Material For Clinical Use Research Articles

Preparation and sterilization of an implantable drug-delivery microdevice for clinical use

Implantable drug-delivery microdevices are a key diagnostic and therapeutic tool in medicine with increasing applications. Preparation of such combination drug-delivery devices for human studies requires the development of methods to ensure sterility, safety and integrity on both the device and drug side. Despite growing applications for these technologies, there has been a lack of clear methodology regarding sterilization and preparation to meet strict guidelines set forth by the Food and Drug Administration (FDA). Our laboratory developed a set of widely applicable and straightforward procedures to prepare drug-device combination products for clinical use that consistently achieve the high-quality standards provided by the FDA. This includes several newly developed methods for preparation of the implant including endotoxin removal, appropriate sterilization of raw materials, formulation of novel pharmaceutical agents, and loading of agents into drug delivery reservoirs. We also discuss protocols and methods developed with FDA to meet regulatory guidelines to ensure continual sterility and endotoxin testing, as well as longer-term stability testing of drugs and biologic agents.•Endotoxin removal and sterilization of raw materials for clinical use.•Formulation and device loading of novel pharmaceutical agents.•Continued testing of pharmaceutical agents and devices to meet regulatory guidelines.

Dosimetry of a sonolucent material for an ultrasound-compatible gynecologic high-dose-rate brachytherapy cylinder using Monte Carlo simulation and radiochromic film

Purposehe purpose of this study was to study the dosimetric characterization of sonolucent material “TPX” to be used toward gynecologic high-dose-rate brachytherapy treatments using ultrasound-compatible cylinders in non–model-based dose calculation workflows. MethodsMonte Carlo simulations were performed using EGSnrc application egs_brachy in cylinders of polymethylpentene (TPX) plastic, water, and PMMA. Simulations were performed of five 192Ir sources placed longitudinally in ∼3.7 cm diameter, 5.0 cm length cylinders (matching physical cylinders used in film measurements). TPX and PMMA dose distributions and percentage depth dose curves were compared relative to water.Film measurements were performed to validate egs_brachy simulations. TPX and PMMA cylinders were placed in a water tank using 3D-printed supports to position film radially and touching the surface of the cylinders. The same five 192Ir dwell positions were delivered as simulated in egs_brachy. ResultsThe egs_brachy and film percentage depth doses agreed within film uncertainties. The egs_brachy relative dose difference between TPX and water was (0.74 ± 0.09)% and between PMMA and water was (-0.79 ± 0.09)% over the dose scoring phantom. Dose differences for TPX and PMMA relative to water were less than ± 1% within 5 cm of the cylinder surface. ConclusionsIn a solid sonolucent sheath of TPX, the dosimetric differences are comparable with PMMA and other applicator materials in clinical use. No additional uncertainty to dose calculation is introduced when treating through TPX cylinders compared with current applicator materials, and therefore, it is acceptable to perform gynecologic brachytherapy treatments with a sonolucent sheath inserted during radiation delivery.

Biomass-DerivedMultilayer-Structured Microparticles for Accelerated Hemostasis and Bone Repair.

It is very desirable to develop advanced sustainable biomedical materials with superior biosafety and bioactivity for clinical applications. Herein, biomass‐derived multilayer‐structured absorbable microparticles (MQxTy) composed of starches and plant polyphenols are readily constructed for the safe and effective treatment of bone defects with intractable bleeding by coating multiple layers of quaternized starch (Q+) and tannic acid onto microporous starch microparticles via facile layer‐by‐layer assembly. MQxTy microparticles exhibit efficient degradability, low cytotoxicity, and good blood compatibility. Among various MQxTy microparticles with distinct Q+/T− double layers, MQ2T2 with outmost polyphenol layer possess the unique properties of platelet adhesion/activation and red blood cell aggregation, resulting in the best hemostatic performance. In a mouse cancellous‐bone‐defect model, MQ2T2 exhibits the favorable hemostatic effect, low inflammation/immune responses, high biodegradability, and promoted bone repair. A proof‐of‐concept study of beagles further confirms the good performance of MQ2T2 in controlling intractable bleeding of bone defects. The present work demonstrates that such biomass‐based multilayer‐structured microparticles are very promising biomedical materials for clinical use.

