To evaluate the effect of printing orientation combined with different postcuring times on the flexural strength of 3D-printed resins. Materials and methods: A total of 480 rectangular specimens with the dimensions of 64×10×3.3 mm were designed and fabricated from two 3D-printed acrylic resins and one heat-polymerized resin (HP). 3D-printed groups were divided into 3 groups according to printing orientations (0-, 45-, 90-degree); each group was subdivided into 4 groups according to postcuring time (30, 60, 90, 120 min.). All specimens were subjected to thermal cycling (10,000 cycles) before testing flexural strength. Fractured surfaces were examined under a scanning electron microscope (SEM). ANOVA and Tukey's post hoc tests were used for data analysis (α = 0.05). Results:The result of this study showed that the highest flexural strength values of 3D-printed resin (NextDent, and ASIGA) were in 0-degree groups. Also, the flexural strength values increased when postcuring time was increased, regardless of the printing orientation; the highest flexural strength was recorded at 120 minutes postcuring time in all orientations. SEM analysis showed a rougher surface with irregular lamellae which represented a ductile fracture confirming that high energy is required for crack propagation and these features markedly increased as postcuring time increased. Conclusion:The results showed that the 0-degree orientation groups showed higher flexural strength compared to other groups. Similarly, with increased postcuring time, the flexural strength increased.

The effect of printing parameters on the surface characteristics of three-dimensional (3D)-printed denture base resins (DBRs) is neglected. Therefore, this study investigated the effect of printing orientation and post-curing time on the surface roughness and hardness. One conventional heat-polymerized (HP) resin and two 3D-printing resins (NextDent (ND) and ASIGA (AS)) were used to fabricate a total of 250-disc (10 × 2.5 mm) specimens. ND and AS specimens were printed with different orientations (0-, 45-, and 90-degree) and each orientation group was subjected to four post-curing times (30, 60, 90, 120 min). Printed specimens were thermo-cycled (10,000 cycles) followed by the measuring of surface roughness (Profilometer (Ra)) and hardness (a Vickers hardness (VH)). ANOVA and post hoc tests were used for data analysis (α = 0.05) at significant levels. AS and ND showed no significant changes in Ra when compared with HP (p ˃ 0.05), except the 45-degree orientation (AS/90 min and AS/120 min) significantly increased surface roughness (p ˂ 0.001). There was no significant difference in Ra with different orientations and post-curing time for both materials AS and ND (p ˃ 0.05). Compared with HP, 3D-printed DBRs showed low VH values (p ˂ 0.001). For AS, 90-degree orientation showed a significant decrease in VH at 60, 90, and 120 min when compared with 0- and 45-degree orientation (p ˂ 0.001), while ND showed no significant difference in VH with different printing orientations (p ˃ 0.05). The VH of AS and ND improved when increasing post-curing time to 120 min (p ˂ 0.001), and the printing orientations and post-curing time did not affect the Ra of 3D-printed DBRs.

Objective. To evaluate empathy and its related factors among undergraduate dental students and interns enrolled in a public dental college in Dammam, Saudi Arabia. Materials and Methods. This cross-sectional study used the Jefferson Scale of Empathy-Health Profession Students (JSE-HPS) version to determine empathy in 362 dental students and interns in Dammam, Saudi Arabia. The JSE-HPS is a 20-item 7-point Likert scale questionnaire, and its score ranges from 20 to 140 with high values indicating increased empathy. Influences of age, gender, class year, previous year’s grade point average (GPA), educational attainment of parents, and monthly family income on empathy were evaluated. Results. Of 501 enrolled students and interns, 362 returned completed questionnaires, and the response rate of the study was 72%. The sample’s empathy score (JSPE-HPS scale) ranged from 70 to 129 with a mean of 96.75 (±13.76). Most participants believed that empathy is important for effective communication with patients (96.1%) and can improve the provider-patient relationship (95.6%). Females demonstrated a significantly higher mean empathy score (99.98 ± 14.01) than males (92.72 ± 12.35) ( P < 0.001 ). Similarly, the participants with high GPA (98.06 ± 13.69) had significantly greater mean empathy scores than those with low GPA (94.84 ± 13.68) ( P = 0.029 ). The mean empathy score increased significantly from junior students (3rd and 4th year students) to senior students (5th and 6th year students) and interns ( P = 0.008 ). Multiple linear regression analysis showed that class year (B = 2.03, P = 0.006 ) and GPA (B = 8.67, P = 0.003 ) were significant factors associated with empathy. Conclusions. Empathy is important for effective patient communication and improved provider-patient relationship. Female gender, high GPA, and class years were associated with empathy. Empathy should be integrated into dental curricula for effective student learning and positive patient care outcomes.

Background The Coronavirus Disease of 2019 (COVID-19) pandemic is a worldwide global public health threat. Although acceptance of COVID-19 vaccination will be a critical step in combating the pandemic, achieving high uptake will be difficult, and potentially made more difficult by social media misinformation. This study aimed to examine the association between social media use and acceptance of receiving COVID-19 vaccine among the general population in Saudi Arabia. Methodology A cross-sectional study was conducted from June 17 to June 19, 2021 among 504 participants of the general population in Saudi Arabia. The data were collected using a three-part online questionnaire (sociodemographic characteristics, medical and vaccination history, pattern of social media use). Results Among 504 participants who completed the survey, 477 participants were acceptant of the vaccine and 27 were non-accepting. A total of 335 individuals had already received the vaccine, 142 were willing to receive the vaccine and 27 were unwilling. One hundred and thirty participants denied using social media for COVID-19 news. Four factors were found to be significant in influencing vaccine acceptance in univariate analysis: having a chronic condition (odds ratio (OR) = 0.367, P = 0.019), believing that infertility is a side effect of the COVID-19 vaccine (OR = 0.298, P = 0.009), being concerned about a serious side effect from the vaccine (somewhat concerned: OR = 0.294, P = 0.022, very concerned: OR = 0.017, P < 0.0001), and basing the decision to be vaccinated on social media information (OR = 0.260, P = 0.006). Two of these factors fell away on multivariate analysis: basing the decision on social media information (OR = 0.356, P = 0.071), and a belief that vaccination causes infertility (OR = 0.0333, P = 0.054), suggesting that the associations are dependent on other factors. Conclusion ‏In conclusion, there was no significant independent relationship between social media usage and people's willingness to receive a COVID-19 vaccination. Further studies to explore the association between social media use and vaccine decisions are required to generalize this observation to the Saudi population.

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