1,721,007 research outputs found
BIORESORBABLE ENGINEERED MEMBRANES FOR GUIDED BONE REGENERATION WITH ANTIMICROBIAL PROPERTIES
Full text linkGli argomenti principali di questa tesi di dottorato sono la rigenerazione ossea e l'analisi del tessuto osseo mediante strategie nanotecnologiche per entrambi gli scopi. In breve, sono stati esplorati lo sviluppo di membrane e impalcature nanostrutturate per le procedure di rigenerazione ossea nella chirurgia orale, insieme all'ottimizzazione dei protocolli di analisi su micro e nanoscala. Sono stati acquisiti, assemblati e testati i componenti necessari per il processo ELS. Sono state testate diverse combinazioni di solventi per la preparazione di membrane a base di policaprolattone (PCL). Successivamente, è stato applicato un processo aria-plasma al fine di aumentare l'idrofilia della membrana. La caratterizzazione qualitativa delle membrane ottenute da ELS, prima e dopo il trattamento al plasma, è stata eseguita insieme all'analisi morfologica mediante microscopia elettronica a scansione.
Il chitosano modificato con lattosio (CTL) è stato aggiunto mediante adsorbimento chimico sulle membrane del PCL al fine di aumentarne la bioattività. L'analisi microscopica confocale ha mostrato un miglior assorbimento del CTL per le membrane trattate con aria-plasma rispetto a quelle non trattate. Inoltre, CTL è stato utilizzato per fornire, sulle membrane, nanoparticelle d'argento (nAg) sintetizzate all'interno della soluzione CTL. L'analisi ETAAS, ha mostrato un maggiore contenuto di nAg nelle membrane trattate con un trattamento plasma-aria a bassa energia e CTL-nAg a pH 7, confermando così i risultati di Raman. Le cellule MG63 coltivate su membrane PCL con o senza CTL, hanno mostrato una crescita più sostenuta dopo 7 giorni sulle membrane rivestite con CTL rispetto alle membrane PCL non trattate e alle membrane trattate con aria-plasma PCL. Inoltre, la presenza di nAg non ha ostacolato la vitalità cellulare rispetto alle membrane PCL, come confermato dal test della lattato deidrogenasi (LDH). L'attività antibatterica delle membrane PCL-nAg è stata testata in termini di inibizione del biofilm su Pseudomonas aeruginosa e Staphylococcus aureus, utilizzando il test MTT. I dati di vitalità e l'imaging SEM hanno mostrato chiaramente che la formazione di biofilm era fortemente inibita sulla superficie delle membrane PCL-CTL-nAg. La resistenza meccanica delle membrane prodotte, imbevute e invecchiate nel fluido corporeo simulato (SBF) è stata testata mediante prove di trazione uniassiali per la valutazione del modulo elastico e la massima deformazione e stress. Come secondo capitolo di questa tesi, è stata esplorata la potenzialità di un altro approccio per produrre membrane a base di fibrina nanostrutturate. Queste membrane sono state ottenute mediante centrifugazione del sangue e sono state adattate con molecole che inducono l'osso, come la nano-idrossiapatite (nHAp). Pertanto, è stata testata la durabilità della membrana incontaminata in SBF. Ad ogni momento, un campione è stato analizzato con SEM con strumenti di elaborazione rivelando un diametro medio della fibra di 0,103 ± 0,05 μm senza differenze statisticamente significative nel tempo; il saggio di degradazione ha mostrato un aumento di due volte del peso correlato all'assorbimento di SBF nei primi 2 giorni. Dal terzo giorno è stato osservato un costante degrado. Successivamente, sono stati studiati gli effetti dell'aggiunta di nHAp durante il processo di formatura di PRF (quindi durante la centrifugazione). Poiché tutte le tecniche sopra menzionate erano orientate a rigenerare l'osso maxillo-facciale, è stato ottimizzato un protocollo di analisi istomorfometrica dell'osso che, al momento della stesura della presente tesi, non era ancora presente all'Università di Trieste). Questo protocollo è stato preparato e implementato con l'analisi ultrastrutturale SEM-EDS (Energy Dispersive Spectroscopy) dei tessuti duri montati sulle diapositive istologiche.The main topics of this doctoral thesis are bone regeneration and bone tissue analysis by means of nanotechnological strategies for both purposes. Briefly, the development of nanostructured membranes and scaffolds for bone regeneration procedures in oral surgery have been explored, together with the optimization of analysis protocols at the micro- and nano-scale. The first attempts were addressed to reproduce some of the recent results reported in the scientific literature. Thereafter the necessary components for the ELS process were acquired, assembled and tested. Different combinations of solvents for the preparation of polycaprolactone (PCL) based membranes were tested. Thereafter, an air-plasma cleaning process was applied in order to increase the membrane hydrophilicity. Qualitative characterization of membranes obtained by ELS, before and after plasma treatment has been performed together with the morphological analysis through Scanning Electronic Microscopy. The determination of surface wettability with contact angle measurements was performed.
