Rechargeable metal-air batteries based on superoxide discharge products are attractive due to the facile one-electron redox process of O2/O2-. Recently, a K-O2 battery has been reported that showed a significantly lower discharge/charge potential gap than the Li-O2 battery systems. Here, we perform first-principles calculations on potassium superoxide (KO2) to unravel the charge transport mechanism in this discharge product. The concentration and mobility of intrinsic carriers are calculated. The results show that hole polarons and negatively charged potassium ion vacancies are the main charge carriers. #link# The conductivity associated with polaron hopping (2 × 10-12 S cm-1) is 8 orders of magnitude higher than that of Li2O2, and the ionic conductivity has a comparable value (1 × 10-13 S cm-1). Our calculation results can rationalize the experimental findings and provide a theoretical basis for the understanding of superoxide discharge products in metal-air batteries.The global minimum of XMg4Y- (X = Si, Ge; Y = In, Tl) and SiMg3In2 contains a planar pentacoordinate atom of group 14 other than carbon. Its design is based on the "localization" approach, replacing one or two peripheral atoms in XMg52- by more electronegative ones. https://www.selleckchem.com/products/Raltitrexed.html diminishes the repulsion and leads to stronger covalent X-Y bonds, stabilizing the planar pentacoordinate atom species.A Au(i)-catalyzed homo- and cross-annulation reaction of alkynyl carboxylic acids offering 3,6-disubstituted 4-hydroxy 2H-pyrones has been demonstrated. The reaction tolerates various substituted alkynyl carboxylic acids and moderate to good yields of α-pyrone scaffolds have been observed. Later, a gram-scale reaction of the acid and the total synthesis of the natural product pseudopyronine A have been carried out successfully.
This study assessed the changes in color and translucency of dentin and enamel after staining and bleaching procedures as well as the contribution of the tissues to color change (CTCC).

Fifty enamel-dentin specimens were obtained from bovine incisors and grouped into 10 blocks based on the similarity of the baseline color. One specimen in each block was used as the control, and the others were intrinsically (blood) or extrinsically (coffee) stained. One stained specimen for each pigment was bleached with 35% hydrogen peroxide. The enamel was separated from the dentin, and the tooth color and translucency parameter (TP) were measured individually and after recombining these substrates. Changes in color (ΔE00), whitening index (WI), and TP caused by the staining and bleaching procedures were estimated through assessing the color differences compared with the controls. CTCC was also calculated by recombining the enamel and dentin tissues from different treatments. The data were analyzed using the paired t test or the two-way repeated measures ANOVA (α = 0.05).

Extrinsic staining procedures produced higher color changes than intrinsic ones, except in dentin. The highest bleaching effect was observed in the dentin of specimens that were extrinsically stained. Similar CTCC values were observed for the dentin and enamel for both the staining and bleaching procedures. Except for the specimens that were treated with intrinsic staining and became more translucent after the bleaching procedure, the other treatments resulted in non-significant TP changes.

Staining the specimens extrinsically resulted in higher color change than staining them intrinsically, and these specimens were more affected by the bleaching procedure. Enamel and dentin demonstrated similar CTCC values.
Staining the specimens extrinsically resulted in higher color change than staining them intrinsically, and these specimens were more affected by the bleaching procedure. Enamel and dentin demonstrated similar CTCC values.This article illustrates a new technique for repositioning the lip in the treatment of gummy smile. In particular, it introduces a formula to precisely calculate how much tissue should be eliminated to avoid the recurrence of gummy smile. The modified lip-repositioning technique (MLRT) also involves the microsurgical division of the tissue components (mucosa, periosteum, and bone) as well as the fixation of the surgically modified tissue to the periosteum component. The results of the technique are shown through case presentations of seven patients with follow-up of up to 3 years. Stable results were achieved with no recurrence of gummy smile.Ridge defects are a very common finding after tooth extraction. Recent literature has shown that the pattern of bone and soft tissue remodeling can obtain up to 50% of the original volume. Many different surgical approaches have been proposed over the years to correct ridge defects, but the results have often been inconsistent or difficult to reproduce on a daily basis. For some time, surgeons have relied on the guided bone regeneration (GBR) technique, taking advantage of a barrier membrane to protect the blood clot, combined with different combinations of autogenous bone and bone grafts from various sources. If some kind of understanding has been reached and certain guidelines adopted for the treatment of horizontal defects, those for tridimensional and vertical defects still present a challenge. About a decade ago, a new biomaterial became available on the market - a membrane made of collagenated porcine bone called cortical lamina - which proved to be reliable and easy to handle for both horizontal and vertical defects. The aim of this article is to review the current literature on the topic and to discuss the material in its three forms through the presentation of three patient cases of differing complexity, each with its unique indications and characteristics.Soft tissue augmentation techniques have become crucial to improve tissue volume and quality in periodontal and peri-implant dental surgery. A clinician's knowledge of the principle of flap design and management is a key aspect for treatment success, particularly in the esthetic area. Implant failures in the esthetic area are one of the most challenging situations in modern dentistry, and often cases have to be resolved through multidisciplinary treatments in which soft tissue management and patient selection are substantial aspects. Ridge defects are commonly treated with bone regeneration-like techniques in order to place implants. However, in young patients, where implant treatment should be carefully selected, fixed prosthetic restorations in combination with mucogingival surgery could be a successful option to enhance esthetics. The present case report describes a treatment approach for implant failure in the esthetic area in young patients, consisting of a combination of connective tissue platform technique, resective surgery, and a Maryland bridge restoration.
The combination of partial edentulism and a worn anterior tooth in the esthetic zone can be a challenge for the dentist. This clinical situation requires extensive knowledge of soft and hard tissue management, surgical planning and execution for implant therapy, and conservative tooth preparation with ideal bonding protocols for the tooth-supported prosthesis. Moreover, an optimal selection of the final restorative materials is imperative to manage occlusal forces and fulfill the patient's esthetic demands.

