Sealing ability of castor oil polymer as a root-end filling material

OBJECTIVE: The purpose of this study was to evaluate the sealing ability of castor oil polymer (COP), mineral trioxide aggregate (MTA) and glass ionomer cement (GIC) as root-end filling materials. Forty-five single-rooted human teeth were cleaned and prepared using a step-back technique. The apical third of each root was resected perpendicularly to the long axis direction. All teeth were obturated with gutta-percha and an endodontic sealer. After, a root-end cavity with 1.25-mm depth was prepared using a diamond bur. The specimens were randomly divided into three experimental groups (n=15), according to the root-end filling material used: G1) COP; G2) MTA; G3) GIC. The external surfaces of the specimens were covered with epoxy adhesive, except the root-end filling. The teeth were immersed in rhodamine B dye for 24 hours. Then, the roots were sectioned longitudinally and the linear dye penetration at the dentin/material interface was determined using a stereomicroscope. ANOVA and Tukey's tests were used to compare the three groups. The G1 group (COP) presented smaller dye penetration, statistically different than the G2 (MTA) and G3 (GIC) groups (p;0.05). The results of this study indicate that the COP presented efficient sealing ability when used as a root-end filling material showing results significantly better than MTA and GIC

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

ANALYSIS OF THE ELEMENT ABUNDANCE IN ROOTS OF HOLM OAKS AT DIFFERENT STAGES OF DECLINE

INFN (Istituto Nazionale di Fisica Nucleare). LNL (Laboratori Nazionali Legnaro), Annual Report

Marginal fit of electroformed copings before and after the coction of the porcelain

The aim of this study was to evaluate the marginal discrepancy of electroforming copings, before and after the porcelain application, varying the cervical preparation of the crowns.Two master die were prepared with stainless steel to complete crown margin designs: chamfer and rounded shoulder. The impressions were taken with a polyvinylsiloxane by the double impression technique and, the insertion and removal axis were standardized by a dental surveyor. Ten type IV plaster dies from each cervical margin were obtained, on which a die spacer was applied before duplicate. The duplicated dies received a silver layer and connected to a copper wire to enable the gold electrodeposition. After cleaning and adjustments all specimens were examined under a microscope (magnificatio X 30). The marginal gap was measured before and after ceramic application. The results were elaborated by descriptive statistical and two-way analysis of variance (ANOVA). The ANOVA revealed no significant difference between marginal gap before and after the ceramic application (p=5%). It was concluded that the porcelain application does not influence the marginal fit of copings, therefore the two marginal endings can be used with the electroforming system

Evaluation of marginal adaptation of ceramic crowns depending on the marginal design and the addition of ceramic

This study evaluates the marginal adaptation of ceramic copings front of two finish lines and addition of ceramic. Hence, two master steel dies were milled with all-ceramic crowns preparation, one with a round shoulder finish line margin design, and the other with a deep chamfer. From each one of them, 15 copings were made, and the marginal discrepancy was evaluated in measuring microscope. The ceramic addition was accomplished in both groups with aid of a silicone matrix, and the discrepancies were measured again, obtaining the final mean gap values. The initial measurements resulted means of 44,0μm for deep chamfer and 24,0μm for the round shoulder, and the final measurements were 53,3μm for the deep chamfer and 27,4μm for the round shoulder. The data were submitted to the analysis of variance for verification of influence of the finish lines and application of the ceramic. When analyzed the interaction among the variables it was not observed statistical differences, but when comparing the two types of finish lines or the groups before and after ceramic addition, statistical differences were found. It is was concluded that the round shoulder finish line presents better values of marginal gap than deep chamfer and the addition of ceramic influences in the final gap values of marginal adaptation

Marginal fit of electroformed copings before and after the coction of the porcelain

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Use of RAPD molecular markers on differentiation of brazilian and chinese Ganoderma lucidum strains

The aim of this work was to analyze the Brazilian and Chinese strains of Ganoderma lucidum with molecular RAPD markers. A similarity matrix was elaborated and the RAPD profiles of G. lucidum strains were also compared to two other Ganoderma spp: G. applanatum and G. lipsiense in order to produce genetic similarity among the species. Based on the primers used, it was possible to determine that the Brazilian strains and Chinese strain CC-22 are alike. The method and the primers selection showed to be appropriate for the genetic identification of G. lucidum strains, enabling them to be improved and used in research, as well as in the world market