FROM THE HISTOLOGICAL STUDIES OF THE VIENNA SCHOOL TO TODAY WHAT HAS CHANGED ?: NEW PROPOSALS FOR HISTOLOGICAL PROCESSING

L\u2019istologia del dente nasce gi\ue0 nel 1500 ma solo all\u2019inizio del ventesimo secolo grazie ai membri della prestigiosa scuola di Vienna assurge a vera scienza in tutta la sua grandezza e completezza, gettando le basi biologiche ed istologiche sulle quali si fonda l\u2019attuale istopatologia dentale dando vita alla Biologia Orale. Grazie a questi studi si sono potute sviluppare le varie branche dell\u2019Odontoiatria moderna quali: parodontologia, endodonzia, pedodonzia ed ortognatondonzia. Dopo, i contributi innovativi di questo prestigioso e pioneristico gruppo di ricerca documentati e divulgati grazie ai loro articoli e libri, le metodologie istologiche e la conoscenza della tecnica istologica hanno avuto un drastico freno fino a diluirsi rendendo quindi difficile trovare manuali o trattati di buon livello riguardanti la processazione del dente e dei suoi tessuti di supporto. In questa tesi, divisa in due parti, si \ue8 voluto recuperare le nozioni di inizio secolo a proposito della manipolazione dei campioni istologici e confrontarli con una nuova procedura che vede nell\u2019utilizzo delle microonde una soluzione per preparare campioni di tessuto calcificato mantenendo ottimi risultati sia in termini di conservazione della struttura tissutale che in quantit\ue0 di tempo necessario a tale procedimento. A questo scopo sono stati processati denti di origine bovina per via della facilit\ue0 di reperimento, la composizione chimica simile a quella dei denti umani e la possibilit\ue0 di poter analizzare non solo tessuti calcificati ma anche ampie porzioni di tessuti molli. Il secondo scopo di questa tesi \ue8 stato quella di effettuare un\u2019analisi critica sulle colorazioni batteriche e come queste possano essere modificate per renderle pi\uf9 fruibili, proporre la colorazione PAS come un adiuvante nella topografia batterica dentale e come una sapiente modifica della famosa ematossilina \u2013 eosina possa rendere questa colorazione molto pi\uf9 informativa. Per ottenere i risultati relativi alla seconda parte della tesi, sono state eseguite delle sezioni seriate relative a denti affetti da infezioni batteriche di diversa tipologia e severit\ue0.Dental histology was born in the 1500s but only at the beginning of the twentieth century, thanks to the members of the prestigious Vienna School, it has raised as true science in all its grandeur and completeness, casting the biological and histological foundations upon which the present dental histopathology giving life to Oral Biology. Thanks to these studies, the various branches of modern dental medicine could be developed such as: periodontology, endodontics, pediatric dentistry and orthodontics. Afterwards, the innovative contributions of this prestigious and pioneering research group, documented and divulged through their articles and books, histological methods and histological knowledge have drastically brake until they are diluted, making it difficult to find good-quality manuals or texts regarding the tooth processing and its supporting tissues. In this thesis, divided into two parts, we wanted to retrieve the early century's notion of manipulation of histological samples and compare them with a new procedure that sees in microwave utilization a solution for preparing calcified tissue samples while maintaining excellent results both in terms of tissue structure andin the amount of time it takes for this procedure. For this purpose, teeth of bovine origin have been processed because of the ease of finding, chemical composition similar to that of human teeth and the possibility to analyze not only calcified tissues but also large portions of soft tissues. The second aim of this thesis was to carry out a critical analysis of bacterial staining and how these can be modified to make them more usable, to propose PAS coloration as an adjuvant in dental bacterial topography and how a wise modification of the famous hematoxylin - eosin make this staining much more informative. To obtain the results for the second part of the thesis, series sections were performed from several posts extracting teeth with bacterial infections of different typology and severity