Synthesis and characterization of multifunctional organic-inorganic composite hydrogel formed with tissue-adhesive property and inhibiting infection

Organic-inorganic composite hydrogel materials have been widely studied. In order to expand the application of organic-inorganic composite hydrogel materials, in this work, we prepared a viscous hydrogel with antibacterial properties (OSA-GelDA@ACP/DA/Ag). First, we used polydopamine coating to deposit elemental silver on the surface of amorphous calcium phosphate (ACP) particles to prepare ACP/DA/Ag particles. Next, dopamine was grafted on the gelatin molecular chain by EDC/NHS to activate the carboxyl group to obtain dopamine-modified gelatin (GelDA). The content of DA in GelDA is about 14.09% by standard curve method. Then, the Schiff base reaction took place between the amino group on the GelDA molecular chain and the aldehyde group on the OSA molecular chain, and an OSA-GelDA viscous hydrogel was prepared. Finally, by changing the content of ACP/DA/Ag3 particles added to the OSA-GelDA gel, the corresponding performance of material was investigated. The results show that the introduction of dopamine provides wet viscosity for the hydrogel, and the ACP/DA/Ag3 particles introduced in the viscous hydrogel provide antibacterial properties. This hydrogel with antibacterial and wet viscosity is expected to become an injectable bone repair material for clinical use.

Long Term Efficacy and Fate of a Right Ventricular Outflow Tract Replacement Using a Novel Developed Material with Optimized Biodegradation and Elasticity

For decades, researchers have investigated the ideal material for clinical use in the cardiovascular field. Several substitute materials are used clinically, but each has drawbacks. Recently we developed poly(e-caprolactone-co-D,L-lactide) (P(CL-DLLA)) polymers with optimized biodegradation and elasticity by adjusting the CL/DLLA composition, and used these polymers in right ventricular outflow tract (RVOT) replacement to evaluate long-term efficacy and outcomes. This P(CL-DLLA) material was processed into a circular patch and used to replace a surgical defect in the RVOT of adult rats. Control rats were implanted with expanded polytetrafluoroethylene (ePTFE). Histologic evaluation was performed at 8, 24, and 48 weeks post-surgery. All animals survived the surgery with no aneurysm formation or thrombus. In all periods, ePTFE demonstrated fibrous tissue. In contrast, at 8 weeks P(CL-DLLA) showed infiltration of macrophages and fibroblast-like cells into the remaining material. At 24 weeks, P(CL-DLLA) was absorbed completely, and muscle-like tissue was present with positive staining for α-sarcomeric actinin and cTnT. At 48 weeks, the cTnT-positive area had increased. The P(CL-DLLA) with optimized elasticity and biodegradation induced cardiac regeneration throughout the 48-week study period. Future application of this material as a cardiovascular scaffold seems promising.

In-vivo histocompatibility and osteogenic potential of biodegradable PLDLA composites containing silica-based bioactive glass fiber.

The purpose of this two-year study was to evaluate the histocompatibility and osteogenic properties of a composite material consisting of poly(l-co-d,l lactide) (PLDLA) and silica-based bioactive glass fibers in vivo. PLDLA and PLDLA/silica-based bioactive glass fibers pins were implanted into the erector spinae muscles and femurs of beagles. Muscle and bone tissue samples were harvested 6, 12, 16, 26, 52, 78, and 104 weeks after implantation. Histology analysis was used to assess the histocompatibility, angiogenesis, and bone-implant contact. Micro-computed tomography was used to evaluate bone formation around the pins. Immunohistochemistry and western blotting revealed the expression level of the osteogenesis-related proteins. Addition of bioactive glass was demonstrated to possess better histocompatibility and reduce the inflammatory reactions in vivo. Moreover, PLDLA/silica-based bioactive glass fibers pins were demonstrated to promote angiogenesis and increase osteogenesis-related proteins expression, and thus played a positive role in osteogenesis and osseointegration after implantation. Our findings indicated that a composite of PLDLA and silica-based bioactive glass fiber is a promising biodegradable material for clinical use.

