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PurposeTo investigate the effect of different in vitro aging protocols on the optical properties and crystalline structure of high‐translucency (HT) zirconia.Materials and methodsThirty‐six specimens of HT and extra‐high translucency (XT) zirconia were divided into three groups: control (CO)—no treatment; hydrothermal aging (HA)—autoclave aging for 12.5 h at 134°C, 2 bar; clinically related aging (CRA)—aging in the chewing simulator for 1.2 million cycles, followed by 50,000 thermocycles (5–55°C) and immersion in HCl (pH 1.2) for 15 h. Optical properties, crystalline structure, and surface roughness were analyzed and compared using analysis of variance (5% significance level).ResultsThere was no statistically significant effect of aging on translucency (p = 0.10), but CRA promoted the development of a high contrast ratio (p = 0.03). Aging did not cause significant color changes for HT (p = 0.65) or XT (p = 0.36). The proportion of monoclinic crystals increased to 40% for HT‐zirconia after HA and 5% after CRA. No monoclinic crystals were detected for XT groups. There was no effect of aging on surface roughness (p = 0.77).ConclusionsAlthough hydrothermal aging has been widely used to verify zirconia crystalline stability, it did not generate an effect similar to clinically related aging on the optical properties and crystalline structure of zirconia. HA affected the crystalline structure of HT‐zirconia, and CRA compromised the optical properties of XT zirconia.

Dental students providing feedback about a course they take, in a timely manner, benefits not only teachers, but also indirectly the students themselves, especially if given with confidence in a constructive manner. Therefore, the aim of this study was to train students on how to give feedback, to ask them to provide feedback before and after the instructions were given, and analyze the change in their responses. Participants were students who attended the second-year preclinical course in prosthodontics. They were asked to provide feedback anonymously with online surveys after completing modules of the course during the academic year. There was no intervention prior to the first feedback; however, before providing the second feedback, students were asked to read a 1-page handout related to feedback modalities. Following this, an interactive workshop in feedback was provided prior to the third survey. The received responses were ranked as either: neutral, positive, negative, or constructive and were analyzed using a mixed repeated measures test with Bonferroni correction at a 0.05 significance level. The results showed a higher number of constructive and positive responses than both neutral and negative feedback (P ≤ 0.05) within the same surveys, but no interaction effect was found between the surveys (P = 0.076). Our data showed an increase in constructive feedback provided by students after the 2 different training methods, but the modality of delivery did not seem to significantly influence the results. In summary, training students on how to provide constructive feedback may be beneficial for teachers to improve their courses.

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