Lactose-modified chitosan (CTL) was added by chemical adsorption on PCL membranes in order to increase their bioactivity. Confocal microscopy analysis showed an improved adsorption of CTL for the membranes treated with air-plasma if compared with the untreated ones. Moreover, CTL was used to deliver, on the membranes, silver nanoparticles (nAg) synthesized within CTL solution. ETAAS analysis, performed to quantify nAg, showed a higher nAg content in membranes treated with a low energy air-plasma treatment and CTL-nAg at pH 7, thus confirming Raman findings. MG63 cells cultured on PCL membranes with or without CTL, showed a more sustained growth after 7 days on the CTL-coated membranes compared with untreated PCL membranes and PCL air-plasma treated membranes. Moreover, the presence of nAg did not hamper cell viability with respect to PCL membranes, as confirmed by lactate dehydrogenase (LDH) assay. The antibacterial activity of PCL-nAg membranes was tested in terms of biofilm inhibition on Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923), using the MTT test. The viability data and the SEM imaging clearly showed that the biofilm formation was strongly inhibited on the surface of PCL-CTL-nAg membranes. Mechanical resistance of the produced membranes, soaked and aged in Simulated Body Fluid (SBF) was tested by means of uniaxial tensile tests for the evaluation of elastic modulus and maximal deformation and stress.
As second chapter of this thesis, the potentiality of another approach to produce nanostructured fibrin-based membranes was explored. These membranes were obtained by means of blood centrifugation and were tailored with bone-inducing molecule, such as nano-hydroxyapatite (nHAp). Thus, the durability of pristine membrane in SBF was tested. At each time point, one sample was analyzed with SEM with ImageJ processing tools revealing a mean fiber diameter of 0.103 ± 0.05μm without any statistically significant differences during time; degradation assay showed a two-folds increase of the weight related to the SBF absorption in the first 2 days. From the third day a constant degradation was observed. In the time frame of this experiment, the dimensional stability of the fibrin structure up to day 7 suggested that PRF membranes may also be used uncovered in the oral cavity. Subsequently, the effects of the nHAp addition during the forming process of PRF (thus during centrifugation) were investigated. As all the above-mentioned techniques were oriented to regenerate maxillofacial bone, a bone histomorphometric analysis protocol that, at the time of writing of the present thesis, was not already present in the University of Trieste) was optimized. This protocol was prepared and implemented with the ultrastructural SEM-EDS (Energy Dispersive Spectroscopy) analysis of hard tissues mounted on the histological slides)
Removal of a maxillary third molar accidentally displaced into the maxillary sinus: presurgical and surgical management
No full textExtraction of impacted maxillary third molar is a common procedure usually performed either by oral surgeons or general dentists. tuber maxillae fractures and oroantral communications are the most frequently listed intraoperative complications, while the displace- ment of the tooth in the maxillary sinus is rarely de- scribed.1 this event may lead to acute or chronic sinus- itis and, for this reason, a timely surgical removal of the tooth from the sinusal cavity is strongly suggested.2
in this exemplary case, a patient was referred to our department twenty days after the accidental displace- ment of the left third upper molar into the maxillary si- nus, during an attempt of extraction. the orthopanoram- ic exam showed the tooth vertically disposed close to the medial wall with an inverted axial position (Figure 1) and, within the limits of this radiological exam, a sinusal mucosa without signs of inflammation. A cone beam computed tomography (cBct) of the maxillofa- cial complex comprising the paranasal sinuses and the osteomeatal complex, was performed for the pre-sur- gical assessment (Figure 2). cBct volume rendering, obtained by using a postprocessing DicoM software (3Diagnosys, 3DM, cantù, como, italy), allowed the manipulation of a three-dimensional visualization of the tooth displaced in the sinus (Figure 3)
Conjunctival chemosis: an uncommon complication after transcrestal lifting of the sinus floor
No full textConjunctival chemosis is non-specific oedema, which may be caused by many systemic and local factors, including allergies; bacterial, viral, and mycotic infections; autoimmune diseases; thyroid disorders; and neoplasms. The orbit is susceptible to the contiguous spread of infections from the maxillary sinus as they are separated only by a thin plate of bone, which could also have congenital bony dehiscence
Reuse of Implant Healing Abutments: Comparative Evaluation of the Efficacy of Two Cleaning Procedures
No full textPURPOSE: To compare the efficacy of two systems in cleaning used healing abutments (HAs).