Tag-Free Site-Specific BMP-2 Immobilization with Long-Acting Bioactivities via a Simple Sugar-Lectin Interaction.

The construction of a biomaterial matrix with biological properties is of great importance to developing functional materials for clinical use. However, the site-specific immobilization of growth factors to endow materials with bioactivities has been a challenge to date. Considering the wide existence of glycosylation in mammalian proteins or recombinant proteins, we establish a bioaffinity-based protein immobilization strategy (bioanchoring method) utilizing the native sugar-lectin interaction between concanavalin A (Con A) and the oligosaccharide chain on glycosylated bone morphogenetic protein-2 (GBMP-2). The interaction realizes the site-specific immobilization of GBMP-2 to a substrate modified with Con A while preserving its bioactivity in a sustained and highly efficient way, as evidenced by its enhanced ability to induce osteodifferentiation compared with that of the soluble GBMP-2. Moreover, the surface with Con A-bioanchored GBMP-2 can be reused to stimulate multiple batches of C2C12 cells to differentiate almost to the same degree. Even after 4 month storage at 4 °C in phosphate-buffered saline (PBS), the Con A-bioanchored GBMP-2 still maintains the bioactivity to stimulate the differentiation of C2C12 cells. Furthermore, the ectopic ossification test proves the in vivo bioactivity of bioanchored GBMP-2. Overall, our results demonstrate that the tag-free and site (i.e., sugar chain)-specific protein immobilization strategy represents a simple and generic alternative, which is promising to apply for other glycoprotein immobilization and application. It should be noted that although the lectin we utilized can only bind to d-mannose/d-glucose, the diversity of the lectin family assures that a specific lectin could be offered for other sugar types, thus expanding the applicable scope further.

Shear Bond Strength of Ceramic Bonded to Different Core Materials and Their Pattern of Failure: An In Vitro Study.

IntroductionIn metal-ceramic restoration, most of the bond failures between the ceramic layer and the metal coping is the chipping of the ceramic layer, thus exposing the metal surface, which compromises the aesthetics. Hence, this leads to the introduction of zirconia-based restorations in dentistry. However, even zirconium coping has the common complication of delamination or porcelain chipping from the zirconium core. Hence, the shear bond strength between the commonly used core materials and ceramic requires investigation to facilitate the materials in clinical use for longevity. Therefore, this study was conducted to compare the shear bond strength between different core materials and ceramic layering to find out the best core material for ceramic bonding.Materials and methodsA total number of 45 samples were made as per ISO standardization (base 5 mm diameter and 1 mm thickness, step with 4 mm diameter and 4 mm in length). These samples were divided into three groups, Group A: Nickel-chromium, Group B: Cobalt-chromium, and Group C: Zirconium. Ceramic layering was layered on the top surface of each sample until an ideal height of 4 mm was obtained, and it was subjected to shear bond strength using a universal testing machine with a 50-KN load cell. This was followed by analyzing the nature of the fracture pattern using scanning electron microscopy (SEM).Results There were no significant differences found for the shear bond strength among group A and group B. The zirconium (group C), however, had significantly lower values than both group A and group B. The microscopic examination also revealed that the failure between the coping and the ceramic layer primarily occurred near the interface with the residual veneering porcelain remaining on the core.ConclusionsIt was found that the shear bond strength of the metal-ceramic group is better than the zirconium ceramic group, however, the fracture between the copings and the ceramic layering is found to be similar for both adhesive and cohesive failure.

