Procjena hidrofilnosti elastomernih otisnih materijala: istraživanje in vitro

Introduction: Hydrophilicity of dental impression materials is crucial for obtaining an accurate impression and necessary for the production of a well-fitting cast restoration. The most common technique for evaluation of hydrophilicity is a contact angle measurement. The aim of the present in vitro study was to compare the water contact angles of four groups of elastomeric impression materials, before and during setting. Material and methods: Flattened specimens (n=10) of tested impression materials were prepared by the use of a Teflon mold with specific dimensions. A 5μl droplet of deionized water fell on the specimen, and photos were taken using a Nikon D3200 DSLR camera and a 105 mm macro lens (Nikorr, Nikon) in specific time points. Results: The CAD/CAM material showed the highest contact angle measurements. The light body polyvinylsiloxane (PVS) material 1, polyether and vinylsiloxanether material showed comparable contact angle measurements especially at the initial time point. A statistically significant reduction of contact angles was reported during setup time for all PVS, PE and vinylsiloxanether materials, while the most expressed reduction of contact angle measurements, and thus the most significant increase of hydrophilicity were reported for light wash PVS material 2. Conclusions: The CAD/CAM impression material showed the most hydrophobic behavior. PVS materials showed excellent hydrophilicity. Polyether and polyvinyloxanether impression materials presented lower contact angle measurements, and thus superior hydrophilicity, compared with other tested materials initially and during setting. All tested impression materials presented a stepwise development of hydrophilicity during the setting stage.Uvod: Hidrofilnost otisnih materijala ključna je za preciznost otiska i prijeko potrebna za izradu nadomjestka s dobrim dosjedom. Najčešća tehnika za njezinu procjenu jest mjerenje kontaktnog kuta. Cilj ovoga istraživanja in vitro bio je usporediti kontaktne kutove vode u četirima skupinama elastomernih otisnih materijala, prije vezivanja i tijekom vezivanja. Materijali i metode: Spljošteni uzorci (n = 10) ispitanih otisnih materijala pripremljeni su u teflonskom kalupu specifičnih dimenzija. Kapljica deionizirane vode od 5 μL kapnuta je na uzorak, a fotografije su snimljene fotoaparatom Nikon D3200 DSLR i 105 mm makroobjektivom (Nikorr, Nikon) u određenim vremenskim točkama. Rezultati: CAD/CAM materijal imao je najveći kontaktni kut. Rijetki materijali polivinilsiloksan (PVS) 1, polieter i vinilsiloksaneter imali su usporedive mjere kontaktnoga kuta, posebno u početnoj vremenskoj točki. Statistički značajno smanjenje kontaktnih kutova zabilježeno je tijekom postavljanja za sve PVS-ove, PE-ove i vinilsiloksan, a najizraženije smanjenje, pa time i najznačajnije povećanje hidrofilnosti, zabilježeno za rijedak PVS 2. Zaključci: CAD/CAM otisni materijal imao je najhidrofobnija svojstva. PVS materijali imali su izvrsnu hidrofilnost. Polieterski i poliviniloksaneterski otisni materijali imali su manji kontaktni kut, pa tako i veću hidrofilnost u usporedbi s drugim ispitivanim materijalima na početku vezivanja i tijekom toga postupka. Svi ispitani otisni materijali postupno su razvijali hidrofilnost tijekom faze vezivanja

Sol-Gel Derived Mg-Based Ceramic Scaffolds Doped with Zinc or Copper Ions: Preliminary Results on Their Synthesis, Characterization, and Biocompatibility

Glass-ceramic scaffolds containing Mg have shown recently the potential to enhance the proliferation, differentiation, and biomineralization of stem cells in vitro, property that makes them promising candidates for dental tissue regeneration. An additional property of a scaffold aimed at dental tissue regeneration is to protect the regeneration process against oral bacteria penetration. In this respect, novel bioactive scaffolds containing Mg2+ and Cu2+ or Zn2+, ions known for their antimicrobial properties, were synthesized by the foam replica technique and tested regarding their bioactive response in SBF, mechanical properties, degradation, and porosity. Finally their ability to support the attachment and long-term proliferation of Dental Pulp Stem Cells (DPSCs) was also evaluated. The results showed that conversely to their bioactive response in SBF solution, Zn-doped scaffolds proved to respond adequately regarding their mechanical strength and to be efficient regarding their biological response, in comparison to Cu-doped scaffolds, which makes them promising candidates for targeted dental stem cell odontogenic differentiation and calcified dental tissue engineering

