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Giomers are hybrid dental materials with controlled fluoride release properties. The aim of this study was to characterise a new experimental flowable giomer (G) in comparison to three commercial flowable giomers: Beautifil flow Plus X F00 (B-F00), Beautifil flow F02 (B-F02) and Beautifil flow Plus X F03 (B-F03), Shofu, Kyoto, Japan. The studied properties are fluoride ion release, residual monomers release and mechanical properties. The data analysis was performed using the ANOVA test and Tukey test for post hoc comparisons between groups. During the first day of the fluoride releasing measurement, the following classification resulted: B-F02 ˃ B-F03 ˃ B-F00 ˃ G and at the end of the investigation period, at 60 days: B-F02 ˃ B-F03 ˃ G ˃ B-F00. The experimental giomer released a lower percentage of total residual monomers than the commercial giomers. The highest value for the mechanical properties was recorded for the commercial giomers. The experimental giomer registered the lowest values for mechanical properties but higher than the imposed standard limit. There were statistically significant differences between the analyzed materials, in terms of fluoride releasing, residual monomer releasing and mechanical properties.

Reconstructive bone surgery of the head and neck could prove challenging in terms of postoperative healing and recovery. Fighting infection during the healing period is one of the critical factors of the long-term survival of an implant. The aim of the study was to develop an innovative composition suitable for an antibacterial craniofacial implant that should have the capacity to continuously and constantly release the amount of gentamicin necessary to prevent the post-surgical infections. For this purpose, a series of composite materials based on dimethacrylic monomers, hydroxyapatite and ZrO2, with (series B) or without the addition of polymethyl methacrylate (series A), reinforced with woven E-glass fibers (FRC) were obtained using the laminate lay-up process. Gentamicin was included in all FRC sample matrices to confer an antimicrobial effect. The results show that after extraction of the residual monomers from the FRC samples in different solvents (chloroform, acetone and ethyl alcohol), the cumulative amount of released gentamicin after 12 days was between 7.05&ndash, 11.38 mg for A samples and 11.21&ndash, 14.52 mg for B samples. The microbiological protocol showed that gentamicin induces a two weeks-lasting antimicrobial effect maintained over the minimal inhibitory concentration for P. aeruginosa and S. aureus.

This report presents the results of a risk assessment of residual chemical additives, monomers and degradation products present in microplastic (MP) particles in the marine environment. Seven cases of different polymer types and product groups are defined that represent the most significant exposures of MPs, and thus potential highrisk cases towards marine organisms. Risk Quotients (RQ) are calculated for three trophic levels, i.e. pelagic/planktonic zooplankton: copepod, benthopelagic fish: atlantic cod and seabird: northern fulmar. Danish Miljøkvalitetskrav (MKK) and European Environmental Quality Standard (EQS) values are used as toxicity threshold values. RQ larger than unity, which indicates potential risk, is estimated for copepod and cod (pelagic community) and the flame-retardant pentabromdiphenylether (PeBDE) used in polyurethane (PUR), the biocide tributyltin (TBT) used in polyvinylchloride (PVC) and PUR, and the flame-retardant hexabromocyclododecane (HBCD) used in expanded polystyrene (EPS). The highest estimated RQ for fulmar (secondary poisoning) is 0.1 for PeBDE used in PUR.

The culture of cells in a three-dimensional (3D) scaffold has been reported as a key issue influencing the newly formed tissue organization, either in vitro or in vivo. Scaffolds can present different material chemistry, geometry, structure, physical properties and degradation, as it has been explored in several chapters of this book. Herein, we intend to give the reader an overview of the most used tests for evaluation of cells cytotoxicity and their response to natural materials in vitro., (undefined), info:eu-repo/semantics/publishedVersion

The synthesis of the poly(N-isopropylacrylamide-co-2-hydroxypropyl-methacrylate) hydrogel along with the analysis of the residual monomers content and influence of monomer and crosslinker molar ratios on the swelling behaviour was investigated. Synthesis of thermosensitive hydrogel based on N-isopropylacrylamide was carried out with the molar ratios of 5, 10, 15 and 20 mol% of monomer 2-hydroxypropyl-methacrylate, in the presence of ethylene glycol dimethacrylate as a crosslinker (1, 1.5, 2 and 3 mol%) and 2,2'-azobis(2-methylpropionitrile) as an initiator in acetone. The quantities of residual monomers in the synthesized copolymers were determined by HPLC method, ranging from 0.19 to 0.49% for N-isopropylacrylamide and from 0.13 to 0.63% for 2- -hydroxypropyl-methacrylate, counting the amount of xerogel. The hydrogels swelling ratio depending on time at 20 and 40°C was examined. It was found that the hydrogel with 5 mol% 2-hydroxypropyl-methacrylate and 1 mol% ethylene glycol dimethacrylate had the highest degree of swelling (( = 29.59) at 20°C, and that the hydrogel with 20 mol% 2-hydroxypropyl-methacrylate and 3 mol% ethylene glycol dimethacrylate had the lowest swelling degree ((=2.17) at 40°C. Predmet ovog rada je sinteza kopolimernog hidrogela poli(N-izopropilakrilamid-ko-2-hidroksipropilmetakrilata), analiza sadržaja rezidualnih monomera i ispitivanje uticaja molskog odnosa monomera i umreživača na karakteristike bubrenja. Sinteza termoosetljivog hidrogela na bazi N-izopropilakrilamida izvršena je sa molarnim udelom 5, 10, 15 i 20 mol% monomera 2-hidroksipropilmetakrilata, u prisustvu umreživača etilenglikoldimetakrilata (u koncentraciji: 1, 1,5 , 2 i 3 mol%) i inicijatora 2,2'-azobis(2-metilpropionitrila) u acetonu. Sadržaj zaostalih monomera u sintetizovanim kopolimerima analiziran je pomoću HPLC metode. Vrednosti se nalaze u granicama od 0,19 do 0,49% za N-izopropilakrilamid i od 0,13 do 0,63% za 2-hidroksipropilmetakrilat računajući na količinu kserogela. Ispitan je stepen bubrenja dobijenih hidrogelova u zavisnosti od temperature. Najveći stepen bubrenja (( = 29,59) pri konstantnoj temperaturi od 20°C dostigao je uzorak hidrogela sa 5 mol% 2-hidroksipropilmetakrilata i 1 mol% umreživača EGDM-a, a najmanji (( = 2.17) pri temperaturi od 40°C dostigao je uzorak hidrogela sa 20 mol% 2-hidroksipropilmetakrilata i 3 mol% umreživača EGDM-a. PR Projekat Ministarstva nauke Republike Srbije, br. TR 34012.

