea study

Purpose: To evaluate the effect of different substrate stiffness [sound dentin (SD), resin composite core (RC) or metal core (MC)] on the stress distribution of a zirconia posterior three-unit fixed partial denture (FPD). Methods: The abutment teeth (first molar and first premolar) were modeled, containing 1.5 mm of axial reduction, and converging axial walls. A static structural analysis was performed using a finite element method and the maximum principal stress criterion to analyze the fixed partial denture (FPD) and the cement layers of both abutment teeth. The materials were considered isotropic, linear, elastic, homogeneous and with bonded contacts. An axial load (300 N) was applied to the occlusal surface of the second premolar. Results: The region of the prosthetic connectors showed the highest tensile stress magnitude in the FPD structure depending on the substrate stiffness with different core materials. The highest stress peak was observed with the use of MC (116.4 MPa) compared to RC and SD. For the cement layer, RC showed the highest values in the molar abutment (14.7 MPa) and the highest values for the premolar abutment (14.4 MPa) compared to SD (14.1 and 13.4 MPa) and MC (13.8 and 13.3 MPa). Both metal core and resin composite core produced adequate stress concentration in the zirconia fixed partial denture during the load incidence. However, more flexible substrates, such as composite cores, can increase the tensile stress magnitude on the cement