572 research outputs found
Alveolar ridge preservation with guided bone regeneration or socket seal technique. A randomised, single-blind controlled clinical trial
OBJECTIVES: To compare radiographic bone changes, following alveolar ridge preservation (ARP) using Guided Bone Regeneration (GBR), a Socket Seal (SS) technique or unassisted socket healing (Control). MATERIAL AND METHODS: Patients requiring a single rooted tooth extraction in the anterior maxilla, were randomly allocated into: GBR, SS and Control groups (n= 14/). Cone Beam Computed Tomography (CBCT) images were recorded postâextraction and at 4 months, the midâbuccal and midâpalatal alveolar ridge heights (BARH/PARH) were measured. The alveolar ridge width, crossâsectional socket and alveolarâprocess area changes, implant placement feasibility, requirement for bone augmentation and postâsurgical complications were also recorded. RESULTS: BARH and PARH was found to increase with the SS (0.65 mm ± 1.1/0.65 mm ± 1.42) techniques, stabilise with GBR (0.07 mm ± 0.83/0.86 mm ±1.37) and decrease in the Control (â0.52 mm ± 0.8/â0.43 mm ± 0.83). Statistically significance was found when comparing the GBR and SS BARH (p = .04/.005) and GBR PARH (p = .02) against the Control. GBR recorded the smallest reduction in alveolar ridge width (â2.17 mm ± 0.84), when compared to the Control (â2.3 mm ± 1.11) (p = .89). A midâsocket crossâsectional area reduction of 4% (â2.27 mm(2) ± 11.89), 1% (â0.88 mm(2) ± 15.48) and 13% (â6.93 mm(2) ± 8.22) was found with GBR, SS and Control groups (GBR vs. Control p = .01). The equivalent alveolar process area reduction was 8% (â7.36 mm(2) ± 10.45), 6% (â7 mm(2) ± 18.97) and 11% (â11.32 mm(2) ± 10.92). All groups supported implant placement, with bone dehiscence noted in 57% (n = 4), 64%(n = 7) and 85%(n = 12) of GBR, SS and Control cases (GBR vs. Control p = .03). GBR had a higher risk of swelling and mucosal colour change, with SS associated with graft sequestration and matrix breakdown. CONCLUSION: GBR ARP was found to be more effective at reducing radiographic bone dimensional changes following tooth extraction
Special limits and non-relativistic solutions
We study special vanishing horizon limit of `boosted' black D3-branes having
a compact light-cone direction. The type IIB solution obtained by taking such a
zero temperature limit is found to describe a nonrelativistic system with
dynamical exponent 3. We discuss about such limits in M2-branes case also.Comment: 10 pages; V2: various changes in interpretations including title; no
change in mathematical results, V3: minor font typo in eq.(7) remove
Performance of 4 Pre-Trained Sentence Transformer Models in the Semantic Query of a Systematic Review Dataset on Peri-Implantitis
Systematic reviews are cumbersome yet essential to the epistemic process of medical science. Finding significant reports, however, is a daunting task because the sheer volume of published literature makes the manual screening of databases time-consuming. The use of Artificial Intelligence could make literature processing faster and more efficient. Sentence transformers are groundbreaking algorithms that can generate rich semantic representations of text documents and allow for semantic queries. In the present report, we compared four freely available sentence transformer pre-trained models (all-MiniLM-L6-v2, all-MiniLM-L12-v2, all-mpnet-base-v2, and All-distilroberta-v1) on a convenience sample of 6110 articles from a published systematic review. The authors of this review manually screened the dataset and identified 24 target articles that addressed the Focused Questions (FQ) of the review. We applied the four sentence transformers to the dataset and, using the FQ as a query, performed a semantic similarity search on the dataset. The models identified similarities between the FQ and the target articles to a varying degree, and, sorting the dataset by semantic similarities using the best-performing model (all-mpnet-base-v2), the target articles could be found in the top 700 papers out of the 6110 dataset. Our data indicate that the choice of an appropriate pre-trained model could remarkably reduce the number of articles to screen and the time to completion for systematic reviews
Momentum relaxation from the fluid/gravity correspondence
We provide a hydrodynamical description of a holographic theory with broken
translation invariance. We use the fluid/gravity correspondence to
systematically obtain both the constitutive relations for the currents and the
Ward identity for momentum relaxation in a derivative expansion. Beyond leading
order in the strength of momentum relaxation, our results differ from a model
previously proposed by Hartnoll et al. As an application of these techniques we
consider charge and heat transport in the boundary theory. We derive the low
frequency thermoelectric transport coefficients of the holographic theory from
the linearised hydrodynamics.Comment: 19 pages + appendix, v2: references added, typos corrected, v3:
version published in JHE
Magnetic effects in a holographic Fermi-like liquid
We explore the magnetic properties of the Fermi-like liquid represented by
the D3-D7' system. The system exhibits interesting magnetic properties such as
ferromagnetism and an anomalous Hall effect, which are due to the Chern-Simons
