The Portuguese translation of the OBC exhibits cross-cultural equivalence for use in Portugal, and the instrument performs with acceptable psychometric properties. The validity of the parafunction construct requires additional research in both Portuguese and other languages.

Background Many different types of oral overuse behaviours occur frequently in adult populations with painful temporomandibular disorders (TMDs). Less is known regarding these behaviours and their associations with TMDs in university students. Objectives Test the association between frequency of different oral overuse behaviours evaluated by the Oral Behaviour Checklist (OBC) and the severity of painful TMDs. Methods In this cross‐sectional study, 1381 students from 19 universities in the Oporto District, Portugal, completed the Research Diagnostic Criteria for TMD (RDC/TMD) Personal History Questionnaire and the OBC, and they received an RDC/TMD clinical examination. The OBC sum score (ranging from 0 to 84 points) was classified as normal (0 ≤ 16 points), low overuse (17 ≤ 24) or high overuse (≥25). Painful TMD subtypes (myalgia, arthralgia or combined) were identified. Associations were tested using multivariable binary logistic regression models (α = .05), adjusted for age and sex, and referencing the normal parafunction group. Results University students with high overuse were more likely to have a painful TMD: myalgia (OR = 1.9, 95% CL: 1.3–3.0); arthralgia (OR = 2.2; 95% CL: 1.4–3.4), combined (OR = 5.0; 95% CL: 3.1–8.1). Students with low overuse were more likely to have only the combined painful TMD (OR = 2.4; 95% CL: 1.4–4.0) but not the individual painful disorders. Of the 21 different behaviours, 13 were reported at least 50% of the time. Conclusions In this university student sample, oral overuse behaviours are widespread, and their overall extent exhibited a dose‐response relationship with respect to severity of painful TMDs based on pain and chronicity. Only some behaviours were independently associated with painful TMDs, suggesting the value of further OBC instrument development.

Three-dimensional printing offers possibilities for the development of new models in endodontics. Numerous studies have used 3D-printed teeth; however, protocols for the standardization of studies still need to be developed. Another problem with 3D-printed teeth is the different areas of literature requested to understand the processes. This review aims to gather evidence about 3D-printed teeth on the following aspects: (1) why they are advantageous; (2) how they are manufactured; (3) problems they present; and (4) future research topics. Natural teeth are still the standard practice in ex vivo studies and pre-clinical courses, but they have several drawbacks. Printed teeth may overcome all limitations of natural teeth. Printing technology relies on 3D data and post-processing tools to form a 3D model, ultimately generating a prototype using 3D printers. The major concerns with 3D-printed teeth are the resin hardness and printing accuracy of the canal anatomy. Guidance is presented for future studies to solve the problems of 3D-printed teeth and develop well-established protocols, for the standardization of methods to be achieved. In the future, 3D-printed teeth have the possibility to become the gold standard in ex vivo studies and endodontic training.

Abstract. This work proposes a new form of integral which arises from infinite partitions. It uses upper and lower series instead of upper and lower Darboux finite sums. It is shown that every Riemann integrable function, both proper and improper, is integrable in the sense proposed here and both integrals have the same value. Furthermore it is shown that the Riemann integral and our integral are equivalent for bounded functions in bounded intervals. The advantage of this new integral is that a single definition allows the integration of bounded or unbounded functions, in bounded or unbounded intervals. The present integral is different from the ordinary Riemann integral, where it is necessary to have the prior definition of bounded functions in bounded intervals.