Surface roughness and oxygen inhibited layer control in bulk-fill and conventional nanohybrid resin composites with and without polishing: in vitro study.

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.

Psychological impact on dental students and professionals in a Lima population during COVID-19s wave: a study with predictive models.

Peru was the country with the highest COVID-19 case fatality rate worldwide during second wave of infection, with dentists and pre-professional students being susceptible to infection due to clinical procedures they perform. This situation could have generated some kind of psychological disorder within this group. Therefore, the present study aimed to assess how COVID-19 pandemic affected this population group during second wave, in relation to depression, anxiety and stress. This observational and cross-sectional study in 368 Peruvian dentists (186 students and 182 professionals), was carried out during August to November 2021. The DASS-21 Scale was used to diagnose depression, anxiety and stress. For the statistical analysis, Pearson's chi-square test was used, in addition to a logit model using odds ratio (OR) to evaluate depression, anxiety and stress with the following factors: gender, age group, marital status, monthly family income, children, academic level, history of COVID-19, COVID-19 symptomatology, close relative with COVID-19, living with vulnerable people and work dedication. In addition, predictive models were constructed considering all possible significant causes. A significance level of p < 0.05 was considered. Dental students and professionals presented significant differences in levels of depression, anxiety and stress (p < 0.001, p = 0.022, p = 0.001; respectively). Male students were 56% less likely to develop stress (OR 0.44; CI 0.22-0.85) compared to females; while those unmarried were 81% less likely to develop stress (OR 0.19; CI 0.04-0.85). Likewise, those with children were 83% less likely to develop stress (OR 0.17; CI 0.06-0.52) and 65% less likely to develop depression (OR 0.35; CI 0.15-0.80). In addition, COVID-19 asymptomatics were 60% less likely to develop depression (OR 0.40; CI 0.17-0.92). However, having relatives with COVID-19 caused almost three times the probability of developing depression (OR 2.96; CI 1.29-6.79) and twice the probability of developing stress (OR 2.49; CI 1.07-5.78). As for dental professionals, it was noticed that those unmarried had almost three times the probability of developing stress (OR 2.93; CI 1.38-6.23); while those who only worked had twice the probability of developing stress (OR 2.37; CI 1.17-4.78). Dental students had a higher prevalence of depression, anxiety and stress. In addition, having children and being asymptomatic were protective predictors for depression, while being male, unmarried and having children were protective predictors for stress. However, having a relative with COVID-19 was a risk predictor for depression and stress. In professionals, only working and being unmarried were risk predictors for stress.