Synthetic blocks for bone regeneration : A systematic review and meta-analysis

This systematic review is aimed at evaluating the effectiveness of synthetic block materials for bone augmentation in preclinical in vivo studies. An electronic search was performed on Pubmed, Scopus, EMBASE. Articles selected underwent risk-of-bias assessment. The outcomes were: new bone formation and residual graft with histomorphometry, radiographic bone density, soft tissue parameters, complications. Meta-analysis was performed to compare new bone formation in test (synthetic blocks) vs. control group (autogenous blocks or spontaneous healing). The search yielded 214 articles. After screening, 39 studies were included, all performed on animal models: rabbits (n = 18 studies), dogs (n = 4), rats (n = 7), minipigs (n = 4), goats (n = 4), and sheep (n = 2). The meta-analysis on rabbit studies showed significantly higher new bone formation for synthetic blocks with respect to autogenous blocks both at four-week (mean difference (MD): 5.91%, 95% confidence intervals (CI): 1.04, 10.79%, p = 0.02) and at eight-week healing (MD: 4.44%, 95% CI: 0.71, 8.17%, p = 0.02). Other animal models evidenced a trend for better outcomes with synthetic blocks, though only based on qualitative analysis. Synthetic blocks may represent a viable resource in bone regenerative surgery for achieving new bone formation. Differences in the animal models, the design of included studies, and the bone defects treated should be considered when generalizing the results. Clinical studies are needed to confirm the effectiveness of synthetic blocks in bone augmentation procedures

Antimicrobial activity, toxicity and accumulated hard-tissue debris (AHTD) removal efficacy of several chelating agents

Aim: To evaluate the antimicrobial, toxicity and cleaning effectiveness of ethylenediaminetetraacetic acid (EDTA) and maleic acid (MA) alone and combined with cetrimide (CTR). Methodology: Cytotoxic and genotoxic effects were assessed on Chinese hamster cells V79 using the MTT, clonogenic and micronucleus assays, respectively. The bacterial inhibitory and bactericidal concentrations (MIC and MBC, respectively) were determined on a strain of Enterococcus faecalis. Antimicrobial tests were performed on a biofilm model after treatment with the chelating agents by using a biofilm eradication concentration (MBEC) and confocal laser scanning microscope (CLSM) assays. Quantification of cell biomass and percentage of live and dead cells in the biomass were assessed for each group. The percentage reduction of accumulated hard-tissue debris (AHTD) after root canal preparation and final irrigation protocols was evaluated by micro-CT. Statistical tests of one-way analysis of variance (anova), Bonferroni test, Kruskal\u2013Wallis test, Dunn\u2019s multiple comparison test and Wilcoxon matched-pairs signed-rank tests were used. Results: Cetrimide alone as well as in combination with EDTA and MA at dilutions of 1/10 and 1/100 was significantly more toxic as compared to untreated controls (P < 0.001). All tested mixtures were nontoxic at a dilution of 1/1000. EDTA retained a weak inhibitory and bactericidal effect against planktonic cells, whilst MA inhibited cells growth and killed 99.9% of the cells when diluted. CTR revealed the most prominent effect, being inhibitory and bactericidal, also when diluted. Cetrimide alone or combined with EDTA was able to remove, respectively, 40% (P < 0.01) and 60% (P < 0.001) of the entire biomass after 1 min. Conversely, MA alone and in combination with CTR did not have a significant effect on biomass reduction. After final irrigation, the AHTD volume was significantly decreased in all groups (P < 0.05). EDTA + CTR and MA + CTR were associated with a significant reduction in the percentage of AHTD on the entire root canal compared to the same solutions without surfactant. Conclusions: 7% MA was less cytotoxic in comparison with 17% EDTA. The addition of cetrimide to EDTA and MA removed accumulated hard-tissue debris effectively from the canal walls and increased their antimicrobial activity when compared to the same solutions without detergents

Can the concentration of citric acid affects its cytotoxicity and antimicrobial activity?

