Novel Lipophilic Acetohydroxamic Acid Derivatives Based on Conformationally Constrained Spiro Carbocyclic 2,6-Diketopiperazine Scaffolds with Potent Trypanocidal Activity

We describe novel acetohydroxamic acid derivatives with potent activity against cultured bloodstream-form Trypanosoma brucei and selectivity indices of >1000. These analogues were derived from conformationally constrained, lipophilic, spiro carbocyclic 2,6-diketopiperazine (2,6-DKP) scaffolds by attaching acetohydroxamic acid moieties to the imidic nitrogen. Optimal activity was achieved by placing benzyl groups adjacent to the basic nitrogen of the 2,6-DKP core. S-Enantiomer 7d was the most active derivative against T. brucei (IC(50) = 6.8 nM) and T. cruzi (IC(50) = 0.21 μM)

Between a Rock and a Hard Place: Habitat Selection in Female-Calf Humpback Whale (Megaptera novaeangliae) Pairs on the Hawaiian Breeding Grounds

The Au'au Channel between the islands of Maui and Lanai, Hawaii comprises critical breeding habitat for humpback whales (Megaptera novaeangliae) of the Central North Pacific stock. However, like many regions where marine mega-fauna gather, these waters are also the focus of a flourishing local eco-tourism and whale watching industry. Our aim was to establish current trends in habitat preference in female-calf humpback whale pairs within this region, focusing specifically on the busy, eastern portions of the channel. We used an equally-spaced zigzag transect survey design, compiled our results in a GIS model to identify spatial trends and calculated Neu's Indices to quantify levels of habitat use. Our study revealed that while mysticete female-calf pairs on breeding grounds typically favor shallow, inshore waters, female-calf pairs in the Au'au Channel avoided shallow waters (<20 m) and regions within 2 km of the shoreline. Preferred regions for female-calf pairs comprised water depths between 40–60 m, regions of rugged bottom topography and regions that lay between 4 and 6 km from a small boat harbor (Lahaina Harbor) that fell within the study area. In contrast to other humpback whale breeding grounds, there was only minimal evidence of typical patterns of stratification or segregation according to group composition. A review of habitat use by maternal females across Hawaiian waters indicates that maternal habitat choice varies between localities within the Hawaiian Islands, suggesting that maternal females alter their use of habitat according to locally varying pressures. This ability to respond to varying environments may be the key that allows wildlife species to persist in regions where human activity and critical habitat overlap

Modified PEEK resin-bonded fixed dental prosthesis as an interim restoration after implant placement

A polyetheretherketone (PEEK) (BioHPP) framework veneered with composite resin was used as an alternative material for the fabrication of an interim 3-pontic resin-bonded fixed dental prosthesis (RBFDP) after implant placement. The low modulus of elasticity (4 GPa) of PEEK combined with the use of indirect light-polymerized resin as a veneering material used for a RBFDP provided an advantage over metal ceramics or ceramics in dampening the occlusal forces and reducing debonding rates. Further long-term clinical evidence is required before recommending the application as a substitute material. © 2016 Editorial Council for the Journal of Prosthetic Dentistr

Removable dental prosthesis splint: An occlusal device for nocturnal bruxing partial denture users

Nocturnal bruxing is a parafunctional activity of the masticatory system that may create problems for removable dental prosthesis (RDP) users. Such problems may include root fractures, increased mobility of abutment teeth, excessive wear of resin denture teeth, minor connector bending, or denture base cracking. This clinical report presents an occlusal device fabricated for an RDP patient. The device used existing ERA attachments for added retention designed with the intended purpose of protecting the definitive fixed and RDP from damage due to nocturnal bruxing activity and providing for even distribution of parafunctional forces. © 2013 by the American College of Prosthodontists

The Effect of Surface Pretreatment and Water Storage on the Bonding Strength of a Resin Composite Cement to Modified PEEK

The bonding quality of bonding to polyether ether ketone (PEEK) after different surface treatments and adhesive regimens was assessed through shear bond strength. MATERIALS AND METHODS: Sixty modified PEEK disks were cut out of BioHPP round blanks using CAD-CAM procedures. Disks were subjected to the following surface pretreatments: (A) Sandblasting with alumina (Rocatec) and application of adhesive bonding agent visiolink (control group) (B) Sandblasting with silica-modified alumina (Cojet), application of silane agent Espe Sil, followed by application of adhesive bonding agent Visio-Bond (C) Sandblasting with silica-modified alumina (Cojet), application of silane containing primer-adhesive Clearfil Ceramic Primer, followed by application of adhesive bonding agent visiolink. A dual-curing resin composite cement (combolign) was luted to all treated surfaces. Each group was further divided to subgroups of 10 specimens which were stored in distilled water at 37°C for 150 days without further thermocycling. Specimens were then submitted to shear bond strength testing. RESULTS: Group (B) was statistically significant different from group (A) (control group). Water storage condition had no significant influence on final bond strength. CONCLUSIONS: Use of different conditioning protocols had a significant effect on the final bond strength of composite resin cement to PEEK surface. Water storage did not significantly influence bonding. Copyright© 2020 Dennis Barber Ltd

