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The objective of this work was to evaluate the potential use of a new polymer (PAMgA) in the development sustained release matrix tablets for the treatment of bowel inflammatory diseases. For this purpose, budesonide, a highly lipophilic compound, was used as model drug. Tablets with two reticulation grades of PAMgA (PAMgA 5 and 40) and with 9 mg of budesonide were developed and characterized. All the studies were carried out using biorelevant media (FaSSGF and FaSSIF). Swelling and erosion of PAMgA tablets was influenced by the reticulation grade of the polymer and the biorelevant media assayed, being water uptake higher for PAMgA 40 tablets in intestinal fluid, whereas PAMgA 5 showed more intense erosion in this biorelevant medium. Budesonide was released slowly from PAMgA tablets, both in gastric and intestinal environment, following Super case II transport kinetics (relaxation-controlled delivery), with a lag time of around 1-2 h. When the dissolution medium was changed sequentially throughout the trial, 75% of the budesonide dose was released in a sustained manner between 4 and 20 h of testing from PAMgA tablets, showing a more controlled budesonide release than Entocort® and Budenofalk® (commercially available sustained release formulations of budesonide). In conclusion, PAMgA polymer allows controlling the release of highly lipophilic drugs as budesonide, being an useful excipient for the development of sustained release matrix tablets., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

Porous ceramics doped with silicon and pure β-TCP were analyzed in terms of internal microstructure, cell behavior, and the percentage of newly formed bone. Additionally the materials were tested to determine which of the two had better properties to load and release vancomycin hydrochloride. Internal pore distribution and porosity were determined through high pressure mercury porosimetry and the specific surface area was measured by the Brunauer Emmet-Teller method. The proliferation and viability of the human osteoblast-like cell line MG-63 was studied to validate both materials. The materials were tested on eight New Zealand rabbits which created defects, 10 mm in diameter, in the calvaria bone. After 8 and 12 weeks a histological and histomorphometric analysis was performed. Si-β-TCP showed a higher porosity and specific surface area. The cytocompatibility test revealed acceptable results in terms of proliferation and viability whereas the percentage of new bone was higher in Si-β-TCP with a two-time study being statistically significant with 12 weeks of healing (p < 0.05).The vancomycin loaded within the ceramic scaffolds were burst released and the material had the ability to inhibit bacterial growth. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2307-2315, 2018., (© 2017 Wiley Periodicals, Inc.)

In recent years, considerable efforts have been done to better understand the peculiar emission properties of upconverting materials due to their widespread applications in different and important technological fields such as upconversion-based photoactivated cancer therapies, photoactivated drug-delivery, magnetic resonance imaging contrast agents, bioimaging. However, one of the most promising applications of upconverting materials concerns the field of sensing, due to their unique emission properties. In fact, the minimal autofluorescence, blinking, photo-bleaching, and high photostability makes them an excellent alternative to organic dyes or quantum dots. This article reviews the state-of-the-art, design, and sensing strategies of upconversion-based sensing platforms, with special attention to upconverting nanoparticles, as well as how the incorporation of these materials into pre-existing diagnostic tests and bioassays have improved their capabilities for the detection of different kinds of analytes., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Calcium phosphate materials (CPM) are widely used in dentistry and maxillofacial surgery. The presence of microbial biofilms and external infections is responsible for the failure of many procedures of dental implants and bone grafts. In an attempt to reduce the percentage of these infectious processes antibiotics have been associated with CPM improving certain conditions. For instance, antibiotics administered orally or intravenously have less effect and the blood flow in relation to this is poor near implants and grafts. Tissue engineering (TE) has employed CPM as a local drug delivery vehicle to be more effective and efficient in bone infections. This review is presented to describe current antibiotics used and the physical and chemical properties of scaffolds., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

We developed a sensor for the detection of specific microRNA (miRNA) sequences that was based on graphene quantum dots (GQDs) and ssDNA-UCNP@SiO2. The proposed sensor exploits the interaction between the sp(2) carbon atoms of the GQD, mainly π-π stacking, and the DNA nucleobases anchored on the upconversion nanoparticles (UCNPs). This interaction brings the GQD to the surface of the ssDNA-UCNP@SiO2 system, enhancing the upconversion emission. On the other hand, hybridization of the single-stranded DNA (ssDNA) chains anchored on the nanoparticles with their complementary miRNA sequences blocks the capacity of the UCNPs to interact with the GQD through π-π stacking. That gives as result a reduction of the fluorescent enhancement, which is dependent on the concentration of miRNA sequences. This effect was used to create a sensor for miRNA sequences with a detection limit of 10 fM.

