The aim of this study was to assess the microhardness and surface roughness of bulk-fill resin composites treated with and without the application of an oxygen-inhibited layer (OIL) and a polishing system. This in vitro experimental study consisted of 72 resin composite blocks divided into three groups: Tetric N-Ceram Bulk Fill, Opus Bulk Fill APS, and Filtek Bulk Fill. Each resin composite group was further divided into two subgroups: with and without OIL control. Subsequently, surface roughness and microhardness were measured before and after polishing. A t-test was used to compare independent and related measures. For the intergroup comparison of variation before and after polishing, the Kruskal–Wallis test with Bonferroni post hoc was used considering a significance level of p < 0.05. When comparing surface roughness, significant differences were observed between Opus Bulk Fill resin composite with and without OIL control (p = 0.003) before polishing. The same occurred when comparing Tetric N-Ceram resin composite with and without OIL control (p = 0.039) after polishing. In addition, the surface roughness of Filtek Bulk Fill, Opus Bulk Fill, and Tetric N-Ceram Bulk Fill resin composites, with and without OIL control, decreased significantly after polishing (p < 0.001), while surface microhardness significantly increased (p < 0.05), with the exception of Opus Bulk Fill resin with OIL control (p = 0.413). In conclusion, OIL control and polishing significantly improved the surface roughness and surface microhardness of Filtek Bulk Fill and Tetric N-Ceram Bulk Fill resin composites. However, in the case of Opus Bulk Fill resin composite, only its surface roughness was significantly improved.

Background Metalloproteinases are proteolytic enzymes that degrade dentin and periodontal collagen; therefore, it is of special interest that dental students know its mechanism of action and how its effects can be inhibited. Therefore, the aim of this research was to evaluate the level of knowledge about metalloproteinases in dental students close to graduate from three universities in Peruvian capital city. Materials and methods In this analytical, observational, cross‐sectional and prospective study, 223 dental students close to graduate in three Peruvian universities were evaluated from September to November 2020. A questionnaire of 20 closed questions with three answers was validated and used to measure the level of general and dental knowledge about metalloproteinases. A logit model was used to evaluate the influence of the following variables: “gender” (X1), “type of university” (X2), “marital status” (X3) and “age group” (X4), in the knowledge levels of the students, considering a p‐value <.05. Results Of the 223 dentistry students, it was obtained that the level of knowledge about metalloproteinases was predominantly low with 82.1%, (95% confidence interval (CI): 77.1%–87.1%) of the total. According to multivariate logistic regression analysis, "type of university" was the only variable that proved to have a significant influence (p = .022) on the level of knowledge about metalloproteinases with an odds ratio of (OR = 0.44; CI: 0.21–0.89), whilst the other variables "age group" (p > .05), "gender" (p = .058) and "marital status" (p = .114) were not considered influential factors. Conclusion The majority of final year dental students in three Peruvian universities presented a low level of overall knowledge about metalloproteinases. In addition, private university students were 56% less likely to pass the subject knowledge test. On contrary, gender, age group and marital status did not significantly influence the level of knowledge of the students.

Background It has been demonstrated that dental restorations with rough surfaces can have several disadvantages such as pigment retention or plaque accumulation, which can facilitate caries formation, color variation, loss of brightness, degradation of restoration, among others. The present study aimed to assess surface roughness in bulk fill and conventional nanohybrid resins with and without polishing, controlling the oxygen inhibited layer. Methods This in vitro and longitudinal experimental study consisted of 120 resin blocks of 6 mm diameter and 4 mm depth, divided into two groups: Bulk Fill (Tetric® N-Ceram Bulk-fill, Opus Bulk Fill APS, Filtek™ Bulk Fill) and conventional nanohybrid (Tetric® N-Ceram, Opallis EA2, Filtek™ Z250 XT). Each resin group was divided into two equal parts, placing glycerin only on one of them, in order to control the oxygen inhibited layer. Subsequently, the surface roughness was measured before and after the polishing procedure with Sof-Lex discs. The data were analyzed with the T-test for related measures, and for comparison between groups before and after polishing, the non-parametric Kruskal Wallis test with the Bonferroni post hoc was used, considering a significance level of p < 0.05. Results Before polishing, the resin composites with the lowest surface roughness were Opus Bulk Fill APS (0.383 ± 0.186 µm) and Opallis EA2 (0.430 ± 0. 177 µm) with and without oxygen inhibited layer control, respectively; while after polishing, those with the lowest surface roughness were Opus Bulk Fill APS (0.213 ± 0.214 µm) and Tetric N-Ceram (0.097 ± 0.099 µm), with and without oxygen inhibited layer control, respectively. Furthermore, before and after polishing, all resins significantly decreased their surface roughness (p < 0.05) except Opus Bulk Fill APS resin with oxygen inhibited layer control (p = 0.125). However, when comparing this decrease among all groups, no significant differences were observed (p < 0.05). Conclusion The Opus Bulk Fill APS resin with oxygen inhibited layer control presented lower surface roughness both before and after polishing, being these values similar at both times. However, after polishing the other bulk fill and conventional nanohybrid resins with and without oxygen inhibited layer control, the surface roughness decreased significantly in all groups, being this decrease similar in all of them.