Using modified polyetheretherketone (PEEK) as an alternative material for endocrown restorations: A short-term clinical report

A modified polyetheretherketone (PEEK) framework material veneered with indirect light-polymerized composite resin was used as an alternative material for the fabrication of an endocrown restoration for an extensively damaged molar. The elastic modulus of the polyetheretherketone framework (4 GPa) veneered with indirect composite resin could dampen the occlusal forces protecting tooth structures better than ceramic materials. This is important in the restoration of extensively damaged molars with weak roots. Long-term clinical evidence is required before recommending the application as a substitute material. © 2016 Editorial Council for the Journal of Prosthetic Dentistr

The Use of a Modified Poly-Ether-Ether-Ketone (PEEK) as an Alternative Framework Material for Removable Dental Prostheses. A Clinical Report

This clinical report presents a modified poly-ether-ether-ketone (PEEK) as an alternative material for the fabrication of distal extension removable dental prosthesis (RDP) frameworks. This material can be used for patients allergic to metals, or who dislike the metallic taste, the weight, and the unpleasant metal display of the denture framework and retentive clasps. This modified PEEK material, known as BioHPP, is a biocompatible, nonallergic, rigid material, with flexibility comparable to bone, high polishing and low absorption properties, low plaque affinity, and good wear resistance. It has been used for years in orthopedics and medical technology. BioHPP frameworks can be constructed either via CAD/CAM manufacturing or via the conventional lost wax technique. The clinical use of a BioHPP RDP framework is presented as an alternative for the treatment of a distal extension case. © 2015 by the American College of Prosthodontist

Effect of Staining Solutions on Color Stability, Gloss and Surface Roughness of Removable Partial Dental Prosthetic Polymers

Purpose: To assess the effect of commonly used solutions on color stability, gloss, and surface roughness of removable partial dental prostheses polymers. Materials and methods: Discs (n = 112) were made of a poly(etheretherketone) (PEEK) polymer, a polyamide, an acetal resin and a heat-cured poly(methylmethacrylate) PMMA acrylic resin polished according to manufacturers’ instructions. Seven specimens of each material were immersed in coffee, red wine, coca cola and distilled water for 30 days at 37οC. Changes of color (ΔΕ*) and color coordinates L*α*b* after immersion were calculated with a colorimeter. Changes in the values of gloss and surface roughness parameters (Sa, Sz, Str, Sdr, Sci, Svi) were also measured. Two-way ANOVA and pairwise comparisons were used to evaluate the effect of material and staining solution on parameter value alterations (α = 0.05). Results: The two-way ANOVA revealed that the interaction between material and staining solution significantly affected color changes after immersion [F(9,96) = 44.67, p &amp;lt; 0.001]. PEEK presented the lowest color change (ΔΕ* = 3.83 ± 2) while polyamide had the highest color change overall (ΔΕ* = 14.59 ± 8.65) (p &amp;lt; 0.001). Coffee caused the highest color (ΔΕ* = 13.08 ± 6.98) and gloss changes (ΔG = –6.36 ± 19.2 GU) among different solutions (p &amp;lt; 0.001). PEEK showed the highest alteration of gloss (ΔG = –11.31 ± 15.49 GU), with significant difference with the other three materials (p &amp;lt; 0.001). Insignificant interaction of material and immersing solution was found for surface roughness parameters (p &amp;gt; 0.05). Conclusions: Among the materials tested, PEEK seemed to be the most stable material when subjected to common, everyday staining solutions. Therefore, PEEK could be a viable solution for an RPDP framework fabrication, expanding the material list of prosthetic options. Further research and clinical trials are required to confirm the above statement. © 2021 by the American College of Prosthodontist

A fixed telescopic prosthesis designed to retrieve and convert to fixed-removable combination case: A clinical report [Most na teleskopima oblikovan s mogućnošću preinake fiksno-mobilnog nadomjestka: Prikaz slučaja]

This clinical report describes a fixed maxillary telescopic dental prosthesis (FTDP) employing milled base metal copings and a metal superstructure veneered with composite resin, for the restoration in a periodontally compromised patient with uncontrolled diabetes. The telescopic prosthesis framework design incorporated occlusal rest seats in key positions along the arch in case of future posterior tooth loss, in order to be converted to fixed - removable combination prosthesis. The mandible was restored with a conventional fixed ceramo-metal dental prosthesis

Prosthetic intervention for the management of low attached palatopharyngeal flaps - A clinical report [Protetska rehabilitacija nisko položenih palatofaringealnih režnjeva - prikaz slučaja]

This clinical report describes a delayed prosthetic management of an adult cleft palate patient, in order to treat hypernasality and inadequate speech pattern associated with the employment of low attached pharyngeal flap. Obturator construction seems to be the treatment of choice for this group of cleft palate patients when further pharyngeal surgery is contraindicated or denied