Periodontal surgery in furcation-involved maxillary molars revisited—an introduction of guidelines for comprehensive treatment

Maxillary molars with interradicular loss of periodontal tissue have an increased risk of additional attachment loss with an impaired long-term prognosis. Since accurate clinical analysis of furcation involvement is not feasible due to limited access, morphological variations and measurement errors, additional diagnostics, e.g., with cone-beam computed tomography, may be required. Surgical treatment options have graduated from a less invasive approach, i.e., keeping as much periodontal attachment as possible, to a more invasive approach: (1) open flap debridement with/without gingivectomy or apically repositioned flap and/or tunnelling; (2) root separation; (3) amputation/trisection of a root (with/without root separation or tunnel preparation); (4) amputation/trisection of two roots; and (5) extraction of the entire tooth. Tunnelling is indicated when the degree of root separation allows for opening of the interradicular region. Alternatively, root separation is performed particularly in root-canal treated teeth with reduced coronal tooth substance requiring crown restorations. As soon as the attachment of one or two roots in maxillary molars is severely reduced, root removal is indicated and performed either as amputation or trisection including the corresponding part of the clinical crown. While the indication for regenerative measures in maxillary molars with furcation involvement is very limited, extraction and replacement with implants is restricted, particularly in sites requiring complex alveolar ridge augmentation and sinus elevation. A systematic approach for decision making in furcation-involved maxillary molars is described in this overview, including what constitutes accurate diagnosis and what indications there are for the different surgical periodontal treatment option

2D sense for faster 3D MRI

Sensitivity encoding in two spatial dimensions (2D SENSE) with a receiver coil array is discussed as a means of improving the encoding efficiency of three-dimensional (3D) Fourier MRI. it is shown that in Fourier imaging with two phase encoding directions, 2D SENSE has key advantages over one-dimensional parallel imaging approaches. By exploiting two dimensions for hybrid encoding, the conditioning of the reconstruction problem can be considerably improved, resulting in superior signal-to-noise behavior. As a consequence, 2D SENSE permits greater scan time reduction, which particularly benefits the inherently time-consuming 3D techniques. Along with the principles of 2D SENSE imaging, the properties of the technique are discussed and investigated by means of simulations. Special attention is given to the role of the coil configuration, yielding practical setups with four and six coils. The in vivo feasibility of the two-dimensional approach is demonstrated for 3D head imaging, permitting four-fold scan time reductio

Same Same but Different? The Predictive Power of Association Types in Brand Buzz for Investor Returns

Brand buzz sentiment–the favorability of public communications about the brand–has become a major source to gauge brand reputation and predict investor returns. In this research, the authors build a prediction model of investor returns by empirically elaborating on its intricate relations with two novel sentiment measures by integrating brand reputation literature with brand buzz research. Accordingly, investor returns are conceptualized as a function of the favorability of buzz associated with the brand’s ability to deliver its outputs (brand ability buzz sentiment) and the favorability of buzz associated with the brand’s societal impact (brand responsibility buzz sentiment) along with their interaction, respectively. Deploying support vector machine learning and panel vector autoregression, preliminary evidence suggests that brand ability buzz sentiment but not brand responsibility buzz sentiment drives investor returns, yet their interaction inhibits investor returns. The proposed model outperforms extant prediction models of investor returns

Gamified Digital Services: How Gameful Experiences Drive Continued Service Usage

Recently, many digital service providers started to gamify their services to promote continued service usage. Although gamification has drawn attention in both practice and research, it remains unclear how users experience gamified services and how these gameful experiences may increase service usage. This research adopts a user-centered perspective to reveal the underlying gameful experience dimensions during gamified service usage and how they drive continued service usage. Findings from Study 1 - a survey with 148 app-users - reveal four essential gameful experience dimensions (skill development, social comparison, social connectedness, and expressive freedom) and how they relate to game mechanics. Study 2, which is based on a survey among 821 app-users, shows that gameful experiences trigger continued service usage through two different types of motivation, namely autonomous and controlled motivation

Technical Parameters of Plastics (Mercox Cl-2B and Various Methylmethacrylates) Used in Scanning Electron Microscopy of Vascular Corrosion Casts

The most frequently used resins for vascular corrosion casting Mercox Cl-2B, Mercox Cl-2B diluted with methylmethacrylate (MMA) monomer and various self prepared MMA and hydroxyproyl-methacrylate mixtures were tested with regard to their thermostability, shrinkage, viscosity and replication quality. It was found that tempering of the plastics improves their thermostability with the exception of Mercox Cl-2B and that shrinkage depends on the amount of monomers a resin contains. In detail; Mercox Cl-2B has the lowest shrinkage (8.018%) whereas a hydroxypropyl-methacrylate mixture possessed the highest (20.408%). But, on the other hand, viscosity decreases with the quantity of monomers. All resins tested were able to replicate structures of 260nm height but the resins\u27 quality of replication was found to be limited by the effects of shrinkage. Finally, a method to estimate the blood volume of organs and tissues with the help of vascular corrosion casts is given

Scanning Electron Microscopy of Vascular Corrosion Casts - Technique and Applications: Updated Review

The present paper states very briefly the main steps leading to the technique of scanning electron microscopy (SEM) of vascular corrosion casts. From the terms presently used (injection method, microcorrosion cast, injection replica, vascular corrosion cast, vascular cast) the use of vascular corrosion cast for lymphatic and blood vessels is recommended. Specification and pretreatment (kind, volume, dosage of anticoagulants, vasoactive substances and spasmolytica used) of the animals examined are referenced as they are available from the literature. The recommendation is given to pay more attention to these parameters than done so far. The steps necessary for producing reasonable and suitable vascular corrosion casts are critically described. Special attention is paid to the physical and chemical properties of the casting media and their significance for polymerization, shrinkage, casting quality, corrosion resistance, and thermal and spatial stability. Emphasis is also focused on the advantages of cutting the vascular corrosion casts embedded in an ice block by a band saw, a self constructed multi-blade cutting device or a mini wheel-saw placed in the chamber of a cryomicrotome. From the drying methods presently used freeze-drying is stressed because of minimal specimen damage. To render casts conductive in most cases sputter-coating is sufficient. It is recommended to run the SEM with 5 - 10 kV since the resolution received still reveals all details the casting media presently can replicate. Further the application of scanning electron microscopy of vascular corrosion casts in fully differentiated normal tissue, in pathologic tissue as well as in developing tissues and organs is stated. Lastly possibilities and conditions are discussed under which SEM of vascular corrosion casts can serve to quantify vascular structures in order to make the technique more than pure descriptive

Resolving the Chatbot Disclosure Dilemma: Leveraging Selective Self-Presentation to Mitigate the Negative Effect of Chatbot Disclosure

Chatbots are increasingly able to pose as humans. However, this does not hold true if their identity is explicitly disclosed to users—a practice that will become a legal obligation for many service providers in the imminent future. Previous studies hint at a chatbot disclosure dilemma in that disclosing the non-human identity of chatbots comes at the cost of negative user responses. As these responses are commonly attributed to reduced trust in algorithms, this research examines how the detrimental impact of chatbot disclosure on trust can be buffered. Based on computer-mediated communication theory, the authors demonstrate that the chatbot disclosure dilemma can be resolved if disclosure is paired with selective presentation of the chatbot’s capabilities. Study results show that while merely disclosing (vs. not disclosing) chatbot identity does reduce trust, pairing chatbot disclosure with selectively presented information on the chatbot’s expertise or weaknesses is able to mitigate this negative effect