AimPsychological distress can be considered a maladaptive response to a stressful situation that occurs when external events or stressors impose demands that cannot be coped with. Therefore, the aim of the present study was to evaluate the sociodemographic factors associated with psychological distress in dental interns from the Peruvian capital facing the COVID-19 pandemic.Materials and methodsThis analytical, observational, cross-sectional study was conducted on 392 Stomatology interns from the Peruvian capital from June to July 2022. The validated COVID-19 Peritraumatic Distress Index (CPDI) scale to detect the levels of psychological distress consisted of four dimensions: negative mood, changes in behavior and cognitive skills, fatigue and hyperreactivity, and somatization. Pearson's chi-square and Fisher's exact test were used for bivariable analysis. In addition, a logit model was used to assess the influence of variables: sex (X1), age group (X2), marital status (X3), monthly economic income (X4), working area in the capital city (X5), and living with people vulnerable to COVID-19 (X6), with the psychological distress levels, considering a significance p &lt; 0.05.ResultsThe prevalence of psychological distress in dental interns was severe in 6.4% [95% confidence interval (CI): 3.9–8.8%] and mild in 37.8% (95% CI: 33.0–42.6%). According to bivariable analysis, the levels of psychological distress by COVID-19 were not significantly associated with sex (p = 0.190), age group (p = 0.418), marital status (p = 0.554), monthly economic income (p = 0.327), working area in the capital city (p = 0.993), and living with people vulnerable to COVID-19 (p = 0.134). In addition, according to the logistic regression analysis, none of the variables studied was considered an influential factor (p &gt; 0.05) in psychological distress presented by dental interns.ConclusionThe 44.2% of dental interns from the Peruvian capital presented psychological distress facing the COVID-19 pandemic, without any of the possible associated variables of this study significantly affecting this behavioral disorder.

Aims and Objectives: Excessive fear of coronavirus disease 2019 (COVID-19) in dental students could cause mood disorders, especially if there are factors in the environment that generate feelings of anxiety or uncertainty. The aim of this study was to evaluate the fear of COVID-19 and its association with depression, anxiety, and stress in Peruvian dental students according to their sociodemographic factors. Materials and Methods: This analytical, observational, and cross-sectional study was conducted in 398 dental students of a public university in the Peruvian capital during April 2021 to July 2021. The Depression, Anxiety and Stress Scale—21 items was used to diagnose depression, anxiety, and stress. The Fear of COVID-19 Scale was used to detect fear of COVID-19. The Pearson’s chi-square test was used for statistical analysis. In addition, a logit model using odds ratio (OR) was performed to evaluate depression, anxiety, and stress of students with the associated factors: fear of COVID-19 and 12 sociodemographic variables (gender, age group, marital status, year of study, origin, companion, living with vulnerable people, history of mental illness, history of COVID-19, loss of close relatives due to COVID-19, occupation, and area of residence). A significance level of P < .05 was considered. In addition, predictive models were developed for the variables depression, anxiety, and stress, considering all possible significant causes. Results: The prevalence of fear of COVID-19, depression, anxiety, and stress was 19.6%, 36.2%, 40.7%, and 19.6%, respectively. According to the adjusted logit model, students who had fear of COVID-19 had OR = 2.74 (95% confidence interval [CI]: 1.62–4.64), OR = 5.59 (95% CI: 3.14–9.97), and OR = 3.31 (95% CI: 1.88–5.83) for developing depression, anxiety, and stress, respectively. In addition, those who reported history of mental illness were four times more likely to develop depression (OR = 4.02, 95% CI: 1.96–8.25) and anxiety (OR = 4.50, 95% CI: 2.06–9.82), whereas those living with people vulnerable to COVID-19 were twice as likely to develop stress (OR = 2.06, 95% CI: 1.16–3.66). Conclusion: The highest prevalence of mood disorders among dental students was anxiety. In addition, those who were afraid of COVID-19 had three times the probability of developing depression and stress, and five times the probability of developing anxiety. On the other hand, the most influential factor in the development of depression and anxiety was history of mental illness, whereas the factor of living with vulnerable people was the most influential factor in the development of stress.