Fatality rate and predictors of mortality in an Italian cohort of hospitalized COVID-19 patients

Clinical features and natural history of coronavirus disease 2019 (COVID-19) differ widely among different countries and during different phases of the pandemia. Here, we aimed to evaluate the case fatality rate (CFR) and to identify predictors of mortality in a cohort of COVID-19 patients admitted to three hospitals of Northern Italy between March 1 and April 28, 2020. All these patients had a confirmed diagnosis of SARS-CoV-2 infection by molecular methods. During the study period 504/1697 patients died; thus, overall CFR was 29.7%. We looked for predictors of mortality in a subgroup of 486 patients (239 males, 59%; median age 71 years) for whom sufficient clinical data were available at data cut-off. Among the demographic and clinical variables considered, age, a diagnosis of cancer, obesity and current smoking independently predicted mortality. When laboratory data were added to the model in a further subgroup of patients, age, the diagnosis of cancer, and the baseline PaO2/FiO2 ratio were identified as independent predictors of mortality. In conclusion, the CFR of hospitalized patients in Northern Italy during the ascending phase of the COVID-19 pandemic approached 30%. The identification of mortality predictors might contribute to better stratification of individual patient risk

Conversion Degree and Push-out Bond Strength of Two Composite Cements

Objectives: Aim of this study was to evaluate, by means of a non-destructive procedure, the degree of conversion (DC) of two different composite cements. Subsequently, the same samples underwent a push-out test to investigate the bond strength at the adhesive interface after DC microRaman evaluation. Methods: 24 single-rooted teeth were cut at the CEJ, endodontically treated and a 8mm post-space deep was made. Teeth were randomly divided in two groups (n=12) and RelyX Fiber Posts were luted using 2 composite cements: Multilink Automix (group A/control) and an experimental cement (group B/self-adhesive). Composites were cured (120s, 400mW/cm2) and each sample was cut, perpendicularly to the long axis, in 2mm-thick slices starting from the CEJ. The sections corresponding to 1mm, 3mm, 5mm were analysed with the microRaman spectrometer; then a push-out test evaluated the resistance to the displacement of the post. Finally the slices were analysed with an optical microscope to evaluate the nature of failure. Data were statistically evaluated (ANOVA, Tukey’s, p<0.05). Results: In group A we recorded higher strength at debonding (p<0.001) and higher DC (p<0.001) compared to group B. In both groups push-out strength was higher at 1mm than at 5mm (p=0.002). Most common failures (POF) are recorded at the cement-dentin interface. Group B didn’t show any POF at cement-post interface. Conclusions: an experimental cement self-adhesive showed a lower DC and a lower bond strength compared to the “traditional technique” composite (group A). Distance from the CEJ didn’t affect the DC, due to autopolymerizing component of both materials

Adhesive Restoration of Endodontically Treated Premolars: Influence of Posts on Cuspal Deflection

PURPOSE: To determine, by means of a non-destructive experimental procedure, the effectiveness of adhesive restorations in reducing the cuspal deflection of endodontically treated premolars, with or without root canal fiber posts. MATERIALS AND METHODS: The cuspal deflection of ten sound, intact maxillary premolars was evaluated. A loading device induced deformation by axial force (ranging from 98 to 294 N) applied on the occlusal surface of teeth while laser sensors registered the amount of deflection. Once tested, teeth were endodontically treated and the marginal ridges were removed. The teeth were randomly divided into two groups and restored with: group 1) dual curing adhesive, flowable composite, and microhybrid composite; group 2) the same materials associated with root canal glass fiber post and composite cement. The cuspal deflection test was repeated with the same protocol after restorative procedures, allowing a direct comparison of the same samples. Statistical analysis was performed using ANOVA at a significance level of 0.05. RESULTS: Different average cuspal deflection was detected in the two groups: composite resin with post insertion resulted in lower deformation compared with composite alone. Mean deflection ranged from 3.43 to 12.17 μm in intact teeth, from 14.42 to 26.93 μm in group 1, and from 15.35 to 20.39 μm in group 2. ANOVA found significant differences (p = 0.02). CONCLUSION: Bonded composite restorations with fiber posts may be more effective than composite alone in reducing the cuspal deflection in endodontically treated premolars in which the marginal ridges have been lost

Correlazione tra la morfologia canalare e le dimensioni del perno in fibra nella ricostruzione adesiva post endodontica

La letteratura scientifica mostra che un dente trattato endodonticamente differisce da un dente sano. I cambiamenti interessano le proprietà chimiche, fisiche ed elastiche della dentina, la resistenza alla fatica, la morfologia e il comportamento bio-meccanico. Nonostante ciò la sopravvivenza nel cavo orale di un dente trattato endodonticamente è influenzata in modo nettamente maggiore dalla quantità e dalla qualità di struttura dentale residua. La rimozione di tessuto cariato e la preparazione del dente per il trattamento endodontico sono quindi i primi fattori che indeboliscono la struttura del dente. L’elemento dentale trattato endodonticamente può richiedere complesse strategie di restauro e una visione di trattamento multidisciplinare. Vi sono situazioni per cui la scelta di inserire un perno in fibra risulta fondamentale per supportare e consentire la realizzazione del restauro protesico coronale, evitando che le forze stressorie si concentrino in zone sensibili e distribuendole uniformemente lungo il canale radicolare. Studi clinici hanno dimostrato che la maggior causa di fallimento, nell’utilizzo di perni in fibra, non è la frattura radicolare, come accade con i perni metallici fusi, ma la decementazione. Le cause principali della decementazione sono la mancanza dell’effetto ferula e l’eccessivo spessore di cemento. Infatti, se il perno non si adatta alla parete adeguatamente, lo spessore di cemento è eccessivo e facilmente vi si creeranno le conclusioni che predispongono al fallimento. Scopo del presente lavoro è trovare il matching dimensionale migliore tra perno in fibra e preparazione canalare inferta dagli ultimi strumenti canalari nella terapia, in termini di diametro, forma e volume in modo da avere il migliore adattamento tra parete canalare e superficie del perno. In particolare, gli Autori intendono facilitare, attraverso l’elaborazione di tavole sinottiche, il clinico nella scelta del perno che si adatta meglio al canale preparato con i diversi sistemi rotanti/reciprocanti di sagomatura canalare

