Evaluation of trueness and precision of removable partial denture metal frameworks manufactured with digital technology and different materials.

PURPOSE: The aim of this study is to evaluate the accuracy of removable partial denture (RPD) frameworks produced using different digital protocols. MATERIALS AND METHODS: 80 frameworks for RPDs were produced using CAD-CAM technology and divided into four groups of twenty (n = 20): Group 1, Titanium frameworks manufactured by digital metal laser sintering (DMLS); Group 2, Co-Cr frameworks manufactured by DMLS; Group 3, Polyamide PA12 castable resin manufactured by multi-jet fusion (MJF); and Group 4, Metal (Co-Cr) casting by using lost-wax technique. After the digital acquisition, eight specific areas were selected in order to measure the Δ-error value at the intaglio surface of RPD. The minimum value required for point sampling density (0.4 mm) was derived from the sensitivity analysis. The obtained Δ-error mean value was used for comparisons: 1. between different manufacturing processes; 2. between different manufacturing techniques in the same area of interest (AOI); and 3. between different AOI of the same group. RESULTS: The Δ-error mean value of each group ranged between -0.002 (Ti) and 0.041 (Co-Cr) mm. The Pearson's Chi-squared test revealed significant differences considering all groups paired two by two, except for group 3 and 4. The multiple comparison test documented a significant difference for each AOI among group 1, 3, and 4. The multiple comparison test showed significant differences among almost all different AOIs of each group. CONCLUSION: All Δ-mean error values of all digital protocols for manufacturing RPD frameworks optimally fit within the clinical tolerance limit of trueness and precision.

Analysis of the trueness and precision of complete denture bases manufactured using digital and analog technologies.

PURPOSE: Digital technology has enabled improvements in the fitting accuracy of denture bases via milling techniques. The aim of this study was to evaluate the trueness and precision of digital and analog techniques for manufacturing complete dentures (CDs). MATERIALS AND METHODS: Sixty identical CDs were manufactured using different production protocols. Digital and analog technologies were compared using the reference geometric approach, and the Δ-error values of eight areas of interest (AOI) were calculated. For each AOI, a precise number of measurement points was selected according to sensitivity analyses to compare the Δ-error of trueness and precision between the original model and manufactured prosthesis. Three types of statistical analysis were performed: to calculate the intergroup cumulative difference among the three protocols, the intergroup among the AOIs, and the intragroup difference among AOIs. RESULTS: There was a statistically significant difference between the dentures made using the oversize process and injection molding process (P < .001), but no significant difference between the other two manufacturing methods (P = .1227). There was also a statistically significant difference between the dentures made using the monolithic process and the other two processes for all AOIs (P = .0061), but there was no significant difference between the other two processes (P = 1). Within each group, significant differences among the AOIs were observed. CONCLUSION: The monolithic process yielded better results, in terms of accuracy (trueness and precision), than the other groups, although all three processes led to dentures with Δ-error values well within the clinical tolerance limit.

On the thermal behavior of protein isolated from different legumes investigated by DSC and TGA.

BACKGROUND: Pea, lentil, faba bean, chickpea and bean proteins are potentially renewable raw materials for bioplastic production that can be obtained from agricultural waste. Plastics are usually processed under heating, and thus thermal stability is a mandatory requirement for the application. In this study, the thermal behavior of several legume protein isolates at different purity degrees was investigated. RESULTS: The thermal stability of proteins extracted from legumes was maximum for chickpeas and minimum for beans and decreased with decreasing protein purity in the range 30-88%. A similar dependence on purity was observed for the glass transition temperature. On the contrary, the denaturation temperature was found not to depend on sample purity and origin and was lower than the degradation temperature only in the case of protein samples with purity higher than 60%. CONCLUSION: Proteins from legumes are suitable to produce thermoplastic biopolymeric materials if isolated at purity higher than 60%. In fact, under this circumstance, they can be denaturized without degrading and thus are suitable for extrusion processing. © 2018 Society of Chemical Industry.

Total Lymphadenectomy and Nodes-Based Prognostic Factors in Surgical Intervention for Esophageal Adenocarcinoma.

BACKGROUND: To evaluate prognostic factors based on the number of resected lymph nodes, we considered 202 patients who underwent radical resection and "total lymphadenectomy" for esophageal adenocarcinoma according to a prospective protocol. METHODS: Fifty-eight tumors surrounded by Barrett's epithelium underwent esophagectomy and esophagogastrostomy, and 144 tumors without Barrett's epithelium underwent esophageal resection at the azygos vein level, total gastrectomy, and Roux-en-Y esophagojejunostomy. All nodes and fat tissue were resected at the following stations: chest 4L and R3, R4, R7, R8, and R9 (TNM seventh edition) and abdomen 1-12 according to the Japanese Classification of Gastric Carcinoma (1998). The nodes were counted, excluding fragments. The correlations between the number of nodes yielded and the ratio of the metastatic lymph nodes/lymph nodes yielded with pT stage, grading measurements, and cancer-specific survival (CSS) were calculated. RESULTS: A total of 6,270 nodes were yielded (interquartile range per patient, 22-38; minimum, 4 nodes; maximum, 61 nodes). In 3 of 21 (14%) stage pT1 cases, less than 10 nodes were counted, in 2 of 27 (8%) stage pT2 cases, less than 20 were counted, and in 73 of 154 (47%) stage pT3-4 cases, less than 30 nodes were counted. The lymph node yield (LNY) and T stage were not correlated (r = 0 .048; p = 0.5). The metastatic lymph nodes to lymph nodes yielded ratio was correlated with pT stage (r = 0.272; p = 0.0001), and G (r = 0.385; p = 0.0001). CSS positively correlated with pT stage (p = 0.02), G (p = 0.001), and metastatic lymph nodes/lymph nodes yielded ratio (p = 0.01) (multivariate analysis). CONCLUSIONS: The total number of lymph nodes to be removed in total and within each T stage indicated as thresholds could not be reached in up to 38.6% of patients. The metastatic lymph nodes/lymph nodes yield ratio not the total LNY, did correlate with cancer-specific survival.

Urban air pollution monitoring and correlation properties between fixed-site stations.

The rich regional air-monitoring network of the Emilia-Romagna region of Italy has been used to quantify the spatial variability of the main pollutants within urban environments and to analyze the correlations between stations. The spatial variability of the concentrations of the majority of pollutants within the city was very high, making it difficult to differentiate and characterize the urban environments and to apply legal limits with uniform criteria. On the other hand, the correlations between the fixed-site monitoring stations were high enough for their data to be retained generally very appropriately for controlling temporal trends. Starting from the high correlation level, a procedure was proposed and tested to derive pollution levels, using short-term measurements, such as passive samplers and mobile-station data. The importance of long-term statistics in urban air pollution mapping was emphasized. Treatment of missing data in time series and quality assurance were indicated as possible fields for applications for the correlation properties.