Sol–Gel Synthesis and Characterization of YSZ Nanofillers for Dental Cements at Different Temperatures

From MDPI via Jisc Publications RouterHistory: accepted 2021-10-26, pub-electronic 2021-10-29Publication status: PublishedFunder: The project is co-financed by Greece and the EuropeanUnion (European Social Fund-ESF) by the Operational Program Human Resources Development,Education and Lifelong Learning 2014–2020.; Grant(s): MIS5047876Background: Yttria-stabilized zirconia nanoparticles can be applied as fillers to improve the mechanical and antibacterial properties of luting cement. The aim of this study was to synthesize yttria-stabilized zirconia nanoparticles by the sol–gel method and to investigate their composition, structure, morphology and biological properties. Methods: Nanopowders of ZrO2 7 wt% Y2O3 (nY-ZrO) were synthesized by the sol–gel method and were sintered at three different temperatures: 800, 1000 and 1200 °C, and their composition, size and morphology were investigated. The biocompatibility was investigated with human gingival fibroblasts (hGFs), while reactive oxygen species (ROS) production was evaluated through fluorescence analysis. Results: All synthesized materials were composed of tetragonal zirconia, while nanopowders sintered at 800 °C and 1000 °C additionally contained 5 and 20 wt% of the cubic phase. By increasing the calcination temperature, the crystalline size of the nanoparticles increased from 12.1 nm for nY-ZrO800 to 47.2 nm for nY-ZrO1200. Nano-sized particles with good dispersion and low agglomeration were received. Cell culture studies with human gingival fibroblasts verified the nanopowders’ biocompatibility and their ROS scavenging activity. Conclusions: the obtained sol–gel derived nanopowders showed suitable properties to be potentially used as nanofillers for dental luting cement

HPLC reaction at modified - with biopolymer scaffolds - surface of dental ceramics