Utility and Cost–Effectiveness of 3D-Printed Materials for Clinical Use

This review summarizes the utility of 3D-printing as a surgical adjunct, reviewing the cost–effectiveness. The relevant literature was analyzed outlining the utility and/or cost–effectiveness of 3D-printing for clinical use. Compared with existing methods, the evidence suggests an advantage of using 3D-printing as a technology in the treatment of complex clinical cases. However, in high frequency cases, the additional preoperative expenses are not justified. Considerable evidence of its clinical benefits exists for the application of 3D-printed anatomical models and teaching tools. However, the evidence supporting 3D-printing’s use as surgical guides or implantable devices is less clear. Furthermore, caution must exist when using these devices in the clinical setting due to a paucity of rigorous testing, global regulation and long-term data.

A review of calcium phosphate cements and acrylic bone cements as injectable materials for bone repair and implant fixation

Treatment of bone defects caused by trauma or disease is a major burden on human healthcare systems. Although autologous bone grafts are considered as the gold standard, they are limited in availability and are associated with post-operative complications. Minimally invasive alternatives using injectable bone cements are currently used in certain clinical procedures, such as vertebroplasty and balloon kyphoplasty. Nevertheless, given the high incidence of fractures and pathologies that result in bone voids, there is an unmet need for injectable materials with desired properties for minimally invasive procedures. This paper provides an overview of the most common injectable bone cement materials for clinical use. The emphasis has been placed on calcium phosphate cements and acrylic bone cements, while enabling the readers to compare the opportunities and challenges for these two classes of bone cements. This paper also briefly reviews antibiotic-loaded bone cements used in bone repair and implant fixation, including their efficacy and cost for healthcare systems. A summary of the current challenges and recommendations for future directions has been brought in the concluding section of this paper.

Study on the application of embolization materials of collagen

The embolization mechanism, advantages and disadvantages as well as clinical application of collagen embolization materials were retrospectively analyzed, and the correlation between their application fields and the selection of embolization materials was discussed, so as to provide references for clinical treatment. Relevant literatures in Pubmed and Web of Science databases were searched, and the literature on clinical application and experimental research of embolic materials was systematically evaluated. Embolic materials should be biodegradable and biocompatible. Embolic materials for clinical use include absorbable gelatin sponge, polyvinyl alcohol particle embolization agent, micro-spring coil and liquid embolization materials. Gelatin embolization materials have the advantages of non-antigenicity, histocompatibility, convenient preparation, excellent compressibility and expansion in water. Endovascular embolization materials have been produced and applied in clinical practice, but new problems and new requirements have been rising. All kinds of embolic materials have advantages and disadvantages, and none of them can be suitable for all diseases. Therefore, it is very important to select suitable embolic materials for safe and effective treatment.

Complex relationship between alumina and selenium-doped carbonated hydroxyapatite as the ceramic additives to electrospun polycaprolactone scaffolds for tissue engineering applications