The patient presented with partial edentulism on site 11, a worn incisal edge, and facial defects on tooth 21. Minimally invasive implant therapy for site 11 was performed with a papilla-sparing flap design that only included the edentulous site, and the soft tissue contouring was started for an immediate provisional restoration. link2 A suturing technique was executed that aimed at maintaining an interproximal papilla. Conservative veneer preparation was performed on tooth 21 in order to bond the restoration to the enamel structure. Final restorations included a custom abutment with a lithium disilicate fused to zirconia crown for the implant on site 11 and a lithium disilicate veneer on tooth 21.

A well-planned single implant and a ceramic veneer restoration was able to fulfill the patient's esthetic expectations. The selection of materials for the final restoration was crucial to manage the occlusal forces and to mimic the shade and shape of the adjacent teeth.
A well-planned single implant and a ceramic veneer restoration was able to fulfill the patient's esthetic expectations. The selection of materials for the final restoration was crucial to manage the occlusal forces and to mimic the shade and shape of the adjacent teeth.This article outlines the prosthetic concepts in the management of implants in the esthetic zone with a view to achieving optimal long-term esthetics and stability. The emphasis is on the understanding and application of the biologic factors and dental technology that influence treatment outcomes. The authors examine the exciting new world of digitalization of dental procedures that has transformed esthetic dentistry, dental technology, and surgery. The digital workflow makes it possible to attain excellence in many kinds of dental restorations, providing high quality while maintaining a very natural-looking appearance. The newest developments in the field of digital systems allow for greater predictability and precision of results as well as more accuracy, which in turn allows for better design quality. The duration of dental treatment and dental technology has also been reduced due to digitalization. Transitioning from an analog to a digital workflow requires a paradigm shift. The techniques to improve the daily workflow in practice and in the dental laboratory integrate advanced CAD/CAM technologies, combining 3D-printed models and high-end esthetic dental restorations in ceramics. An interdisciplinary approach, detailed in this article, is key to optimal case management.The socket-shield technique shows promising results in the esthetic zone. It is a technically challenging procedure but is effective in maintaining the buccal plate after tooth extraction and avoiding tissue collapse. Therefore, it could be considered a valid option in the immediate implant scenario. A careful shield preparation and handling are paramount for the success of the treatment and to minimize complications. Raising a flap can improve visibility and simplify the procedure. This article reports on a case in which a small crestal approach is used to visualize the root and the buccal plate, combined with a buccal semilunar flap, to gain access to the apical area. This surgical management is especially indicated when long roots are involved, in order to determine the correct axis for cutting and sectioning the root and to remove the apex if conventional drills are not long enough. Possible esthetic complications of raising a flap are also discussed.This article describes a novel concept for treatment planning and execution in the digital era. The aim of the presented workflow was to design, plan, communicate, perform, fabricate, deliver, and maintain a smile makeover restoration entirely through digital technology. The interdisciplinary treatment plan is described from the planning through the diagnostic mock-up to the final restoration. In digital designing, the dental morphology and tooth shape seen by the clinician and technician are interpreted by the computer as a 3D geometric mathematic model. Controlling the geometry provides freedom for the clinician to develop a restorative digital plan that can be followed throughout the patient's treatment. link3 Moreover, new ceramic materials used with computer-assisted techniques have considerably broadened the choices for dental teams and have enhanced the results that can be achieved.