Changes in pneumatization of the maxillary air sinuses in Korean adults following biomimetic oral appliance therapy

ObjectiveFor the treatment of obstructive sleep apnea in adults, mandibular advancement devices (MADs) are often used. Since adults with a prognathic mandibular phenotype are at risk of developing an unfavorable facial profile, midfacial development using biomimetic oral appliance therapy might provide a suitable alternative. However, the effect of this procedure on the maxillary air sinuses is unknown; therefore, changes in sinus pneumatization were investigated in this study.MethodsAfter obtaining informed consent, 16 consecutive Korean adults with midfacial hypoplasia had 3D cone-beam (CB) CT scans taken, and biomimetic upper appliances (DNA appliance®, Vivos Therapeutics, Inc., USA) were constructed.All subjects were instructed to wear the device 12–16 h/day. Each month, examination for the progress of midfacial development was recorded. Post-treatment, a follow-up 3D CBCT scan was undertaken with no device in the patient's mouth. Pre- and post-treatment linear and volumetric measurements were obtained using appropriate software, and compared statistically using t-tests.ResultsThe mean age of the sample was 25.0 yrs ± 8.7. The mean treatment time was 15.5 mths ± 5.2. Post-treatment, the transpalatal bone width increased from 35.3 mm ± 3.0 to 38.5 mm ± 2.0 (P < 0.001); the maxillary air sinus volume on the left side increased from 18.8 cm³ ± 6.5 to 20.0 cm³ ± 6.0 (P < 0.05), and from 18.5 cm³ ± 5.7 to 19.7 cm³ ± 5.8 (P < 0.05) on the right side.ConclusionsBiomimetic oral appliance therapy may be able to increase the maxillary air sinus volume in adults. In view of these preliminary findings, further studies on the effect of enhanced pneumatization on paranasal sinus function and sleep parameters are warranted.     

Impact of biomineralization on resin/biomineralized dentin bond longevity in a minimally invasive approach: An “in vitro” 18-month follow-up

ObjectivesTo determine the impact of treating caries-affected dentin (CAD) with: 0.2% sodium fluoride (NaF), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP/MI Paste?) or peptide P₁₁-4 (Curodont? Repair) on the longevity of resin/CAD interface at storage times of 24 -h, 6- and 18-month.Methods255 caries-free third molars were used, and CAD was produced by a biological method. The teeth were randomly distributed into: G1- Sound dentin (SD); G2- CAD; G3- CAD + 0.2% NaF (CAD/NaF); G4- CAD + CPP-ACP (CAD/ACP); G5- CAD + Curodont? Repair (CAD/P₁₁-4). The Filtek Z350 composite resin block was bonded to dentin using Adper? Single 2 (4 mm/height). Resin/dentin blocks were stored in a solution of Simulated Body Fluid at 37 °C, pressures were modified to simulate natural pulpal pressures. Specimens were investigated by microtensile bond strength (μTBS) (n = 8), Scanning Electron Microscopy (to assess the failure mode) (n = 8), nanoinfiltration (to assess the interface sealing) (n = 3), in situ zymography (to assess the gelatinolytic activity) (n = 3) and micro-computed microtomography (μ-CT) (to assess the mineralization) (n = 3). Data from μTBS, μ-CT and, nanoinfiltration and hybrid layer formation/degradation were submitted to two-way ANOVA and Tukey tests, and failure patterns and in situ zymography to Kruskal–Wallis and Dunn tests (α = 5%).ResultsThe highest mineral density change by μ-CT, smallest silver nitrate infiltration and proteolytic activity in the adhesive layer were obtained significantly for the groups SD, CAD/ACP and CAD/P₁₁-4, with most mixed fractures at 18-month (p < 0.001). CAD/NaF showed significantly similar values to CAD, CAD and CAD/NaF which presented a high percentage of adhesive fracture (p < 0.001) at all time periods.SignificanceTreating caries-affected dentin with remineralizing agents CPP-ACP and Curodont? Repair, has the potential to be a clinically relevant treatment protocol to increase the longevity of adhesive restorations.     

Three-dimensional graphene oxide-coated polyurethane foams beneficial to myogenesis

Abstract

The development of three dimensional (3D) scaffolds for promoting and stimulating cell growth is one of the greatest concerns in biomedical and tissue engineering. In the present study, novel biomimetic 3D scaffolds composed of polyurethane (PU) foam and graphene oxide (GO) nanosheets were designed, and their potential as 3D scaffolds for skeletal tissue regeneration was explored. The GO-coated PU foams (GO-PU foams) were characterized by scanning electron microscopy and Raman spectroscopy. It was revealed that the 3D GO-PU foams consisted of an interconnected foam-like network structure with an approximate 300 μm pore size, and the GO was uniformly distributed in the PU foams. On the other hand, the myogenic stimulatory effects of GO on skeletal myoblasts were also investigated. Moreover, the cellular behaviors of the skeletal myoblasts within the 3D GO-PU foams were evaluated by immunofluorescence analysis. Our findings showed that GO can significantly promote spontaneous myogenic differentiation without any myogenic factors, and the 3D GO-PU foams can provide a suitable 3D microenvironment for cell growth. Furthermore, the 3D GO-PU foams stimulated spontaneous myogenic differentiation via the myogenic stimulatory effects of GO. Therefore, this study suggests that the 3D GO-PU foams are beneficial to myogenesis, and can be used as biomimetic 3D scaffolds for skeletal tissue engineering.     