The future of nanomedicine belongs to composite nanostructures with complex and precisely tailored synergistic interactions between individual components. A composite scaffold was fabricated by electrospinning ε-polycaprolactone microfibers containing dispersed alumina and selenite-doped carbonated hydroxyapatite (Se-CHAP). The effects of the two coexisting ceramic components were investigated by testing the composites using a range of experimental techniques, including diffractometric, vibrational spectroscopic, porosimetric, mechanical and biological ones. No preferential orientation of the microfibers in the scaffolds was detected, but the fiber diameters increased and their curliness decreased as a function of the weight ratio between alumina and Se-CHAP. Synergistic breaking of the polymeric structure occurred due to the interaction of alumina and Se-CHAP in the polymeric matrix. The density of the composites decreased as Se-CHAP replaced alumina, but porosity was maximal in the material containing equal amounts of the two ceramic components, reiterating the complex synergistic interaction between them. Mechanical properties exhibited an equally complex relationship, with the composition containing alumina and Se-CHAP in 3:1 wt ratio displaying the highest toughness and strain at break and the composition containing alumina and Se-CHAP in 1:1 weight ratio exhibiting the lowest tensile strength and Young's modulus, lower than the materials supplemented with only alumina and only Se-CHAP. In-vitro cell studies on the human fibroblast HFB4 cell line demonstrated that the cells grew and spread on all polymeric scaffolds, but the adhesion, spread and infiltration increased in direct proportion with the Se-CHAP phase content. Also, although no significant loss of viability was detected in cells grown on any of the composite matrices, thus proving their biocompatibility, the lowest viability was detected on the matrices supplemented with the two ceramic additives in 1:1 weight ratio. Overall, no single composition proved most optimal for all the properties analyzed – microstructural, porosimetric, mechanical, biological. Rather, a compromise must be made between these different properties in search of the composition with the most optimal performance, with the caveat that fine changes in the weight ratio between alumina and Se-CHAP could produce significant repercussions at the level of material properties. The variable weight ratio between the two ceramic additives, however, allows for the tuning of the material properties for the desired application. This fundamental principle can be taken advantage of in the further optimization of this and similar materials for clinical use.

Needs assessment in genetic testing education: A survey of parents of children with autism spectrum disorder in the united states.

Understanding parents' educational needs concerning genetic testing for their children with autism spectrum disorder (ASD) is important in developing tailored, evidence-based health education materials for clinical use. Since research is lacking in this area, to bridge the gap, we examined genetic testing education needs using a nationwide sample of parents of biological children with ASD in the United States. Prospective participants were recruited from the interactive autism network, and 552 parents of biological children with ASD completed the online survey. Most participants (73.7%) were interested in receiving health education about genetic testing. Yet, the majority of them (64.7%) reported that they did not receive the information needed from physicians. Parents who identified as racial/ethnic minorities (P = 0.029), who had an education degree below college (P = 0.002), or displayed low/no awareness of genetic testing (P = 0.003) were more interested in receiving health education regarding genetic testing. Parents' most desired topics for health education include the accuracy of genetic testing (88.4%), cost (85.9%), relevant benefits of such testing (83.8%), testing procedure (77.8%), eligibility to undergo genetic testing for their children with ASD (62.4%), potential harms caused by genetic testing (56.1%), previous use and experience among individuals affected by ASD (50.8%), and confidentiality issues (48.0%). Furthermore, web-based education was the preferable approach (85.4%). Our findings can help develop health education programs and/or materials regarding genetic testing for parents and physicians to facilitate better physician-parent communication and assist parents in making informed medical decisions regarding genetic testing. Autism Res 2019, 12: 1162-1170. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: This study examined educational needs on genetic testing among 552 American parents of children with autism spectrum disorder (ASD). Results showed that most parents expressed interests in receiving health education regarding genetic testing (73.7%) and favored online education resources (85.4%). Preferred topics included accuracy, cost, and testing benefits. Our findings can help develop genetic testing related health education programs and materials for parents of children with ASD.

Photopolymerizable Resins for 3D-Printing Solid-Cured Tissue Engineered Implants.