term in the effective gravitational action. We investigate the spectrum of
quasi-normal modes in the presence of a magnetic field and show that the
magnetic field mitigates the instability towards a striped phase. In addition,
we find a critical magnetic field above which the zero sound mode becomes
massive.Comment: 18 pages, 15 figure
Influence of periodontal surgery on the subgingival microbiome-A systematic review and meta-analysis
Universal scaling properties of extremal cohesive holographic phases
We show that strongly-coupled, translation-invariant holographic IR phases at
finite density can be classified according to the scaling behaviour of the
metric, the electric potential and the electric flux introducing four critical
exponents, independently of the details of the setup. Solutions fall into two
classes, depending on whether they break relativistic symmetry or not. The
critical exponents determine key properties of these phases, like thermodynamic
stability, the (ir)relevant deformations around them, the low-frequency scaling
of the optical conductivity and the nature of the spectrum for electric
perturbations. We also study the scaling behaviour of the electric flux through
bulk minimal surfaces using the Hartnoll-Radicevic order parameter, and
characterize the deviation from the Ryu-Takayanagi prescription in terms of the
critical exponents.Comment: v4: corrected a typo in eqn (3.29), now (3.28). Conclusions unchange
Probing the nanoadhesion of Streptococcus sanguinis to titanium implant surfaces by atomic force microscopy
The authors would kindly like to thank the BecasChile PhD Scholarship Programme for funding this research
Is alveolar ridge preservation an overtreatment?
The morphology and dimensions of the postextraction alveolar ridge are important for the surgical and restorative phases of implant treatment. Adequate new bone formation and preservation of alveolar ridge dimensions following extraction will facilitate installation of the implant in a restorative position, while preservation of soft tissue contour and volume is essential for an aesthetic and implant-supported restoration with healthy peri-implant tissues. Alveolar ridge preservation (ARP) refers to any procedure that aims to: (i) limit dimensional changes in the alveolar ridge after extraction facilitating implant placement without additional extensive bone and soft tissue augmentation procedures (ii) promote new bone formation in the healing alveolus, and (iii) promote soft tissue healing at the entrance of the alveolus and preserve the alveolar ridge contour. Although ARP is a clinically validated and safe approach, in certain clinical scenarios, the additional clinical benefit of ARP over unassisted socket healing has been debated and it appears that for some clinicians may represent an overtreatment. The aim of this critical review was to discuss the evidence pertaining to the four key objectives of ARP and to determine where ARP can lead to favorable outcomes when compared to unassisted socket healing
Differences between first- and second-generation autologous platelet concentrates.
Autologous platelet concentrates (APCs) applied alone or combined with other biomaterials are popular bioactive factors employed in regenerative medicine. The main biological rationale of using such products is to concentrate blood-derived growth factors and cells into the wound microenvironment to enhance the body's natural healing capacity. First-generation APC is represented by platelet-rich plasma (PRP). While different protocols have been documented for PRP preparation, they overall consist of twoâcycles of centrifugation and have important limitations related to the use of an anticoagulant first and an activator afterward, which may interfere with the natural healing process and the release of bioactive molecules. The second generation of platelet concentrates is represented by leukocyte and platelet-rich fibrin (L-PRF). L-PRF protocols involve a single centrifugation cycle and do not require the use of anticoagulants and activators, which makes the preparation more straight forward, less expensive, and eliminates potential risks associated with the use of activators. However, since no anticoagulant is employed, blood undergoes rapid clotting within the blood collection tube; hence, a timely management of L-PRF is crucial. This review provides an overview on the most documented protocols for APC preparations and critically discusses the main differences between first- and second-generation APCs in terms of cell content, protein release, and the formation of a 3D fibrin network. It appears evident that the inconsistency in reporting protocol parameters by most studies has contributed to conflicting conclusions regarding the efficacy of different APC formulations and has significantly limited the ability to interpret the results of individual clinical studies. In the future, the use of a standardized classification system, together with a detailed reporting on APC protocol parameters is warranted to make study outcomes comparable. This will also allow to clarify important aspects on the mechanism of action of APCs (like the role of leukocytes and centrifugation parameters) and to optimize the use of APCs in regenerative medicine
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