Short fiber-reinforced composite resins as post-and-core materials for endodontically treated teeth: A systematic review and meta-analysis of in vitro studies

STATEMENT OF PROBLEM As the use of traditional posts has been associated with complications and failure outcomes, the introduction of novel materials and minimally invasive dentistry has shifted toward the use of composite resin post-and-core restorations for endodontically treated teeth. As a further process, to improve stress absorption environment in restored teeth, the invention of short fiber-reinforced composite resins (SFRCs) as post-and-core restorations has recently emerged. However, evidence regarding its performance is still scarce, and a synthesis of existing data is lacking. PURPOSE The purpose of this systematic review and meta-analysis was to assess the performance of SFRC post-and-core restorations, regarding fracture resistance and failure mode and considering both cyclic and static loading. MATERIAL AND METHODS An electronic search in 5 databases was conducted up to August 2022, and the protocol of the study was registered a priori. The search terms included "fiber reinforced composite," "core build-up," and "post." Studies were considered if they compared SFRC restorations with other types of conventional posts and teeth restored using bulk fill composite resin. The internal validity of the studies was assessed by using a custom-made risk of bias tool. RESULTS A total of 1271 records were identified, of which 13 were considered for full-text assessment. Eight were ultimately included, all being in vitro studies, and 7 of them were deemed eligible for quantitative syntheses. The results varied considerably across studies with divergent fracture resistance values and percentages of catastrophic failure being reported. Standard depth (6 mm) SFRCs presented fewer repetitions until fracture on average, compared with the individually made FRCs (3 studies: mean difference (MD): -4062; 95% CI: -6148, -1975; P<.001) under cyclic loading. Under static loading, SFRCs (standard depth) presented a nearly 300 N lower fracture force compared with that of intact teeth, (3 studies: MD: -297; 95%CI: -378, -216; P<.001). CONCLUSIONS Evidence on the laboratory fracture and failure performance of SFRCs is limited, and future studies should incorporate more standardized experimental conditions, as well as SFRCs with limited sacrifice of tooth substrate within the root canal of endodontically treated teeth

Adaptation of the Canadian Fire Weather Index to Mediterranean forests

The Canadian Fire Weather Index (FWI) is one of the most used tools to forecast forest fire hazard. In this paper, we propose an adaptation of the FWI to take into account the Mediterranean vegetation and climate, to improve FWI performances for areas with these characteristics. In particular, the FWI has been calibrated for two Mediterranean regions (Algarve, Portugal and Peloponnese, Greece) by fitting the experimental data, collected in the field, for the forest fuel moisture content, with the values expected by the application of the original Canadian FWI. Field data were collected during the 2010 and 2011 fire seasons. The satisfactory results obtained by the adaptation of parameters from the original FWI, in spite of the small sample areas and limited time of collection, allowed us to verify the usefulness of the method in describing the fuel moisture dynamics and obtaining indexes closer to the characteristics of the Mediterranean forests considered. The adapted FWI, if further tested and extended to other sample areas, may help in a more detailed and precise application of the FWI index by improving the daily forest fire hazard forecast, to become also a better support for the Civil Protection Agency of Mediterranean countries

Classifications of atmospheric circulation patterns

We review recent advances in classifications of circulation patterns as a specific research area within synoptic climatology. The review starts with a general description of goals of classification and the historical development in the field. We put circulation classifications into a broader context within climatology and systematize the varied methodologies and approaches. We characterize three basic groups of classifications: subjective (also called manual), mixed (hybrid), and objective (computer-assisted, automated). The roles of cluster analysis and principal component analysis in the classification process are clarified. Several recent methodological developments in circulation classifications are identified and briefly described: the introduction of nonlinear methods, objectivization of subjective catalogs, efforts to optimize classifications, the need for intercomparisons of classifications, and the progress toward an optimum, if possible unified, classification method. Among the recent tendencies in the applications of circulation classifications, we mention a more extensive use in climate studies, both of past, present, and future climates, innovative applications in the ensemble forecasting, increasing variety of synoptic-climatological investigations, and steps above from the troposphere. After introducing the international activity within the field of circulation classifications, the COST733 Action, we briefly describe outputs of the inventory of classifications in Europe, which was carried out within the Action. Approaches to the evaluation of classifications and their mutual comparisons are also reviewed. A considerable part of the review is devoted to three examples of applications of circulation classifications: in historical climatology, in analyses of recent climate variations, and in analyses of outputs from global climate models