MATERIALS AND METHODS: A total of 60 used HAs were randomized into two groups: one treated with an automatic cleaning system, and the other with conventional decontamination procedures. After sterilization and staining, the HAs were microscopically analyzed and underwent a cellular adhesion in vitro assay.
RESULTS: Contaminated areas were observed with different frequencies in the two groups (3.6% test; 78.2% control; P < .001). In vitro assay showed a uniform cell distribution in test HAs, while areas of debris without adhering cells were a common finding in the control HAs.
CONCLUSION: Further studies investigating the chemical composition and clinical influence of biologic remnants are necessary before considering reusing HAs
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Response to: “Direct oral anticoagulants, vitamin K antagonists and simple single tooth extraction”
No full textN/
Presence of microbrush remnants on the adhesion surface: A microscopical analysis
Full text linkObjectives: the aim of this ex vivo report was to evaluate, on a microscopical analysis, the presence of microbrush remnants on in the adhesive surface in extracted teeth.Methods: Twenty extracted teeth were divided into four groups. Half of the teeth were prepared as Class I cavities, whereas the other half as Class II cavities, according to Black classification. The teeth were conditioned with primer and bonding, both applied with microbrushes. Each of these groups was divided into halves, and the two sub-groups received a polymerization process or not, respectively. The teeth were then analyzed by scanning electron microscopy working in environmental mode.Results: All of the analyzed surfaces (100%) showed the presence of residual bristles on the adhesion surface.Conclusions: Microscopical analysis showed the presence of residual bristles in the 100% of the surfaces treated with Black Classes I and II cavities. Further studies are necessary to evaluate the influence of this factor on the adhesion strength and capacity. Clinical Significance: Clinician should be aware of the realistic possibility of the presence of bristles belonging to disposable applicators in the adhesive interface of Black's class I and II cavities. The impact of these remnants has still to be ascertained
Prevalence of dental caries among schoolchildren from North-eastern Italian population
No full textBACKGROUND:
The longitudinal aspect of dental caries has not been previously reported for the Italian population. The primary object of the present study is to collect information of the prevalence of dental decay among the schoolchildren of primary school of Gradisca d'Isonzo (GO) and to analyze the tendency of caries among the students followed since the first year of school.
METHODS:
Subsequent examinations hold from 2011 to 2015 has been conducted by two calibrated examiners. Oral hygiene instruction and motivation followed the visits. According to WHO principals DMFT and dmft were recorded. The children in the survey were divided into 5 groups according to their ages (6, 7, 8 and 9 years), and these groups were considered separately. Descriptive and statistical analysis of the data was conducted.
RESULTS:
More than 400 pupils were recruited, resulting in almost 900 examinations during 5 years. Overall, the %dft ≥1 children range from 18.9% (10 years, 2013) to 53.5% (8 years, 2011) across the different age groups. Overall, the %DFT≥1 children range from 8.3% (6 years, 2011) to 44.1% (10 years, 2012) across the different age groups.
CONCLUSIONS:
Within the limits of the present study, the WHO goals are still not met, among the population in exam. Our results show a trend of decay diminution that enhances in the cohort of 10-aged children suggesting the importance of dental education. Furthermore, the lack of pediatric initiatives of oral hygiene may be overcome by a national intensive educational program, supported by further scientific evidence
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