Tissue engineering is a quite promising science at the area of tissue regeneration. Scaffolds are commonly used in tissue engineering in order to provide a friendly micro-environment for 3D cell development. They have been used in soft and hard tissue development, commonly in medical practice. In dentistry, scaffolds have been used at periodontal regeneration and implantology. Moreover, in tissue engineering bioactivity and biocompatibility of materials is of great importance. Dental ceramic although is considered biocompatible, is incapable of interacting with the surrounding tissues. Bioactive modification of dental ceramic discs is already investigated. Coatings of bioactive glass – ceramic (1:1 wt), ceramic (50%), HAp (35%) and bioactive glass s (15%) (in system SiO2 45%, Na2O 24,5%, CaO 24,5%, P2O5 6%) and ceramic (50%), Al2O3 (7,5%) and bioactive glass (42,5%) were made. Furthermore, bioactivity of bioactive glass and hydroxyapatite (HAp) is well established, while in HAp is reported to be more chemically stable compared to bioactive glass. Moreover, materials like Al2O3 may reinforce dental porcelain and improve mechanical properties. Cell proliferation and morphology were investigated with scanning electron microscopy. Ceramic discs with coating of ceramic and bioglass (1:1) seem to benefit compared to all others. On these specimens, an HCAp film is developed at day 15th. Besides, Ca–P aggregates were observed at the surface. Overall, it could be concluded that the presence of Ca–P aggregates on the cells’ surface, enhances the hypothesis that PDLC interactions with modified ceramics might trigger the growth of such aggregates, while a network consisting of cells and Ca-P aggregates is continuously developing. Biopolymer scaffolds attached on bioactive glass modified dental ceramics could act as vehicles, in order to guide periodontal ligament cell (PDLC) proliferation and finally tissue development. This could have a beneficial effect on long term prognosis of fixed restorations. The aim of this study was to investigate the optimum proliferation pattern of human PDLC on composite scaffolds (chitin/chitosan/chitosan-gelatin), attached on bioactive glass modified dental ceramics. Three types of scaffolds were used: made of chitin, chitosan and chitosan – gelatin, with pore size 120- 250μm. They were fabricated thhrough Particulate leaching, supercritical CO2 foaming and Critical Point Drying, on the surface of ceramic disks, being coated with a mixture of bioactive glass – ceramic (1:1 wt) and thermally treated. The mostly used method, was Particulate leaching, in all cases. Composite scaffolds were incubated at 370C up to 15 days on well plates, either with culture medium (DMEM supplemented with 10% FCS) or with culture medium in the presence of 105 cells PDLC. To evaluate cell proliferation the MTS technique (Aqueous Non – Radioactive Cell proliferation assay, Promega) was used. Cell proliferation was evaluated at 1, 3, 7, 10 and 15 days. Finally, optical density (OD) was measured at a test wavelength of 490 nm and a reference wavelength of 630 nm. MTS assay. OD values of day 1 confirmed the presence of cells at all scaffolds. In cases of CHN and CHS, the number of attached cells was progressively decreasing, while the rate of cell death was significantly higher for CHN. On the contrary, proliferation rate on CH-G presented a peak after 7 days, a slowdown until day 12 and then attained a constant rate until the end of the experiment. In conclusion, all 3 types of examined composites ceramic-scaffolds were successfully loaded with PDL cells. However, only in CH-G composites ceramic-scaffolds the human PDL cells proliferated, then decreased and finally remained stable, while in case of CHN and CHS the number of cells was progressively decreasing. The successful cellular response could support the development of a protocol for tissue engineering on the materials used.