This article addresses one of the leading challenging areas for those studying performance art today: its temporal dynamic, linked to the present, to the here and now. This temporal inscription is effectively at the core of the ontology of these pieces, which has repercussions in the relationship this art form has with the physical and conceptual spaces it occupies, and in the management of art collections that include them. Analysis of performance art temporalities will lead to a discussion of the spaces this genre has been occupying in artistic institutions. The values held by these spaces will be explored, and new ways of understanding them, especially in the relationship between university, museum and theatre will be proposed. This is the triad discussed by Jan Naderveen Pieterse in 1997 will serve as an analogy to reflect upon these issues. In this context, performance art pieces, artistic projects, and curatorial programmes from the Portuguese panorama will be presented as examples.

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The removal of necrotic and vital pulp substrates and microorganisms and their toxins from the root canal system (RCS) has been found to be the basis for a successful endodontic treatment. In this study, our aim was to evaluate the effect of passive ultrasonic irrigation (PUI) on the elimination of the organic remnant tissue from infected, narrow and curved mandibular root canals during their instrumentation. For this purpose, mesiobuccal canals from mandibular first molars were instrumented with the RaCe rotary system, using PUI activation or conventional irrigation (CI) and two apical diameters (#25 and #35). The root canal cleanness of the samples was evaluated by microscopy and using a modified Langeland’s ordinal scale. Parametric and non-parametric statistical analyses and principal coordinates analysis (PCoA) of the samples were performed. When PUI was used, there was a significant reduction of the organic remnant in the apical enlargement of 25 at 2 mm from the apex (p < 0.001). After pooling the groups, regardless of the depth of the observation (2 and 4 mm from the apex), the pair #35 + PUI vs. #25 + CI showed statistically significant differences (p < 0.001). The effect of PUI explained 65% of the overall variance when compared with the CI samples. The use of PUI reduced the organic material of narrow infected and curved root canals with an apical enlargement of #25 and #35. When PUI is not used, a biomechanical instrumentation up to a diameter ≥#35 is recommended.