Background: There has been no unanimity concerning the ideal concentration of citric acid for safe use in clinical practice. This study evaluated the cytotoxicity and the antibacterial activity in infected dentinal tubules of 10% and 1% citric acid (CA) solutions. Methods: The cytotoxicity of CA solutions in DMEM (diluted 1/10, 1/100) was assessed in L-929 fibroblasts. A broth macrodilution method (MIC and MBC) was used to assess CA antibacterial concentration. The antimicrobial activity of CA solutions was also evaluated after their final rinse inside root canals in previously Enterococcus faecalis-contaminated dentinal tubules. Ten infected dentine samples were rinsed for 5 min with 5% NaOCl and subsequently with 1% citric acid for 3 min. Another 10 were rinsed with 5% NaOCl and 10% citric acid for 3 min; the remaining four specimens were utilized as positive controls. Two uncontaminated specimens were used as negative controls. After LIVE/DEAD BacLight staining, the samples were assessed using CLSM to analyze the percentage of residual live and dead cells. Results: Both undiluted and diluted CA solutions showed severe toxicity; no changes from normal morphology were displayed when diluted 1/100. The MIC and MBC of CA were 6.25 mg/mL and 12.50 mg/mL, respectively. CA solutions demonstrated significantly low levels of bacterial counts than the positive control group, reporting a value of 9.3% for the 10% solution versus the 1% solution (35.2%). Conclusions: Despite its valuable antimicrobial properties, the cytotoxic effects of citric acid should be considered during endodontic treatment

Food Risk/Benefit Communication: A Systematic Review

A systematic review relevant to the following research questions was conducted (1) the extent to which different theoretical frameworks have been applied to food risk/benefit communication and (2) the impact such food risk/benefit communication interventions have had on related risk/benefit attitudes and behaviors. Fifty four papers were identified. The analysis revealed that (primarily European or US) research interest has been relatively recent. Certain food issues were of greater interest to researchers than others, perhaps reflecting the occurrence of a crisis, or policy concern. Three broad themes relevant to the development of best practice in risk (benefit) communication were identified: the characteristics of the target population; the contents of the information; and the characteristics of the information sources. Within these themes, independent and dependent variables differed considerably. Overall, acute risk (benefit) communication will require advances in communication process whereas chronic communication needs to identify audience requirements. Both citizen's risk/benefit perceptions and (if relevant) related behaviors need to be taken into account, and recommendations for behavioral change need to be concrete and actionable. The application of theoretical frameworks to the study of risk (benefit) communication was infrequent, and developing predictive models of effective risk (benefit) communication may be contingent on improved theoretical perspectives

Duchenne muscular dystrophy fibroblast nodules : a cell-based assay for screening anti-fibrotic agents

Severe muscle fibrosis is the endpoint of many chronic myopathies. Identification of factors that regulate fibrosis is important for understanding its pathogenesis and for developing anti-fibrotic treatments that prevent muscle destruction. We have developed an in vitro model for screening potential anti-fibrotic agents. The model consists of three-dimensional clusters (nodules) of fibroblasts derived from Duchenne muscular dystrophy (DMD) muscle. The primary fibroblasts spontaneously and quickly form nodules resembling fibrotic foci (cells plus extracellular matrix) when grown on a solid substrate. We tested the anti-fibrotic action of suramin, decorin, and spironolactone (all with established anti-fibrotic activity) on the model. All three agents significantly reduced nodule number, and spironolactone and suramin significantly reduced nodule diameter. Nodule secretion of soluble collagen was also significantly reduced by decorin and spironolactone treatment, whereas suramin had no significant effect. Collagen I and fibronectin protein expression was significantly reduced in the culture medium of control and DMD fibroblasts by spironolactone treatment, but not by decorin and suramin treatment. Finally, in DMD fibroblast monolayers, collagen deposition was significantly reduced by all three agents. Spironolactone significantly reduced collagen I and fibronectin transcript levels, whereas decorin reduced only fibronectin. Our in vitro model of fibrogenesis has thus revealed differing anti-fibrotic effects in the three anti-fibrotic agents tested. It therefore appears as a useful and sensitive system for the testing of anti-fibrotic drugs and could be adapted for the high-throughput screening of new anti-fibrotic molecules