Background: There is a lack of evidence regarding success of implants placed in atrophic premaxilla using the nasal floor elevation technique., Purpose: This study aimed to compare implants placed in augmented bone in the anterior maxilla using the nasal floor elevation technique with implants placed in the maxillary sinus region using the sinus lift technique., Materials and Methods: A within-patient controlled clinical trial was performed on 14 patients receiving 78 implants. The implants were assigned to one of two study groups on the basis of implant location. A total of 37 implants were placed in the nasal fossa region (NF group), and 41 implants were placed in the maxillary sinus region (MS group). Patients were followed up for 4.5 ± 2.2 years, with comparable follow-up times for implants in NF and MS groups (4.7 ± 2.1 and 4.9 ± 2.1 years, respectively; p > .05). Treatment outcomes were assessed and statistically analyzed., Results: Implant success rate was 89.2% in the NF group and 95.0% in the MS group, with no statistically significant difference between them (p > .05). No nasal or sinus membrane perforation or other complications were reported within the follow-up period. Significant differences were found between the two groups in terms of residual bone height, augmented bone height, and implant diameter., Conclusions: Nasal floor elevation is an effective and safe procedure that can be used for implant placement in atrophic premaxilla with success rates that are comparable to those of implants placed in the maxillary sinus., (© 2014 Wiley Periodicals, Inc.)

Herein, we present a phototriggered drug delivery system based on light responsive nanoparticles, which is able to release doxorubicin upon NIR light illumination. The proposed system is based on upconversion fluorescence nanoparticles of β-NaYF4:Yb,Tm@SiO2-PEG with a mean diameter of 52±2.5 nm that absorb the NIR light and emit UV light. The UV radiation causes the degradation of photodegradable ortho-nitrobenzyl alcohol derivates, which are attached on one side to the surface of the nanoparticles and on the other to doxorubicin. This degradation triggers the doxorubicin release. This drug delivery system has been tested "in vitro" with HeLa cells. The results of this study demonstrated that this system caused negligible cytotoxicity when they were not illuminated with NIR light. In contrast, under NIR light illumination, the HeLa cell viability was conspicuously reduced. These results demonstrated the suitability of the proposed system to control the release of doxorubicin via an external NIR light stimulus.

Onlay grafts made of monolithic microporous monetite bioresorbable bioceramics have the capacity to conduct bone augmentation. However, there is heterogeneity in the graft behaviour in vivo that seems to correlate with the host anatomy. In this study, we sought to investigate the metabolic activity of the regenerated bone in monolithic monetite onlays by using positron emission tomography-computed tomography (PET-CT) in rats. This information was used to optimize the design of monetite onlays with different macroporous architecture that were then fabricated using a 3D-printing technique. In vivo, bone augmentation was attempted with these customized onlays in rabbits. PET-CT findings demonstrated that bone metabolism in the calvarial bone showed higher activity in the inferior and lateral areas of the onlays. Histological observations revealed higher bone volume (up to 47%), less heterogeneity and more implant osseointegration (up to 38%) in the augmented bone with the customized monetite onlays. Our results demonstrated for the first time that it is possible to achieve osseointegration of dental implants in bone augmented with 3D-printed synthetic onlays. It was also observed that designing the macropore geometry according to the bone metabolic activity was a key parameter in increasing the volume of bone augmented within monetite onlays., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