Degree of conversion and adhesion of methacrylate-based resin cements with phosphonic or phosphoric acid acrylate to glass fiber posts at different regions of intraradicular dentin

This study evaluated the degree of conversion (DC) and adhesion of methacrylate-based resin cements to glass fiber posts at different regions of intraradicular dentin. Single-rooted teeth (N = 24, n = 12 per group) were cut at the cement-enamel junction (CEJ), endodontically treated and post space (depth = 8 mm) was prepared. Teeth were randomly divided into two groups according to the resin cements: (a) Group ML: methacrylate-based cement with phosphonic acid acrylate (Multilink Automix, Ivoclar Vivadent); (b) Group RXU: methacrylate-based cement with phosphoric acid acrylate (RelyX Unicem 2 Automix, 3 M ESPE). Fiber-reinforced composite root posts (RelyX Fiber Post, 3 M ESPE) were cemented according to the manufacturers instructions of the resin cements. Root slices of 2-mm thickness (n = 3 per tooth) were cut below the CEJ 1, 3, and 5 mm apically. The DC of each section was analyzed with micro-Raman spectrometer and push-out test was performed in the Universal Testing Machine (0.5 mm/min). After debonding, all specimens were analyzed using optical microscope to categorize the failure modes. While data (MPa) were statistically evaluated using Kruskal Wallis, Mann-Whitney U tests for DC data 3-way ANOVA and Tukeys tests were used (α = 0.05). Regardless of the resin cement type, the mean push-out bond strength results (MPa), were significantly higher for the coronal slices (ML: 9.1 ± 2.7; RXU: 7.3 ± 4.1) than those of the most apical ones (ML: 7 ± 4.9; RXU: 2.89 ± 1.5) (p = 0.002). Resin cement type and (p < 0.001) root level (p = 0.002) significantly affected the DC values, while the interaction terms were not significant (p = 0.606). Overall, DC was significantly higher for ML (67 ± 8.2%) than RXU (26 ± 8.8%) (p < 0.001). Adhesive failures at the cement-dentin interface were more commonly experienced in RXU than in ML, whereas ML presented more incidences of adhesive failures at the cement-post interface. Considering the push-out bond strength, DC and failure types, methacrylate-based cement with phosphonic acid acrylate should be preferred to those containing phosphoric acid to adhere glass fiber posts in the root cana

Effect of restorative, endodontic, and fatigue treatments on the cuspal deflection of maxillary premolars subjected to different cyclic occlusal forces: an in vitro study

This study aimed to determine the effect of adhesive direct composite restorations, endodontic treatments, and fatigue treatments on the cuspal deflection of maxillary premolars subjected to different cyclic occlusal forces. Thirty intact maxillary second premolars were selected. Ten teeth were left untreated (group IN), 10 teeth were subjected to endodontic and restorative treatment (group FL), and the remaining 10 teeth were subjected to endodontic, restorative, and fatigue treatments (group FT). All teeth were subjected to 5 occlusal compressive loading forces (98, 147, 196, 245, and 294 N) with a universal testing device. A total of 15 experimental groups were obtained with 3 tooth conditions (IN, FL, FT) and 5 different occlusal loading values. Deflection amounts (μm) were measured with laser sensors and recorded, and obtained data were statistically analyzed with one-way analysis of variance at a significance level of .05. Mean cuspal deflection values (μm) and SDs of experimental groups ranged as follows: IN-98 (24.4 ± 19.8), IN-147 (34.8 ± 28.9), IN-196 (43.8 ± 34.7), IN-245 (54.5 ± 46.4), IN-294 (60.3 ± 50.6), FL-98 (56 ± 49.1), FL-147 (62.6 ± 49.6), FL-196 (72.4 ± 52.1), FL-245 (81.3 ± 56), FL-294 (92.2 ± 60.9), FT-98 (77.2 ± 80.9), FT-147 (83.4 ± 81.3), FT-196 (92.6 ± 83.7), FT-245 (102.7 ± 85.4), and FT-294 (124.2 ± 89.5). Mean values of three main experimental groups were as follows: IN (43.5 μm), FL (72.9 μm) and FT (96.0 μm). Significant differences were found between the three main groups and relevant subgroups (P < .001). Highest cuspal deflection values (CDV) were obtained in FT groups. Lowest CDV were obtained in IN groups. FL groups showed higher deflection values than IN groups. CDV increased progressively as the teeth were restored and subjected to fatigue treatment