Η ιστομηχανική είναι μια ταχέως εξελισσόμενη επιστήμη. Εφαρμογές της έχουν χρησιμοποιηθεί σε πολλούς τομείς της ιατρικής. Συνήθως, χρησιμοποιούνται μοσχεύματα, αλλά και μεμβράνες και ικριώματα για την ανάπλαση ιστών και οργάνων. Τα ικριώματα, όπως ήδη έχει αναφερθεί, λειτουργούν ως οχήματα μεταφοράς και ανάπτυξης κυττάρων. Διακρίνονται σε διάφορες κατηγορίες με βάση τον ρυθμό απορρόφησης , τη σύνθεσή τους και τη δομή τους. Έτσι, υπάρχουν ικριώματα μόνιμα και προσωρινά, φυσικά, συνθετικά συνδυασμός φυσικών – συνθετικών ικριωμάτων και τέλος πορώδη και ινώδη. Στην παρούσα μελέτη διερευνήθηκε καταρχήν η δυνατότητα τροποποίησης -με βιοενεργείς επιστρώσεις- της επιφάνειας οδοντιατρικού κεραμικού βάθρου, η παρασκευή βιοπολυμερών ικριωμάτων στην τρποποιημένη επιφάνεια και τελικά η κυτταρική ανταπόκριση κυττάρων περιοδοντικού ιστού σε τρεις κατηγορίες σύνθετων υλικών (κεραμικά δοκίμια-βιοπολυμερή ικριώματα): α) κεραμικό δοκίμιο- ικρίωμα χιτίνης, β) κεραμικό δοκίμιο- ικρίωμα χιτοζάνης και γ) κεραμικό δοκίμιο – ικρίωμα χιτοζάνης ζελατίνης, με απώτερο στόχο την αναγέννηση περιοδοντικού ιστού στην κρίσιμη περιοχή του αυχενικού ορίου ακίνητων προσθετικών αποκαταστάσεων. Αυτό αποτελεί και την καινοτομία στην παρούσα διδακτορική διατριβή. Η επίτευξη του παραπάνω στόχου θα συνέβαλε ουσιαστικά στη βελτίωση της πρόγνωσης Ακίνητων Προσθετικών Αποκαταστάσεων, επειδή η δευτερογενής τερηδόνα αποτελεί συχνή επιπλοκή. Στη βιβλιογραφία αναφέρεται τροποποίηση της επιφάνειας κεραμικών δοκιμίων με βιοενεργείς επιστρώσεις (Κοκοτή και συν. 2001, Κοντονασάκη 2003). Διερευνήθηκε περαιτέρω η δυνατότητα βελτίωσης της τροποποίησης της επιφάνειας με προσθήκη στα μίγματα επιστρώσεων χημικού υδροξυαπατίτη (HΑp) και αλουμίνας (Al2ο3). Πραγματοποιήθηκε εμβάπτιση των δοκιμίων σε διάλυμα που προσομοιάζει τα υγρά του σώματος, αλλά και θρεπτικό μέσο καλλιέργειας κυττάρων( DMEM). Έχοντας ως κριτήρια την έναρξη σχηματισμού υδροξυκαρβονικού απατίτη, αλλά και την παρουσία κυττάρων στις επιφάνειες, επιλέχθηκε η επίστρωση με κατά βάρος αναλογία κεραμικού– βιοενεργής υάλου 1:1. Ακόμη, παρασκευάστηκαν ικριώματα σε επαφή με τις επιφάνειες των τροποποιημένων δοκιμίων. Οι τρόποι παρασκευής που χρησιμοποιήθηκαν ήταν οι εξής: απομάκρυνση σωματιδίων (Particulate leaching), αφρισμός με χρήση CO2 υψηλής πίεσης και ξήρανση κρίσιμου σημείου (Critical Point Drying). Κυρίως εφαρμόστηκε η πρώτη μέθοδος με τη χρήση μη υδατοδιαλυτών σωματιδίων. Οι πόροι , δε, ήταν ανοικτοί και η κατανομή τους ομοιόμορφη, όπως διαπιστώθηκε, τόσο από τον προσδιορισμό του πορώδους και του μεγέθους των πόρων με τη βοήθεια μικροφωτογραφιών ηλεκτρονικού μικροσκοπίου (SEM). Το μέγεθος, δε, των πόρων ήταν 120- 250μm. Η σύνδεση των ικριωμάτων με την τροποποιημένη επιφάνεια δοκιμίου, παρατηρείται σε όλη σχεδόν την επιφάνεια στις μικροφωτογραφίες SEM Οφείλεται, δε, στη συγγένεια χημικών ομάδων της βιοενεργής υάλου τόσο με τη χιτοζάνη, όσο και με τη χιτίνη. Επιπλέον, μελετήθηκε ο ρυθμός αποδόμησης ικριωμάτων, μέσα σε διάλυμα SBF. Βρέθηκε ότι η αποδόμηση ξεκινά την 7η ημέρα και είναι ομαλή και για τις τρεις κατηγορίες. Επίσης, για τη διερεύνηση της κυτταρικής ανταπόκρισης στα σύνθετα αυτά ικριώματα, ακολούθησε η εμβάπτισή τους σε διάλυμα θρεπτικού μέσου κυτταροκαλλιεργειών και ο ενοφθαλμισμός 105 κυττάρων σε κάθε σύνθετο δείγμα. Σημειώθηκε αποπτωτική πορεία κυττάρων τόσο στα ικριώματα χιτίνης, όσο και σε αυτά της χιτοζάνης. Στην περίπτωση των ικριωμάτων χιτίνης, μάλιστα, η μείωση των κυττάρων και η αποπτωτική πορεία ήταν ραγδαίες. Στην περίπτωση των σύνθετων δειγμάτων με ικρίωμα χιτοζάνης παρατηρήθηκε το ίδιο φαινόμενο, αλλά σε πιο ήπια μορφή. Τέλος, μόνο στα ικριώματα χιτοζάνης- ζελατίνης καταγράφηκε αποπτωτική πορεία την πρώτη εβδομάδα, ενώ στη συνέχεια σημειώθηκε αύξηση και τελικά φαίνεται ότι σταθεροποιήθηκε ο αριθμός των κυττάρων. Παράλληλα, παρατηρήθηκε η αποδόμηση των ικριωμάτων μετά την παραμονή τους σε θρεπτικό μέσο καλλιέργειας κυττάρων. Είναι σημαντικό να επισημανθεί ότι η εικόνα αποδόμησης διαφοροποιείται από την παρουσία ή την απουσία κυττάρων. Το συμπέρασμα αυτό προκύπτει από τη συγκριτική μελέτη μικροφωτογραφιών SEM σύνθετων ικριωμάτων που παρέμειναν σε θρεπτικό μέσο με παρουσία ή όχι κυττάρων περιοδοντικού ιστού. Τα παραπάνω ευρήματα θα μπορούσαν να αποτελέσουν αρχή, ώστε να διερευνηθεί περεταίρω το σύνθετο υλικό με το ικρίωμα χιτοζάνης –ζελατίνης, ώστε τελικά να δημιουργηθούν in vivo μοντέλα με στόχο τη διερεύνηση της ανάπλασης περιοδοντικού ιστού, ειδικά στην περιοχή του ορίου των ακίνητων προσθετικών αποκαταστάσεων

