TY - JOUR A1 - Diloksumpan, Paweena A1 - de Ruijter, Mylène A1 - Castilho, Miguel A1 - Gbureck, Uwe A1 - Vermonden, Tina A1 - van Weeren, P René A1 - Malda, Jos A1 - Levato, Riccardo T1 - Combining multi-scale 3D printing technologies to engineer reinforced hydrogel-ceramic interfaces JF - Biofabrication N2 - Multi-material 3D printing technologies that resolve features at different lengths down to the microscale open new avenues for regenerative medicine, particularly in the engineering of tissue interfaces. Herein, extrusion printing of a bone-biomimetic ceramic ink and melt electrowriting (MEW) of spatially organized polymeric microfibres are integrated for the biofabrication of an osteochondral plug, with a mechanically reinforced bone-to-cartilage interface. A printable physiological temperature-setting bioceramic, based on α-tricalcium phosphate, nanohydroxyapatite and a custom-synthesized biodegradable and crosslinkable poloxamer, was developed as bone support. The mild setting reaction of the bone ink enabled us to print directly within melt electrowritten polycaprolactone meshes, preserving their micro-architecture. Ceramic-integrated MEW meshes protruded into the cartilage region of the composite plug, and were embedded with mechanically soft gelatin-based hydrogels, laden with articular cartilage chondroprogenitor cells. Such interlocking design enhanced the hydrogel-to-ceramic adhesion strength >6.5-fold, compared with non-interlocking fibre architectures, enabling structural stability during handling and surgical implantation in osteochondral defects ex vivo. Furthermore, the MEW meshes endowed the chondral compartment with compressive properties approaching those of native cartilage (20-fold reinforcement versus pristine hydrogel). The osteal and chondral compartment supported osteogenesis and cartilage matrix deposition in vitro, and the neo-synthesized cartilage matrix further contributed to the mechanical reinforcement at the ceramic-hydrogel interface. This multi-material, multi-scale 3D printing approach provides a promising strategy for engineering advanced composite constructs for the regeneration of musculoskeletal and connective tissue interfaces. KW - biofabrication KW - melt electrowriting KW - bioinspired interface KW - bone and cartilage tissue engineering KW - microfibres KW - ceramics Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-254005 VL - 12 IS - 2 ER - TY - THES A1 - Kelmendi, Arsim T1 - Aushärtung von Kompositen bei Belichtung durch unterschiedliche Schichtstärken von Keramik T1 - Curing of composites when exposed to different layer thicknesses of ceramic N2 - Ästhetische Restaurationsverfahren sind in den meisten Zahnarztpraxen mittlerweile Routine. Zielsetzung: Diese Studie ging der Frage nach, inwieweit die Aushärtung von Kompositen unter Keramikrestaurationen möglich ist. Material und Methoden: Anhand von 426 mit Tetric Ceram® und 102 mit Variolink® hergestellten Proben wurden folgende Abhängigkeiten berücksichtigt: Lichtgerät und Belichtungsdauer, Schichtstärke und Farbe der Keramik, Härtemodus des Composits - im vorliegenden Fall ob lichthärtendes oder dualhärtendes Composit - und schließlich beim dualhärtenden Composit, der Einfluss einer kurzen Wartezeit zwischen Anmischen der Paste und Lichtpolymerisation. Diskussion: Um eine ausreichende Aushärtung und gute Haftfestigkeit von lichthärtenden Befestigungscomposites unter keramischen Restaurationen zu gewährleisten, ist eine ungehinderte Belichtung mit einem Polymerisationslicht für mindestens 25 Sekunden erforderlich, vorzugsweise aus sechs Richtungen, insbesondere dann, wenn die Keramik dunkler eingefärbt ist. Bei der Bestrahlung von Keramikschichten mit einer Wandstärke ≥ 2 mm werden dualhärtende Komposite und längere Belichtungszeiten empfohlen. N2 - Esthetic restorative procedures are routine in most dental practices. Objectives: this study pursued the question of the extent to which composites can be cured under ceramic restorations. Materials and Methods: Using 540 specimens made with Tetric Ceram®, and 102 specimens made with Variolink® the following dependency factors were taken into account: light device, and the exposure time, the layer thickness and color of the ceramic, the curing mode of the composite - in the present case whether it is a light-curing or dual-curing composite - and lastly, in the case of the dual-curing composite, the influence of a short waiting time between mixing the paste and light polymerisation. Conclusion: Discussion: To ensure adequate curing and good bond strength of light-cured luting composites under ceramic restorations, unobstructed exposure to light with a curing light for at least 25 seconds is required, preferably from six directions, and especially when the ceramic is darker shaded. When irradiating ceramic layers with a wall thickness of ≥ 2 mm, dual-curing composites and longer exposure times are recommended. KW - Komposit Keramik KW - ceramics KW - composite resins KW - dental bonding Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-269789 ER - TY - JOUR A1 - Schmitter, Marc A1 - Bömicke, Wolfgang A1 - Behnisch, Rouven A1 - Lorenzo Bermejo, Justo A1 - Waldecker, Moritz A1 - Rammelsberg, Peter A1 - Ohlmann, Brigitte T1 - Ceramic crowns and sleep bruxism: first results from a randomized trial JF - Journal of Clinical Medicine N2 - Background: This randomized clinical trial was conducted to assess whether sleep bruxism (SB) is associated with an increased rate of technical complications (ceramic defects) in lithium disilicate (LiDi) or zirconia (Z) molar single crowns (SCs). Methods: Adult patients were classified as affected or unaffected by SB based on structured questionnaires, clinical signs, and overnight portable electromyography (BruxOff) and block randomized into four groups according to SB status and crown material (LiDi or Z): LiDi-SB (n = 29), LiDi-no SB (n = 24), Z-SB (n = 23), and Z-no SB (n = 27). Differences in technical complications (main outcome) and survival and success rates (secondary outcomes) one year after crown cementation were assessed using Fisher’s exact test with significance level α = 0.05. Results: No technical complications occurred. Restoration survival rates were 100% in the LiDi-SB and LiDi-no SB groups, 95.7% in the Z-SB group, and 96.3% in the Z-no SB group (p > 0.999). Success rates were 96.6% in the LiDi-SB group, 95.8% in the LiDi-no SB group (p > 0.999), 91.3% in the Z-SB group, and 96.3% in the Z-no SB group (p ≥ 0.588). Conclusions: With a limited observation time and sample size, no effect of SB on technical complication, survival, and success rates of molar LiDi and Z SCs was detected. KW - bruxism KW - cad-cam KW - ceramics KW - clinical studies/trials KW - prosthetic dentistry/prosthodontics KW - clinical outcomes Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301480 SN - 2077-0383 VL - 12 IS - 1 ER -