Plastic debris are accumulating in our oceans and are degraded into smaller pieces which eventually becomes small enough to be available to lower thropic level organisms. Microplastics, commonly defined as plastic particles

Un materiale da otturazione ideale dovrebbe garantire una stabilità chimica e una facilità d’uso, ed essere biocompatibile. Nelle resine composite per uso odontoiatrico sono presenti monomeri metilacrilici come il Bis-fenolo A glicidilmetacrilato (Bis-GMA) considerato citotossico se rilasciato. Nel presente lavoro di tesi di Dottorato di Ricerca in Scienze della Prevenzione, è stato valutato (in vitro) l’effetto del rilascio di sei materiali compositi a base di resina in ambiente acquoso sulle cellule fibroblasti L-929. E’ stata vista la macroreazione dei fibroblasti all’esposizione diretta dei campioni in funzione del grado di conversione polimerica. E’ stata osservata mediante microscopia ottica la reazione di lisi. Si è calcolata e confrontata la citotossicità di matrici polimeriche con frazioni differenti di monomeri non polimerizzati. Considerato che la frazione di monomeri non polimerizzata non è uniformemente distribuita nella matrice, si è identificata l’origine principale dei monomeri citotossici rilasciati. Per questa identificazione si è utilizzata la microscopia confocale a fluorescenza. I risultati ottenuti confermano che la superficie esterna di tutti i materiali è citotossica. .Eliminata la parte esterna, la continuità dell’azione citotossica del materiale massivo è principalmente dovuta a rilascio dall’interno della porosità, da parte di pori interconnessi con l’ambiente acquoso. An ideal dental filling material should guarantee a chemical stability and a facility of use, and to be biocompatible. In modern dentistry, the composite resin contains methacrylic monomers as (Bis-GMA) Bis-phenol Glycidyl Methacrylate. In the present thesis of Doctorate of Research in Sciences of the Prevention, it has been valuated (in vitro) the effect of six resin-based materials in aqueous environment using fibroblasts L-929. Has been observed the macroreactionof cell-line of fibroblasts when exposed directly to the samples as a function of degree of polymerization conversion. Reaction of lysis has been observed by optical microscopy. The cytotoxicity of bulk material was calculated and compared with the different fraction of non polymerized monomers and is not evenly distributed into the matrix. Using confocale fluorescent microscopy has been identified the main source of released cytotoxic monomers. The obtained results confirm that the surface layers of all materials are cytotoxic, and the prolonged cytotoxic effect noted when surface layer was removed is due to the porosity in the bulk material interconnected with the aqueous environment.

The aim of this work was to correlate the degree of conversion with residual monomer release and water absorption of 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy) phenyl]propane (BisGMA) and triethyleneglycol dimethacrylate (TEGDMA) (TB copolymers) obtained by photopolymerization, using canforquinone/ethyl 4-dimethylaminobenzoate (CQ/EDB) photoinitiator. The monomer release from the copolymers was evaluated by immersion in ethanol/water and HPLC (high performance liquid chromatography) analysis. Water absorption from artificial saliva was determined by mass variation. The results show that the composition of the TB copolymers influences the polymerization kinetics, the amount of the released monomers, the degree of conversion and the amount of adsorbed water. A clear correlation can be found between these properties. O objetivo deste trabalho é correlacionar o grau de conversão de copolímeros de 2,2-bis[4-(2-hidróxi-3-metacriloiloxipropóxi) fenil]propano (BisGMA) e dimetacrilato de trietilenoglicol (TEGDMA) (copolímeros TB) obtidos por fotopolimerização, usando o sistema fotoiniciador canforquinona/etil 4-dimetilaminobenzoato (CQ/EDB), com a eluição de monômeros e a absorção de água. A eluição de monômeros foi avaliada a partir da imersão dos polímeros em etanol/água e análise por CLAE (cromatografia líquida de alto rendimento). A absorção de água de saliva artificial foi determinada gravimetricamente. Os resultados mostram que a composição dos copolímeros TB influencia a cinética de polimerização, a quantidade de monômeros eluídos, o grau de conversão e a quantidade de água adsorvida. Uma boa correlação foi encontrada entre estas propriedades.