A provisionalization sequence is essential for obtaining a predictable final prosthetic outcome. An assessment of the mechanical behavior of interim prosthetic materials could orient clinicians towards selecting an appropriate material for each clinical case. The aim of this study was to comparatively evaluate the mechanical behavior—with compressive and three-point flexural tests—of certain 3D-printed and conventional resins used to obtain interim fixed dental prostheses. Four interim resin materials were investigated: two 3D-printed resins and two conventional resins (an auto-polymerized resin and a pressure/heat-cured acrylic resin). Cylindrically shaped samples (25 × 25 mm/diameter × height) were obtained for the compression tests and bar-shaped samples (80 × 20 × 5 mm/length × width × thickness) were produced for the flexural tests, observing the producers’ recommendations. The resulting 40 resin samples were subjected to mechanical tests using a universal testing machine. Additionally, a fractographic analysis of failed samples in bending was performed. The results showed that the additive manufactured samples exhibited higher elastic moduli (2.4 ± 0.02 GPa and 2.6 ± 0.18 GPa) than the conventional samples (1.3 ± 0.19 GPa and 1.3 ± 0.38 GPa), as well as a higher average bending strength (141 ± 17 MPa and 143 ± 15 MPa) when compared to the conventional samples (88 ± 10 MPa and 76 ± 7 MPa); the results also suggested that the materials were more homogenous when produced via additive manufacturing.
All social and economic systems worldwide, including the educational one have been disrupted by escalating the global COVID-19 pandemic. One of the most impacted areas were the medical and dental education fields, due to the forced break from clinical practice during the lockdown, which affected both the educational part, as well as the patients. Thus, the main goal of our research was to investigate the impact of the COVID-19 pandemic on the dental students’ education as related to their perceptions and evaluations, in Carol Davila University of Medicine and Pharmacy, Bucharest, Romania. A cross-sectional study was conducted on 878 dental students who reported their perception of the psychological and educational impact of this period by completing a Google Forms questionnaire. Collected data were statistically analyzed using Stata/IC 16. There was a severe psychological impact among the respondents, the levels of stress being perceived as high and very high (33.83%, n = 297; 28.59%, n = 251), similar to high and very high anxiety feelings (26.54%, n = 233; 24.26%, n = 213). Very high educational impact from the point of view of the acquisition of practical skills (48.52%, n = 426) and future professional perspectives (38.95%, n = 342) were recorded. While online theoretical learning ability was principally low (37.93%, n = 333) despite consistently modified time allocated to the individual study (44.35%, n = 389), most of the students evaluated the efficiency of lecturers in online courses as neutral (41.12%, n = 361). New dentistry teaching programs will have to be adopted taking into account the dynamics of the pandemic and its strong impact on our students, in order to improve both their wellbeing and the sustainability of dental education.
The purpose of this study is to outline relevant elements regarding the biochemical interactions between prosthetic materials used for obtaining implant-supported restorations and the oral environment. Implant-supported prostheses have seen unprecedented development in recent years, benefiting from the emergence of both new prosthetic materials (with increased biocompatibility and very good mechanical behavior), and computerized manufacturing technologies, which offer predictability, accuracy, and reproducibility. On the other hand, the quality of conventional materials for obtaining implant-supported prostheses is acknowledged, as they have already proven their clinical performance. The properties of PMMA (poly (methyl methacrylate))—which is a representative interim material frequently used in prosthodontics—and of PEEK (polyether ether ketone)—a biomaterial which is placed on the border between interim and final prosthetic use—are highlighted in order to illustrate the complex way these materials interact with the oral environment. In regard to definitive prosthetic materials used for obtaining implant-supported prostheses, emphasis is placed on zirconia-based ceramics. Zirconia exhibits several distinctive advantages (excellent aesthetics, good mechanical behavior, biocompatibility), through which its clinical applicability has become increasingly wide. Zirconia’s interaction with the oral environment (fibroblasts, osteoblasts, dental pulp cells, macrophages) is presented in a relevant synthesis, thus revealing its good biocompatibility.
Background and Objectives: The SARS-CoV-2 pandemic led to changes in population daily patterns. In order to adapt oral health promotion measures for future similar conditions, the main objective of the study was to assess changes in dental hygiene and eating and smoking habits during the government lockdown in Romania. Materials and Methods: The cross-sectional study was conducted immediately after the end of the lockdown and consisted of 800 adult subjects. Data collection was done via an online survey. Participants were divided into two groups: non-medical/dental practitioners (N-M/D group) and medical/dental practitioners (M/D group). Results: An increased use of dental floss from 27% (pre-lockdown) to 30.5% (during lockdown) was identified in the M/D group, while the manual toothbrush usage increased to 64.8% (during lockdown) from 61.7% (pre-lockdown) in the N-MD/group. No significant differences regarding toothbrushing frequency were observed in either group. A change in the number of daily snacks was identified in both groups (3–4 snacks per day: from 11% to 20.2% in the N-M/D group, from 13.1% to 22.2% in the M/D group). The consumption of sweets as a preferred snack was also noticed. A decrease of tobacco consumers was assessed in the lockdown period (from 66.6% to 60.4% in the M/D group, from 68.5% to 61.9% in the N-/M/D group). Conclusions: Oral habits were changed during the pandemic lockdown through the increase in the frequency of the consumption of snacks and sweets and the decrease in frequency of smokers. Only minor changes were observed in oral hygiene.
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