In this work, we describe a new methodology for the preparation of monodisperse and thermosensitive microgels with magnetic core. In order to produce such a material, hydrophobic magnetic Fe(3)O(4) nanoparticles were prepared by two methods: thermal decomposition and coprecipitation. The surface of these nanoparticles was modified by addition of 3-butenoic acid, and after that these nanoparticles were dispersed in water and submitted to free radical polymerization at 70 °C in the presence of N-isopropylacrylamide (NIPAM) and bisacrylamide. The result of this reaction was monodisperse microgels with a magnetic core. By varying the amount of 3-butenoic acid, it was possible to obtain hybrid microgels with different magnetic core sizes and different architectures., (© 2011 American Chemical Society)

The cohesion of calcium phosphate cements can be improved by the addition of substances to either the solid or liquid phase during the setting reaction. This study reports the effect of silica gel on brushite cement cohesion. The cement was prepared using a mixture of beta-tricalcium phosphate (beta-TCP) and monocalcium phosphate monohydrate as the solid phase, while the liquid phase comprised carboxylic acids silica gel. This cement presents a shorter final setting time (FST), better cohesion and higher amount of unreacted beta-TCP than the cement prepared without silica gel. Furthermore, in vivo experiments using rabbits as an animal model showed that after 8 weeks of implantation cements modified with silica gel showed a similar new bone formation volume and more remaining graft in comparison with unmodified cements. Thus, the silica gel could be efficiently applied to reduce cement disintegration and to decrease the resorption rate of brushite cements.

Purpose: The purpose of this study was to evaluate the combination of anorganic bovine bone allograft (ABB) with platelet-rich plasma (PRP) when used in vertical bone augmentation., Materials and Methods: Sixteen healthy 6-month-old female New Zealand rabbits were used in this study. Rabbits were randomly divided into two groups of eight animals each. Created calvarial defects were grafted with ABB or PRP in the first group whereas, in the second group, one cylinder was filled with PRP+ABB and the contralateral cylinder was left ungrafted to be filled by autologous blood (control cylinder). Six weeks after intervention, animals were sacrificed and biopsies were taken. Densitometric, histologic, and histomorphometric analyses were performed to evaluate bone mineral density, vertical bone augmentation, and remaining graft volume, respectively. Statistical analyses were performed with the Mann-Whitney test, using a significance level of P < .05., Results: Six weeks after rabbit calvariae were augmented, data analysis revealed that the mixture of PRP and ABB produced twice the vertical bone volume of ABB alone (P < .0001)., Conclusion: Based upon this study of 16 rabbits, it appears that the combination of ABB with PRP resulted in increased vertical bone augmentation when compared with autologous blood in similarly sized created defects.

Onlay autografting is amongst the most predictable techniques for craniofacial vertical bone augmentation, however, complications related to donor site surgery are common and synthetic alternatives to onlay autografts are desirable. Recent studies have shown that the acidic calcium phosphates, brushite and monetite, are osteoconductive, osteoinductive and resorb faster in vivo than hydroxyapatite. Moreover, they can be 3D printed allowing precise host bone-implant conformation. The objectives of this study were to confirm that craniofacial screw fixation of 3D printed monetite blocks was possible and to compare the resulting vertical bone augmentation with autograft. 3D printed monolithic monetite onlay implants were fixed with osteosynthesis screws on the calvarial bone surface of New Zealand rabbits. After 8 weeks, integration between the implant and the calvarial bone surface was observed in all cases. Histomorphometry revealed that 42% of the monetite was resorbed and that the new bone formed within the implant occupied 43% of its volume, sufficient for immediate dental implant placement. Bone tissue within the autologous onlay occupied 60% of the volume. We observed that patterns of regeneration within the implants differed throughout the material and propose that this was due to the anatomy and blood supply pattern in the region. Rapid prototyped monetite being resorbable osteoconductive and osteoinductive would appear to be a promising biomaterial for many bone regeneration strategies.