With the advent of inexpensive and highly accurate 3D printing devices, a tremendous flurry of research activity has been unleashed into new resorbable, polymeric materials that can be printed using three approaches: hydrogels for bioprinting and bioplotting, sintered polymer powders, and solid cured (photocrosslinked) resins. Additionally, there is a race to understand the role of extracellular matrix components and cell signalling molecules and to fashion ways to incorporate these materials into resorbable implants. These chimeric materials along with microfluidic devices to study organs or create labs on chips, are all receiving intense attention despite the limited number of polymer systems that can accommodate the biofabrication processes necessary to render these constructs. Perhaps most telling is the limited number of photo-crosslinkable, resorbable polymers and fabrication additives (e.g., photoinitiators, solvents, dyes, dispersants, emulsifiers, or bioactive molecules such as micro-RNAs, peptides, proteins, exosomes, micelles, or ceramic crystals) available to create resins that have been validated as biocompatible. Advances are needed to manipulate 4D properties of 3D printed scaffolds such as pre-implantation cell culture, mechanical properties, resorption kinetics, drug delivery, scaffold surface functionalization, cell attachment, cell proliferation, cell maturation, or tissue remodelling; all of which are necessary for regenerative medicine applications along with expanding the small set of materials in clinical use. This manuscript presents a review of the foundation of the most common photopolymerizable resins for solidcured scaffolds and medical devices, namely, polyethylene glycol (PEG), poly(D, L-lactide) (PDLLA), poly-ε-caprolactone (PCL), and poly(propylene fumarate) (PPF), along with methodological advances for 3D Printing tissue engineered implants (e.g., via stereolithography [SLA], continuous Digital Light Processing [cDLP], and Liquid Crystal Display [LCD]).

Poly (propylene fumarate)/β-calcium phosphate composites for enhanced bone repair

A composite based on poly (propylene fumarate) (PPF) was investigated as a potential bone repair material for clinical use and it showed low heat release, suitable mechanical property and good biocompatibility. The in situ curing process would finish in less than 10 min. Compared with PMMA, PPF/TCP showed great decrease in heat release as the maximum temperature during curing process was 54.7 °C ± 1.69 °C. The compressive strength was between 109 ± 2 and 133 ± 6 MPa and the compressive modulus was 146 ± 11 to 161 ± 27 MPa, which were believed to be compatible and further supportive to surrounding bone. Besides, the surface morphology and hydrophilicity could be tailored by adjusting the content of β-calcium phosphate (β-TCP). Relatively stable pH value during degradation in PBS solution implied that it would not bring about acidification when implanted in vivo. In addition, PPF/TCP would boost mineralization and the apatite-like deposits on surface may advance the integrity of bone and materials. Moreover, the PPF/TCP obviously degraded and new bone formed especially when loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2) in vivo. In summary, PPF/TCP composites showed suitable physical and chemical properties as well as good bioactivity and may therefore be a promising material for bone repair.

Osteocytes respond to particles of clinically-relevant conventional and cross-linked polyethylene and metal alloys by up-regulation of resorptive and inflammatory pathways

Periprosthetic osteolysis is a major cause of implant failure in total hip replacements. Aseptic loosening caused by osteolytic lesions is associated with the production of bioactive wear particles from the articulations of implants. Wear particles infiltrate the surrounding tissue of implants, promoting inflammation as well as bone resorption. Osteocytes have been shown to both regulate physiological osteoclastogenesis and directly remodel their perilacunar bone matrix by the process of osteocytic osteolysis. We hypothesise that osteocytes respond to wear debris of orthopaedic implant materials by adopting a pro-catabolic phenotype and thus contribute to periprosthetic osteolysis through the known pathways of bone loss. Osteocyte responses to particles derived from clinically relevant materials, ultra-high molecular weight polyethylene (UHMWPE), highly cross-linked polyethylene (XLPE) and metal alloys, Ti6Al4V and CoCrMo, were examined in vitro in human primary osteocyte-like cultures. Osteocyte-like cells exposed to both polyethylene and metal wear particle types showed upregulated expression of catabolic markers associated with osteocytic osteolysis, MMP13, carbonic anhydrase 2 (CA2) and cathepsin K (CTSK). In addition, pro-osteoclastogenesis markers RANKL and M-CSF were induced, as well as the expression of pro-inflammatory cytokines, IL-6 and TNFα, albeit with different kinetics. These findings suggest a previously unrecognised action of wear particles of multiple orthopaedic materials on osteocytes, and suggest a multifaceted role for osteocytes in periprosthetic osteolysis. Statement of SignificanceThis study addresses periprosthetic osteolysis, a major clinical problem leading to aseptic loosening of orthopaedic implants. It is well accepted that wear particles of polyethylene and of other implant materials stimulate the activity of bone resorbing osteoclasts. Our recent work provided evidence that commercial particles of ultra-high molecular weight polyethylene (UHMWPE) stimulated osteocytes to adopt a bone catabolic state. In this study we demonstrate for the first time that particles derived from materials in clinical use, conventional UHMWPE, highly cross-linked polyethylene (XLPE), and Ti6Al4V and CoCrMo metal alloys, all stimulate human osteocyte activities of osteocyte-regulated osteoclastogenesis, osteocytic osteolysis, proinflammatory responses, osteocyte apoptosis, albeit to varying extents. This study provides further mechanistic insight into orthopaedic wear particle mediated bone disease in terms of the osteocyte, the most abundant and key controlling cell type in bone.

