RESUMO
PURPOSE: To assess the influence of denture brushing on the surface roughness, hardness, and color stability of conventional, thermoformed, and CAD-CAM denture base materials. MATERIALS AND METHODS: Seven different denture base materials were included in this study; conventional heat-polymerized acrylic resin (PMMA) served as control, polyamide, acetal, two categories of milled acrylic discs (AvaDent and IvoCad), and two categories of 3D-printed resins (NextDent and FormLabs). The specimens were constructed according to manufacturers' instructions and then subjected to simulated brushing (20,000 cycles). According to the brushing method, the specimens were split into three groups, no brushing, brushing with water, and brushing with toothpaste. Surface roughness, hardness, and color change were evaluated before and after brushing. Collected data were analyzed using ANOVA, and post-hoc Tukey's tests (α = 0.05). RESULTS: A significant difference was noted between the surface roughness of the tested materials before and after denture brushing (p < 0.05), and milled resin showed the least Ra values. Denture brushing with water significantly increased the Ra of PMMA (p = 0.004) and IvoCad (p = 0.032), while brushing using toothpaste did not show a significant increase. The brushing protocols did not alter the hardness of tested materials except that of PMMA (p = 0.001). The color stability of the tested materials showed comparable results with both brushing protocols. CONCLUSION: The tested properties showed variations between the types of denture base resins. Hardness and color stability of CAD-CAM and thermoformed denture base resins were not altered by denture brushing and showed comparable results with both brushing methods. Surface roughness was the only property that showed alteration after denture brushing.
RESUMO
Background The pandemic-induced physical closure of educational institutions led to challenges for senior dental students that might affect their psychological status. This study aimed to assess stress, anxiety, and subjective worries among dental interns post-COVID-19. Methodology A self-structured questionnaire was sent to Alexandria University and Taibah University dental interns. The questionnaire included sociodemographic data, self-reported comorbidities, behavioral risk factors, Kessler Psychological Distress Scale (K-10), Generalized Anxiety Disorder 7-Item (GAD-7) scale, and future subjective worries regarding the dental profession post-COVID-19. Results A total of 129 interns participated, with the majority (79.1%) being females. Overall, 90.7% were unmarried, 80.6% lived with a family, 93.8% were free from systemic comorbidities, 82.17% were satisfied with their current life, and 63.6% felt positive quite often. K-10 distress levels were reported as very high (38%) and high (33.3%), and perceived satisfaction with current social life was significantly associated with moderate-to-high distress levels. Feeling positive about life quite often was significantly associated with very high distress levels. Mild GAD-7 anxiety levels were reported in 40.3% and were significantly associated with females, who perceived positive satisfaction with their current social life and felt positive about life. Most agreed that their profession would be risky, their ability to perform their job to the best would be jeopardized, and they would need extra precautions in clinical training post-COVID-19; however, they disagree with postponing their training until COVID-19 cases declined entirely. Conclusions Dental interns were affected by the lockdown, especially female interns. Psychological therapy is advised for stressed dental students.
