Background: The quarantine associated with the COVID-19 pandemic forced dental schools to suspend their clinical training and to shift to distant learning methods. The aim of this study is to investigate the impact of quarantine on the self-perceived preparedness of dental graduates and to explore the efficacy of online education from students’ perspectives. Methods: The questionnaire distributed to dental students comprised of two main sections. The first part covered the online education experience, and the second part measured the level of self-perceived preparedness for a range of cognitive, communication and professional skills. Results: The survey yielded a response rate of 72%. The majority of students (77%) agreed that they missed educational experiences as a result of the lockdown. More than half of them felt less motivated to follow-up with distant e-learning and believed that online assessment is not a good method for evaluation. A high percentage of the students (66%) thought that online group discussions had a positive value while 67% preferred online lectures compared to theatre lectures. Majority of students particularly 5th year (78.7%) (p < 0.001) stated that the quarantine increased their collaboration with their colleagues. According to 87% of students, the experience most negatively affected was their clinical training. In general, students showed satisfactory self-perceived preparedness related to a range of attributes and professional skills. Conclusions: The data showed that students partially appreciated the online system, whereas they did not consider it a substitute for face to face clinical practice. The overall self-perceived preparedness level was promising; however students had reservations regarding independent practice following graduation.

Bioactive glasses have been shown to stimulate osteogenesis both in vivo and in vitro. However, the molecular mechanisms underlying this process are still poorly understood. In this study, we have investigated the behaviour of osteoblast-like cells (MG63), cultured in the presence of bioglass particles. Three types of granules were used: 45S5 bioactive glass, 45S5 granules preincubated in tris buffer and 60S non-reactive glass, used as control. Phase contrast microscopy permitted step-by-step visualization of cell cultures in contact with the particles. Ultrastructural observations of undecalcified sections revealed direct contacts of the cells and an electron-dense layer located at the periphery of the material. Protein synthesis was evaluated biochemically and showed a gradual increase throughout the culture time in the three types of cultures. Alkaline phosphatase was detected in situ, in clusters of packed cells either in contact with the material or in the background cell layer. Semi-quantitative RT-PCR analysis of the main osteoblastic markers showed that gene expression was maintained in all three cultures. The fact that osteocalcin was not detected, supports the fact that the MG63 cell line is composed of less differentiated osteogenic cells rather than mature osteoblasts. We also demonstrated for the first time in this cell line, the expression of Msx-2, Dlx-3 and Dlx-7 homeogenes, known to regulate in vivo foetal skeletogenesis as well as adult skeletal regeneration. However, no significant differences could be recognised in the expression pattern of bone markers between the three types of cultures. Yet these preliminary results indicate that bioactive glasses provided a suitable environment for the growth and proliferation of osteoblasts in vitro, since no drastic changes in phenotype expression of pre-osteoblasts was noted.

The aim of this study was to evaluate the strength of the bond between newly introduced self-adhesive resin cements and tooth structures (i.e., enamel and dentin). Three self-adhesive cements (SmartCem2, RelyX Unicem, seT SDI) were tested. Cylindrical-shaped cement specimens (diameter, 3 mm; height, 3 mm) were bonded to enamel and dentin. Test specimens were incubated at 37 °C for 24 h. The shear bond strength (SBS) was tested in a Zwick Roll testing machine. Results were analyzed by one-way ANOVA and t-test. Statistically significant differences were defined at the α = 0.05 level. Bond failures were categorized as adhesive, cohesive, or mixed. The SBS values ranged from 3.76 to 6.81 MPa for cements bonded to enamel and from 4.48 to 5.94 MPa for cements bonded to dentin (p > 0.05 between surfaces). There were no statistically significant differences between the SBS values to enamel versus dentin for any given cement type. All cements exhibited adhesive failure at the resin/tooth interface. Regardless of their clinical simplicity, the self-adhesive resin cements examined in this study exhibit limited bond performance to tooth structures; therefore, these cements must be used with caution.