One-year Clinical Performance of Flowable Bulk-fill Composite vs Conventional Compomer Restorations in Primary Molars.

To evaluate the clinical performance of a flowable bulk-fill composite vs a compomer in Class II cavities of primary molars. In a clinical study, 100 restorations were placed in two randomly assigned comparable Class II cavities in 32 children (aged 6.7 ± 1.2 years) with at least one bulk-fill composite (Venus Bulk Fill, Heraeus Kulzer) and one compomer (Dyract eXtra, Dentsply). After caries excavation, the adhesive Scotchbond Universal (3M Oral Care) was applied in self-etching mode. According to the manufacturer's instructions, Venus Bulk Fill was used for the entire Class II cavity of primary molars without a cover layer. After visible-light curing, both restorations were finished and polished. Both restorative materials were evaluated at baseline and after one year, including esthetic, functional, and biological parameters, using the FDI criteria. The Mann-Whitney U-test was used to determine the difference in the complete scores at baseline and after one year (p < 0.05). After one year, 99 restorations were reevaluated; one tooth had exfoliated physiologically. Concerning the esthetic parameters, Dyract eXtra showed slightly higher scores than Venus Bulk Fill. Both materials showed similar scores regarding functional and biological parameters. No severe postoperative sensitivities or side-effects were reported. There was no statistically significant difference between the performance of Venus Bulk Fill and Dyract eXtra for primary molars. The flowable bulk-fill composite Venus Bulk Fill can be considered as an alternative material for clinical use in primary teeth, but longer-term studies might still be needed.

Bone tissue reaction, setting time, solubility, and pH of root repair materials.

This study aims to compare the bone tissue reaction, setting time, solubility, and pH of NeoMTA Plus, Biodentine (BD), and MTA Angelus (MTA-A). Initial and final setting times (n = 7) and solubility up to 7days (n = 11) were evaluated in accordance with ASTM C266-15 and ANSI/ADA Specification No. 57, respectively. pH (n = 10) was measured up to 28days. Bone tissue reactions in 48 rats' femur were histologically analyzed after 7, 30, and 90days. ANOVA and Tukey's tests compared setting time, solubility, and pH data; bone reactions data were compared by Kruskal-Wallis and Dunn's tests. NeoMTA Plus had longer initial and final setting times than MTA-A and BD (P < 0.05). At 7days, BD showed the highest solubility, similar to NeoMTA Plus (P > 0.05) and different from MTA-A (P < 0.05). NeoMTA Plus had a progressive mass loss over time; at 7days, it was significantly different from the initial mass (P < 0.05). BD showed higher pH in the periods assessed when compared to the other materials (P < 0.05). Bone tissue repair had no differences between groups in each experimental period (P > 0.05). All groups presented no difference from 30 to 90days (P > 0.05) and had better bone repair at 90days than at 7days (P < 0.05). NeoMTA Plus, BD, and MTA-A showed satisfactory setting time, high mass loss, alkaline pH, and allowed bone repair. Calcium silicate-based cements are indicated for multiple clinical situations. NeoMTA Plus and BD showed satisfactory physical-chemical and biological properties, being considered as alternatives to MTA-A, as root repair materials for clinical use.

