400 research outputs found

    Exact Correlators from Conformal Ward Identities in Momentum Space and Perturbative Realizations

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    The general solution of the conformal Ward identities (CWI's) in momentum space, and their matching to perturbation theory, allows to uncover some specific characteristics of the breaking of conformal symmetry, induced by the anomaly. It allows to compare perturbative features of the 1-particle irreducible (1PI, nonlocal) anomaly action with the prediction of a similar (but exact) nonlocal action identified by the CWI's. The two predictions can be exactly matched at the level of 3-point functions. The analysis of the TJJTJJ and TTTTTT shows that both approaches - based either on 1PI or on the exact solutions of the CWI's - predict massless (dynamical) scalar exchanges in 3-point functions as the signature of the conformal anomaly. In a local formulation such 1PI actions exhibit a ghost in the spectrum which may induce ghost condensation. We also discuss alternative approaches, which take to Wess-Zumino forms of the action with an asymptotic dilaton, which should be considered phenomenological alternatives to the exact nonlocal action. If derived by a Weyl gauging, they also include a ghost in the spectrum. The two formulations, nonlocal and of WZ type, can be unified under the assumption that they describe the same anomaly phenomenon at two separate (UV/IR) ends of the renormalization group flow, possibly separated by a vacuum rearrangement at an intermediate scale. A similar analysis is presented for an N=1\mathcal{N}=1 supersymmetric Yang-Mills theory. We comment on the possibile cosmological implications of such quasi Nambu-Goldstone modes as ultralight dilatons and axions.Comment: 48 pages, 12 figures, (typos corrected) Proceedings of the Corfu Summer Institute 2018 "School and Workshops on Elementary Particle Physics and Gravity" 1-27 September 2018 Corfu, Greec

    Tailored Brushing Method (TBM): an innovative simple protocol to improve the oral care

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    Background. The objective of this study is to describe and assess the effectiveness and acceptability of a modern tailored protocol of oral hygiene, based on the concordance between professionals and patients, and based on the proper choice of best tools for oral hygiene regardless of the technique used. This new method has been called Tailored Brushing Method (TBM). Material and methods. Two groups of adult patients (n=200) were involved in this research, according to specific inclusion criteria. Test group followed the indications of the new Tailored Brushing Method, while control group was involved in a standard protocol of oral hygiene with the suggestions of a brushing technique and the typical approach based on the compliance. Plaque Index, bleeding on Probing index and patients' acceptability of the methods (Visual Analog Scale) were assessed at different time points. Descriptive and statistical analyses were performed. Results and conclusions. Test group had statistically lower Plaque Index and Bleeding on Probing after 30 days, in comparison with control group. Test group expressed a better acceptance of the new tailored method. This research suggests to use a tailored approach to oral hygiene, overcoming the need of patient's compliance, often affected by bias such as alteration of the protocols and wrong brushing maneuvers

    Retrospective analysis of the correlation between the facial biotype and the inclination of the upper canine cusp axis to the occlusal plane

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    Permanent maxillary canines are the second most frequently impacted teeth and the prevalence of this clinical condition is estimated to be 1-2% in the general population. The diagnosis of maxillary canine impaction should be based on both clinical and radiographic examinations. The aim of this study was to evaluate the presence of a correlation between the facial biotype and the inclination of the upper cusp axis. A correlation between the total radicular length of the lateral incisors was also evaluated, by comparing the side of impaction with the healthy side. Twenty three patients with a diagnosis of unilateral upper cusp impaction were recruited. For each patient, dental casts and radiographic material (panoramic radiographs and lateral cephalograms) were examined. Statistical analyses were done with Spearman's rank correlation coefficient or Spearman's rho (V). X-ray examinations demonstrated that canine impaction was associated to other dental anomalies (32% of the sample). The mean S angle measurements were 22.9° ± 4.1°, and mean values of the T angle were 34.7°± 4.0°. The mean distance “d” value was 14.6 mm ± 1.2 mm. The mean values of the angle between the upper cusp axis and the perpendicular-to-Fh plane were 20.8 °± 2.6°. Among the 23 subjects recruited, 5 showed values included in the range 25°-45° and 1 an inclination > 45°. The results obtained in the present study demonstrate a significant inverse correlation between the MM angle and the inclination of the upper cusp axis to the perpendicular-to-Fh plan

    Influence of PRF in the healing of bone and gingival tissues. Clinical and histological evaluations

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    INTRODUCTION: The healing of bone tissues around dental implants is based primarily on a correct osseointegration. BACKGROUND: Typically, implants stability and peri-implant tissues health are anticipated to decrease during the early weeks of healing; this is followed by an increase in stability. AIM: The aim of the present study is to assess a predictable protocol in order to increase the peri-implant tissues maintenance around post-extractive dental implants, thanks to the use of Platelet-Rich Fibrin (PRF) membrane. MATERIALS AND METHODS: This is a retrospective observational study of 127 tapered dental implants placed in the immediate post-extraction sites of maxillary bone of 59 patients. Atraumatic dental extraction and flapless implant surgery was performed in all reported cases. The cortical bone position relative to the implant reference point was evaluated at implant placement and 10 to 24 months following implantology. The gap between bone tissue and the implant surface was measured up to a maximum of 3 mm. After placing implants we have filled the surgical site with a PRF gel, so as to fill the gap between bone tissue and the implant surface, and then we have covered the surgical site with a PRF membrane, so as to coat the gap between the alveolar crest and the implant. RESULTS: In all cases, we observed the complete covering of the dental implants, with newly formed soft tissue of variable thickness between 1 and 3 mm. Cortical bone adaptation from the time of implant placement up to 30 months following prosthetic restoration ranged from 0.4 mm to 1.7 mm. CONCLUSIONS: Our study showed a series of successful rehabilitations, with post-extraction implantology technique, in 99.8 percent of cases, despite the success rates in the medium and long-term post-extraction implantology reported in the literature range between 92.7 percent and 98.0 percent. Long-term maintenance of crestal bone and the rapid healing of soft tissue dimension with maintenance of peri-implant papilla were observed as outcomes after post-extractive implants insertion

    Potential use of human periapical cyst-mesenchymal stem cells (hPCy-MSCs) as a novel stem cell source for regenerative medicine applications

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    Mesenchymal stem cells (MSCs) are attracting growing interest by the scientific community due to their huge regenerative potential. Thus, the plasticity of MSCs strongly suggests the utilization of these cells for regenerative medicine applications. The main issue about the clinical use of MSCs is related to the complex way to obtain them from healthy tissues; this topic has encouraged scientists to search for novel and more advantageous sources of these cells in easily accessible tissues. The oral cavity hosts several cell populations expressing mesenchymal stem cell like-features, furthermore, the access to oral and dental tissues is simple and isolation of cells is very efficient. Thus, oral-derived stem cells are highly attractive for clinical purposes. In this context, human periapical cyst mesenchymal stem cells (hPCy-MSCs) exhibit characteristics similar to other dental-derived MSCs, including their extensive proliferative potential, cell surface marker profile and the ability to differentiate into various cell types such as osteoblasts, adipocytes and neurons. Importantly, hPCy-MSCs are easily collected from the surgically removed periapical cysts; this reusing of biological waste guarantees a smart source of stem cells without any impact on the surrounding healthy tissues. In this review, we report the most interesting research topics related to hPCy-MSCs with a newsworthy discussion about the future insights. This newly discovered cell population exhibits interesting and valuable potentialities that could be of high impact in the future regenerative medicine applications
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