An ideal material for maxillofacial vertical bone augmentation procedures should not only be osteoconductive, biocompatible and mechanically strong, but should also be applied using minimally invasive procedures and remain stable with respect to the original bone surfaces. This way, implant exposure and infection might be reduced and good mechanical stability may be achieved. Calcium phosphate cements are proven biocompatible and osteoconductive materials that can be injected using minimally invasive procedures. Among these cements, brushite based cements have the added advantage of being biodegradable in vivo. Therefore, this material has the potential for use in the aforementioned procedures. An in vivo study was performed in rabbits to evaluate the potential use of brushite cements in minimally invasive maxillofacial vertical bone augmentation procedures. In this study, we injected self-setting brushite cements on the subperiosteal bone surface using a minimally invasive tunnelling technique. The cement pastes were stable on the bone surface and hardened soon after they were injected thereby negating the need for additional supports such as membranes or meshes. The animals were sacrificed 8 weeks after the intervention and histological observations revealed signs of successful vertical bone augmentation. Therefore, we have demonstrated a minimally invasive vertical bone augmentation procedure that is an attractive alternative to current surgical procedures in terms of increased simplicity, reduced trauma, and lower cost of surgery.

The aim of this study was to evaluate whether local application of monetite granules would induce bone regeneration in critical size defects on rabbits calvaria. Novel monetite granules were synthesized by thermal conversion of preset brushite cement. Twelve female New Zealand rabbits were used for this study. Two identical 10-mm-diameter bicortical cranial defects were created in each animal. One of the defects was grafted with monetite granules while the contralateral was left unfilled as negative control. Animals were sacrificed at 4 and 8 weeks after surgery, and biopsies were taken for histological and histomorphometrical evaluation under light microscopy. Wilcoxon test was used for statistical analysis. The histological observations showed signs of graft resorption as newly formed bone tissue grew surrounding and penetrating the monetite granules. Histomorphometric evaluation showed that the augmented bone volume as well as the augmented mineral tissue was higher in the defects treated with monetite granules (p < 0.05) 8 weeks after the intervention. In this animal model, local application of the novel monetite granules in bone defects enhances bone healing significantly., (2008 Wiley Periodicals, Inc.)

Doxycycline (DOXY) is a wide spectrum antibiotic used in the treatment of dental, periodontal, and bone infections. Brushite cements are calcium phosphate biomaterials especially interesting for bone regeneration processes. In this work, we describe the preparation of a brushite cement containing DOXY and the drug release from the cement. DOXY solutions were mixed with the cement powder and after a 50% burst release in the first 12 h, a slow and controlled release was achieved over 3.5 days. The release of DOXY hyclate was controlled by both, diffusion and Ca(2+) interaction. Formation of DOXY-Ca(2+) chelates was detected in the cement structure using solid state fluorescence. The brushite cement loaded with DOXY hyclate had antibacterial activity against periodontal pathogens: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Bacteroides frosthytus. This new biomaterial may be helpful for the treatment of periodontal diseases., (Copyright 2007 Wiley Periodicals, Inc.)

Background: The use of platelet-rich plasma (PRP) in bone augmentation procedures is well documented; however, the exact benefit of this material is not yet established., Purpose: This study aimed to evaluate the benefits of using PRP, when only used, and compare it to Bio-Oss (Geistlich Biomaterials, Wolhusen, Switzerland) in vertical bone augmentation capacity., Materials and Methods: The study was performed in calvaria of eight adult female New Zealand rabbits using titanium bone conduction cylinder. Two titanium cylinders were fixed into perforated slits made on the parietal bone of each rabbit. On each rabbit, one chamber was grafted with Bio-Oss, and the contralateral was filled with PRP. Animals were sacrificed 4 weeks after intervention and biopsies were taken. Densitometric, histological, and histomorphometric analyses were performed to evaluate bone mineral density, vertical bone augmentation, and remaining graft volume, respectively. Statistical analyses were performed with Mann-Whitney test, using a significance level of p < .05., Results: Densitometric and histomorphometric data analysis revealed that mean bone mineral densities and bone augmentation were significantly lower in the cylinders treated with PRP (p < .0001) 4 weeks after implantation., Conclusion: This study showed no beneficial effect of using PRP on osseous regeneration. In addition, it was emphasized that Bio-Oss presents good osteoconductive properties by achieving suitable bone volume values.