Material properties on enamel and fissure of surface pre-reacted glass-ionomer filler-containing dental sealant

PurposeIn pediatric dentistry, sealants have been used to prevent caries. Due to its material properties such as fluoride-releasing ability and physical strength, surface pre-reacted glass (S-PRG) filler is added primarily to resin-based dental materials for clinical use. In this study, we investigated the properties of S-PRG filler containing sealant. MethodsBefore using sealant, the primer was applied to extracted bovine incisors. Scanning electron microscopy (SEM) observation revealed that the primer treatment caused no structural changes of enamel surface, unlike conventional phosphoric acid etching. Further, shear bond strength test was performed to measure the initial strength and durability after thermal cycling. Bond strength of S-PRG filler containing sealant was comparable to those of other sealants even though the former does not involve phosphoric acid etching. In addition, after treating the enamel surface with the primer or phosphoric acid, it showed excellent flowability in the primer group compared to phosphoric acid treatment. ResultsSEM observation showed that the sealant sealed the enamel surface as it migrated to reach the deep areas of the fissures. When the marginal sealing ability of the sealant was evaluated based on dye penetration, no dye penetration in the marginal region was observed in any specimens. In addition, measurement of the pH of an acid solution containing a cured specimen of the sealant containing S-PRG filler showed that the solution's pH became more alkaline as the immersion time increased. ConclusionThese findings suggest that the sealant is an extremely effective material for preventing caries.

Histopathologic Evaluation of Hyaluronic Acid and Plasma-Rich Platelet Injection into Rabbit Vocal Cords: An Experimental Study.

Various materials are used by otolaryngologists for vocal cord injections in the management of vocal cord paralysis. An ideal injection material should be long-term effective, readily available, cheap, easy to prepare, have no donor morbidity, easy to use, biocompatible, resistant to resorption or migration, and easy to extract during revision. In this study, we aimed to see the histopathological effects of hyaluronic acid (HYA) and platelet-rich plasma (PRP) injections into the vocal cords of New Zealand rabbits. PRP was injected into the right vocal cords of twelve rabbits, which was prepared from their serum (PRP group). HYA was injected into the left vocal cords of first six rabbits (numbered 1-6) (HYA group), and the left vocal cords of the other six rabbits (numbered 7-12) were followed with no intervention (control group). Two months later, histomorphological findings in the vocal cords were assessed by two experienced pathologists in seven parameters: chronic inflammation, mucosal atrophy, necrosis, neovascularization, fibrosis, foreign body reaction, and muscular atrophy. They were scored double-blinded as negative (0), mild (+1), moderate (+2), and severe (+3). Fisher's chi-square test was used to evaluate any statistical significance among the three groups. Chronic inflammation, mucosal atrophy, necrosis, foreign body reaction, and muscular atrophy parameters were scored as "0" for each preparate by both pathologists. For neovascularization and fibrosis, a stasistically significant difference was seen among the three groups (p<0.05). Neovascularization was increased in the PRP and HYA groups compared with the control group. No significant difference was observed in fibrosis when the groups were compared separately. After two months, two of the six vocal cords injected with HYA revealed HYA; however, none of the PRP-injected vocal cords showed PRP. HYA and PRP can be safely injected into vocal cords. Our findings show that HYA is a biocompatible and safe injection material for clinical use. Only two of the six vocal cords showed HYA at the end of two months, suggesting that HYA is a short-term effective material. Similarly, PRP was also shown to be a short-term effective material and can be used in patients for testing purpose before using a long-term effective material. The advantages of PRP are that it is inexpensive, readily available, and completely inert as it is prepared from the subject itself.