Biomimetic models for monooxygenases

The microsomal mixed function oxidase system contains the cytochrome P-450 oxidative drug metabolizing family of enzymes. The catalytic cycle of cytochrome P-450 is believed to involve the formation of an active iron-oxygen species which is responsible for oxygen transfer to the substrate. This assumption is supported by the fact that a number of peroxidative agents can replace NADPH, the reductase, and oxygen as co-reactants in most oxidative reactions of microsomal cytochrome P-450. We have found that a mixture of either ferrous or ferric ions with hydrogen peroxide (Fenton and Ruff reagents) can serve as biomimetic models for cytochrome P-450 in hydroxylation, exposidation, sulfoxidation, and N-demethylation of various drugs. The existance of an iron-oxo active species in both Fenton and Ruff type reactions has been postulated and provides reaction cycles similar to those of cytochrome p-450. Other model systems for the hepatic hydroxylation and epoxidation using transition metal complexes with porphyrin are also discussed. The present paper reviews the various biomimetic models of the heme cytochrome P-450 and emphasizes their simulation of hepatic drug metabolism and their potential medical and industrial applications.     

猫眼草素的结构和立体化学

根据生源学说、光谱分析及化学合成,将猫眼草素的原定结构A式修改为B_1式。分子中氧杂环上的两个取代基互为反式,并以外消旋体(R,R+S,S)的形式存在。     

九里香抗生育活性物质——月橘烯碱的仿生合成研究

月橘烯碱是从芸香科植物九里香根中分出的双吲哚生物碱。药理实验结果表明它具有抗着床和抗早孕的活性。本文报道其仿生合成:吲哚经3位醛基化、与丙酮缩合成化合物Ⅱ;将氮原子保护后进行wittig反应,脱保护基得到β-异戊二烯吲哚(Ⅴ);经分子间Diels-Alder加成反应得消旋月橘烯碱(Ⅵ)。     

纳米晶胶原基骨材料在临床上的应用

目的 观察纳米晶胶原基骨材料（nano-hydroxyapatite／collagen，nHAC）种植人体后的骨修复效果，探讨该材料的临床应用前景。方法 采用仿生方法制备纳米相羟基磷灰石／胶原复合材料，并用于临床，通过影像学方法观察和评价病人骨创愈合情况。结果 纳米晶胶原基骨材料在成分与微结构上与天然骨类似，种植人体后患者无高热、渗出和免疫排斥反应，骨修复情况良好。结论 纳米晶胶原基骨材料是优良的骨修复材料之一。     

Development of hybrid scaffold with biomimetic 3D architecture for bone regeneration

In the present study, a biomimetic three-dimensional hybrid scaffold has been designed considering the bone natural architecture with favorable interconnected porous structure, nano-microscale features and mechanical strength. The chief components of the hybrid scaffold are core-sheath nanofibers and hydrogel, suitably arranged to create a bone like microenvironment. Specifically, the core-sheath nanofibers were coiled tightly into a ring to mimic the osteon, and reinforced in a hydrogel matrix. Morphological analysis using SEM and 4D-X-ray microscopy revealed that the hybrid scaffold consists of coiled rings of nanofibers in highly porous hydrogel matrix showing structural similarity to osteons. The reinforcement of electrospun nanofibers in hydrogel influenced the mechanical properties of scaffold. The potential application of the biomimetic hybrid scaffold, and the role of its specific architecture, was subsequently investigated in vitro using a human osteosarcoma fibroblast cell line. Furthermore, DNA quantification, alkaline-phosphatase and alizarin assay validated the potential of fabricated scaffold for bone tissue-regeneration.     

Development and evaluation of silk fibroin-based nerve grafts used for peripheral nerve regeneration

Silk fibroin (SF), derived from natural silk long used as a textile material, has recently become an important biomaterial for tissue engineering applications. We have previously reported on good in vitro biocompatibility of SF fibers with peripheral nerve tissues and cells. In the present study, we developed a novel biomimetic design of the SF-based nerve graft (SF graft) which was composed of a SF-nerve guidance conduit (NGC) inserted with oriented SF filaments. The SF-NGC prepared via well-established procedures exhibits an eggshell-like microstructure that is responsible for its superior mechanical and permeable properties beneficial to nerve regeneration. The SF graft was used for bridge implantation across a 10-mm long sciatic nerve defect in rats, and the outcome of peripheral nerve repair at 6 months post-implantation was evaluated by a combination of electrophysiological assessment, FluoroGold retrograde tracing and histological investigation. The examined functional and morphological parameters show that SF grafts could promote peripheral nerve regeneration with effects approaching those elicited by nerve autografts which are generally considered as the gold standard for treating large peripheral nerve defects, thus raising a potential possibility of using these newly developed nerve grafts as a promising alternative to nerve autografts.     

The use of plant waxes as templates for micro- and nanopatterning of surfaces

Small wax sculptures on plant surfaces are responsible for a variety of functions, including the maintenance of sability, self-cleaning properties, prevention of insect attachment and reflection of light. Here we report on a method for using recrystallized plant wax crystals on flat technical surfaces for generating micro- and nanopatterned polymers with particular functions. Therefore a more than 4-thousand year old replica technique called the “lost wax technique” has been adapted for reproduction of complex, high aspect ratio surfaces and the large scale reproduction of micro- and nanopatterned surfaces. Highly ordered pyrolytic graphite substrates, covered with perpendicularly oriented platelets formed by the primary alcohol octacosan-1-ol, the main component of wheat (Triticum aestivum) leaf waxes, were used as templates to make an epoxy resin surfaces with high aspect ratio platelets 400–700 nm wide and 10–50 μm thick. The technique holds great promise on the reproduction of micro- and nanopatterned surfaces.