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Purpose: To evaluate the effect of different surface modification methods on the microtensile bond strength (μTBS) of four resin-matrix CAD/CAM ceramics after artificial aging., Materials and Methods: Specimens of four CAD/CAM materials (Shofu Block HC, Lava Ultimate, Brilliant Crios, and Vita Enamic) were prepared and divided into four groups. Each group received one of the following treatments: group 1 (INT): no surface modification; group 2: sandblasting with 29-μm Al2O3 particles (SB); group 3: hydrofluoric acid etching (9%) + silane (HF+Si); group 4: sandblasting with 30-μm particles of the CoJet system (CJ). The specimens of each group were luted together in pairs using resin cement (RelyX Ultimate). After one week of water storage (37°C), the sandwich specimens were sectioned into rectangular microspecimens and half of them were immediately subjected to μTBS testing, while the other half was tested after six months. Data were statistically analyzed using FFANOVA including the factors of material, treatment, and storage time, with α = 0.05., Results: After one week, the lowest μTBS was observed for INT, while the highest was found for either mechanical (SB and CJ) or chemical (HF+Si) treatments (p < 0.05). After six months, a significant decrease in μTBS was observed depending on treatment (p < 0.05), while artificial aging significantly influenced the μTBS of all experimental groups (p < 0.05). During the two storage periods, the failure type was mainly interfacial and was associated with the type of surface modification., Conclusion: After artificial aging, the μTBS appeared to depend on srface modification, while the parameter "material" did not influence the results. Consequently, adhesive strategies should be oriented towards surface modification techniques.

Computer-aided design/computer-aided manufacturing (CAD/CAM) technology was developed to ensure the sufficient strength of tooth restorations, to improve esthetic restorations with a natural appearance and to make the techniques easier, faster and more accurate. In the view of the limited research on the surface treatments of the CAD/CAM materials and the need to evaluate the ideal surface characteristics of a material to achieve the best adhesion to tooth tissues, this study aimed to investigate the surface roughness and morphology of four different CAD/CAM materials using four different surface treatments. The CAD/CAM materials used in this study were three composites (Shofu Block HC, Lava Ultimate and Brilliant Crios) and a hybrid ceramic (Enamic). The surface of the specimens of each material received one of the following treatments: no surface treatment, sandblasting with 29 μm Al 2 O 3 particles, 9% hydrofluoric acid etching and silane application, and the tribochemical method using CoJet System. Surface roughness was evaluated using optical profilometry, and surface morphology was observed by means of scanning electron microscopy. All surface treatments resulted in higher surface roughness values compared to the control group. Different treatments affected the surface properties of the materials, presumably due to discrepancies in their composition and structure.

The purpose of this study was to present and evaluate a blended-learning course developed for undergraduate (B.D.S.), postgraduate, and diploma (hygiene and therapy) students at the University of Sheffield School of Clinical Dentistry. Blended learning is the integration of classroom face-to-face learning with online learning. The overall methodology used for this study was action research. The data were collected using three processes: questionnaires to collect contextual data from the students taking the course; a student-led, nominal group technique to collect group data from the participants; and a non-participant observer technique to record the context in which certain group and individual behaviors occurred. The online component of the course was accepted as a valuable resource by 65 percent of those responding. While online information-sharing occurred (31 percent of the students posted in forums), there was no evidence of online collaboration, with only 8 percent replying to forum postings. Accessibility of the online environment was one of the main concerns of the students at the nominal group sessions. Differences regarding overall engagement with the course between the student groups (years) were observed during the sessions. The majority of the students were satisfied with the Information and Communication Technologies (ICT) course. No statistically significant differences between males and females were found, but there were differences between different student cohorts (year groups).