<i>Artemisinin</i> Loaded Cerium-Doped Nanopowders Improved In Vitro the Biomineralization in Human Periodontal Ligament Cells

Background: A promising strategy to enhance bone regeneration is the use of bioactive materials doped with metallic ions with therapeutic effects and their combination with active substances and/or drugs. The aim of the present study was to investigate the osteogenic capacity of human periodontal ligament cells (hPDLCs) in culture with artemisinin (ART)-loaded Ce-doped calcium silicate nanopowders (NPs); Methods: Mesoporous silica, calcium-doped and calcium/cerium-doped silicate NPs were synthesized via a surfactant-assisted cooperative self-assembly process. Human periodontal ligament cells (hPDLCs) were isolated and tested for their osteogenic differentiation in the presence of ART-loaded and unloaded NPs through alkaline phosphatase (ALP) activity and Alizarine red S staining, while their antioxidant capacity was also evaluated; Results: ART promoted further the osteogenic differentiation of hPDLCs in the presence of Ce-doped NPs. Higher amounts of Ce in the ART-loaded NPs inversely affected the mineral deposition process by the hPDLCs. ART and Ce in the NPs have a synergistic role controlling the redox status and reducing ROS production from the hPDLCs; Conclusions: By monitoring the Ce amount and ART concentration, mesoporous NPs with optimum properties can be developed towards bone tissue regeneration demonstrating also potential application in periodontal tissue regeneration strategies

SBA-15 Mesoporous Silica as Delivery Vehicle for rhBMP-2 Bone Morphogenic Protein for Dental Applications

(1) Background: A proposed approach to promote periodontal tissue regeneration in cases of peri-implantitis is the local administration of growth factors at the implant site. Recombinant human bone morphogenetic protein-2 (rh-BMP-2) can effectively promote bone regeneration and osseointegration and the development of appropriate carriers for its delivery is of paramount importance. The aim of the present study was to develop SBA-15 mesoporous nanoparticles (MSNs) with varying porosity, evaluate their biocompatibility with human Periodontal Ligament Cells (hPDLCs) and to investigate their effectiveness as carriers of rh-BMP-2. (2) Methods: SBA-15 type mesoporous silicas were synthesized via sol–gel reaction. The calcined SBA-15 samples were characterized by N2 porosimetry, Fourier transform–infrared spectrometry (FTIR), Scanning (SEM) and Transmission Electron Microscopy (TEM). Rh-BMP-2 loading and release kinetics were evaluated by UV spectroscopy. (3) Results: MSNs presented hexagonally arranged, tubular pores of varying length and diameter. Slightly higher loading capacity was achieved for SBA-15 with large pores that presented good hemocompatibility. MTT assay revealed no cytotoxic effects for all the tested materials, while SBA-15 with large pores induced a significant upregulation of cell viability at day 5. (4) Conclusions: SBA-15 MSNs may prove a valuable delivery platform towards the effective release of bone-inducing proteins

Synthesis and Characterization of Mesoporous Mg- and Sr-Doped Nanoparticles for Moxifloxacin Drug Delivery in Promising Tissue Engineering Applications

International audienceMesoporous silica-based nanoparticles (MSNs) are considered promising drug carriers because of their ordered pore structure, which permits high drug loading and release capacity. The dissolution of Si and Ca from MSNs can trigger osteogenic differentiation of stem cells towards extracellular matrix calcification, while Mg and Sr constitute key elements of bone biology and metabolism. The aim of this study was the synthesis and characterization of sol–gel-derived MSNs co-doped with Ca, Mg and Sr. Their physico-chemical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy (XRF), Brunauer Emmett Teller and Brunauer Joyner Halenda (BET/BJH), dynamic light scattering (DLS) and ζ-potential measurements. Moxifloxacin loading and release profiles were assessed with high performance liquid chromatography (HPLC) cell viability on human periodontal ligament fibroblasts and their hemolytic activity in contact with human red blood cells (RBCs) at various concentrations were also investigated. Doped MSNs generally retained their textural characteristics, while different compositions affected particle size, hemolytic activity and moxifloxacin loading/release profiles. All co-doped MSNs revealed the formation of hydroxycarbonate apatite on their surface after immersion in simulated body fluid (SBF) and promoted mitochondrial activity and cell proliferation